src/img2pdf.py: expand error message about alpha channel

This commit is contained in:
Johannes 'josch' Schauer 2018-03-27 10:39:24 +02:00
parent 920506b867
commit ade5768d72
Signed by untrusted user: josch
GPG key ID: F2CBA5C78FBD83E1

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@ -638,7 +638,12 @@ def get_imgmetadata(imgdata, imgformat, default_dpi, colorspace, rawdata=None):
ics = imgdata.mode
if ics in ["LA", "PA", "RGBA"]:
raise Exception("Image contains transparency which cannot be retained in PDF")
logging.warn("Image contains transparency which cannot be retained in PDF.")
logging.warn("img2pdf will not perform a lossy operation.")
logging.warn("You can remove the alpha channel using imagemagick:")
logging.warn(" $ convert input.png -background white -alpha remove -alpha off output.png")
raise Exception("Refusing to work on images with alpha channel")
# Since commit 07a96209597c5e8dfe785c757d7051ce67a980fb or release 4.1.0
# Pillow retrieves the DPI from EXIF if it cannot find the DPI in the JPEG