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-rw-r--r--.gitignore1
-rw-r--r--makefile4
-rw-r--r--src/build/build.mak27
-rw-r--r--src/build/png.py2752
-rw-r--r--src/build/png2bdc.c426
-rw-r--r--src/build/png2bdc.py361
6 files changed, 3116 insertions, 455 deletions
diff --git a/.gitignore b/.gitignore
index f3ee176fc10..69a16083596 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@
src/regtests/chdman/temp
src/regtests/jedutil/output
/sta
+*.pyc
diff --git a/makefile b/makefile
index b2beab1296c..bea2a002633 100644
--- a/makefile
+++ b/makefile
@@ -991,9 +991,9 @@ $(OBJ)/%.lh: $(SRC)/%.lay $(SRC)/build/file2str.py
@echo Converting $<...
@$(PYTHON) $(SRC)/build/file2str.py $< $@ layout_$(basename $(notdir $<))
-$(OBJ)/%.fh: $(SRC)/%.png $(PNG2BDC_TARGET) $(SRC)/build/file2str.py
+$(OBJ)/%.fh: $(SRC)/%.png $(SRC)/build/png2bdc.py $(SRC)/build/file2str.py
@echo Converting $<...
- @$(PNG2BDC) $< $(OBJ)/temp.bdc
+ @$(PYTHON) $(SRC)/build/png2bdc.py $< $(OBJ)/temp.bdc
@$(PYTHON) $(SRC)/build/file2str.py $(OBJ)/temp.bdc $@ font_$(basename $(notdir $<)) UINT8
$(DRIVLISTOBJ): $(DRIVLISTSRC)
diff --git a/src/build/build.mak b/src/build/build.mak
index 900acb20632..429aec233a6 100644
--- a/src/build/build.mak
+++ b/src/build/build.mak
@@ -21,13 +21,11 @@ OBJDIRS += \
MAKEDEP_TARGET = $(BUILDOUT)/makedep$(BUILD_EXE)
MAKEMAK_TARGET = $(BUILDOUT)/makemak$(BUILD_EXE)
MAKELIST_TARGET = $(BUILDOUT)/makelist$(BUILD_EXE)
-PNG2BDC_TARGET = $(BUILDOUT)/png2bdc$(BUILD_EXE)
VERINFO_TARGET = $(BUILDOUT)/verinfo$(BUILD_EXE)
MAKEDEP = $(MAKEDEP_TARGET)
MAKEMAK = $(MAKEMAK_TARGET)
MAKELIST = $(MAKELIST_TARGET)
-PNG2BDC = $(PNG2BDC_TARGET)
VERINFO = $(VERINFO_TARGET)
ifneq ($(TERM),cygwin)
@@ -35,7 +33,6 @@ ifeq ($(OS),Windows_NT)
MAKEDEP = $(subst /,\,$(MAKEDEP_TARGET))
MAKEMAK = $(subst /,\,$(MAKEMAK_TARGET))
MAKELIST = $(subst /,\,$(MAKELIST_TARGET))
-PNG2BDC = $(subst /,\,$(PNG2BDC_TARGET))
VERINFO = $(subst /,\,$(VERINFO_TARGET))
endif
endif
@@ -45,7 +42,6 @@ BUILD += \
$(MAKEDEP_TARGET) \
$(MAKEMAK_TARGET) \
$(MAKELIST_TARGET) \
- $(PNG2BDC_TARGET) \
$(VERINFO_TARGET) \
@@ -107,26 +103,6 @@ $(MAKELIST_TARGET): $(MAKELISTOBJS) $(LIBOCORE) $(ZLIB)
#-------------------------------------------------
-# png2bdc
-#-------------------------------------------------
-
-PNG2BDCOBJS = \
- $(BUILDOBJ)/png2bdc.o \
- $(OBJ)/lib/util/astring.o \
- $(OBJ)/lib/util/corefile.o \
- $(OBJ)/lib/util/corealloc.o \
- $(OBJ)/lib/util/bitmap.o \
- $(OBJ)/lib/util/png.o \
- $(OBJ)/lib/util/palette.o \
- $(OBJ)/lib/util/unicode.o \
-
-$(PNG2BDC_TARGET): $(PNG2BDCOBJS) $(LIBOCORE) $(ZLIB)
- @echo Linking $@...
- $(LD) $(LDFLAGS) $^ $(BASELIBS) -o $@
-
-
-
-#-------------------------------------------------
# verinfo
#-------------------------------------------------
@@ -147,9 +123,6 @@ $(MAKEDEP_TARGET):
$(MAKELIST_TARGET):
@echo $@ should be built natively. Nothing to do.
-$(PNG2BDC_TARGET):
- @echo $@ should be built natively. Nothing to do.
-
$(VERINFO_TARGET):
@echo $@ should be built natively. Nothing to do.
diff --git a/src/build/png.py b/src/build/png.py
new file mode 100644
index 00000000000..1e0b31fb316
--- /dev/null
+++ b/src/build/png.py
@@ -0,0 +1,2752 @@
+#!/usr/bin/env python
+
+# png.py - PNG encoder/decoder in pure Python
+#
+# Copyright (C) 2006 Johann C. Rocholl <johann@browsershots.org>
+# Portions Copyright (C) 2009 David Jones <drj@pobox.com>
+# And probably portions Copyright (C) 2006 Nicko van Someren <nicko@nicko.org>
+#
+# Original concept by Johann C. Rocholl.
+#
+# LICENCE (MIT)
+#
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation files
+# (the "Software"), to deal in the Software without restriction,
+# including without limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of the Software,
+# and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+"""
+Pure Python PNG Reader/Writer
+
+This Python module implements support for PNG images (see PNG
+specification at http://www.w3.org/TR/2003/REC-PNG-20031110/ ). It reads
+and writes PNG files with all allowable bit depths
+(1/2/4/8/16/24/32/48/64 bits per pixel) and colour combinations:
+greyscale (1/2/4/8/16 bit); RGB, RGBA, LA (greyscale with alpha) with
+8/16 bits per channel; colour mapped images (1/2/4/8 bit).
+Adam7 interlacing is supported for reading and
+writing. A number of optional chunks can be specified (when writing)
+and understood (when reading): ``tRNS``, ``bKGD``, ``gAMA``.
+
+For help, type ``import png; help(png)`` in your python interpreter.
+
+A good place to start is the :class:`Reader` and :class:`Writer`
+classes.
+
+Requires Python 2.3. Limited support is available for Python 2.2, but
+not everything works. Best with Python 2.4 and higher. Installation is
+trivial, but see the ``README.txt`` file (with the source distribution)
+for details.
+
+This file can also be used as a command-line utility to convert
+`Netpbm <http://netpbm.sourceforge.net/>`_ PNM files to PNG, and the
+reverse conversion from PNG to PNM. The interface is similar to that
+of the ``pnmtopng`` program from Netpbm. Type ``python png.py --help``
+at the shell prompt for usage and a list of options.
+
+A note on spelling and terminology
+----------------------------------
+
+Generally British English spelling is used in the documentation. So
+that's "greyscale" and "colour". This not only matches the author's
+native language, it's also used by the PNG specification.
+
+The major colour models supported by PNG (and hence by PyPNG) are:
+greyscale, RGB, greyscale--alpha, RGB--alpha. These are sometimes
+referred to using the abbreviations: L, RGB, LA, RGBA. In this case
+each letter abbreviates a single channel: *L* is for Luminance or Luma
+or Lightness which is the channel used in greyscale images; *R*, *G*,
+*B* stand for Red, Green, Blue, the components of a colour image; *A*
+stands for Alpha, the opacity channel (used for transparency effects,
+but higher values are more opaque, so it makes sense to call it
+opacity).
+
+A note on formats
+-----------------
+
+When getting pixel data out of this module (reading) and presenting
+data to this module (writing) there are a number of ways the data could
+be represented as a Python value. Generally this module uses one of
+three formats called "flat row flat pixel", "boxed row flat pixel", and
+"boxed row boxed pixel". Basically the concern is whether each pixel
+and each row comes in its own little tuple (box), or not.
+
+Consider an image that is 3 pixels wide by 2 pixels high, and each pixel
+has RGB components:
+
+Boxed row flat pixel::
+
+ list([R,G,B, R,G,B, R,G,B],
+ [R,G,B, R,G,B, R,G,B])
+
+Each row appears as its own list, but the pixels are flattened so
+that three values for one pixel simply follow the three values for
+the previous pixel. This is the most common format used, because it
+provides a good compromise between space and convenience. PyPNG regards
+itself as at liberty to replace any sequence type with any sufficiently
+compatible other sequence type; in practice each row is an array (from
+the array module), and the outer list is sometimes an iterator rather
+than an explicit list (so that streaming is possible).
+
+Flat row flat pixel::
+
+ [R,G,B, R,G,B, R,G,B,
+ R,G,B, R,G,B, R,G,B]
+
+The entire image is one single giant sequence of colour values.
+Generally an array will be used (to save space), not a list.
+
+Boxed row boxed pixel::
+
+ list([ (R,G,B), (R,G,B), (R,G,B) ],
+ [ (R,G,B), (R,G,B), (R,G,B) ])
+
+Each row appears in its own list, but each pixel also appears in its own
+tuple. A serious memory burn in Python.
+
+In all cases the top row comes first, and for each row the pixels are
+ordered from left-to-right. Within a pixel the values appear in the
+order, R-G-B-A (or L-A for greyscale--alpha).
+
+There is a fourth format, mentioned because it is used internally,
+is close to what lies inside a PNG file itself, and has some support
+from the public API. This format is called packed. When packed,
+each row is a sequence of bytes (integers from 0 to 255), just as
+it is before PNG scanline filtering is applied. When the bit depth
+is 8 this is essentially the same as boxed row flat pixel; when the
+bit depth is less than 8, several pixels are packed into each byte;
+when the bit depth is 16 (the only value more than 8 that is supported
+by the PNG image format) each pixel value is decomposed into 2 bytes
+(and `packed` is a misnomer). This format is used by the
+:meth:`Writer.write_packed` method. It isn't usually a convenient
+format, but may be just right if the source data for the PNG image
+comes from something that uses a similar format (for example, 1-bit
+BMPs, or another PNG file).
+
+And now, my famous members
+--------------------------
+"""
+
+# http://www.python.org/doc/2.2.3/whatsnew/node5.html
+from __future__ import generators
+
+__version__ = "0.0.17"
+
+from array import array
+try: # See :pyver:old
+ import itertools
+except ImportError:
+ pass
+import math
+# http://www.python.org/doc/2.4.4/lib/module-operator.html
+import operator
+import struct
+import sys
+import zlib
+# http://www.python.org/doc/2.4.4/lib/module-warnings.html
+import warnings
+try:
+ # `cpngfilters` is a Cython module: it must be compiled by
+ # Cython for this import to work.
+ # If this import does work, then it overrides pure-python
+ # filtering functions defined later in this file (see `class
+ # pngfilters`).
+ import cpngfilters as pngfilters
+except ImportError:
+ pass
+
+
+__all__ = ['Image', 'Reader', 'Writer', 'write_chunks', 'from_array']
+
+
+# The PNG signature.
+# http://www.w3.org/TR/PNG/#5PNG-file-signature
+_signature = struct.pack('8B', 137, 80, 78, 71, 13, 10, 26, 10)
+
+_adam7 = ((0, 0, 8, 8),
+ (4, 0, 8, 8),
+ (0, 4, 4, 8),
+ (2, 0, 4, 4),
+ (0, 2, 2, 4),
+ (1, 0, 2, 2),
+ (0, 1, 1, 2))
+
+def group(s, n):
+ # See http://www.python.org/doc/2.6/library/functions.html#zip
+ return zip(*[iter(s)]*n)
+
+def isarray(x):
+ """Same as ``isinstance(x, array)`` except on Python 2.2, where it
+ always returns ``False``. This helps PyPNG work on Python 2.2.
+ """
+
+ try:
+ return isinstance(x, array)
+ except TypeError:
+ # Because on Python 2.2 array.array is not a type.
+ return False
+
+try:
+ array.tobytes
+except AttributeError:
+ try: # see :pyver:old
+ array.tostring
+ except AttributeError:
+ def tostring(row):
+ l = len(row)
+ return struct.pack('%dB' % l, *row)
+ else:
+ def tostring(row):
+ """Convert row of bytes to string. Expects `row` to be an
+ ``array``.
+ """
+ return row.tostring()
+else:
+ def tostring(row):
+ """ Python3 definition, array.tostring() is deprecated in Python3
+ """
+ return row.tobytes()
+
+# Conditionally convert to bytes. Works on Python 2 and Python 3.
+try:
+ bytes('', 'ascii')
+ def strtobytes(x): return bytes(x, 'iso8859-1')
+ def bytestostr(x): return str(x, 'iso8859-1')
+except (NameError, TypeError):
+ # We get NameError when bytes() does not exist (most Python
+ # 2.x versions), and TypeError when bytes() exists but is on
+ # Python 2.x (when it is an alias for str() and takes at most
+ # one argument).
+ strtobytes = str
+ bytestostr = str
+
+def interleave_planes(ipixels, apixels, ipsize, apsize):
+ """
+ Interleave (colour) planes, e.g. RGB + A = RGBA.
+
+ Return an array of pixels consisting of the `ipsize` elements of
+ data from each pixel in `ipixels` followed by the `apsize` elements
+ of data from each pixel in `apixels`. Conventionally `ipixels`
+ and `apixels` are byte arrays so the sizes are bytes, but it
+ actually works with any arrays of the same type. The returned
+ array is the same type as the input arrays which should be the
+ same type as each other.
+ """
+
+ itotal = len(ipixels)
+ atotal = len(apixels)
+ newtotal = itotal + atotal
+ newpsize = ipsize + apsize
+ # Set up the output buffer
+ # See http://www.python.org/doc/2.4.4/lib/module-array.html#l2h-1356
+ out = array(ipixels.typecode)
+ # It's annoying that there is no cheap way to set the array size :-(
+ out.extend(ipixels)
+ out.extend(apixels)
+ # Interleave in the pixel data
+ for i in range(ipsize):
+ out[i:newtotal:newpsize] = ipixels[i:itotal:ipsize]
+ for i in range(apsize):
+ out[i+ipsize:newtotal:newpsize] = apixels[i:atotal:apsize]
+ return out
+
+def check_palette(palette):
+ """Check a palette argument (to the :class:`Writer` class)
+ for validity. Returns the palette as a list if okay; raises an
+ exception otherwise.
+ """
+
+ # None is the default and is allowed.
+ if palette is None:
+ return None
+
+ p = list(palette)
+ if not (0 < len(p) <= 256):
+ raise ValueError("a palette must have between 1 and 256 entries")
+ seen_triple = False
+ for i,t in enumerate(p):
+ if len(t) not in (3,4):
+ raise ValueError(
+ "palette entry %d: entries must be 3- or 4-tuples." % i)
+ if len(t) == 3:
+ seen_triple = True
+ if seen_triple and len(t) == 4:
+ raise ValueError(
+ "palette entry %d: all 4-tuples must precede all 3-tuples" % i)
+ for x in t:
+ if int(x) != x or not(0 <= x <= 255):
+ raise ValueError(
+ "palette entry %d: values must be integer: 0 <= x <= 255" % i)
+ return p
+
+def check_sizes(size, width, height):
+ """Check that these arguments, in supplied, are consistent.
+ Return a (width, height) pair.
+ """
+
+ if not size:
+ return width, height
+
+ if len(size) != 2:
+ raise ValueError(
+ "size argument should be a pair (width, height)")
+ if width is not None and width != size[0]:
+ raise ValueError(
+ "size[0] (%r) and width (%r) should match when both are used."
