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#!/usr/bin/env python3
##
## 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
def b2p(v):
return bytes([v])
########################################
## 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.defChar = -1 # default character for glyphs not present
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, length64, 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 = 16
CACHED_HEADER_SIZE = 32
try:
fp.write(b'b')
fp.write(b'd')
fp.write(b'c')
fp.write(b'f')
fp.write(b'n')
fp.write(b't')
fp.write(b2p(1))
fp.write(b2p(0))
fp.write(b2p(length64 >> 56 & 0xff))
fp.write(b2p(length64 >> 48 & 0xff))
fp.write(b2p(length64 >> 40 & 0xff))
fp.write(b2p(length64 >> 32 & 0xff))
fp.write(b2p(length64 >> 24 & 0xff))
fp.write(b2p(length64 >> 16 & 0xff))
fp.write(b2p(length64 >> 8 & 0xff))
fp.write(b2p(length64 >> 0 & 0xff))
fp.write(b2p(hash32 >> 24 & 0xff))
fp.write(b2p(hash32 >> 16 & 0xff))
fp.write(b2p(hash32 >> 8 & 0xff))
fp.write(b2p(hash32 >> 0 & 0xff))
fp.write(b2p(numChars >> 24 & 0xff))
fp.write(b2p(numChars >> 16 & 0xff))
fp.write(b2p(numChars >> 8 & 0xff))
fp.write(b2p(numChars >> 0 & 0xff))
fp.write(b2p(font.height >> 8 & 0xff))
fp.write(b2p(font.height >> 0 & 0xff))
fp.write(b2p(font.yOffs >> 8 & 0xff))
fp.write(b2p(font.yOffs >> 0 & 0xff))
fp.write(b2p(font.defChar >> 24 & 0xff))
fp.write(b2p(font.defChar >> 16 & 0xff))
fp.write(b2p(font.defChar >> 8 & 0xff))
fp.write(b2p(font.defChar >> 0 & 0xff))
# Write a blank table at first (?)
charTable = [0]*(numChars * CACHED_CHAR_SIZE)
for i in range(numChars * CACHED_CHAR_SIZE):
fp.write(b2p(charTable[i]))
# 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
for j in range(len(dBuffer)):
fp.write(b2p(dBuffer[j]))
destIndex = tableIndex * CACHED_CHAR_SIZE
charTable[destIndex + 0] = i >> 24 & 0xff
charTable[destIndex + 1] = i >> 16 & 0xff
charTable[destIndex + 2] = i >> 8 & 0xff
charTable[destIndex + 3] = i >> 0 & 0xff
charTable[destIndex + 4] = c.width >> 8 & 0xff
charTable[destIndex + 5] = c.width >> 0 & 0xff
charTable[destIndex + 8] = c.xOffs >> 8 & 0xff
charTable[destIndex + 9] = c.xOffs >> 0 & 0xff
charTable[destIndex + 10] = c.yOffs >> 8 & 0xff
charTable[destIndex + 11] = c.yOffs >> 0 & 0xff
charTable[destIndex + 12] = c.bmWidth >> 8 & 0xff
charTable[destIndex + 13] = c.bmWidth >> 0 & 0xff
charTable[destIndex + 14] = c.bmHeight >> 8 & 0xff
charTable[destIndex + 15] = c.bmHeight >> 0 & 0xff
tableIndex += 1
# Seek back to the beginning and rewrite the table
fp.seek(CACHED_HEADER_SIZE, 0)
for i in range(numChars * CACHED_CHAR_SIZE):
fp.write(b2p(charTable[i]))
fp.close()
return 0
except:
print(sys.exc_info[1])
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, 0)
return error
########################################
## Program entry point
########################################
if __name__ == "__main__":
sys.exit(main())
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