Bug 75129 – CIFilter version of Sepia Tone filter doesn't match software

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Chris Marrin]

The formula used to compute sepia in the CIFilter is very different from that in the CSS filters spec, so it needs to change to use a Color Matrix filter to get the formula right.

[Radar WebKit Bug Importer]

<rdar://problem/10621337>

[Chris Marrin]

Created attachment 121930 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 121930 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=121930&action=review

> Source/WebCore/platform/graphics/ca/mac/PlatformCALayerMac.mm:706
> +static double interp(double from, double to, double t)
> +{
> +    return from * (1 - t) + to * t;
> +}

This is what WebCore::blend() is for.

> Source/WebCore/platform/graphics/ca/mac/PlatformCALayerMac.mm:761
> +            if (t < 0)
> +                t = 0;
> +            else if (t > 1)
> +                t = 1;

Use std::min/max?

> Source/WebCore/platform/graphics/ca/mac/PlatformCALayerMac.mm:765
> +            [caFilter setValue:[CIVector vectorWithX:interp(1, 0.393, t) Y:interp(0, 0.769, t) Z:interp(0, 0.189, t) W:0] forKey:@"inputRVector"];
> +            [caFilter setValue:[CIVector vectorWithX:interp(0, 0.349, t) Y:interp(1, 0.686, t) Z:interp(0, 0.168, t) W:0] forKey:@"inputGVector"];
> +            [caFilter setValue:[CIVector vectorWithX:interp(0, 0.272, t) Y:interp(0, 0.534, t) Z:interp(1, 0.131, t) W:0] forKey:@"inputBVector"];

Is there a canonical reference for those numeric values?

> LayoutTests/ChangeLog:8
> +        Updated hw sepia tone results to match changes. Updated sw results because

hw -> hardware, or more specifically "Core Image filter on Core Animation layer"

[Chris Marrin]

Committed r104652: <http://trac.webkit.org/changeset/104652>