possible bug -alpha shape IM 7
Posted: 2018-06-19T10:29:13-07:00
There is a difference in how -alpha shape works between IM 6 and IM 7, but no difference for -alpha copy. In -alpha shape for IM 7, you need to add -negate. I know that IM 7 alpha channels are opposite polarity from IM 6. But I do not think this should be this way as a matter of consistency.
Examples from http://www.imagemagick.org/Usage/masking/#alpha_copy and http://www.imagemagick.org/Usage/masking/#alpha_shape
-alpha copy:
-alpha shape:
Examples from http://www.imagemagick.org/Usage/masking/#alpha_copy and http://www.imagemagick.org/Usage/masking/#alpha_shape
-alpha copy:
Code: Select all
convert alpha_extract.png -alpha copy alpha_copy6.pngCode: Select all
magick alpha_extract.png -alpha copy alpha_copy7.png-alpha shape:
Code: Select all
convert alpha_extract.png -background red -alpha shape alpha_shape6.pngCode: Select all
magick alpha_extract.png -background red -alpha shape alpha_shape7a.pngCode: Select all
magick alpha_extract.png -background red -negate -alpha shape alpha_shape7b.png