test for transparency as follows. if result is 1, then totally opaque, if result is 0, then totally transparent. Thus any result less than 1 has some transparency.
transparency=`convert yourimage -resize 1x1 -alpha on -channel o -format "%[fx:u.a]" info:` examples: convert -size 100x100 xc:black -resize 1x1 -alpha on -channel o -format "%[fx:u.a]" info: 1 convert -size 100x100 xc:none -resize 1x1 -alpha on -channel o -format "%[fx:u.a]" info: 0 convert -size 100x100 gradient: -alpha copy -resize 1x1 -alpha on -channel o -format "%[fx:u.a]" info: 0.499992 _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