+ % (size[0], width))
+ if height is not None and height != size[1]:
+ raise ValueError(
+ "size[1] (%r) and height (%r) should match when both are used."
+ % (size[1], height))
+ return size
+
+def check_color(c, greyscale, which):
+ """Checks that a colour argument for transparent or
+ background options is the right form. Returns the colour
+ (which, if it's a bar integer, is "corrected" to a 1-tuple).
+ """
+
+ if c is None:
+ return c
+ if greyscale:
+ try:
+ l = len(c)
+ except TypeError:
+ c = (c,)
+ if len(c) != 1:
+ raise ValueError("%s for greyscale must be 1-tuple" %
+ which)
+ if not isinteger(c[0]):
+ raise ValueError(
+ "%s colour for greyscale must be integer" % which)
+ else:
+ if not (len(c) == 3 and
+ isinteger(c[0]) and
+ isinteger(c[1]) and
+ isinteger(c[2])):
+ raise ValueError(
+ "%s colour must be a triple of integers" % which)
+ return c
+
+class Error(Exception):
+ def __str__(self):
+ return self.__class__.__name__ + ': ' + ' '.join(self.args)
+
+class FormatError(Error):
+ """Problem with input file format. In other words, PNG file does
+ not conform to the specification in some way and is invalid.
+ """
+
+class ChunkError(FormatError):
+ pass
+
+
+class Writer:
+ """
+ PNG encoder in pure Python.
+ """
+
+ def __init__(self, width=None, height=None,
+ size=None,
+ greyscale=False,
+ alpha=False,
+ bitdepth=8,
+ palette=None,
+ transparent=None,
+ background=None,
+ gamma=None,
+ compression=None,
+ interlace=False,
+ bytes_per_sample=None, # deprecated
+ planes=None,
+ colormap=None,
+ maxval=None,
+ chunk_limit=2**20):
+ """
+ Create a PNG encoder object.
+
+ Arguments:
+
+ width, height
+ Image size in pixels, as two separate arguments.
+ size
+ Image size (w,h) in pixels, as single argument.
+ greyscale
+ Input data is greyscale, not RGB.
+ alpha
+ Input data has alpha channel (RGBA or LA).
+ bitdepth
+ Bit depth: from 1 to 16.
+ palette
+ Create a palette for a colour mapped image (colour type 3).
+ transparent
+ Specify a transparent colour (create a ``tRNS`` chunk).
+ background
+ Specify a default background colour (create a ``bKGD`` chunk).
+ gamma
+ Specify a gamma value (create a ``gAMA`` chunk).
+ compression
+ zlib compression level: 0 (none) to 9 (more compressed);
+ default: -1 or None.
+ interlace
+ Create an interlaced image.
+ chunk_limit
+ Write multiple ``IDAT`` chunks to save memory.
+
+ The image size (in pixels) can be specified either by using the
+ `width` and `height` arguments, or with the single `size`
+ argument. If `size` is used it should be a pair (*width*,
+ *height*).
+
+ `greyscale` and `alpha` are booleans that specify whether
+ an image is greyscale (or colour), and whether it has an
+ alpha channel (or not).
+
+ `bitdepth` specifies the bit depth of the source pixel values.
+ Each source pixel value must be an integer between 0 and
+ ``2**bitdepth-1``. For example, 8-bit images have values
+ between 0 and 255. PNG only stores images with bit depths of
+ 1,2,4,8, or 16. When `bitdepth` is not one of these values,
+ the next highest valid bit depth is selected, and an ``sBIT``
+ (significant bits) chunk is generated that specifies the
+ original precision of the source image. In this case the
+ supplied pixel values will be rescaled to fit the range of
+ the selected bit depth.
+
+ The details of which bit depth / colour model combinations the
+ PNG file format supports directly, are somewhat arcane
+ (refer to the PNG specification for full details). Briefly:
+ "small" bit depths (1,2,4) are only allowed with greyscale and
+ colour mapped images; colour mapped images cannot have bit depth
+ 16.
+
+ For colour mapped images (in other words, when the `palette`
+ argument is specified) the `bitdepth` argument must match one of
+ the valid PNG bit depths: 1, 2, 4, or 8. (It is valid to have a
+ PNG image with a palette and an ``sBIT`` chunk, but the meaning
+ is slightly different; it would be awkward to press the
+ `bitdepth` argument into service for this.)
+
+ The `palette` option, when specified, causes a colour mapped
+ image to be created: the PNG colour type is set to 3; greyscale
+ must not be set; alpha must not be set; transparent must not be
+ set; the bit depth must be 1,2,4, or 8. When a colour mapped
+ image is created, the pixel values are palette indexes and
+ the `bitdepth` argument specifies the size of these indexes
+ (not the size of the colour values in the palette).
+
+ The palette argument value should be a sequence of 3- or
+ 4-tuples. 3-tuples specify RGB palette entries; 4-tuples
+ specify RGBA palette entries. If both 4-tuples and 3-tuples
+ appear in the sequence then all the 4-tuples must come
+ before all the 3-tuples. A ``PLTE`` chunk is created; if there
+ are 4-tuples then a ``tRNS`` chunk is created as well. The
+ ``PLTE`` chunk will contain all the RGB triples in the same
+ sequence; the ``tRNS`` chunk will contain the alpha channel for
+ all the 4-tuples, in the same sequence. Palette entries
+ are always 8-bit.
+
+ If specified, the `transparent` and `background` parameters must
+ be a tuple with three integer values for red, green, blue, or
+ a simple integer (or singleton tuple) for a greyscale image.
+
+ If specified, the `gamma` parameter must be a positive number
+ (generally, a float). A ``gAMA`` chunk will be created.
+ Note that this will not change the values of the pixels as
+ they appear in the PNG file, they are assumed to have already
+ been converted appropriately for the gamma specified.
+
+ The `compression` argument specifies the compression level to
+ be used by the ``zlib`` module. Values from 1 to 9 specify
+ compression, with 9 being "more compressed" (usually smaller
+ and slower, but it doesn't always work out that way). 0 means
+ no compression. -1 and ``None`` both mean that the default
+ level of compession will be picked by the ``zlib`` module
+ (which is generally acceptable).
+
+ If `interlace` is true then an interlaced image is created
+ (using PNG's so far only interace method, *Adam7*). This does
+ not affect how the pixels should be presented to the encoder,
+ rather it changes how they are arranged into the PNG file.
+ On slow connexions interlaced images can be partially decoded
+ by the browser to give a rough view of the image that is
+ successively refined as more image data appears.
+
+ .. note ::
+
+ Enabling the `interlace` option requires the entire image
+ to be processed in working memory.
+
+ `chunk_limit` is used to limit the amount of memory used whilst
+ compressing the image. In order to avoid using large amounts of
+ memory, multiple ``IDAT`` chunks may be created.
+ """
+
+ # At the moment the `planes` argument is ignored;
+ # its purpose is to act as a dummy so that
+ # ``Writer(x, y, **info)`` works, where `info` is a dictionary
+ # returned by Reader.read and friends.
+ # Ditto for `colormap`.
+
+ width, height = check_sizes(size, width, height)
+ del size
+
+ if width <= 0 or height <= 0:
+ raise ValueError("width and height must be greater than zero")
+ if not isinteger(width) or not isinteger(height):
+ raise ValueError("width and height must be integers")
+ # http://www.w3.org/TR/PNG/#7Integers-and-byte-order
+ if width > 2**32-1 or height > 2**32-1:
+ raise ValueError("width and height cannot exceed 2**32-1")
+
+ if alpha and transparent is not None:
+ raise ValueError(
+ "transparent colour not allowed with alpha channel")
+
+ if bytes_per_sample is not None:
+ warnings.warn('please use bitdepth instead of bytes_per_sample',
+ DeprecationWarning)
+ if bytes_per_sample not in (0.125, 0.25, 0.5, 1, 2):
+ raise ValueError(
+ "bytes per sample must be .125, .25, .5, 1, or 2")
+ bitdepth = int(8*bytes_per_sample)
+ del bytes_per_sample
+ if not isinteger(bitdepth) or bitdepth < 1 or 16 < bitdepth:
+ raise ValueError("bitdepth (%r) must be a postive integer <= 16" %
+ bitdepth)
+
+ self.rescale = None
+ if palette:
+ if bitdepth not in (1,2,4,8):
+ raise ValueError("with palette, bitdepth must be 1, 2, 4, or 8")
+ if transparent is not None:
+ raise ValueError("transparent and palette not compatible")
+ if alpha:
+ raise ValueError("alpha and palette not compatible")
+ if greyscale:
+ raise ValueError("greyscale and palette not compatible")
+ else:
+ # No palette, check for sBIT chunk generation.
+ if alpha or not greyscale:
+ if bitdepth not in (8,16):
+ targetbitdepth = (8,16)[bitdepth > 8]
+ self.rescale = (bitdepth, targetbitdepth)
+ bitdepth = targetbitdepth
+ del targetbitdepth
+ else:
+ assert greyscale
+ assert not alpha
+ if bitdepth not in (1,2,4,8,16):
+ if bitdepth > 8:
+ targetbitdepth = 16
+ elif bitdepth == 3:
+ targetbitdepth = 4
+ else:
+ assert bitdepth in (5,6,7)
+ targetbitdepth = 8
+ self.rescale = (bitdepth, targetbitdepth)
+ bitdepth = targetbitdepth
+ del targetbitdepth
+
+ if bitdepth < 8 and (alpha or not greyscale and not palette):
+ raise ValueError(
+ "bitdepth < 8 only permitted with greyscale or palette")
+ if bitdepth > 8 and palette:
+ raise ValueError(
+ "bit depth must be 8 or less for images with palette")
+
+ transparent = check_color(transparent, greyscale, 'transparent')
+ background = check_color(background, greyscale, 'background')
+
+ # It's important that the true boolean values (greyscale, alpha,
+ # colormap, interlace) are converted to bool because Iverson's
+ # convention is relied upon later on.
+ self.width = width
+ self.height = height
+ self.transparent = transparent
+ self.background = background
+ self.gamma = gamma
+ self.greyscale = bool(greyscale)
+ self.alpha = bool(alpha)
+ self.colormap = bool(palette)
+ self.bitdepth = int(bitdepth)
+ self.compression = compression
+ self.chunk_limit = chunk_limit
+ self.interlace = bool(interlace)
+ self.palette = check_palette(palette)
+
+ self.color_type = 4*self.alpha + 2*(not greyscale) + 1*self.colormap
+ assert self.color_type in (0,2,3,4,6)
+
+ self.color_planes = (3,1)[self.greyscale or self.colormap]
+ self.planes = self.color_planes + self.alpha
+ # :todo: fix for bitdepth < 8
+ self.psize = (self.bitdepth/8) * self.planes
+
+ def make_palette(self):
+ """Create the byte sequences for a ``PLTE`` and if necessary a
+ ``tRNS`` chunk. Returned as a pair (*p*, *t*). *t* will be
+ ``None`` if no ``tRNS`` chunk is necessary.
+ """
+
+ p = array('B')
+ t = array('B')
+
+ for x in self.palette:
+ p.extend(x[0:3])
+ if len(x) > 3:
+ t.append(x[3])
+ p = tostring(p)
+ t = tostring(t)
+ if t:
+ return p,t
+ return p,None
+
+ def write(self, outfile, rows):
+ """Write a PNG image to the output file. `rows` should be
+ an iterable that yields each row in boxed row flat pixel
+ format. The rows should be the rows of the original image,
+ so there should be ``self.height`` rows of ``self.width *
+ self.planes`` values. If `interlace` is specified (when
+ creating the instance), then an interlaced PNG file will
+ be written. Supply the rows in the normal image order;
+ the interlacing is carried out internally.
+
+ .. note ::
+
+ Interlacing will require the entire image to be in working
+ memory.
+ """
+
+ if self.interlace:
+ fmt = 'BH'[self.bitdepth > 8]
+ a = array(fmt, itertools.chain(*rows))
+ return self.write_array(outfile, a)
+ else:
+ nrows = self.write_passes(outfile, rows)
+ if nrows != self.height:
+ raise ValueError(
+ "rows supplied (%d) does not match height (%d)" %
+ (nrows, self.height))
+
+ def write_passes(self, outfile, rows, packed=False):
+ """
+ Write a PNG image to the output file.
+
+ Most users are expected to find the :meth:`write` or
+ :meth:`write_array` method more convenient.
+
+ The rows should be given to this method in the order that
+ they appear in the output file. For straightlaced images,
+ this is the usual top to bottom ordering, but for interlaced
+ images the rows should have already been interlaced before
+ passing them to this function.
+
+ `rows` should be an iterable that yields each row. When
+ `packed` is ``False`` the rows should be in boxed row flat pixel
+ format; when `packed` is ``True`` each row should be a packed
+ sequence of bytes.
+ """
+
+ # http://www.w3.org/TR/PNG/#5PNG-file-signature
+ outfile.write(_signature)
+
+ # http://www.w3.org/TR/PNG/#11IHDR
+ write_chunk(outfile, 'IHDR',
+ struct.pack("!2I5B", self.width, self.height,
+ self.bitdepth, self.color_type,
+ 0, 0, self.interlace))
+
+ # See :chunk:order
+ # http://www.w3.org/TR/PNG/#11gAMA
+ if self.gamma is not None:
+ write_chunk(outfile, 'gAMA',
+ struct.pack("!L", int(round(self.gamma*1e5))))
+
+ # See :chunk:order
+ # http://www.w3.org/TR/PNG/#11sBIT
+ if self.rescale:
+ write_chunk(outfile, 'sBIT',
+ struct.pack('%dB' % self.planes,
+ *[self.rescale[0]]*self.planes))
+
+ # :chunk:order: Without a palette (PLTE chunk), ordering is
+ # relatively relaxed. With one, gAMA chunk must precede PLTE
+ # chunk which must precede tRNS and bKGD.
+ # See http://www.w3.org/TR/PNG/#5ChunkOrdering
+ if self.palette:
+ p,t = self.make_palette()
+ write_chunk(outfile, 'PLTE', p)
+ if t:
+ # tRNS chunk is optional. Only needed if palette entries
+ # have alpha.
+ write_chunk(outfile, 'tRNS', t)
+
+ # http://www.w3.org/TR/PNG/#11tRNS
+ if self.transparent is not None:
+ if self.greyscale:
+ write_chunk(outfile, 'tRNS',
+ struct.pack("!1H", *self.transparent))
+ else:
+ write_chunk(outfile, 'tRNS',
+ struct.pack("!3H", *self.transparent))
+
+ # http://www.w3.org/TR/PNG/#11bKGD
+ if self.background is not None:
+ if self.greyscale:
+ write_chunk(outfile, 'bKGD',
+ struct.pack("!1H", *self.background))
+ else:
+ write_chunk(outfile, 'bKGD',
+ struct.pack("!3H", *self.background))
+
+ # http://www.w3.org/TR/PNG/#11IDAT
+ if self.compression is not None:
+ compressor = zlib.compressobj(self.compression)
+ else:
+ compressor = zlib.compressobj()
+
+ # Choose an extend function based on the bitdepth. The extend
+ # function packs/decomposes the pixel values into bytes and
+ # stuffs them onto the data array.
+ data = array('B')
+ if self.bitdepth == 8 or packed:
+ extend = data.extend
+ elif self.bitdepth == 16:
+ # Decompose into bytes
+ def extend(sl):
+ fmt = '!%dH' % len(sl)
+ data.extend(array('B', struct.pack(fmt, *sl)))
+ else:
+ # Pack into bytes
+ assert self.bitdepth < 8
+ # samples per byte
+ spb = int(8/self.bitdepth)
+ def extend(sl):
+ a = array('B', sl)
+ # Adding padding bytes so we can group into a whole
+ # number of spb-tuples.
