[cairo] Linear colorspace not a good idea
mike at easysw.com
Tue Mar 14 03:29:36 PST 2006
Bill Spitzak wrote:
> Although I wrote a lot of arguments in favor of using linear space (see
> http://mysite.verizon.net/spitzak/conversion/index.html), there are
> serious problems with using this for GUI. I think Cairo has to do all
> compositing in the device space (ie sRGB for most of the devices we are
> interested in, but allow the backend to decide).
> First is that there is a huge supply of icons that have been designed to
> be composited in sRGB space and will have bad edges otherwise when put
> atop the background they are designed for.
Images either have an implied profile or an embedded profile, and that
profile must be used in order to get the proper output.
Apple's Quartz2D manages multiple colorspaces - this does introduce
some complexity and it is sometimes confusing for developers when
they draw RGB=255,0,0 and get a slightly different color on the
screen, but ultimately it results in consistent output that is
properly matched to the screen/surface you are drawing to. IMHO,
*that* is the model Cairo needs to adopt - surfaces with attached
profiles which define the mapping from a linear RGB colorspace to/from
Michael Sweet, Easy Software Products mike at easysw dot com
Internet Printing and Publishing Software http://www.easysw.com
More information about the cairo