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src/img2pdf.py: work around PIL not reporting a colorspace for 16bit grayscale PNGs

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Johannes 'josch' Schauer 2018-08-17 12:57:46 +02:00
parent ccca845606
commit c0ed810036
Signed by: josch
GPG key ID: F2CBA5C78FBD83E1
1 changed files with 10 additions and 1 deletions
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src/img2pdf.py
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@ -688,7 +688,16 @@ def get_imgmetadata(imgdata, imgformat, default_dpi, colorspace, rawdata=None):
if c.name == ics:
color = c
if color is None:
color = Colorspace.other
# PIL does not provide the information about the original
# colorspace for 16bit grayscale PNG images. Thus, we retrieve
# that info manually by looking at byte 10 in the IHDR chunk. We
# know where to find that in the file because the IHDR chunk must
# be the first chunk
if rawdata is not None and imgformat == ImageFormat.PNG \
and rawdata[25] == 0:
color = Colorspace.L
else:
raise ValueError("unknown colorspace")
if color == Colorspace.CMYK and imgformat == ImageFormat.JPEG:
# Adobe inverts CMYK JPEGs for some reason, and others
# have followed suit as well. Some software assumes the