+ l = float(len(a))
+ extra = math.ceil(l / float(spb))*spb - l
+ a.extend([0]*int(extra))
+ # Pack into bytes
+ l = group(a, spb)
+ l = map(lambda e: reduce(lambda x,y:
+ (x << self.bitdepth) + y, e), l)
+ data.extend(l)
+ if self.rescale:
+ oldextend = extend
+ factor = \
+ float(2**self.rescale[1]-1) / float(2**self.rescale[0]-1)
+ def extend(sl):
+ oldextend(map(lambda x: int(round(factor*x)), sl))
+
+ # Build the first row, testing mostly to see if we need to
+ # changed the extend function to cope with NumPy integer types
+ # (they cause our ordinary definition of extend to fail, so we
+ # wrap it). See
+ # http://code.google.com/p/pypng/issues/detail?id=44
+ enumrows = enumerate(rows)
+ del rows
+
+ # First row's filter type.
+ data.append(0)
+ # :todo: Certain exceptions in the call to ``.next()`` or the
+ # following try would indicate no row data supplied.
+ # Should catch.
+ i,row = enumrows.next()
+ try:
+ # If this fails...
+ extend(row)
+ except:
+ # ... try a version that converts the values to int first.
+ # Not only does this work for the (slightly broken) NumPy
+ # types, there are probably lots of other, unknown, "nearly"
+ # int types it works for.
+ def wrapmapint(f):
+ return lambda sl: f(map(int, sl))
+ extend = wrapmapint(extend)
+ del wrapmapint
+ extend(row)
+
+ for i,row in enumrows:
+ # Add "None" filter type. Currently, it's essential that
+ # this filter type be used for every scanline as we do not
+ # mark the first row of a reduced pass image; that means we
+ # could accidentally compute the wrong filtered scanline if
+ # we used "up", "average", or "paeth" on such a line.
+ data.append(0)
+ extend(row)
+ if len(data) > self.chunk_limit:
+ compressed = compressor.compress(tostring(data))
+ if len(compressed):
+ write_chunk(outfile, 'IDAT', compressed)
+ # Because of our very witty definition of ``extend``,
+ # above, we must re-use the same ``data`` object. Hence
+ # we use ``del`` to empty this one, rather than create a
+ # fresh one (which would be my natural FP instinct).
+ del data[:]
+ if len(data):
+ compressed = compressor.compress(tostring(data))
+ else:
+ compressed = strtobytes('')
+ flushed = compressor.flush()
+ if len(compressed) or len(flushed):
+ write_chunk(outfile, 'IDAT', compressed + flushed)
+ # http://www.w3.org/TR/PNG/#11IEND
+ write_chunk(outfile, 'IEND')
+ return i+1
+
+ def write_array(self, outfile, pixels):
+ """
+ Write an array in flat row flat pixel format as a PNG file on
+ the output file. See also :meth:`write` method.
+ """
+
+ if self.interlace:
+ self.write_passes(outfile, self.array_scanlines_interlace(pixels))
+ else:
+ self.write_passes(outfile, self.array_scanlines(pixels))
+
+ def write_packed(self, outfile, rows):
+ """
+ Write PNG file to `outfile`. The pixel data comes from `rows`
+ which should be in boxed row packed format. Each row should be
+ a sequence of packed bytes.
+
+ Technically, this method does work for interlaced images but it
+ is best avoided. For interlaced images, the rows should be
+ presented in the order that they appear in the file.
+
+ This method should not be used when the source image bit depth
+ is not one naturally supported by PNG; the bit depth should be
+ 1, 2, 4, 8, or 16.
+ """
+
+ if self.rescale:
+ raise Error("write_packed method not suitable for bit depth %d" %
+ self.rescale[0])
+ return self.write_passes(outfile, rows, packed=True)
+
+ def convert_pnm(self, infile, outfile):
+ """
+ Convert a PNM file containing raw pixel data into a PNG file
+ with the parameters set in the writer object. Works for
+ (binary) PGM, PPM, and PAM formats.
+ """
+
+ if self.interlace:
+ pixels = array('B')
+ pixels.fromfile(infile,
+ (self.bitdepth/8) * self.color_planes *
+ self.width * self.height)
+ self.write_passes(outfile, self.array_scanlines_interlace(pixels))
+ else:
+ self.write_passes(outfile, self.file_scanlines(infile))
+
+ def convert_ppm_and_pgm(self, ppmfile, pgmfile, outfile):
+ """
+ Convert a PPM and PGM file containing raw pixel data into a
+ PNG outfile with the parameters set in the writer object.
+ """
+ pixels = array('B')
+ pixels.fromfile(ppmfile,
+ (self.bitdepth/8) * self.color_planes *
+ self.width * self.height)
+ apixels = array('B')
+ apixels.fromfile(pgmfile,
+ (self.bitdepth/8) *
+ self.width * self.height)
+ pixels = interleave_planes(pixels, apixels,
+ (self.bitdepth/8) * self.color_planes,
+ (self.bitdepth/8))
+ if self.interlace:
+ self.write_passes(outfile, self.array_scanlines_interlace(pixels))
+ else:
+ self.write_passes(outfile, self.array_scanlines(pixels))
+
+ def file_scanlines(self, infile):
+ """
+ Generates boxed rows in flat pixel format, from the input file
+ `infile`. It assumes that the input file is in a "Netpbm-like"
+ binary format, and is positioned at the beginning of the first
+ pixel. The number of pixels to read is taken from the image
+ dimensions (`width`, `height`, `planes`) and the number of bytes
+ per value is implied by the image `bitdepth`.
+ """
+
+ # Values per row
+ vpr = self.width * self.planes
+ row_bytes = vpr
+ if self.bitdepth > 8:
+ assert self.bitdepth == 16
+ row_bytes *= 2
+ fmt = '>%dH' % vpr
+ def line():
+ return array('H', struct.unpack(fmt, infile.read(row_bytes)))
+ else:
+ def line():
+ scanline = array('B', infile.read(row_bytes))
+ return scanline
+ for y in range(self.height):
+ yield line()
+
+ def array_scanlines(self, pixels):
+ """
+ Generates boxed rows (flat pixels) from flat rows (flat pixels)
+ in an array.
+ """
+
+ # Values per row
+ vpr = self.width * self.planes
+ stop = 0
+ for y in range(self.height):
+ start = stop
+ stop = start + vpr
+ yield pixels[start:stop]
+
+ def array_scanlines_interlace(self, pixels):
+ """
+ Generator for interlaced scanlines from an array. `pixels` is
+ the full source image in flat row flat pixel format. The
+ generator yields each scanline of the reduced passes in turn, in
+ boxed row flat pixel format.
+ """
+
+ # http://www.w3.org/TR/PNG/#8InterlaceMethods
+ # Array type.
+ fmt = 'BH'[self.bitdepth > 8]
+ # Value per row
+ vpr = self.width * self.planes
+ for xstart, ystart, xstep, ystep in _adam7:
+ if xstart >= self.width:
+ continue
+ # Pixels per row (of reduced image)
+ ppr = int(math.ceil((self.width-xstart)/float(xstep)))
+ # number of values in reduced image row.
+ row_len = ppr*self.planes
+ for y in range(ystart, self.height, ystep):
+ if xstep == 1:
+ offset = y * vpr
+ yield pixels[offset:offset+vpr]
+ else:
+ row = array(fmt)
+ # There's no easier way to set the length of an array
+ row.extend(pixels[0:row_len])
+ offset = y * vpr + xstart * self.planes
+ end_offset = (y+1) * vpr
+ skip = self.planes * xstep
+ for i in range(self.planes):
+ row[i::self.planes] = \
+ pixels[offset+i:end_offset:skip]
+ yield row
+
+def write_chunk(outfile, tag, data=strtobytes('')):
+ """
+ Write a PNG chunk to the output file, including length and
+ checksum.
+ """
+
+ # http://www.w3.org/TR/PNG/#5Chunk-layout
+ outfile.write(struct.pack("!I", len(data)))
+ tag = strtobytes(tag)
+ outfile.write(tag)
+ outfile.write(data)
+ checksum = zlib.crc32(tag)
+ checksum = zlib.crc32(data, checksum)
+ checksum &= 2**32-1
+ outfile.write(struct.pack("!I", checksum))
+
+def write_chunks(out, chunks):
+ """Create a PNG file by writing out the chunks."""
+
+ out.write(_signature)
+ for chunk in chunks:
+ write_chunk(out, *chunk)
+
+def filter_scanline(type, line, fo, prev=None):
+ """Apply a scanline filter to a scanline. `type` specifies the
+ filter type (0 to 4); `line` specifies the current (unfiltered)
+ scanline as a sequence of bytes; `prev` specifies the previous
+ (unfiltered) scanline as a sequence of bytes. `fo` specifies the
+ filter offset; normally this is size of a pixel in bytes (the number
+ of bytes per sample times the number of channels), but when this is
+ < 1 (for bit depths < 8) then the filter offset is 1.
+ """
+
+ assert 0 <= type < 5
+
+ # The output array. Which, pathetically, we extend one-byte at a
+ # time (fortunately this is linear).
+ out = array('B', [type])
+
+ def sub():
+ ai = -fo
+ for x in line:
+ if ai >= 0:
+ x = (x - line[ai]) & 0xff
+ out.append(x)
+ ai += 1
+ def up():
+ for i,x in enumerate(line):
+ x = (x - prev[i]) & 0xff
+ out.append(x)
+ def average():
+ ai = -fo
+ for i,x in enumerate(line):
+ if ai >= 0:
+ x = (x - ((line[ai] + prev[i]) >> 1)) & 0xff
+ else:
+ x = (x - (prev[i] >> 1)) & 0xff
+ out.append(x)
+ ai += 1
+ def paeth():
+ # http://www.w3.org/TR/PNG/#9Filter-type-4-Paeth
+ ai = -fo # also used for ci
+ for i,x in enumerate(line):
+ a = 0
+ b = prev[i]
+ c = 0
+
+ if ai >= 0:
+ a = line[ai]
+ c = prev[ai]
+ p = a + b - c
+ pa = abs(p - a)
+ pb = abs(p - b)
+ pc = abs(p - c)
+ if pa <= pb and pa <= pc: Pr = a
+ elif pb <= pc: Pr = b
+ else: Pr = c
+
+ x = (x - Pr) & 0xff
+ out.append(x)
+ ai += 1
+
+ if not prev:
+ # We're on the first line. Some of the filters can be reduced
+ # to simpler cases which makes handling the line "off the top"
+ # of the image simpler. "up" becomes "none"; "paeth" becomes
+ # "left" (non-trivial, but true). "average" needs to be handled
+ # specially.
+ if type == 2: # "up"
+ type = 0
+ elif type == 3:
+ prev = [0]*len(line)
+ elif type == 4: # "paeth"
+ type = 1
+ if type == 0:
+ out.extend(line)
+ elif type == 1:
+ sub()
+ elif type == 2:
+ up()
+ elif type == 3:
+ average()
+ else: # type == 4
+ paeth()
+ return out
+
+
+def from_array(a, mode=None, info={}):
+ """Create a PNG :class:`Image` object from a 2- or 3-dimensional
+ array. One application of this function is easy PIL-style saving:
+ ``png.from_array(pixels, 'L').save('foo.png')``.
+
+ .. note :
+
+ The use of the term *3-dimensional* is for marketing purposes
+ only. It doesn't actually work. Please bear with us. Meanwhile
+ enjoy the complimentary snacks (on request) and please use a
+ 2-dimensional array.
+
+ Unless they are specified using the *info* parameter, the PNG's
+ height and width are taken from the array size. For a 3 dimensional
+ array the first axis is the height; the second axis is the width;
+ and the third axis is the channel number. Thus an RGB image that is
+ 16 pixels high and 8 wide will use an array that is 16x8x3. For 2
+ dimensional arrays the first axis is the height, but the second axis
+ is ``width*channels``, so an RGB image that is 16 pixels high and 8
+ wide will use a 2-dimensional array that is 16x24 (each row will be
+ 8*3==24 sample values).
+
+ *mode* is a string that specifies the image colour format in a
+ PIL-style mode. It can be:
+
+ ``'L'``
+ greyscale (1 channel)
+ ``'LA'``
+ greyscale with alpha (2 channel)
+ ``'RGB'``
+ colour image (3 channel)
+ ``'RGBA'``
+ colour image with alpha (4 channel)
+
+ The mode string can also specify the bit depth (overriding how this
+ function normally derives the bit depth, see below). Appending
+ ``';16'`` to the mode will cause the PNG to be 16 bits per channel;
+ any decimal from 1 to 16 can be used to specify the bit depth.
+
+ When a 2-dimensional array is used *mode* determines how many
+ channels the image has, and so allows the width to be derived from
+ the second array dimension.
+
+ The array is expected to be a ``numpy`` array, but it can be any
+ suitable Python sequence. For example, a list of lists can be used:
+ ``png.from_array([[0, 255, 0], [255, 0, 255]], 'L')``. The exact
+ rules are: ``len(a)`` gives the first dimension, height;
+ ``len(a[0])`` gives the second dimension; ``len(a[0][0])`` gives the
+ third dimension, unless an exception is raised in which case a
+ 2-dimensional array is assumed. It's slightly more complicated than
+ that because an iterator of rows can be used, and it all still
+ works. Using an iterator allows data to be streamed efficiently.
+
+ The bit depth of the PNG is normally taken from the array element's
+ datatype (but if *mode* specifies a bitdepth then that is used
+ instead). The array element's datatype is determined in a way which
+ is supposed to work both for ``numpy`` arrays and for Python
+ ``array.array`` objects. A 1 byte datatype will give a bit depth of
+ 8, a 2 byte datatype will give a bit depth of 16. If the datatype
+ does not have an implicit size, for example it is a plain Python
+ list of lists, as above, then a default of 8 is used.
+
+ The *info* parameter is a dictionary that can be used to specify
+ metadata (in the same style as the arguments to the
+ :class:``png.Writer`` class). For this function the keys that are
+ useful are:
+
+ height
+ overrides the height derived from the array dimensions and allows
+ *a* to be an iterable.
+ width
+ overrides the width derived from the array dimensions.
+ bitdepth
+ overrides the bit depth derived from the element datatype (but
+ must match *mode* if that also specifies a bit depth).
+
+ Generally anything specified in the
+ *info* dictionary will override any implicit choices that this
+ function would otherwise make, but must match any explicit ones.
+ For example, if the *info* dictionary has a ``greyscale`` key then
+ this must be true when mode is ``'L'`` or ``'LA'`` and false when
+ mode is ``'RGB'`` or ``'RGBA'``.
+ """
+
+ # We abuse the *info* parameter by modifying it. Take a copy here.
+ # (Also typechecks *info* to some extent).
+ info = dict(info)
+
+ # Syntax check mode string.
+ bitdepth = None
+ try:
+ # Assign the 'L' or 'RGBA' part to `gotmode`.
+ if mode.startswith('L'):
+ gotmode = 'L'
+ mode = mode[1:]
+ elif mode.startswith('RGB'):
+ gotmode = 'RGB'
+ mode = mode[3:]
+ else:
+ raise Error()
+ if mode.startswith('A'):
+ gotmode += 'A'
+ mode = mode[1:]
+
+ # Skip any optional ';'
+ while mode.startswith(';'):
+ mode = mode[1:]
+
+ # Parse optional bitdepth
+ if mode:
+ try:
+ bitdepth = int(mode)
+ except (TypeError, ValueError):
+ raise Error()
+ except Error:
+ raise Error("mode string should be 'RGB' or 'L;16' or similar.")
