Legacy ImageMagick Discussions Archive

I need to compose three images together.
The problem is image b_4_0.png is opaque and has transparency (semi-transparent). The black pixels should not be there.

Code: Select all

magick -size 300x300 canvas:transparent \
  img/a_4_0.png -geometry +114+55 -compose over -composite \
  img/b_4_0.png -geometry +109+75 -compose screen -composite \
  img/c_4_0.png -geometry +118+119 -compose over -composite \
  result.png

Result:

What it should look like:

Code: Select all

magick identify -format '%[opaque]' img/a_4_0.png # false
magick identify -format '%[opaque]' img/b_4_0.png # true
magick identify -format '%[opaque]' img/c_4_0.png # false

The image b_4_0.png is opaque, sure it has to do something with this or the min max mean values

Images: img.zip

"screen" affect alpha in the same was as "over" affects alpha: where a source pixel is opaque, the result is opaque.

If you don't want this, your can extract the alpha to mpr, then "CopyOpacity" after the "screen".

can you give me an example

Code: Select all

magick -size 300x300 canvas:transparent \
  a_4_0.png -geometry +114+55 -compose over -composite \
  \( +clone -alpha extract +write mpr:ALP +delete \) \
  b_4_0.png -geometry +109+75 -compose screen -composite \
  mpr:ALP -alpha off -geometry +0+0 -compose CopyOpacity -composite \
  c_4_0.png -geometry +118+119 -compose over -composite \
  result.png

Legacy ImageMagick Discussions Archive

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