Legacy ImageMagick Discussions Archive

related to http://www.imagemagick.org/discourse-server/viewtopic.php?f=2&t=21646

Since HCL colorspace is wider than RGB, we should choose a saturation strategy when converting into RGB colorspace. Existing code simply clamps into [0, 1], not so bad.
But it's more useful if hue and luma are ...

ConvertRGBToHCL()/ConvertHCLToRGB() doesn't work correctly!

I myself tried to replace the composite code with HCL version, then referring gem.c to copy & paste, and found it.
Here is a patch for branches/ImageMagick-6. I've not checked trunk yet.

--- a/magick/gem.c
+++ b/magick/gem.c
@@ -142,5 ...

branches/ImageMagick-6

Recently added HCL support routines, ConverRGBToHCL() and ConvertHCLToRGB() in gem.c, will be fixed by a patch I posted with http://www.imagemagick.org/discourse-server/viewtopic.php?f=2&t=21646 .
It fixes:

RGB -> HCL: Wrong hue will be returned if g < b < r.
HCL -> RGB ...

I got branches/ImageMagick-6 @ r8922-r8923, working well. Thank you, but...

It's hard for me to say,
now I know that it's better to use HCL from the point of view of Photoshop compatibility.
As of yesterday, I never believed ImageMagick supported HCL...

I sat down and explored the Subversion ...

I want HueHSL/SaturationHSL/ColorizeHSL/LuminizeHSL composite operators. Are there any answers or suggestions?

I utilize ImageMagick to process a lot of PSD files created by various tools, mostly Adobe Photoshop series.
Adobe Photoshop has non-RGB-based (nor CMY-based) blending modes i.e. hue ...