+ mode = gotmode
+
+ # Get bitdepth from *mode* if possible.
+ if bitdepth:
+ if info.get('bitdepth') and bitdepth != info['bitdepth']:
+ raise Error("mode bitdepth (%d) should match info bitdepth (%d)." %
+ (bitdepth, info['bitdepth']))
+ info['bitdepth'] = bitdepth
+
+ # Fill in and/or check entries in *info*.
+ # Dimensions.
+ if 'size' in info:
+ # Check width, height, size all match where used.
+ for dimension,axis in [('width', 0), ('height', 1)]:
+ if dimension in info:
+ if info[dimension] != info['size'][axis]:
+ raise Error(
+ "info[%r] should match info['size'][%r]." %
+ (dimension, axis))
+ info['width'],info['height'] = info['size']
+ if 'height' not in info:
+ try:
+ l = len(a)
+ except TypeError:
+ raise Error(
+ "len(a) does not work, supply info['height'] instead.")
+ info['height'] = l
+ # Colour format.
+ if 'greyscale' in info:
+ if bool(info['greyscale']) != ('L' in mode):
+ raise Error("info['greyscale'] should match mode.")
+ info['greyscale'] = 'L' in mode
+ if 'alpha' in info:
+ if bool(info['alpha']) != ('A' in mode):
+ raise Error("info['alpha'] should match mode.")
+ info['alpha'] = 'A' in mode
+
+ planes = len(mode)
+ if 'planes' in info:
+ if info['planes'] != planes:
+ raise Error("info['planes'] should match mode.")
+
+ # In order to work out whether we the array is 2D or 3D we need its
+ # first row, which requires that we take a copy of its iterator.
+ # We may also need the first row to derive width and bitdepth.
+ a,t = itertools.tee(a)
+ row = t.next()
+ del t
+ try:
+ row[0][0]
+ threed = True
+ testelement = row[0]
+ except (IndexError, TypeError):
+ threed = False
+ testelement = row
+ if 'width' not in info:
+ if threed:
+ width = len(row)
+ else:
+ width = len(row) // planes
+ info['width'] = width
+
+ # Not implemented yet
+ assert not threed
+
+ if 'bitdepth' not in info:
+ try:
+ dtype = testelement.dtype
+ # goto the "else:" clause. Sorry.
+ except AttributeError:
+ try:
+ # Try a Python array.array.
+ bitdepth = 8 * testelement.itemsize
+ except AttributeError:
+ # We can't determine it from the array element's
+ # datatype, use a default of 8.
+ bitdepth = 8
+ else:
+ # If we got here without exception, we now assume that
+ # the array is a numpy array.
+ if dtype.kind == 'b':
+ bitdepth = 1
+ else:
+ bitdepth = 8 * dtype.itemsize
+ info['bitdepth'] = bitdepth
+
+ for thing in 'width height bitdepth greyscale alpha'.split():
+ assert thing in info
+ return Image(a, info)
+
+# So that refugee's from PIL feel more at home. Not documented.
+fromarray = from_array
+
+class Image:
+ """A PNG image. You can create an :class:`Image` object from
+ an array of pixels by calling :meth:`png.from_array`. It can be
+ saved to disk with the :meth:`save` method.
+ """
+
+ def __init__(self, rows, info):
+ """
+ .. note ::
+
+ The constructor is not public. Please do not call it.
+ """
+
+ self.rows = rows
+ self.info = info
+
+ def save(self, file):
+ """Save the image to *file*. If *file* looks like an open file
+ descriptor then it is used, otherwise it is treated as a
+ filename and a fresh file is opened.
+
+ In general, you can only call this method once; after it has
+ been called the first time and the PNG image has been saved, the
+ source data will have been streamed, and cannot be streamed
+ again.
+ """
+
+ w = Writer(**self.info)
+
+ try:
+ file.write
+ def close(): pass
+ except AttributeError:
+ file = open(file, 'wb')
+ def close(): file.close()
+
+ try:
+ w.write(file, self.rows)
+ finally:
+ close()
+
+class _readable:
+ """
+ A simple file-like interface for strings and arrays.
+ """
+
+ def __init__(self, buf):
+ self.buf = buf
+ self.offset = 0
+
+ def read(self, n):
+ r = self.buf[self.offset:self.offset+n]
+ if isarray(r):
+ r = r.tostring()
+ self.offset += n
+ return r
+
+
+class Reader:
+ """
+ PNG decoder in pure Python.
+ """
+
+ def __init__(self, _guess=None, **kw):
+ """
+ Create a PNG decoder object.
+
+ The constructor expects exactly one keyword argument. If you
+ supply a positional argument instead, it will guess the input
+ type. You can choose among the following keyword arguments:
+
+ filename
+ Name of input file (a PNG file).
+ file
+ A file-like object (object with a read() method).
+ bytes
+ ``array`` or ``string`` with PNG data.
+
+ """
+ if ((_guess is not None and len(kw) != 0) or
+ (_guess is None and len(kw) != 1)):
+ raise TypeError("Reader() takes exactly 1 argument")
+
+ # Will be the first 8 bytes, later on. See validate_signature.
+ self.signature = None
+ self.transparent = None
+ # A pair of (len,type) if a chunk has been read but its data and
+ # checksum have not (in other words the file position is just
+ # past the 4 bytes that specify the chunk type). See preamble
+ # method for how this is used.
+ self.atchunk = None
+
+ if _guess is not None:
+ if isarray(_guess):
+ kw["bytes"] = _guess
+ elif isinstance(_guess, str):
+ kw["filename"] = _guess
+ elif hasattr(_guess, 'read'):
+ kw["file"] = _guess
+
+ if "filename" in kw:
+ self.file = open(kw["filename"], "rb")
+ elif "file" in kw:
+ self.file = kw["file"]
+ elif "bytes" in kw:
+ self.file = _readable(kw["bytes"])
+ else:
+ raise TypeError("expecting filename, file or bytes array")
+
+
+ def chunk(self, seek=None, lenient=False):
+ """
+ Read the next PNG chunk from the input file; returns a
+ (*type*,*data*) tuple. *type* is the chunk's type as a string
+ (all PNG chunk types are 4 characters long). *data* is the
+ chunk's data content, as a string.
+
+ If the optional `seek` argument is
+ specified then it will keep reading chunks until it either runs
+ out of file or finds the type specified by the argument. Note
+ that in general the order of chunks in PNGs is unspecified, so
+ using `seek` can cause you to miss chunks.
+
+ If the optional `lenient` argument evaluates to True,
+ checksum failures will raise warnings rather than exceptions.
+ """
+
+ self.validate_signature()
+
+ while True:
+ # http://www.w3.org/TR/PNG/#5Chunk-layout
+ if not self.atchunk:
+ self.atchunk = self.chunklentype()
+ length,type = self.atchunk
+ self.atchunk = None
+ data = self.file.read(length)
+ if len(data) != length:
+ raise ChunkError('Chunk %s too short for required %i octets.'
+ % (type, length))
+ checksum = self.file.read(4)
+ if len(checksum) != 4:
+ raise ValueError('Chunk %s too short for checksum.', tag)
+ if seek and type != seek:
+ continue
+ verify = zlib.crc32(strtobytes(type))
+ verify = zlib.crc32(data, verify)
+ # Whether the output from zlib.crc32 is signed or not varies
+ # according to hideous implementation details, see
+ # http://bugs.python.org/issue1202 .
+ # We coerce it to be positive here (in a way which works on
+ # Python 2.3 and older).
+ verify &= 2**32 - 1
+ verify = struct.pack('!I', verify)
+ if checksum != verify:
+ (a, ) = struct.unpack('!I', checksum)
+ (b, ) = struct.unpack('!I', verify)
+ message = "Checksum error in %s chunk: 0x%08X != 0x%08X." % (type, a, b)
+ if lenient:
+ warnings.warn(message, RuntimeWarning)
+ else:
+ raise ChunkError(message)
+ return type, data
+
+ def chunks(self):
+ """Return an iterator that will yield each chunk as a
+ (*chunktype*, *content*) pair.
+ """
+
+ while True:
+ t,v = self.chunk()
+ yield t,v
+ if t == 'IEND':
+ break
+
+ def undo_filter(self, filter_type, scanline, previous):
+ """Undo the filter for a scanline. `scanline` is a sequence of
+ bytes that does not include the initial filter type byte.
+ `previous` is decoded previous scanline (for straightlaced
+ images this is the previous pixel row, but for interlaced
+ images, it is the previous scanline in the reduced image, which
+ in general is not the previous pixel row in the final image).
+ When there is no previous scanline (the first row of a
+ straightlaced image, or the first row in one of the passes in an
+ interlaced image), then this argument should be ``None``.
+
+ The scanline will have the effects of filtering removed, and the
+ result will be returned as a fresh sequence of bytes.
+ """
+
+ # :todo: Would it be better to update scanline in place?
+ # Yes, with the Cython extension making the undo_filter fast,
+ # updating scanline inplace makes the code 3 times faster
+ # (reading 50 images of 800x800 went from 40s to 16s)
+ result = scanline
+
+ if filter_type == 0:
+ return result
+
+ if filter_type not in (1,2,3,4):
+ raise FormatError('Invalid PNG Filter Type.'
+ ' See http://www.w3.org/TR/2003/REC-PNG-20031110/#9Filters .')
+
+ # Filter unit. The stride from one pixel to the corresponding
+ # byte from the previous pixel. Normally this is the pixel
+ # size in bytes, but when this is smaller than 1, the previous
+ # byte is used instead.
+ fu = max(1, self.psize)
+
+ # For the first line of a pass, synthesize a dummy previous
+ # line. An alternative approach would be to observe that on the
+ # first line 'up' is the same as 'null', 'paeth' is the same
+ # as 'sub', with only 'average' requiring any special case.
+ if not previous:
+ previous = array('B', [0]*len(scanline))
+
+ def sub():
+ """Undo sub filter."""
+
+ ai = 0
+ # Loop starts at index fu. Observe that the initial part
+ # of the result is already filled in correctly with
+ # scanline.
+ for i in range(fu, len(result)):
+ x = scanline[i]
+ a = result[ai]
+ result[i] = (x + a) & 0xff
+ ai += 1
+
+ def up():
+ """Undo up filter."""
+
+ for i in range(len(result)):
+ x = scanline[i]
+ b = previous[i]
+ result[i] = (x + b) & 0xff
+
+ def average():
+ """Undo average filter."""
+
+ ai = -fu
+ for i in range(len(result)):
+ x = scanline[i]
+ if ai < 0:
+ a = 0
+ else:
+ a = result[ai]
+ b = previous[i]
+ result[i] = (x + ((a + b) >> 1)) & 0xff
+ ai += 1
+
+ def paeth():
+ """Undo Paeth filter."""
+
+ # Also used for ci.
+ ai = -fu
+ for i in range(len(result)):
+ x = scanline[i]
+ if ai < 0:
+ a = c = 0
+ else:
+ a = result[ai]
+ c = previous[ai]
+ b = previous[i]
+ p = a + b - c
+ pa = abs(p - a)
+ pb = abs(p - b)
+ pc = abs(p - c)
+ if pa <= pb and pa <= pc:
+ pr = a
+ elif pb <= pc:
+ pr = b
+ else:
+ pr = c
+ result[i] = (x + pr) & 0xff
+ ai += 1
+
+ # Call appropriate filter algorithm. Note that 0 has already
+ # been dealt with.
+ (None,
+ pngfilters.undo_filter_sub,
+ pngfilters.undo_filter_up,
+ pngfilters.undo_filter_average,
+ pngfilters.undo_filter_paeth)[filter_type](fu, scanline, previous, result)
+ return result
+
+ def deinterlace(self, raw):
+ """
+ Read raw pixel data, undo filters, deinterlace, and flatten.
+ Return in flat row flat pixel format.
+ """
+
+ # Values per row (of the target image)
+ vpr = self.width * self.planes
+
+ # Make a result array, and make it big enough. Interleaving
+ # writes to the output array randomly (well, not quite), so the
+ # entire output array must be in memory.
+ fmt = 'BH'[self.bitdepth > 8]
+ a = array(fmt, [0]*vpr*self.height)
+ source_offset = 0
+
+ for xstart, ystart, xstep, ystep in _adam7:
+ if xstart >= self.width:
+ continue
+ # The previous (reconstructed) scanline. None at the
+ # beginning of a pass to indicate that there is no previous
+ # line.
+ recon = None
+ # Pixels per row (reduced pass image)
+ ppr = int(math.ceil((self.width-xstart)/float(xstep)))
+ # Row size in bytes for this pass.
+ row_size = int(math.ceil(self.psize * ppr))
+ for y in range(ystart, self.height, ystep):
+ filter_type = raw[source_offset]
+ source_offset += 1
+ scanline = raw[source_offset:source_offset+row_size]
+ source_offset += row_size
+ recon = self.undo_filter(filter_type, scanline, recon)
+ # Convert so that there is one element per pixel value
+ flat = self.serialtoflat(recon, ppr)
+ if xstep == 1:
+ assert xstart == 0
+ offset = y * vpr
+ a[offset:offset+vpr] = flat
+ else:
+ offset = y * vpr + xstart * self.planes
+ end_offset = (y+1) * vpr
+ skip = self.planes * xstep
+ for i in range(self.planes):
+ a[offset+i:end_offset:skip] = \
+ flat[i::self.planes]
+ return a
+
+ def iterboxed(self, rows):
+ """Iterator that yields each scanline in boxed row flat pixel
+ format. `rows` should be an iterator that yields the bytes of
+ each row in turn.
+ """
+
+ def asvalues(raw):
+ """Convert a row of raw bytes into a flat row. Result will
+ be a freshly allocated object, not shared with
+ argument.
+ """
+
+ if self.bitdepth == 8:
+ return array('B', raw)
+ if self.bitdepth == 16:
+ raw = tostring(raw)
+ return array('H', struct.unpack('!%dH' % (len(raw)//2), raw))
+ assert self.bitdepth < 8
+ width = self.width
+ # Samples per byte
+ spb = 8//self.bitdepth
+ out = array('B')
+ mask = 2**self.bitdepth - 1
+ shifts = map(self.bitdepth.__mul__, reversed(range(spb)))
+ for o in raw:
+ out.extend(map(lambda i: mask&(o>>i), shifts))
+ return out[:width]
+
+ return itertools.imap(asvalues, rows)
+
+ def serialtoflat(self, bytes, width=None):
+ """Convert serial format (byte stream) pixel data to flat row
+ flat pixel.
+ """
+
+ if self.bitdepth == 8:
+ return bytes
+ if self.bitdepth == 16:
+ bytes = tostring(bytes)
+ return array('H',
+ struct.unpack('!%dH' % (len(bytes)//2), bytes))
+ assert self.bitdepth < 8
+ if width is None:
+ width = self.width
+ # Samples per byte
+ spb = 8//self.bitdepth
+ out = array('B')
+ mask = 2**self.bitdepth - 1
+ shifts = map(self.bitdepth.__mul__, reversed(range(spb)))
+ l = width
+ for o in bytes:
+ out.extend([(mask&(o>>s)) for s in shifts][:l])
+ l -= spb
+ if l <= 0:
+ l = width
+ return out
+
+ def iterstraight(self, raw):
+ """Iterator that undoes the effect of filtering, and yields
+ each row in serialised format (as a sequence of bytes).
+ Assumes input is straightlaced. `raw` should be an iterable
+ that yields the raw bytes in chunks of arbitrary size.
+ """
+
+ # length of row, in bytes
+ rb = self.row_bytes
+ a = array('B')
+ # The previous (reconstructed) scanline. None indicates first
+ # line of image.
