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fixes #211

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replace the gif optimization with a working version
This commit is contained in:
David Schmidt 2013-05-23 14:06:09 +02:00
parent cb28745049
commit a466b3e099
1 changed files with 65 additions and 30 deletions
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95
PIL/GifImagePlugin.py
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@ -293,7 +293,6 @@ def _save(im, fp, filename):
o8(8)) # bits
imOut.encoderconfig = (8, interlace)
ImageFile._save(imOut, fp, [("gif", (0,0)+im.size, 0, rawmode)])
fp.write(b"\0") # end of image data
@ -303,6 +302,7 @@ def _save(im, fp, filename):
try:
fp.flush()
except: pass
def _save_netpbm(im, fp, filename):
@ -329,42 +329,77 @@ def getheader(im, palette=None, info=None):
optimize = info and info.get("optimize", 0)
# start of header
s = [
b"GIF87a" + # magic
o16(im.size[0]) + # size
o16(im.size[1]) +
o8(7 + 128) + # flags: bits + palette
o8(0) + # background
o8(0) # reserved/aspect
o16(im.size[1])
]
if optimize:
# minimize color palette
i = 0
maxcolor = 0
for count in im.histogram():
if count:
maxcolor = i
i = i + 1
# if the user adds a palette, use it
if palette is not None and isinstance(palette, bytes):
paletteBytes = palette
else:
maxcolor = 256
# global palette
if im.mode == "P":
# colour palette
if palette is not None and isinstance(palette, bytes):
paletteBytes = palette
usedPaletteColors = []
if optimize:
# minimize color palette if wanted
i = 0
for count in im.histogram():
if count:
usedPaletteColors.append(i)
i += 1
countUsedPaletteColors = len(usedPaletteColors)
# create the global palette
if im.mode == "P":
# colour palette
if countUsedPaletteColors > 0:
paletteBytes = b"";
# pick only the used colors from the palette
for i in usedPaletteColors:
paletteBytes += im.im.getpalette("RGB")[i*3:i*3+3]
else :
paletteBytes = im.im.getpalette("RGB")[:768]
else:
paletteBytes =im.im.getpalette("RGB")[:maxcolor*3]
s.append(paletteBytes)
else:
# greyscale
for i in range(maxcolor):
s.append(o8(i) * 3)
# greyscale
if countUsedPaletteColors > 0:
paletteBytes = b"";
# add only the used grayscales to the palette
for i in usedPaletteColors:
paletteBytes += o8(i)*3
else :
paletteBytes = bytes([i//3 for i in range(768)])
# TODO improve this, maybe add numpy support
# replace the palette color id of all pixel with the new id
if countUsedPaletteColors > 0 and countUsedPaletteColors < 256:
imageBytes = bytearray(im.tobytes())
for i in range(len(imageBytes)):
for newI in range(countUsedPaletteColors):
if imageBytes[i] == usedPaletteColors[newI]:
imageBytes[i] = newI
im.frombytes(bytes(imageBytes))
# calculate the palette size for the header
import math
colorTableSize = math.ceil(math.log(len(paletteBytes)//3, 2))-1
s.append(o8(colorTableSize + 128)) # size of global color table + global color table flag
s.append(o8(0) + o8(0)) # background + reserved/aspect
# end of screen descriptor header
# add the missing amount of bytes
# the palette can only be 2<<n in size
actualTargetSizeDiff = (2<<colorTableSize) - len(paletteBytes)//3
if actualTargetSizeDiff > 0:
paletteBytes += o8(0) * 3 * actualTargetSizeDiff
# global color palette
s.append(paletteBytes)
return s
def getdata(im, offset = (0, 0), **params):
"""Return a list of strings representing this image.