- From: Thomas DeWeese <Thomas.DeWeese@Kodak.com>
- Date: Sun, 28 Nov 2004 20:56:40 -0500
- To: Bert Bos <bert@w3.org>
- CC: www-svg@w3.org
Hi Bert, Bert Bos wrote: > c) The 'rendering-color-space' property appears to be redundant with > CSS3 Color's 'color-profile' property. I think the two are in fact quite different. The 'color-profile' property (which has been in SVG since 1.0) at least in SVG, is used to provide a color space for a raster image (it isn't as clear what it's intent is in CSS 3 although the description appears to talk about images quite a bit). This means that the code values are interpreted "as is" in the provided color space. The rendering-color-space property indicates what color space the compositing should take place in. The content is color converted to the compositing color space before compositing occurs and assuming a higher level element has a different rendering color space the result is color converted after all the compositing is completed. Put another way color-profile is used to achieve either color effects or to 'fix' broken image content. rendering-color-space is used to control compositing to ensure that clipping or other effects (linear vs gamma corrected) don't degrade image quality. To take a concrete example if you used a simple BGR ICC profile and applied it to an image with color-profile your red and blue channels would appear swapped in the final image. If you used the same profile to set the rendering-color-space for the document (or the group containing the image) there should be no visible difference. I will note that this analysis is complicated by the fact that the definition of color-profile in CSS 3 is not very clear, in particular it's not clear if this only applies to referenced raster content or any element/subtree[1]. So most of this is based on the definition of color-profile property in SVG - which may not be 100% accurate, although hopefully it is (otherwise CSS 3 has a conflict with SVG 1.0). [1] Even if it applies to any element as long as it retains it's "set the color space" behavior I think it is quite different. Although I would really have to wonder about it's value in this case.
Received on Monday, 29 November 2004 01:56:43 UTC