+ recon = None
+ for some in raw:
+ a.extend(some)
+ while len(a) >= rb + 1:
+ filter_type = a[0]
+ scanline = a[1:rb+1]
+ del a[:rb+1]
+ recon = self.undo_filter(filter_type, scanline, recon)
+ yield recon
+ if len(a) != 0:
+ # :file:format We get here with a file format error:
+ # when the available bytes (after decompressing) do not
+ # pack into exact rows.
+ raise FormatError(
+ 'Wrong size for decompressed IDAT chunk.')
+ assert len(a) == 0
+
+ def validate_signature(self):
+ """If signature (header) has not been read then read and
+ validate it; otherwise do nothing.
+ """
+
+ if self.signature:
+ return
+ self.signature = self.file.read(8)
+ if self.signature != _signature:
+ raise FormatError("PNG file has invalid signature.")
+
+ def preamble(self, lenient=False):
+ """
+ Extract the image metadata by reading the initial part of
+ the PNG file up to the start of the ``IDAT`` chunk. All the
+ chunks that precede the ``IDAT`` chunk are read and either
+ processed for metadata or discarded.
+
+ If the optional `lenient` argument evaluates to True, checksum
+ failures will raise warnings rather than exceptions.
+ """
+
+ self.validate_signature()
+
+ while True:
+ if not self.atchunk:
+ self.atchunk = self.chunklentype()
+ if self.atchunk is None:
+ raise FormatError(
+ 'This PNG file has no IDAT chunks.')
+ if self.atchunk[1] == 'IDAT':
+ return
+ self.process_chunk(lenient=lenient)
+
+ def chunklentype(self):
+ """Reads just enough of the input to determine the next
+ chunk's length and type, returned as a (*length*, *type*) pair
+ where *type* is a string. If there are no more chunks, ``None``
+ is returned.
+ """
+
+ x = self.file.read(8)
+ if not x:
+ return None
+ if len(x) != 8:
+ raise FormatError(
+ 'End of file whilst reading chunk length and type.')
+ length,type = struct.unpack('!I4s', x)
+ type = bytestostr(type)
+ if length > 2**31-1:
+ raise FormatError('Chunk %s is too large: %d.' % (type,length))
+ return length,type
+
+ def process_chunk(self, lenient=False):
+ """Process the next chunk and its data. This only processes the
+ following chunk types, all others are ignored: ``IHDR``,
+ ``PLTE``, ``bKGD``, ``tRNS``, ``gAMA``, ``sBIT``.
+
+ If the optional `lenient` argument evaluates to True,
+ checksum failures will raise warnings rather than exceptions.
+ """
+
+ type, data = self.chunk(lenient=lenient)
+ method = '_process_' + type
+ m = getattr(self, method, None)
+ if m:
+ m(data)
+
+ def _process_IHDR(self, data):
+ # http://www.w3.org/TR/PNG/#11IHDR
+ if len(data) != 13:
+ raise FormatError('IHDR chunk has incorrect length.')
+ (self.width, self.height, self.bitdepth, self.color_type,
+ self.compression, self.filter,
+ self.interlace) = struct.unpack("!2I5B", data)
+
+ check_bitdepth_colortype(self.bitdepth, self.color_type)
+
+ if self.compression != 0:
+ raise Error("unknown compression method %d" % self.compression)
+ if self.filter != 0:
+ raise FormatError("Unknown filter method %d,"
+ " see http://www.w3.org/TR/2003/REC-PNG-20031110/#9Filters ."
+ % self.filter)
+ if self.interlace not in (0,1):
+ raise FormatError("Unknown interlace method %d,"
+ " see http://www.w3.org/TR/2003/REC-PNG-20031110/#8InterlaceMethods ."
+ % self.interlace)
+
+ # Derived values
+ # http://www.w3.org/TR/PNG/#6Colour-values
+ colormap = bool(self.color_type & 1)
+ greyscale = not (self.color_type & 2)
+ alpha = bool(self.color_type & 4)
+ color_planes = (3,1)[greyscale or colormap]
+ planes = color_planes + alpha
+
+ self.colormap = colormap
+ self.greyscale = greyscale
+ self.alpha = alpha
+ self.color_planes = color_planes
+ self.planes = planes
+ self.psize = float(self.bitdepth)/float(8) * planes
+ if int(self.psize) == self.psize:
+ self.psize = int(self.psize)
+ self.row_bytes = int(math.ceil(self.width * self.psize))
+ # Stores PLTE chunk if present, and is used to check
+ # chunk ordering constraints.
+ self.plte = None
+ # Stores tRNS chunk if present, and is used to check chunk
+ # ordering constraints.
+ self.trns = None
+ # Stores sbit chunk if present.
+ self.sbit = None
+
+ def _process_PLTE(self, data):
+ # http://www.w3.org/TR/PNG/#11PLTE
+ if self.plte:
+ warnings.warn("Multiple PLTE chunks present.")
+ self.plte = data
+ if len(data) % 3 != 0:
+ raise FormatError(
+ "PLTE chunk's length should be a multiple of 3.")
+ if len(data) > (2**self.bitdepth)*3:
+ raise FormatError("PLTE chunk is too long.")
+ if len(data) == 0:
+ raise FormatError("Empty PLTE is not allowed.")
+
+ def _process_bKGD(self, data):
+ try:
+ if self.colormap:
+ if not self.plte:
+ warnings.warn(
+ "PLTE chunk is required before bKGD chunk.")
+ self.background = struct.unpack('B', data)
+ else:
+ self.background = struct.unpack("!%dH" % self.color_planes,
+ data)
+ except struct.error:
+ raise FormatError("bKGD chunk has incorrect length.")
+
+ def _process_tRNS(self, data):
+ # http://www.w3.org/TR/PNG/#11tRNS
+ self.trns = data
+ if self.colormap:
+ if not self.plte:
+ warnings.warn("PLTE chunk is required before tRNS chunk.")
+ else:
+ if len(data) > len(self.plte)/3:
+ # Was warning, but promoted to Error as it
+ # would otherwise cause pain later on.
+ raise FormatError("tRNS chunk is too long.")
+ else:
+ if self.alpha:
+ raise FormatError(
+ "tRNS chunk is not valid with colour type %d." %
+ self.color_type)
+ try:
+ self.transparent = \
+ struct.unpack("!%dH" % self.color_planes, data)
+ except struct.error:
+ raise FormatError("tRNS chunk has incorrect length.")
+
+ def _process_gAMA(self, data):
+ try:
+ self.gamma = struct.unpack("!L", data)[0] / 100000.0
+ except struct.error:
+ raise FormatError("gAMA chunk has incorrect length.")
+
+ def _process_sBIT(self, data):
+ self.sbit = data
+ if (self.colormap and len(data) != 3 or
+ not self.colormap and len(data) != self.planes):
+ raise FormatError("sBIT chunk has incorrect length.")
+
+ def read(self, lenient=False):
+ """
+ Read the PNG file and decode it. Returns (`width`, `height`,
+ `pixels`, `metadata`).
+
+ May use excessive memory.
+
+ `pixels` are returned in boxed row flat pixel format.
+
+ If the optional `lenient` argument evaluates to True,
+ checksum failures will raise warnings rather than exceptions.
+ """
+
+ def iteridat():
+ """Iterator that yields all the ``IDAT`` chunks as strings."""
+ while True:
+ try:
+ type, data = self.chunk(lenient=lenient)
+ except ValueError, e:
+ raise ChunkError(e.args[0])
+ if type == 'IEND':
+ # http://www.w3.org/TR/PNG/#11IEND
+ break
+ if type != 'IDAT':
+ continue
+ # type == 'IDAT'
+ # http://www.w3.org/TR/PNG/#11IDAT
+ if self.colormap and not self.plte:
+ warnings.warn("PLTE chunk is required before IDAT chunk")
+ yield data
+
+ def iterdecomp(idat):
+ """Iterator that yields decompressed strings. `idat` should
+ be an iterator that yields the ``IDAT`` chunk data.
+ """
+
+ # Currently, with no max_length paramter to decompress, this
+ # routine will do one yield per IDAT chunk. So not very
+ # incremental.
+ d = zlib.decompressobj()
+ # Each IDAT chunk is passed to the decompressor, then any
+ # remaining state is decompressed out.
+ for data in idat:
+ # :todo: add a max_length argument here to limit output
+ # size.
+ yield array('B', d.decompress(data))
+ yield array('B', d.flush())
+
+ self.preamble(lenient=lenient)
+ raw = iterdecomp(iteridat())
+
+ if self.interlace:
+ raw = array('B', itertools.chain(*raw))
+ arraycode = 'BH'[self.bitdepth>8]
+ # Like :meth:`group` but producing an array.array object for
+ # each row.
+ pixels = itertools.imap(lambda *row: array(arraycode, row),
+ *[iter(self.deinterlace(raw))]*self.width*self.planes)
+ else:
+ pixels = self.iterboxed(self.iterstraight(raw))
+ meta = dict()
+ for attr in 'greyscale alpha planes bitdepth interlace'.split():
+ meta[attr] = getattr(self, attr)
+ meta['size'] = (self.width, self.height)
+ for attr in 'gamma transparent background'.split():
+ a = getattr(self, attr, None)
+ if a is not None:
+ meta[attr] = a
+ if self.plte:
+ meta['palette'] = self.palette()
+ return self.width, self.height, pixels, meta
+
+
+ def read_flat(self):
+ """
+ Read a PNG file and decode it into flat row flat pixel format.
+ Returns (*width*, *height*, *pixels*, *metadata*).
+
+ May use excessive memory.
+
+ `pixels` are returned in flat row flat pixel format.
+
+ See also the :meth:`read` method which returns pixels in the
+ more stream-friendly boxed row flat pixel format.
+ """
+
+ x, y, pixel, meta = self.read()
+ arraycode = 'BH'[meta['bitdepth']>8]
+ pixel = array(arraycode, itertools.chain(*pixel))
+ return x, y, pixel, meta
+
+ def palette(self, alpha='natural'):
+ """Returns a palette that is a sequence of 3-tuples or 4-tuples,
+ synthesizing it from the ``PLTE`` and ``tRNS`` chunks. These
+ chunks should have already been processed (for example, by
+ calling the :meth:`preamble` method). All the tuples are the
+ same size: 3-tuples if there is no ``tRNS`` chunk, 4-tuples when
+ there is a ``tRNS`` chunk. Assumes that the image is colour type
+ 3 and therefore a ``PLTE`` chunk is required.
+
+ If the `alpha` argument is ``'force'`` then an alpha channel is
+ always added, forcing the result to be a sequence of 4-tuples.
+ """
+
+ if not self.plte:
+ raise FormatError(
+ "Required PLTE chunk is missing in colour type 3 image.")
+ plte = group(array('B', self.plte), 3)
+ if self.trns or alpha == 'force':
+ trns = array('B', self.trns or '')
+ trns.extend([255]*(len(plte)-len(trns)))
+ plte = map(operator.add, plte, group(trns, 1))
+ return plte
+
+ def asDirect(self):
+ """Returns the image data as a direct representation of an
+ ``x * y * planes`` array. This method is intended to remove the
+ need for callers to deal with palettes and transparency
+ themselves. Images with a palette (colour type 3)
+ are converted to RGB or RGBA; images with transparency (a
+ ``tRNS`` chunk) are converted to LA or RGBA as appropriate.
+ When returned in this format the pixel values represent the
+ colour value directly without needing to refer to palettes or
+ transparency information.
+
+ Like the :meth:`read` method this method returns a 4-tuple:
+
+ (*width*, *height*, *pixels*, *meta*)
+
+ This method normally returns pixel values with the bit depth
+ they have in the source image, but when the source PNG has an
+ ``sBIT`` chunk it is inspected and can reduce the bit depth of
+ the result pixels; pixel values will be reduced according to
+ the bit depth specified in the ``sBIT`` chunk (PNG nerds should
+ note a single result bit depth is used for all channels; the
+ maximum of the ones specified in the ``sBIT`` chunk. An RGB565
+ image will be rescaled to 6-bit RGB666).
+
+ The *meta* dictionary that is returned reflects the `direct`
+ format and not the original source image. For example, an RGB
+ source image with a ``tRNS`` chunk to represent a transparent
+ colour, will have ``planes=3`` and ``alpha=False`` for the
+ source image, but the *meta* dictionary returned by this method
+ will have ``planes=4`` and ``alpha=True`` because an alpha
+ channel is synthesized and added.
+
+ *pixels* is the pixel data in boxed row flat pixel format (just
+ like the :meth:`read` method).
+
+ All the other aspects of the image data are not changed.
+ """
+
+ self.preamble()
+
+ # Simple case, no conversion necessary.
+ if not self.colormap and not self.trns and not self.sbit:
+ return self.read()
+
+ x,y,pixels,meta = self.read()
+
+ if self.colormap:
+ meta['colormap'] = False
+ meta['alpha'] = bool(self.trns)
+ meta['bitdepth'] = 8
+ meta['planes'] = 3 + bool(self.trns)
+ plte = self.palette()
+ def iterpal(pixels):
+ for row in pixels:
+ row = map(plte.__getitem__, row)
+ yield array('B', itertools.chain(*row))
+ pixels = iterpal(pixels)
+ elif self.trns:
+ # It would be nice if there was some reasonable way
+ # of doing this without generating a whole load of
+ # intermediate tuples. But tuples does seem like the
+ # easiest way, with no other way clearly much simpler or
+ # much faster. (Actually, the L to LA conversion could
+ # perhaps go faster (all those 1-tuples!), but I still
+ # wonder whether the code proliferation is worth it)
+ it = self.transparent
+ maxval = 2**meta['bitdepth']-1
+ planes = meta['planes']
+ meta['alpha'] = True
+ meta['planes'] += 1
+ typecode = 'BH'[meta['bitdepth']>8]
+ def itertrns(pixels):
+ for row in pixels:
+ # For each row we group it into pixels, then form a
+ # characterisation vector that says whether each
+ # pixel is opaque or not. Then we convert
+ # True/False to 0/maxval (by multiplication),
+ # and add it as the extra channel.
+ row = group(row, planes)
+ opa = map(it.__ne__, row)
+ opa = map(maxval.__mul__, opa)
+ opa = zip(opa) # convert to 1-tuples
+ yield array(typecode,
+ itertools.chain(*map(operator.add, row, opa)))
+ pixels = itertrns(pixels)
+ targetbitdepth = None
+ if self.sbit:
+ sbit = struct.unpack('%dB' % len(self.sbit), self.sbit)
+ targetbitdepth = max(sbit)
+ if targetbitdepth > meta['bitdepth']:
+ raise Error('sBIT chunk %r exceeds bitdepth %d' %
+ (sbit,self.bitdepth))
+ if min(sbit) <= 0:
+ raise Error('sBIT chunk %r has a 0-entry' % sbit)
+ if targetbitdepth == meta['bitdepth']:
+ targetbitdepth = None
+ if targetbitdepth:
+ shift = meta['bitdepth'] - targetbitdepth
+ meta['bitdepth'] = targetbitdepth
+ def itershift(pixels):
+ for row in pixels:
+ yield map(shift.__rrshift__, row)
+ pixels = itershift(pixels)
+ return x,y,pixels,meta
+
+ def asFloat(self, maxval=1.0):
+ """Return image pixels as per :meth:`asDirect` method, but scale
+ all pixel values to be floating point values between 0.0 and
+ *maxval*.
+ """
+
+ x,y,pixels,info = self.asDirect()
+ sourcemaxval = 2**info['bitdepth']-1
+ del info['bitdepth']
+ info['maxval'] = float(maxval)
+ factor = float(maxval)/float(sourcemaxval)
+ def iterfloat():
+ for row in pixels:
+ yield map(factor.__mul__, row)
+ return x,y,iterfloat(),info
+
+ def _as_rescale(self, get, targetbitdepth):
+ """Helper used by :meth:`asRGB8` and :meth:`asRGBA8`."""
