- From: Chris Lilley <chris@w3.org>
- Date: Tue, 15 Oct 2013 00:38:07 +0200
- To: Michael Mullany <michael@sencha.com>
- CC: Rik Cabanier <cabanier@gmail.com>, "public-fx@w3.org" <public-fx@w3.org>
Hello Michael, Monday, October 14, 2013, 11:35:34 PM, you wrote: > How much more math would that introduce? Very little. As you note, just converting to a polar colourspace and doing the computations there is an appropriate way to manipulate hue and chroma/saturation. > If it is a lot, can it be > implemented in hardware on limited devices? Multiplies and adds are not a lot. Especially for CSS where the one calculation gives the result; its not like raster images where the same calculation is done for each pixel (so thousands or millions of times). >> Are you aware of any user complaints (apart from yourself :-)) > Only 2 so far, but I can blog about this and see how many people think it's a big deal. > http://stackoverflow.com/questions/19187905/why-doesnt-hue-rotation-by-180deg-and-180deg-yield-the-original-color As that thread notes, using unsaturated pastel colours gives the expected result; and not clamping to a 0..1 (0..255) range also gives the expected result. Filters uses early clamping, each stage clamps. As a result, four hue angle rotates of 90 degrees on yellow gives you, well, dark brown. This is not exactly a subtle difference, and might be expected to trigger 'user complaints'. > https://code.google.com/p/chromium/issues/detail?id=237524 -- Best regards, Chris mailto:chris@w3.org
Received on Monday, 14 October 2013 22:38:11 UTC