On Tue, Feb 5, 2013 at 11:27 PM, Alan Gresley <alan@css-class.com> wrote: > On 5/02/2013 3:52 PM, Brad Kemper wrote: > > Wrong and correction. A pre-multiplied gradient of yellow to >>> transparent to blue compiste of a whitye background is identical to >>> a gradient of yellow to white to blue (fully opaque). >>> >>> What do you want to achieve with a gradient that has alpha >>> transparency and have you tested any of this by observing the >>> difference between pre-multiplied colorspace and non pre-multiplied >>> colorspace? >>> >> >> As I recall, last time I had a problem with the way Safari does >> gradients, it was a solid color to transparent, and the stuff >> underneath it was variable, some white, some other colors. I just >> wanted the color to fade to transparent over the varied background, >> but instead it looked dirtier as it faded out. >> > > Was this for a gradient with two color stops or three color stops? For a > gradient with two color stops, you can avoid the dirtier composite color > (really just less lighter ~ HSL) by going to it transparent counterpart. > Like red to transparent-red or yellow to transparent-yellow. For a gradient > with two color stops (transparent at one end), a non pre-multiplied > gradient going back to it transparent-color is the same as a pre-multiplied > gradient going to transparent (the keyword does not have a special meaning). > > BTW, the way Safari does gradients is the way that Firefox does gradients > prefixed and now un-prefixed (since FF16). The gradients are done in non > pre-multiplied colorspace. The spec says they should be premultiplied so Opera and IE have implemented it that way. I'm unsure what we can do next. I have not seen anyone offer to update the spec text...
Received on Tuesday, 5 February 2013 20:54:31 UTC