+
+ width,height,pixels,meta = get()
+ maxval = 2**meta['bitdepth'] - 1
+ targetmaxval = 2**targetbitdepth - 1
+ factor = float(targetmaxval) / float(maxval)
+ meta['bitdepth'] = targetbitdepth
+ def iterscale():
+ for row in pixels:
+ yield map(lambda x: int(round(x*factor)), row)
+ if maxval == targetmaxval:
+ return width, height, pixels, meta
+ else:
+ return width, height, iterscale(), meta
+
+ def asRGB8(self):
+ """Return the image data as an RGB pixels with 8-bits per
+ sample. This is like the :meth:`asRGB` method except that
+ this method additionally rescales the values so that they
+ are all between 0 and 255 (8-bit). In the case where the
+ source image has a bit depth < 8 the transformation preserves
+ all the information; where the source image has bit depth
+ > 8, then rescaling to 8-bit values loses precision. No
+ dithering is performed. Like :meth:`asRGB`, an alpha channel
+ in the source image will raise an exception.
+
+ This function returns a 4-tuple:
+ (*width*, *height*, *pixels*, *metadata*).
+ *width*, *height*, *metadata* are as per the
+ :meth:`read` method.
+
+ *pixels* is the pixel data in boxed row flat pixel format.
+ """
+
+ return self._as_rescale(self.asRGB, 8)
+
+ def asRGBA8(self):
+ """Return the image data as RGBA pixels with 8-bits per
+ sample. This method is similar to :meth:`asRGB8` and
+ :meth:`asRGBA`: The result pixels have an alpha channel, *and*
+ values are rescaled to the range 0 to 255. The alpha channel is
+ synthesized if necessary (with a small speed penalty).
+ """
+
+ return self._as_rescale(self.asRGBA, 8)
+
+ def asRGB(self):
+ """Return image as RGB pixels. RGB colour images are passed
+ through unchanged; greyscales are expanded into RGB
+ triplets (there is a small speed overhead for doing this).
+
+ An alpha channel in the source image will raise an
+ exception.
+
+ The return values are as for the :meth:`read` method
+ except that the *metadata* reflect the returned pixels, not the
+ source image. In particular, for this method
+ ``metadata['greyscale']`` will be ``False``.
+ """
+
+ width,height,pixels,meta = self.asDirect()
+ if meta['alpha']:
+ raise Error("will not convert image with alpha channel to RGB")
+ if not meta['greyscale']:
+ return width,height,pixels,meta
+ meta['greyscale'] = False
+ typecode = 'BH'[meta['bitdepth'] > 8]
+ def iterrgb():
+ for row in pixels:
+ a = array(typecode, [0]) * 3 * width
+ for i in range(3):
+ a[i::3] = row
+ yield a
+ return width,height,iterrgb(),meta
+
+ def asRGBA(self):
+ """Return image as RGBA pixels. Greyscales are expanded into
+ RGB triplets; an alpha channel is synthesized if necessary.
+ The return values are as for the :meth:`read` method
+ except that the *metadata* reflect the returned pixels, not the
+ source image. In particular, for this method
+ ``metadata['greyscale']`` will be ``False``, and
+ ``metadata['alpha']`` will be ``True``.
+ """
+
+ width,height,pixels,meta = self.asDirect()
+ if meta['alpha'] and not meta['greyscale']:
+ return width,height,pixels,meta
+ typecode = 'BH'[meta['bitdepth'] > 8]
+ maxval = 2**meta['bitdepth'] - 1
+ maxbuffer = struct.pack('=' + typecode, maxval) * 4 * width
+ def newarray():
+ return array(typecode, maxbuffer)
+
+ if meta['alpha'] and meta['greyscale']:
+ # LA to RGBA
+ def convert():
+ for row in pixels:
+ # Create a fresh target row, then copy L channel
+ # into first three target channels, and A channel
+ # into fourth channel.
+ a = newarray()
+ pngfilters.convert_la_to_rgba(row, a)
+ yield a
+ elif meta['greyscale']:
+ # L to RGBA
+ def convert():
+ for row in pixels:
+ a = newarray()
+ pngfilters.convert_l_to_rgba(row, a)
+ yield a
+ else:
+ assert not meta['alpha'] and not meta['greyscale']
+ # RGB to RGBA
+ def convert():
+ for row in pixels:
+ a = newarray()
+ pngfilters.convert_rgb_to_rgba(row, a)
+ yield a
+ meta['alpha'] = True
+ meta['greyscale'] = False
+ return width,height,convert(),meta
+
+def check_bitdepth_colortype(bitdepth, colortype):
+ """Check that `bitdepth` and `colortype` are both valid,
+ and specified in a valid combination. Returns if valid,
+ raise an Exception if not valid.
+ """
+
+ if bitdepth not in (1,2,4,8,16):
+ raise FormatError("invalid bit depth %d" % bitdepth)
+ if colortype not in (0,2,3,4,6):
+ raise FormatError("invalid colour type %d" % colortype)
+ # Check indexed (palettized) images have 8 or fewer bits
+ # per pixel; check only indexed or greyscale images have
+ # fewer than 8 bits per pixel.
+ if colortype & 1 and bitdepth > 8:
+ raise FormatError(
+ "Indexed images (colour type %d) cannot"
+ " have bitdepth > 8 (bit depth %d)."
+ " See http://www.w3.org/TR/2003/REC-PNG-20031110/#table111 ."
+ % (bitdepth, colortype))
+ if bitdepth < 8 and colortype not in (0,3):
+ raise FormatError("Illegal combination of bit depth (%d)"
+ " and colour type (%d)."
+ " See http://www.w3.org/TR/2003/REC-PNG-20031110/#table111 ."
+ % (bitdepth, colortype))
+
+def isinteger(x):
+ try:
+ return int(x) == x
+ except (TypeError, ValueError):
+ return False
+
+
+# === Legacy Version Support ===
+
+# :pyver:old: PyPNG works on Python versions 2.3 and 2.2, but not
+# without some awkward problems. Really PyPNG works on Python 2.4 (and
+# above); it works on Pythons 2.3 and 2.2 by virtue of fixing up
+# problems here. It's a bit ugly (which is why it's hidden down here).
+#
+# Generally the strategy is one of pretending that we're running on
+# Python 2.4 (or above), and patching up the library support on earlier
+# versions so that it looks enough like Python 2.4. When it comes to
+# Python 2.2 there is one thing we cannot patch: extended slices
+# http://www.python.org/doc/2.3/whatsnew/section-slices.html.
+# Instead we simply declare that features that are implemented using
+# extended slices will not work on Python 2.2.
+#
+# In order to work on Python 2.3 we fix up a recurring annoyance involving
+# the array type. In Python 2.3 an array cannot be initialised with an
+# array, and it cannot be extended with a list (or other sequence).
+# Both of those are repeated issues in the code. Whilst I would not
+# normally tolerate this sort of behaviour, here we "shim" a replacement
+# for array into place (and hope no-one notices). You never read this.
+#
+# In an amusing case of warty hacks on top of warty hacks... the array
+# shimming we try and do only works on Python 2.3 and above (you can't
+# subclass array.array in Python 2.2). So to get it working on Python
+# 2.2 we go for something much simpler and (probably) way slower.
+try:
+ array('B').extend([])
+ array('B', array('B'))
+# :todo:(drj) Check that TypeError is correct for Python 2.3
+except TypeError:
+ # Expect to get here on Python 2.3
+ try:
+ class _array_shim(array):
+ true_array = array
+ def __new__(cls, typecode, init=None):
+ super_new = super(_array_shim, cls).__new__
+ it = super_new(cls, typecode)
+ if init is None:
+ return it
+ it.extend(init)
+ return it
+ def extend(self, extension):
+ super_extend = super(_array_shim, self).extend
+ if isinstance(extension, self.true_array):
+ return super_extend(extension)
+ if not isinstance(extension, (list, str)):
+ # Convert to list. Allows iterators to work.
+ extension = list(extension)
+ return super_extend(self.true_array(self.typecode, extension))
+ array = _array_shim
+ except TypeError:
+ # Expect to get here on Python 2.2
+ def array(typecode, init=()):
+ if type(init) == str:
+ return map(ord, init)
+ return list(init)
+
+# Further hacks to get it limping along on Python 2.2
+try:
+ enumerate
+except NameError:
+ def enumerate(seq):
+ i=0
+ for x in seq:
+ yield i,x
+ i += 1
+
+try:
+ reversed
+except NameError:
+ def reversed(l):
+ l = list(l)
+ l.reverse()
+ for x in l:
+ yield x
+
+try:
+ itertools
+except NameError:
+ class _dummy_itertools:
+ pass
+ itertools = _dummy_itertools()
+ def _itertools_imap(f, seq):
+ for x in seq:
+ yield f(x)
+ itertools.imap = _itertools_imap
+ def _itertools_chain(*iterables):
+ for it in iterables:
+ for element in it:
+ yield element
+ itertools.chain = _itertools_chain
+
+
+# === Support for users without Cython ===
+
+try:
+ pngfilters
+except NameError:
+ class pngfilters(object):
+ def undo_filter_sub(filter_unit, scanline, previous, result):
+ """Undo sub filter."""
+
+ ai = 0
+ # Loops starts at index fu. Observe that the initial part
+ # of the result is already filled in correctly with
+ # scanline.
+ for i in range(filter_unit, len(result)):
+ x = scanline[i]
+ a = result[ai]
+ result[i] = (x + a) & 0xff
+ ai += 1
+ undo_filter_sub = staticmethod(undo_filter_sub)
+
+ def undo_filter_up(filter_unit, scanline, previous, result):
+ """Undo up filter."""
+
+ for i in range(len(result)):
+ x = scanline[i]
+ b = previous[i]
+ result[i] = (x + b) & 0xff
+ undo_filter_up = staticmethod(undo_filter_up)
+
+ def undo_filter_average(filter_unit, scanline, previous, result):
+ """Undo up filter."""
+
+ ai = -filter_unit
+ for i in range(len(result)):
+ x = scanline[i]
+ if ai < 0:
+ a = 0
+ else:
+ a = result[ai]
+ b = previous[i]
+ result[i] = (x + ((a + b) >> 1)) & 0xff
+ ai += 1
+ undo_filter_average = staticmethod(undo_filter_average)
+
+ def undo_filter_paeth(filter_unit, scanline, previous, result):
+ """Undo Paeth filter."""
+
+ # Also used for ci.
+ ai = -filter_unit
+ for i in range(len(result)):
+ x = scanline[i]
+ if ai < 0:
+ a = c = 0
+ else:
+ a = result[ai]
+ c = previous[ai]
+ b = previous[i]
+ p = a + b - c
+ pa = abs(p - a)
+ pb = abs(p - b)
+ pc = abs(p - c)
+ if pa <= pb and pa <= pc:
+ pr = a
+ elif pb <= pc:
+ pr = b
+ else:
+ pr = c
+ result[i] = (x + pr) & 0xff
+ ai += 1
+ undo_filter_paeth = staticmethod(undo_filter_paeth)
+
+ def convert_la_to_rgba(row, result):
+ for i in range(3):
+ result[i::4] = row[0::2]
+ result[3::4] = row[1::2]
+ convert_la_to_rgba = staticmethod(convert_la_to_rgba)
+
+ def convert_l_to_rgba(row, result):
+ """Convert a grayscale image to RGBA. This method assumes
+ the alpha channel in result is already correctly
+ initialized.
+ """
+ for i in range(3):
+ result[i::4] = row
+ convert_l_to_rgba = staticmethod(convert_l_to_rgba)
+
+ def convert_rgb_to_rgba(row, result):
+ """Convert an RGB image to RGBA. This method assumes the
+ alpha channel in result is already correctly initialized.
+ """
+ for i in range(3):
+ result[i::4] = row[i::3]
+ convert_rgb_to_rgba = staticmethod(convert_rgb_to_rgba)
+
+
+# === Command Line Support ===
+
+def read_pam_header(infile):
+ """
+ Read (the rest of a) PAM header. `infile` should be positioned
+ immediately after the initial 'P7' line (at the beginning of the
+ second line). Returns are as for `read_pnm_header`.
+ """
+
+ # Unlike PBM, PGM, and PPM, we can read the header a line at a time.
+ header = dict()
+ while True:
+ l = infile.readline().strip()
+ if l == strtobytes('ENDHDR'):
+ break
+ if not l:
+ raise EOFError('PAM ended prematurely')
+ if l[0] == strtobytes('#'):
+ continue
+ l = l.split(None, 1)
+ if l[0] not in header:
+ header[l[0]] = l[1]
+ else:
+ header[l[0]] += strtobytes(' ') + l[1]
+
+ required = ['WIDTH', 'HEIGHT', 'DEPTH', 'MAXVAL']
+ required = [strtobytes(x) for x in required]
+ WIDTH,HEIGHT,DEPTH,MAXVAL = required
+ present = [x for x in required if x in header]
+ if len(present) != len(required):
+ raise Error('PAM file must specify WIDTH, HEIGHT, DEPTH, and MAXVAL')
+ width = int(header[WIDTH])
+ height = int(header[HEIGHT])
+ depth = int(header[DEPTH])
+ maxval = int(header[MAXVAL])
+ if (width <= 0 or
+ height <= 0 or
+ depth <= 0 or
+ maxval <= 0):
+ raise Error(
+ 'WIDTH, HEIGHT, DEPTH, MAXVAL must all be positive integers')
+ return 'P7', width, height, depth, maxval
+
+def read_pnm_header(infile, supported=('P5','P6')):
+ """
+ Read a PNM header, returning (format,width,height,depth,maxval).
+ `width` and `height` are in pixels. `depth` is the number of
+ channels in the image; for PBM and PGM it is synthesized as 1, for
+ PPM as 3; for PAM images it is read from the header. `maxval` is
+ synthesized (as 1) for PBM images.
+ """
+
+ # Generally, see http://netpbm.sourceforge.net/doc/ppm.html
+ # and http://netpbm.sourceforge.net/doc/pam.html
+
+ supported = [strtobytes(x) for x in supported]
+
+ # Technically 'P7' must be followed by a newline, so by using
+ # rstrip() we are being liberal in what we accept. I think this
+ # is acceptable.
+ type = infile.read(3).rstrip()
+ if type not in supported:
+ raise NotImplementedError('file format %s not supported' % type)
+ if type == strtobytes('P7'):
+ # PAM header parsing is completely different.
+ return read_pam_header(infile)
+ # Expected number of tokens in header (3 for P4, 4 for P6)
+ expected = 4
+ pbm = ('P1', 'P4')
+ if type in pbm:
+ expected = 3
+ header = [type]
+
+ # We have to read the rest of the header byte by byte because the
+ # final whitespace character (immediately following the MAXVAL in
+ # the case of P6) may not be a newline. Of course all PNM files in
+ # the wild use a newline at this point, so it's tempting to use
+ # readline; but it would be wrong.
+ def getc():
+ c = infile.read(1)
+ if not c:
+ raise Error('premature EOF reading PNM header')
+ return c
+
+ c = getc()
+ while True:
+ # Skip whitespace that precedes a token.
+ while c.isspace():
+ c = getc()
+ # Skip comments.
+ while c == '#':
+ while c not in '\n\r':
+ c = getc()
+ if not c.isdigit():
+ raise Error('unexpected character %s found in header' % c)
+ # According to the specification it is legal to have comments
+ # that appear in the middle of a token.
+ # This is bonkers; I've never seen it; and it's a bit awkward to
+ # code good lexers in Python (no goto). So we break on such
+ # cases.
