GraphicsMagick

I'm converting an application from IM to GM, and I was using
-draw "image dst-over ...
to draw something 'under' another png with sertain sections transparant, but GM throws this error:
Non-conforming drawing primitive definition (image)

I checked the available compose operators:
http://www.graphicsmagick.org/GraphicsMagick.html#details-compose
but I don't think GM has the operator I need,
(even worse: whichever operator I test it doesn't seem to do anything different... Xor and subtract should at least have something visible where the first-loaded png is not translucent?)

Re: [GM-help] compose operator 'dst-over' From: Bob Friesenhahn <bfriesen@si...> - 2009-05-29 16:07 On Fri, 29 May 2009, Stijn Sanders wrote: > I'm converting an application from IM to GM, and I was using -draw > "image dst-over ... to draw something 'under' another png with > sertain sections transparant, but GM throws this error: > Non-conforming drawing primitive definition (image) I think that the underlying algorithm is similar to GM's 'Over' composite operation. However, ImageMagick is swapping the pixel roles for DstOver as if the two images were interchanged. > I checked the available compose operators: > http://www.graphicsmagick.org/GraphicsMagick.html#details-compose > but I don't think GM has the operator I need, (even worse: whichever > operator I test it doesn't seem to do anything different... Xor and > subtract should at least have something visible where the > first-loaded png is not translucent?) I think that 'gm composite' will offer more control. The -draw operator is an additive environment which always has a backing canvas and composition is on top of whatever is already drawn on that canvas. When transitioning from ImageMagick to GraphicsMagick, it does not help with understanding that ImageMagick renamed all of its composite operators since the fork. Bob -- Bob Friesenhahn bfriesen@..., http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/

Re: [GM-help] compose operator 'dst-over' From: Stijn Sanders <SandersS@sp...> - 2009-06-02 06:57 > I think that the underlying algorithm is similar to GM's > 'Over' composite operation. However, ImageMagick is > swapping the pixel roles for DstOver as if the two > images were interchanged. I've tried "DstOver", but gives me: "Non-conforming drawing primitive definition (image)" It's also not listed with the "-compose" operators... (It's indeed missing from CompositeOperator in http://cvs.graphicsmagick.org/cgi-bin/cvsweb.cgi/GraphicsMagick/magick/image.h?rev=1.662;content-type=text/x-cvsweb-markup ) > I think that 'gm composite' will offer more control. The > -draw operator is an additive environment which always has a > backing canvas and composition is on top of whatever is > already drawn on that canvas. I could look into converting to a "composite" call, but it would take some time, and I'll probably end up with 'double code' since I guess the 'dst-over' templates will need their arguments in a different order than the normal 'over' ones... That's a lot of code-impact for something that was 'switchable' by selecting a different operator before... Also, I find it very worrysome that whichever 'draw image' operator I selected I got the same result... (Looking at http://cvs.graphicsmagick.org/cgi-bin/cvsweb.cgi/GraphicsMagick/magick/draw.c line 2730, the CompositeImage call is indeed not getting it's operator from draw_info...)

Re: [GM-help] compose operator 'dst-over' From: Bob Friesenhahn <bfriesen@si...> - 2009-06-02 16:11 On Tue, 2 Jun 2009, Stijn Sanders wrote: > > I've tried "DstOver", but gives me: > "Non-conforming drawing primitive definition (image)" > It's also not listed with the "-compose" operators... > > (It's indeed missing from CompositeOperator in > http://cvs.graphicsmagick.org/cgi-bin/cvsweb.cgi/GraphicsMagick/magick/image.h?rev=1.662;content-type=text/x-cvsweb-markup > ) Right. It is currently not supported. > Also, I find it very worrysome that whichever 'draw image' operator > I selected I got the same result... (Looking at > http://cvs.graphicsmagick.org/cgi-bin/cvsweb.cgi/GraphicsMagick/magick/draw.c > line 2730, the CompositeImage call is indeed not getting it's > operator from draw_info...) It seems that cvsweb is confused because of a strange change date (2012) in changes made by by Cristy many years ago, and because draw.c and render.c got swapped at some time in GM's history. This link brings up the current version of draw.c, which is not used to support -draw at all: http://cvs.graphicsmagick.org/cgi-bin/cvsweb.cgi/GraphicsMagick/magick/draw.c?rev=1.623;content-type=text%2Fx-cvsweb-markup The code actually used is part of magick/render.c: http://cvs.graphicsmagick.org/cgi-bin/cvsweb.cgi/GraphicsMagick/magick/render.c?rev=1.179;content-type=text%2Fx-cvsweb-markup the key dispatch code is under "case ImagePrimitive" which shows that DrawAffineImage() is used to do the composition, which ultimately always does the equivalent of "Over" composition regardless of which composition operator was specified. In summary, using -draw is not going to get you anywhere fast, even if I add "DstOver" support to CompositeImage() since -draw is not using the same code as the 'composite' command does. Bob -- Bob Friesenhahn bfriesen@..., http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/

Re: [GM-help] compose operator 'dst-over' From: Bob Friesenhahn <bfriesen@si...> - 2009-06-02 18:27 To clarify, I do indend to implement DstOver composition and properly support the composite operator specified by -draw 'image ...' but the implementation will take time and not start immediately so it may be best to seek an alternative (e.g. investigate 'gm composite') at this time. Bob -- Bob Friesenhahn bfriesen@..., http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/

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