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[Solved] Recent Change Queery
Posted: 2012-10-17T13:01:41-07:00
by Alan Hadley
Has anything changed in the Magick Core API that could affect DrawGradientImage() and SparseColorImage(). I had them working a while ago but now they both produce complex fractal like patterns? I tried drawing a gradient on the command line and it worked OK with my version of IM, so it is probably some sort of settings change.
Alan
Re: Recent Change Queery
Posted: 2012-10-17T15:05:18-07:00
by fmw42
see
viewtopic.php?f=4&t=21269
RGB is now sRGB and sRGB is now RGB. Also grayscale images (including some gradients) are linear and not non-linear as they used to be.
Grayscale values and gradients can be either linear or non-linear depending upon how the gray is defined. Named shades of gray and black and white are non-linear, gray(...) is linear.
see also
http://www.imagemagick.org/Usage/color_ ... #grayscale
Re: [Solved] Recent Change Queery
Posted: 2012-10-18T23:09:04-07:00
by Alan Hadley
It was my mistake, some assembly language that converts to 8bits per channel and premultiplies by alpha for display on windows had a bug. I was extracting bytes 0,2,4 and 6 when I should have taken bytes 1,3,5 and 7. This has no effect when an 8 bits per channel picture is converted to 16 bits, but after processing the lsb and msb of each channel will usually be different.
Sorry to have wasted your time.
Alan