+ token = strtobytes('')
+ while c.isdigit():
+ token += c
+ c = getc()
+ # Slight hack. All "tokens" are decimal integers, so convert
+ # them here.
+ header.append(int(token))
+ if len(header) == expected:
+ break
+ # Skip comments (again)
+ while c == '#':
+ while c not in '\n\r':
+ c = getc()
+ if not c.isspace():
+ raise Error('expected header to end with whitespace, not %s' % c)
+
+ if type in pbm:
+ # synthesize a MAXVAL
+ header.append(1)
+ depth = (1,3)[type == strtobytes('P6')]
+ return header[0], header[1], header[2], depth, header[3]
+
+def write_pnm(file, width, height, pixels, meta):
+ """Write a Netpbm PNM/PAM file.
+ """
+
+ bitdepth = meta['bitdepth']
+ maxval = 2**bitdepth - 1
+ # Rudely, the number of image planes can be used to determine
+ # whether we are L (PGM), LA (PAM), RGB (PPM), or RGBA (PAM).
+ planes = meta['planes']
+ # Can be an assert as long as we assume that pixels and meta came
+ # from a PNG file.
+ assert planes in (1,2,3,4)
+ if planes in (1,3):
+ if 1 == planes:
+ # PGM
+ # Could generate PBM if maxval is 1, but we don't (for one
+ # thing, we'd have to convert the data, not just blat it
+ # out).
+ fmt = 'P5'
+ else:
+ # PPM
+ fmt = 'P6'
+ file.write('%s %d %d %d\n' % (fmt, width, height, maxval))
+ if planes in (2,4):
+ # PAM
+ # See http://netpbm.sourceforge.net/doc/pam.html
+ if 2 == planes:
+ tupltype = 'GRAYSCALE_ALPHA'
+ else:
+ tupltype = 'RGB_ALPHA'
+ file.write('P7\nWIDTH %d\nHEIGHT %d\nDEPTH %d\nMAXVAL %d\n'
+ 'TUPLTYPE %s\nENDHDR\n' %
+ (width, height, planes, maxval, tupltype))
+ # Values per row
+ vpr = planes * width
+ # struct format
+ fmt = '>%d' % vpr
+ if maxval > 0xff:
+ fmt = fmt + 'H'
+ else:
+ fmt = fmt + 'B'
+ for row in pixels:
+ file.write(struct.pack(fmt, *row))
+ file.flush()
+
+def color_triple(color):
+ """
+ Convert a command line colour value to a RGB triple of integers.
+ FIXME: Somewhere we need support for greyscale backgrounds etc.
+ """
+ if color.startswith('#') and len(color) == 4:
+ return (int(color[1], 16),
+ int(color[2], 16),
+ int(color[3], 16))
+ if color.startswith('#') and len(color) == 7:
+ return (int(color[1:3], 16),
+ int(color[3:5], 16),
+ int(color[5:7], 16))
+ elif color.startswith('#') and len(color) == 13:
+ return (int(color[1:5], 16),
+ int(color[5:9], 16),
+ int(color[9:13], 16))
+
+def _add_common_options(parser):
+ """Call *parser.add_option* for each of the options that are
+ common between this PNG--PNM conversion tool and the gen
+ tool.
+ """
+ parser.add_option("-i", "--interlace",
+ default=False, action="store_true",
+ help="create an interlaced PNG file (Adam7)")
+ parser.add_option("-t", "--transparent",
+ action="store", type="string", metavar="#RRGGBB",
+ help="mark the specified colour as transparent")
+ parser.add_option("-b", "--background",
+ action="store", type="string", metavar="#RRGGBB",
+ help="save the specified background colour")
+ parser.add_option("-g", "--gamma",
+ action="store", type="float", metavar="value",
+ help="save the specified gamma value")
+ parser.add_option("-c", "--compression",
+ action="store", type="int", metavar="level",
+ help="zlib compression level (0-9)")
+ return parser
+
+def _main(argv):
+ """
+ Run the PNG encoder with options from the command line.
+ """
+
+ # Parse command line arguments
+ from optparse import OptionParser
+ import re
+ version = '%prog ' + __version__
+ parser = OptionParser(version=version)
+ parser.set_usage("%prog [options] [imagefile]")
+ parser.add_option('-r', '--read-png', default=False,
+ action='store_true',
+ help='Read PNG, write PNM')
+ parser.add_option("-a", "--alpha",
+ action="store", type="string", metavar="pgmfile",
+ help="alpha channel transparency (RGBA)")
+ _add_common_options(parser)
+
+ (options, args) = parser.parse_args(args=argv[1:])
+
+ # Convert options
+ if options.transparent is not None:
+ options.transparent = color_triple(options.transparent)
+ if options.background is not None:
+ options.background = color_triple(options.background)
+
+ # Prepare input and output files
+ if len(args) == 0:
+ infilename = '-'
+ infile = sys.stdin
+ elif len(args) == 1:
+ infilename = args[0]
+ infile = open(infilename, 'rb')
+ else:
+ parser.error("more than one input file")
+ outfile = sys.stdout
+ if sys.platform == "win32":
+ import msvcrt, os
+ msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
+
+ if options.read_png:
+ # Encode PNG to PPM
+ png = Reader(file=infile)
+ width,height,pixels,meta = png.asDirect()
+ write_pnm(outfile, width, height, pixels, meta)
+ else:
+ # Encode PNM to PNG
+ format, width, height, depth, maxval = \
+ read_pnm_header(infile, ('P5','P6','P7'))
+ # When it comes to the variety of input formats, we do something
+ # rather rude. Observe that L, LA, RGB, RGBA are the 4 colour
+ # types supported by PNG and that they correspond to 1, 2, 3, 4
+ # channels respectively. So we use the number of channels in
+ # the source image to determine which one we have. We do not
+ # care about TUPLTYPE.
+ greyscale = depth <= 2
+ pamalpha = depth in (2,4)
+ supported = map(lambda x: 2**x-1, range(1,17))
+ try:
+ mi = supported.index(maxval)
+ except ValueError:
+ raise NotImplementedError(
+ 'your maxval (%s) not in supported list %s' %
+ (maxval, str(supported)))
+ bitdepth = mi+1
+ writer = Writer(width, height,
+ greyscale=greyscale,
+ bitdepth=bitdepth,
+ interlace=options.interlace,
+ transparent=options.transparent,
+ background=options.background,
+ alpha=bool(pamalpha or options.alpha),
+ gamma=options.gamma,
+ compression=options.compression)
+ if options.alpha:
+ pgmfile = open(options.alpha, 'rb')
+ format, awidth, aheight, adepth, amaxval = \
+ read_pnm_header(pgmfile, 'P5')
+ if amaxval != '255':
+ raise NotImplementedError(
+ 'maxval %s not supported for alpha channel' % amaxval)
+ if (awidth, aheight) != (width, height):
+ raise ValueError("alpha channel image size mismatch"
+ " (%s has %sx%s but %s has %sx%s)"
+ % (infilename, width, height,
+ options.alpha, awidth, aheight))
+ writer.convert_ppm_and_pgm(infile, pgmfile, outfile)
+ else:
+ writer.convert_pnm(infile, outfile)
+
+
+if __name__ == '__main__':
+ try:
+ _main(sys.argv)
+ except Error, e:
+ print >>sys.stderr, e
diff --git a/src/build/png2bdc.c b/src/build/png2bdc.c
deleted file mode 100644
index 197ded22fcc..00000000000
--- a/src/build/png2bdc.c
+++ /dev/null
@@ -1,426 +0,0 @@
-// license:BSD-3-Clause
-// copyright-holders:Aaron Giles
-/***************************************************************************
-
- png2bdc.c
-
- Super-simple PNG to BDC file generator
-
-****************************************************************************
-
- Format of PNG data:
-
- Multiple rows of characters. A black pixel means "on". All other colors
- mean "off". Each row looks like this:
-
- * 8888 *** *
- * 4444 * * **
- * 2222 * * *
- * 1111 * * *
- * * * *
- ** *** ***
- *
- *
-
- ****** ****
-
- The column of pixels on the left-hand side (column 0) indicates the
- character cell height. This column must be present on each row and
- the height must be consistent for each row.
-
- Protruding one pixel into column 1 is the baseline indicator. There
- should only be one row with a pixel in column 1 for each line, and
- that pixel row index should be consistent for each row.
-
- In columns 2-5 are a 4-hex-digit starting character index number. This
- is encoded as binary value. Each column is 4 pixels tall and represents
- one binary digit. The character index number is the unicode character
- number of the first character encoded in this row; subsequent
- characters in the row are at increasing character indices.
-
- Starting in column 6 and beyond are the actual character bitmaps.
- Below them, in the second row after the last row of the character,
- is a solid line that indicates the width of the character, and also
- where the character bitmap begins and ends.
-
-***************************************************************************/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <ctype.h>
-#include <new>
-#include "png.h"
-
-
-//**************************************************************************
-// CONSTANTS & DEFINES
-//**************************************************************************
-
-#define CACHED_CHAR_SIZE 12
-#define CACHED_HEADER_SIZE 16
-
-
-
-//**************************************************************************
-// TYPE DEFINITIONS
-//**************************************************************************
-
-// a render_font contains information about a single character in a font
-struct render_font_char
-{
- render_font_char() : width(0), xoffs(0), yoffs(0), bmwidth(0), bmheight(0) { }
-
- INT32 width; // width from this character to the next
- INT32 xoffs, yoffs; // X and Y offset from baseline to top,left of bitmap
- INT32 bmwidth, bmheight; // width and height of bitmap
- bitmap_argb32 * bitmap; // pointer to the bitmap containing the raw data
-};
-
-
-// a render_font contains information about a font
-struct render_font
-{
- render_font() : height(0), yoffs(0) { }
-
- int height; // height of the font, from ascent to descent
- int yoffs; // y offset from baseline to descent
- render_font_char chars[65536]; // array of characters
-};
-
-
-
-//**************************************************************************
-// INLINE FUNCTIONS
-//**************************************************************************
-
-inline int pixel_is_set(bitmap_argb32 &bitmap, int y, int x)
-{
- return (bitmap.pix32(y, x) & 0xffffff) == 0;
-}
-
-
-
-//**************************************************************************
-// MAIN
-//**************************************************************************
-
-//-------------------------------------------------
-// write_data - write data to the given file and
-// throw an exception if an error occurs
-//-------------------------------------------------
-
-static void write_data(core_file &file, UINT8 *base, UINT8 *end)
-{
- UINT32 bytes_written = core_fwrite(&file, base, end - base);
- if (bytes_written != end - base)
- {
- fprintf(stderr, "Error writing to destination file\n");
- throw;
- }
-}
-
-
-//-------------------------------------------------
-// render_font_save_cached - write the cached
-// data out to the file
-//-------------------------------------------------
-
-static bool render_font_save_cached(render_font &font, const char *filename, UINT32 hash)
-{
- // attempt to open the file
- core_file *file;
- file_error filerr = core_fopen(filename, OPEN_FLAG_WRITE | OPEN_FLAG_CREATE, &file);
- if (filerr != FILERR_NONE)
- return true;
-
- try
- {
- // determine the number of characters
- int numchars = 0;
- for (int chnum = 0; chnum < 65536; chnum++)
- if (font.chars[chnum].width > 0)
- numchars++;
-
- // write the header
- dynamic_buffer tempbuffer(65536);
- UINT8 *dest = &tempbuffer[0];
- *dest++ = 'f';
- *dest++ = 'o';
- *dest++ = 'n';
- *dest++ = 't';
- *dest++ = hash >> 24;
- *dest++ = hash >> 16;
- *dest++ = hash >> 8;
- *dest++ = hash & 0xff;
- *dest++ = font.height >> 8;
- *dest++ = font.height & 0xff;
- *dest++ = font.yoffs >> 8;
- *dest++ = font.yoffs & 0xff;
- *dest++ = numchars >> 24;
- *dest++ = numchars >> 16;
- *dest++ = numchars >> 8;
- *dest++ = numchars & 0xff;
- write_data(*file, tempbuffer, dest);
-
- // write the empty table to the beginning of the file
- dynamic_buffer chartable(numchars * CACHED_CHAR_SIZE + 1, 0);
- write_data(*file, &chartable[0], &chartable[numchars * CACHED_CHAR_SIZE]);
-
- // loop over all characters
- int tableindex = 0;
- for (int chnum = 0; chnum < 65536; chnum++)
- {
- render_font_char &ch = font.chars[chnum];
- if (ch.width > 0)
- {
- // write out a bit-compressed bitmap if we have one
- if (ch.bitmap != NULL)
- {
- // write the data to the tempbuffer
- dest = tempbuffer;
- UINT8 accum = 0;
- UINT8 accbit = 7;
-
- // bit-encode the character data
- for (int y = 0; y < ch.bmheight; y++)
- {
- int desty = y + font.height + font.yoffs - ch.yoffs - ch.bmheight;
- const UINT32 *src = (desty >= 0 && desty < font.height) ? &ch.bitmap->pix32(desty) : NULL;
- for (int x = 0; x < ch.bmwidth; x++)
- {
- if (src != NULL && src[x] != 0)
- accum |= 1 << accbit;
- if (accbit-- == 0)
- {
- *dest++ = accum;
- accum = 0;
- accbit = 7;
- }
- }
- }
-
- // flush any extra
- if (accbit != 7)
- *dest++ = accum;
-
- // write the data
- write_data(*file, tempbuffer, dest);
-
- // free the bitmap and texture
- global_free(ch.bitmap);
- ch.bitmap = NULL;
- }
-
- // compute the table entry
- dest = &chartable[tableindex++ * CACHED_CHAR_SIZE];
- *dest++ = chnum >> 8;
- *dest++ = chnum & 0xff;
- *dest++ = ch.width >> 8;
- *dest++ = ch.width & 0xff;
- *dest++ = ch.xoffs >> 8;
- *dest++ = ch.xoffs & 0xff;
- *dest++ = ch.yoffs >> 8;
- *dest++ = ch.yoffs & 0xff;
- *dest++ = ch.bmwidth >> 8;
- *dest++ = ch.bmwidth & 0xff;
- *dest++ = ch.bmheight >> 8;
- *dest++ = ch.bmheight & 0xff;
- }
- }
-
- // seek back to the beginning and rewrite the table
- core_fseek(file, CACHED_HEADER_SIZE, SEEK_SET);
- write_data(*file, &chartable[0], &chartable[numchars * CACHED_CHAR_SIZE]);
-
- // all done
- core_fclose(file);
- return false;
- }
- catch (...)
