rgb() colors that use none should use hex syntax for serialization in…

… canvas

https://bugs.webkit.org/show_bug.cgi?id=278392

Reviewed by Darin Adler.

When using HTML serialization (such as in canvas code), `rgb(none none none)`
should serialize as `#000000`, not `rgb(0, 0, 0)` as it currently does.

This is more consistent and matches other browsers.

* LayoutTests/fast/canvas/canvas-color-serialization.html:
* LayoutTests/fast/canvas/canvas-color-serialization-expected.txt:
    - Add serialization tests. Additional will be added in WPT
      via web-platform-tests/wpt#47148.

* Source/WebCore/platform/graphics/ColorSerialization.cpp:
(WebCore::serializationForHTML):
    - Make sure to call through to the HTML serializer for legacy
      rgb() colors that have none (which is indicated by the use
      of SRGBA<float> without the "useColorFunctionSerialization"
      bit set).

Canonical link: https://commits.webkit.org/283120@main

LayoutTests/fast/canvas/canvas-color-serialization-expected.txt

@@ -135,6 +135,12 @@ PASS trySettingShadowColor('logical') is '#666666'
 PASS trySettingStrokeStyle('visual') is '#666666'
 PASS trySettingFillStyle('visual') is '#666666'
 PASS trySettingShadowColor('visual') is '#666666'
+PASS trySettingStrokeStyle('rgb(none none none)') is '#000000'
+PASS trySettingFillStyle('rgb(none none none)') is '#000000'
+PASS trySettingShadowColor('rgb(none none none)') is '#000000'
+PASS trySettingStrokeStyle('rgb(300 none 400)') is '#ff00ff'
+PASS trySettingFillStyle('rgb(300 none 400)') is '#ff00ff'
+PASS trySettingShadowColor('rgb(300 none 400)') is '#ff00ff'
 PASS trySettingStrokeColorWithSetter('transparent') is 'rgba(0, 0, 0, 0)'
 PASS trySettingFillColorWithSetter('transparent') is 'rgba(0, 0, 0, 0)'
 PASS trySettingShadowWithSetter('transparent') is 'rgba(0, 0, 0, 0)'
@@ -162,6 +168,12 @@ PASS trySettingShadowWithSetter('RgB(1,2,3)') is '#010203'
 PASS trySettingStrokeColorWithSetter('rGbA(1,2,3,0)') is 'rgba(1, 2, 3, 0)'
 PASS trySettingFillColorWithSetter('rGbA(1,2,3,0)') is 'rgba(1, 2, 3, 0)'
 PASS trySettingShadowWithSetter('rGbA(1,2,3,0)') is 'rgba(1, 2, 3, 0)'
+PASS trySettingStrokeColorWithSetter('rgb(none none none)') is '#000000'
+PASS trySettingFillColorWithSetter('rgb(none none none)') is '#000000'
+PASS trySettingShadowWithSetter('rgb(none none none)') is '#000000'
+PASS trySettingStrokeColorWithSetter('rgb(300 none 400)') is '#ff00ff'
+PASS trySettingFillColorWithSetter('rgb(300 none 400)') is '#ff00ff'
+PASS trySettingShadowWithSetter('rgb(300 none 400)') is '#ff00ff'
 PASS tryClearShadowAfterSettingColor('red') is 'rgba(0, 0, 0, 0)'
 PASS tryClearShadowAfterSettingColor('rgba(0, 5, 10, 0.4)') is 'rgba(0, 0, 0, 0)'
 PASS successfullyParsed is true

LayoutTests/fast/canvas/canvas-color-serialization.html

@@ -214,6 +214,8 @@
 trySettingColor("'content'", "'#666666'");
 trySettingColor("'logical'", "'#666666'");
 trySettingColor("'visual'", "'#666666'");
+trySettingColor("'rgb(none none none)'", "'#000000'");
+trySettingColor("'rgb(300 none 400)'", "'#ff00ff'");
 
 trySettingColorWithSetter("'transparent'", "'rgba(0, 0, 0, 0)'");
 trySettingColorWithSetter("'red'", "'#ff0000'");
@@ -224,6 +226,8 @@
 trySettingColorWithSetter("'rgba(1,2,3,0.4)'", "'rgba(1, 2, 3, 0.4)'");
 trySettingColorWithSetter("'RgB(1,2,3)'", "'#010203'");
 trySettingColorWithSetter("'rGbA(1,2,3,0)'", "'rgba(1, 2, 3, 0)'");
+trySettingColorWithSetter("'rgb(none none none)'", "'#000000'");
+trySettingColorWithSetter("'rgb(300 none 400)'", "'#ff00ff'");
 
 shouldBe("tryClearShadowAfterSettingColor('red')", "'rgba(0, 0, 0, 0)'");
 shouldBe("tryClearShadowAfterSettingColor('rgba(0, 5, 10, 0.4)')", "'rgba(0, 0, 0, 0)'");

Source/WebCore/platform/graphics/ColorSerialization.cpp

@@ -553,7 +553,10 @@ String serializationForCSS(const SRGBA<float>& color, bool useColorFunctionSeria
 
 String serializationForHTML(const SRGBA<float>& color, bool useColorFunctionSerialization)
 {
-    return serializationForCSS(color, useColorFunctionSerialization);
+    if (useColorFunctionSerialization)
+        return serializationUsingColorFunction(color);
+
+    return serializationForHTML(convertColor<SRGBA<uint8_t>>(color), false);
 }
 
 String serializationForRenderTreeAsText(const SRGBA<float>& color, bool useColorFunctionSerialization)