Merge d820fde70a into 63a5717bc7

See previous the commit description for more details about the floating
points operations.

The hwb test cases in `css-color-functions` are now rendered identically
to what firefox does (I haven't checked the others tests, but they
aren't affected by this commit).

Libraries/LibGfx/Color.h

@@ -400,7 +400,8 @@ public:
 
     constexpr Color with_opacity(float opacity) const
     {
-        return with_alpha(alpha() * opacity);
+        VERIFY(opacity >= 0 && opacity <= 1);
+        return with_alpha(static_cast<u8>(round(alpha() * opacity)));
     }
 
     constexpr Color darkened(float amount = 0.5f) const
@@ -549,9 +550,9 @@ public:
             break;
         }
 
-        u8 out_r = (u8)(r * 255);
-        u8 out_g = (u8)(g * 255);
-        u8 out_b = (u8)(b * 255);
+        auto out_r = static_cast<u8>(round(r * 255));
+        auto out_g = static_cast<u8>(round(g * 255));
+        auto out_b = static_cast<u8>(round(b * 255));
         return Color(out_r, out_g, out_b);
     }
 

Libraries/LibWeb/CSS/StyleValues/CSSColorValue.cpp

@@ -45,7 +45,7 @@ ValueComparingNonnullRefPtr<CSSColorValue> CSSColorValue::create_from_color(Colo
     return make_rgb_color(color);
 }
 
-Optional<float> CSSColorValue::resolve_hue(CSSStyleValue const& style_value)
+Optional<double> CSSColorValue::resolve_hue(CSSStyleValue const& style_value)
 {
     // <number> | <angle> | none
     auto normalized = [](double number) {
@@ -67,11 +67,11 @@ Optional<float> CSSColorValue::resolve_hue(CSSStyleValue const& style_value)
     return {};
 }
 
-Optional<float> CSSColorValue::resolve_with_reference_value(CSSStyleValue const& style_value, float one_hundred_percent_value)
+Optional<double> CSSColorValue::resolve_with_reference_value(CSSStyleValue const& style_value, float one_hundred_percent_value)
 {
     // <percentage> | <number> | none
     auto normalize_percentage = [one_hundred_percent_value](Percentage const& percentage) {
-        return static_cast<float>(percentage.as_fraction()) * one_hundred_percent_value;
+        return percentage.as_fraction() * one_hundred_percent_value;
     };
 
     if (style_value.is_percentage())
@@ -94,7 +94,7 @@ Optional<float> CSSColorValue::resolve_with_reference_value(CSSStyleValue const&
     return {};
 }
 
-Optional<float> CSSColorValue::resolve_alpha(CSSStyleValue const& style_value)
+Optional<double> CSSColorValue::resolve_alpha(CSSStyleValue const& style_value)
 {
     // <number> | <percentage> | none
     auto normalized = [](double number) {

Libraries/LibWeb/CSS/StyleValues/CSSColorValue.h

@@ -48,9 +48,9 @@ protected:
     {
     }
 
-    static Optional<float> resolve_hue(CSSStyleValue const&);
-    static Optional<float> resolve_with_reference_value(CSSStyleValue const&, float one_hundred_percent_value);
-    static Optional<float> resolve_alpha(CSSStyleValue const&);
+    static Optional<double> resolve_hue(CSSStyleValue const&);
+    static Optional<double> resolve_with_reference_value(CSSStyleValue const&, float one_hundred_percent_value);
+    static Optional<double> resolve_alpha(CSSStyleValue const&);
 
 private:
     ColorType m_color_type;

Libraries/LibWeb/CSS/StyleValues/CSSHWB.cpp

@@ -25,8 +25,8 @@ Color CSSHWB::to_color(Optional<Layout::NodeWithStyle const&>) const
         return Color(gray, gray, gray, to_byte(alpha_val));
     }
 
-    float value = 1 - b_val;
-    float saturation = 1 - (w_val / value);
+    auto value = 1 - b_val;
+    auto saturation = 1 - (w_val / value);
     return Color::from_hsv(h_val, saturation, value).with_opacity(alpha_val);
 }
 

Tests/LibGfx/TestColor.cpp

@@ -21,3 +21,10 @@ TEST_CASE(all_green)
     EXPECT_EQ(Color(Color::NamedColor::Green), Color::from_xyz50(0.385152, 0.716887, 0.097081));
     EXPECT_EQ(Color(Color::NamedColor::Green), Color::from_xyz65(0.357584, 0.715169, 0.119195));
 }
+
+TEST_CASE(hsv)
+{
+    EXPECT_EQ(Color(51, 179, 51), Color::from_hsv(120, 0.714285714, .7));
+    EXPECT_EQ(Color(51, 179, 51, 128), Color::from_hsv(120, 0.714285714, .7).with_opacity(0.5));
+    EXPECT_EQ(Color(87, 128, 77), Color::from_hsv(108, 0.4, .5));
+}

Tests/LibWeb/Ref/expected/wpt-import/css/css-color/hwb-004-ref.html

@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Color 4: CSS Color 4: hwb</title>
+<style>
+    .test { background-color: rgb(20% 70% 20%); width: 12em; height: 12em; } /* hwb(120 20% 30%) converted to sRGB */
+</style>
+<body>
+    <p>Test passes if you see a single square, and not two rectangles of different colors.</p>
+    <div class="test"></div>
+</body>

Tests/LibWeb/Ref/input/wpt-import/css/css-color/hwb-004.html

@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Color 4: hwb</title>
+<link rel="author" title="Sam Weinig" href="mailto:weinig@apple.com">
+<link rel="help" href="https://drafts.csswg.org/css-color-4/#the-hwb-notation">
+<link rel="match" href="../../../../expected/wpt-import/css/css-color/hwb-004-ref.html">
+<meta name="assert" content="hwb with no alpha">
+<style>
+    .test { background-color: red; width: 12em; height: 6em; margin-top: 0; }
+    .ref { background-color: rgb(20% 70% 20%); width: 12em; height: 6em; margin-bottom: 0; } /* hwb(120 20% 30%) converted to sRGB */
+    .test { background-color: hwb(120 20% 30%); }
+</style>
+<body>
+    <p>Test passes if you see a single square, and not two rectangles of different colors.</p>
+    <div class="ref"></div>
+    <div class="test"></div>
+</body>