On Friday, July 9, 2010, 4:43:53 PM, Jeremias wrote:

JM> Hi Chris

JM> On 07.07.2010 17:43:31 Chris Lilley wrote:

>> JM> Adding support for the remaining methods from SVG Color 1.2 won't be all
>> JM> that hard. There's cielch() that requires a formula to convert the
>> JM> values to CIE Lab. 

>> Yes. That's pretty trivial, L is the same and c,h are the polar form of a,b.

JM> Right, I've seen that formula somewhere. Should be easy. Some cos() &
JM> sin() something.

a = C cos(H)
b = C sin(H)

H is in degrees, by the way and normalised to 0 <= H < 360

and for the other way

C = sqrt(a*a + b*b)
H = atan2 (b, a)

because a can be zero.

>> JM> And finally, the device-specific colors which also
>> JM> be fairly easy with a little additional work in XML Graphics Commons.

>> They are easy to parse, but device-specific colours introduce a
>> complication in that they are just a recipe for an output device, not a
>> colour. So they can't be easily combined with other colours (e.g. used
>> in a gradient, combined using opacity, etc). The sRGB fallback colour
>> needs to be retained, used if  a device-specific colour is mixed with
>> another colour.

JM> I have that mapped already.  I just hope XSL-FO 2.0 will do that the same
JM> way. http://wiki.apache.org/xmlgraphics/ColorHandling

I was just reading that page today.

Yes, the intention is that XSL FO and SVG do colour management the same way 
(and CSS too, when it gets around to it). SVG WG and the FO subgroup of XSL WG 
coordinate to ensure that this happens.

-- 
 Chris Lilley                    mailto:[email protected]
 Technical Director, Interaction Domain
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG


---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to