- {
- core_fclose(file);
- osd_rmfile(filename);
- return true;
- }
-}
-
-
-//-------------------------------------------------
-// bitmap_to_chars - convert a bitmap to
-// characters in the given font
-//-------------------------------------------------
-
-static bool bitmap_to_chars(bitmap_argb32 &bitmap, render_font &font)
-{
- // loop over rows
- int rowstart = 0;
- while (rowstart < bitmap.height())
- {
- // find the top of the row
- for ( ; rowstart < bitmap.height(); rowstart++)
- if (pixel_is_set(bitmap, rowstart, 0))
- break;
- if (rowstart >= bitmap.height())
- break;
-
- // find the bottom of the row
- int rowend;
- for (rowend = rowstart + 1; rowend < bitmap.height(); rowend++)
- if (!pixel_is_set(bitmap, rowend, 0))
- {
- rowend--;
- break;
- }
-
- // find the baseline
- int baseline;
- for (baseline = rowstart; baseline <= rowend; baseline++)
- if (pixel_is_set(bitmap, baseline, 1))
- break;
- if (baseline > rowend)
- {
- fprintf(stderr, "No baseline found between rows %d-%d\n", rowstart, rowend);
- break;
- }
-
- // set or confirm the height
- if (font.height == 0)
- {
- font.height = rowend - rowstart + 1;
- font.yoffs = baseline - rowend;
- }
- else
- {
- if (font.height != rowend - rowstart + 1)
- {
- fprintf(stderr, "Inconsistent font height at rows %d-%d\n", rowstart, rowend);
- break;
- }
- if (font.yoffs != baseline - rowend)
- {
- fprintf(stderr, "Inconsistent baseline at rows %d-%d\n", rowstart, rowend);
- break;
- }
- }
-
- // decode the starting character
- int chstart = 0;
- for (int x = 0; x < 4; x++)
- for (int y = 0; y < 4; y++)
- chstart = (chstart << 1) | pixel_is_set(bitmap, rowstart + y, 2 + x);
-
- // print info
-// printf("Row %d-%d, baseline %d, character start %X\n", rowstart, rowend, baseline, chstart);
-
- // scan the column to find characters
- int colstart = 0;
- while (colstart < bitmap.width())
- {
- render_font_char &ch = font.chars[chstart];
-
- // find the start of the character
- for ( ; colstart < bitmap.width(); colstart++)
- if (pixel_is_set(bitmap, rowend + 2, colstart))
- break;
- if (colstart >= bitmap.width())
- break;
-
- // find the end of the character
- int colend;
- for (colend = colstart + 1; colend < bitmap.width(); colend++)
- if (!pixel_is_set(bitmap, rowend + 2, colend))
- {
- colend--;
- break;
- }
-
- // skip char which code is already registered
- if (ch.width <= 0)
- {
- // print info
-// printf(" Character %X - width = %d\n", chstart, colend - colstart + 1);
-
- // allocate a bitmap
- ch.bitmap = global_alloc(bitmap_argb32(colend - colstart + 1, font.height));
-
- // plot the character
- for (int y = rowstart; y <= rowend; y++)
- for (int x = colstart; x <= colend; x++)
- ch.bitmap->pix32(y - rowstart, x - colstart) = pixel_is_set(bitmap, y, x) ? 0xffffffff : 0x00000000;
-
- // set the character parameters
- ch.width = colend - colstart + 1;
- ch.xoffs = 0;
- ch.yoffs = font.yoffs;
- ch.bmwidth = ch.bitmap->width();
- ch.bmheight = ch.bitmap->height();
- }
-
- // next character
- chstart++;
- colstart = colend + 1;
- }
-
- // next row
- rowstart = rowend + 1;
- }
-
- // return non-zero (TRUE) if we errored
- return (rowstart < bitmap.height());
-}
-
-
-//-------------------------------------------------
-// main - main entry point
-//-------------------------------------------------
-
-int main(int argc, char *argv[])
-{
- // validate arguments
- if (argc < 3)
- {
- fprintf(stderr, "Usage:\n%s <input.png> [<input2.png> [...]] <output.bdc>\n", argv[0]);
- return 1;
- }
- const char *bdcname = argv[argc - 1];
-
- // iterate over input files
- static render_font font;
- bool error = false;
- for (int curarg = 1; curarg < argc - 1; curarg++)
- {
- // load the png file
- const char *pngname = argv[curarg];
- core_file *file;
- file_error filerr = core_fopen(pngname, OPEN_FLAG_READ, &file);
- if (filerr != FILERR_NONE)
- {
- fprintf(stderr, "Error %d attempting to open PNG file\n", filerr);
- error = true;
- break;
- }
-
- bitmap_argb32 bitmap;
- png_error pngerr = png_read_bitmap(file, bitmap);
- core_fclose(file);
- if (pngerr != PNGERR_NONE)
- {
- fprintf(stderr, "Error %d reading PNG file\n", pngerr);
- error = true;
- break;
- }
-
- // parse the PNG into characters
- error = bitmap_to_chars(bitmap, font);
- if (error)
- break;
- }
-
- // write out the resulting font
- if (!error)
- error = render_font_save_cached(font, bdcname, 0);
-
- // cleanup after ourselves
- return error ? 1 : 0;
-}
diff --git a/src/build/png2bdc.py b/src/build/png2bdc.py
new file mode 100644
index 00000000000..7d4d7df5d3e
--- /dev/null
+++ b/src/build/png2bdc.py
@@ -0,0 +1,361 @@
+#!/usr/bin/env python
+##
+## license:BSD-3-Clause
+## copyright-holders:Aaron Giles, Andrew Gardner
+## ****************************************************************************
+##
+## png2bdc.c
+##
+## Super-simple PNG to BDC file generator
+##
+## ****************************************************************************
+##
+## Format of PNG data:
+##
+## Multiple rows of characters. A black pixel means "on". All other colors
+## mean "off". Each row looks like this:
+##
+## * 8888 *** *
+## * 4444 * * **
+## * 2222 * * *
+## * 1111 * * *
+## * * * *
+## ** *** ***
+## *
+## *
+##
+## ****** ****
+##
+## The column of pixels on the left-hand side (column 0) indicates the
+## character cell height. This column must be present on each row and
+## the height must be consistent for each row.
+##
+## Protruding one pixel into column 1 is the baseline indicator. There
+## should only be one row with a pixel in column 1 for each line, and
+## that pixel row index should be consistent for each row.
+##
+## In columns 2-5 are a 4-hex-digit starting character index number. This
+## is encoded as binary value. Each column is 4 pixels tall and represents
+## one binary digit. The character index number is the unicode character
+## number of the first character encoded in this row; subsequent
+## characters in the row are at increasing character indices.
+##
+## Starting in column 6 and beyond are the actual character bitmaps.
+## Below them, in the second row after the last row of the character,
+## is a solid line that indicates the width of the character, and also
+## where the character bitmap begins and ends.
+##
+## ***************************************************************************
+
+##
+## Python note:
+## This is a near-literal translation of the original C++ code. As such there
+## are some very non-pythonic things done throughout. The conversion was done
+## this way so as to insure compatibility as much as possible given the small
+## number of test cases.
+##
+
+import os
+import png
+import sys
+
+
+########################################
+## Helper classes
+########################################
+class RenderFontChar:
+ """
+ Contains information about a single character in a font.
+ """
+
+ def __init__(self):
+ """
+ """
+ self.width = 0 # width from this character to the next
+ self.xOffs = 0 # X offset from baseline to top,left of bitmap
+ self.yOffs = 0 # Y offset from baseline to top,left of bitmap
+ self.bmWidth = 0 # width of bitmap
+ self.bmHeight = 0 # height of bitmap
+ self.bitmap = None # pointer to the bitmap containing the raw data
+
+
+class RenderFont:
+ """
+ Contains information about a font
+ """
+
+ def __init__(self):
+ self.height = 0 # height of the font, from ascent to descent
+ self.yOffs = 0 # y offset from baseline to descent
+ self.chars = list() # array of characters
+ for i in range(0, 65536):
+ self.chars.append(RenderFontChar())
+
+
+
+########################################
+## Helper functions
+########################################
+def pixelIsSet(value):
+ return (value & 0xffffff) == 0
+
+
+def renderFontSaveCached(font, filename, hash32):
+ """
+ """
+ fp = open(filename, "wb")
+ if not fp:
+ return 1
+
+ # Write the header
+ numChars = 0
+ for c in font.chars:
+ if c.width > 0:
+ numChars += 1
+
+ CACHED_CHAR_SIZE = 12
+ CACHED_HEADER_SIZE = 16
+
+ try:
+ fp.write('f')
+ fp.write('o')
+ fp.write('n')
+ fp.write('t')
+ fp.write(bytearray([hash32 >> 24 & 0xff]))
+ fp.write(bytearray([hash32 >> 16 & 0xff]))
+ fp.write(bytearray([hash32 >> 8 & 0xff]))
+ fp.write(bytearray([hash32 >> 0 & 0xff]))
+ fp.write(bytearray([font.height >> 8 & 0xff]))
+ fp.write(bytearray([font.height >> 0 & 0xff]))
+ fp.write(bytearray([font.yOffs >> 8 & 0xff]))
+ fp.write(bytearray([font.yOffs >> 0 & 0xff]))
+ fp.write(bytearray([numChars >> 24 & 0xff]))
+ fp.write(bytearray([numChars >> 16 & 0xff]))
+ fp.write(bytearray([numChars >> 8 & 0xff]))
+ fp.write(bytearray([numChars >> 0 & 0xff]))
+
+ # Write a blank table at first (?)
+ charTable = [0]*(numChars * CACHED_CHAR_SIZE)
+ fp.write(bytearray(charTable))
+
+ # Loop over all characters
+ tableIndex = 0
+
+ for i in range(len(font.chars)):
+ c = font.chars[i]
+ if c.width == 0:
+ continue
+
+ if c.bitmap:
+ dBuffer = list()
+ accum = 0
+ accbit = 7
+
+ # Bit-encode the character data
+ for y in range(0, c.bmHeight):
+ src = None
+ desty = y + font.height + font.yOffs - c.yOffs - c.bmHeight
+ if desty >= 0 and desty < font.height:
+ src = c.bitmap[desty]
+ for x in range(0, c.bmWidth):
+ if src is not None and src[x] != 0:
+ accum |= 1 << accbit
+ accbit -= 1
+ if accbit+1 == 0:
+ dBuffer.append(accum)
+ accum = 0
+ accbit = 7
+
+ # Flush any extra
+ if accbit != 7:
+ dBuffer.append(accum)
+
+ # Write the data
+ fp.write(bytearray(dBuffer))
+
+ destIndex = tableIndex * CACHED_CHAR_SIZE
+ charTable[destIndex + 0] = i >> 8 & 0xff
+ charTable[destIndex + 1] = i >> 0 & 0xff
+ charTable[destIndex + 2] = c.width >> 8 & 0xff
+ charTable[destIndex + 3] = c.width >> 0 & 0xff
+ charTable[destIndex + 4] = c.xOffs >> 8 & 0xff
+ charTable[destIndex + 5] = c.xOffs >> 0 & 0xff
+ charTable[destIndex + 6] = c.yOffs >> 8 & 0xff
+ charTable[destIndex + 7] = c.yOffs >> 0 & 0xff
+ charTable[destIndex + 8] = c.bmWidth >> 8 & 0xff
+ charTable[destIndex + 9] = c.bmWidth >> 0 & 0xff
+ charTable[destIndex + 10] = c.bmHeight >> 8 & 0xff
+ charTable[destIndex + 11] = c.bmHeight >> 0 & 0xff
+ tableIndex += 1
+
+ # Seek back to the beginning and rewrite the table
+ fp.seek(CACHED_HEADER_SIZE, 0)
+ fp.write(bytearray(charTable))
+
+ fp.close()
+ return 0
+
+ except:
+ return 1
+
+
+def bitmapToChars(pngObject, font):
+ """
+ Convert a bitmap to characters in the given font
+ """
+ # Just cache the bitmap into a list of lists since random access is paramount
+ bitmap = list()
+ width = pngObject.asRGBA8()[0]
+ height = pngObject.asRGBA8()[1]
+ rowGenerator = pngObject.asRGBA8()[2]
+ for row in rowGenerator:
+ cRow = list()
+ irpd = iter(row)
+ for r,g,b,a in zip(irpd, irpd, irpd, irpd):
+ cRow.append(a << 24 | r << 16 | g << 8 | b)
+ bitmap.append(cRow)
+
+ rowStart = 0
+ while rowStart < height:
+ # Find the top of the row
+ for i in range(rowStart, height):
+ if pixelIsSet(bitmap[rowStart][0]):
+ break
+ rowStart += 1
+ if rowStart >= height:
+ break
+
+ # Find the bottom of the row
+ rowEnd = rowStart + 1
+ for i in range(rowEnd, height):
+ if not pixelIsSet(bitmap[rowEnd][0]):
+ rowEnd -= 1
+ break
+ rowEnd += 1
+
+ # Find the baseline
+ baseline = rowStart
+ for i in range(rowStart, rowEnd+1):
+ if pixelIsSet(bitmap[baseline][1]):
+ break
+ baseline += 1
+ if baseline > rowEnd:
+ sys.stderr.write("No baseline found between rows %d-%d\n" % (rowStart, rowEnd))
+ break
+
+ # Set or confirm the height
+ if font.height == 0:
+ font.height = rowEnd - rowStart + 1
+ font.yOffs = baseline - rowEnd
+ else:
+ if font.height != (rowEnd - rowStart + 1):
+ sys.stderr.write("Inconsistent font height at rows %d-%d\n" % (rowStart, rowEnd))
+ break
+ if font.yOffs != (baseline - rowEnd):
+ sys.stderr.write("Inconsistent baseline at rows %d-%d\n" % (rowStart, rowEnd))
+ break
+
+ # decode the starting character
+ chStart = 0
+ for x in range(0, 4):
+ for y in range(0, 4):
+ chStart = (chStart << 1) | pixelIsSet(bitmap[rowStart+y][2+x])
+
+ # Print debug info
+ # print("Row %d-%d, baseline %d, character start %X" % (rowStart, rowEnd, baseline, chStart))
+
+ # scan the column to find characters
+ colStart = 0
+ while (colStart < width):
+ ch = RenderFontChar()
+
+ # Find the start of the character
+ for i in range(colStart, width):
+ if pixelIsSet(bitmap[rowEnd+2][colStart]):
+ break
+ colStart += 1
+ if colStart >= width:
+ break
+
+ # Find the end of the character
+ colEnd = colStart + 1
+ for i in range(colEnd, width):
+ if not pixelIsSet(bitmap[rowEnd+2][colEnd]):
+ colEnd -= 1
+ break
+ colEnd += 1
+
+ # Skip char which code is already registered
+ if ch.width <= 0:
+ # Print debug info
+ # print " Character %X - width = %d" % (chStart, colEnd - colStart + 1)
+
+ # Plot the character
+ ch.bitmap = list()
+ for y in range(rowStart, rowEnd+1):
+ ch.bitmap.append(list())
+ for x in range(colStart, colEnd+1):
+ if pixelIsSet(bitmap[y][x]):
+ ch.bitmap[-1].append(0xffffffff)
+ else:
+ ch.bitmap[-1].append(0x00000000)
+
+ # Set the character parameters
+ ch.width = colEnd - colStart + 1
+ ch.xOffs = 0
+ ch.yOffs = font.yOffs
+ ch.bmWidth = len(ch.bitmap[0])
+ ch.bmHeight = len(ch.bitmap)
+
+ # Insert the character into the list
+ font.chars[chStart] = ch
+
+ # Next character
+ chStart += 1
+ colStart = colEnd + 1
+
+ # Next row
+ rowStart = rowEnd + 1
+
+ # Return non-zero if we errored
+ return (rowStart < height)
+
+
+
+########################################
+## Main
+########################################
+def main():
+ if len(sys.argv) < 3:
+ sys.stderr.write("Usage:\n%s <input.png> [<input2.png> [...]] <output.bdc>\n" % sys.argv[0])
+ return 1
+ bdcName = sys.argv[-1]
+
+ font = RenderFont()
+ for i in range(1, len(sys.argv)-1):
+ filename = sys.argv[i]
+ if not os.path.exists(filename):
+ sys.stderr.write("Error attempting to open PNG file.\n")
+ return 1
+
+ pngObject = png.Reader(filename)
+ try:
+ pngObject.validate_signature()
+ except:
+ sys.stderr.write("Error reading PNG file.\n")
+ return 1
+
+ error = bitmapToChars(pngObject, font)
+ if error:
+ return 1
+
+ error = renderFontSaveCached(font, bdcName, 0)
+ return error
+
+
+
+########################################
+## Program entry point
+########################################
+if __name__ == "__main__":
+ sys.exit(main())