Composite - image watermark to convert

[vyoralek]

Please what is convert equal for this:

Code: Select all

composite -dissolve 15 watermark.png input.jpg output.jpg

I try this:

Code: Select all

convert input.jpg watermark.png -compose dissolve -define compose:args=15 -composite output.jpg

but output image not same - not contain watermark image

[vyoralek]

My problem may be caused by version... on my hosting is version 6.2.8

[anthony]

That should work as expected.

Okay the define option for convert was added in IM v6.5.3-4 so your IM is too old to specify compose arguments.

however you can still do it by doing the dissolve yourself.

Code: Select all

   convert input.jpg \
   \( watermark.png -matte -channel A -evaluate multiply 0.15 +channel \) \
               -composite  output.jpg

This multiplies the alpha channel of the overlay by 15% (make it mostly transparent) and then does a normal overlay.

Note a later version of IM would use -alpha set instead of -matte