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Composite - image watermark to convert

Posted: 2010-12-14T05:36:09-07:00
by vyoralek
Please what is convert equal for this:

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composite -dissolve 15 watermark.png input.jpg output.jpg
I try this:

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convert input.jpg watermark.png -compose dissolve -define compose:args=15 -composite output.jpg
but output image not same - not contain watermark image :(

Re: Composite - image watermark to convert

Posted: 2010-12-14T06:35:58-07:00
by vyoralek
My problem may be caused by version... on my hosting is version 6.2.8 :(

Re: Composite - image watermark to convert

Posted: 2010-12-14T18:57:40-07:00
by 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.

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   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