On 25 February 2012 17:02, Alexandre Prokoudine <[email protected]> wrote: > On Sat, Feb 25, 2012 at 2:19 AM, Andrew Chadwick wrote: >> The OpenRaster spec currently states (working from memory here) that >> ORA files may use uses the SVG compositing ops[1]. These do not >> provide colorize layer modes, nor modes for luminosity-setting, >> hue-setting or saturation-setting. > > I've just asked in w3s svg mailing list, and Rik Cabanier replied: > > "I'm working on a new CSS composting spec that will add those missing > blend modes. > There will be a new CSS keyword 'blending' that will let you specify a > blend mode on an HTML or SVG element."
Interesting, thank you. I'll keep an eye on that[1]. Looking at the fact that other open source image editors don't seem to have implemented what appears to me to be a fairly conceptually obvious transformation (take a perceptually-relevant luma of one pixel in the target combined layer and the hue and value of the corresponding pixel in the layer above it and combine them to make a new pixel RGB value) but instead seem to just use simpler and less perceptually-relevant H¹ + S²V² combinations in ordinary HSV space, I'm wondering if there's some patent-related reason for not doing so. Case in point from my recent minitrawl for PDF patents: US patent 6421460[2] seems especially dangerous (though TBH that seems to forbid almost all possible ways of combining layers using alpha and some combining function in a graphics program, and *many* implementations surely exist). I don't want to make a system which cannot be sold and used in the US. Entertainingly we could use the PDF method directly if MyPaint also wrote PDF files thanks to a general but highly limited patent grant of Adobe's[3]. Is there any reason why GIMP and Krita aren't (by quick experimentation and/or code analysis) using this? [1] http://lists.w3.org/Archives/Public/www-svg/2012Feb/0092.html [2] http://www.google.com/patents/US6421460 - "Blending colors in the presence of transparency" [3] http://partners.adobe.com/public/developer/support/topic_legal_notices.html - making PDFs only -- Andrew Chadwick _______________________________________________ CREATE mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/create
