Proper support for multiple text decorations.

Source/core/rendering/InlineTextBox.cpp

Index: Source/core/rendering/InlineTextBox.cpp
diff --git a/Source/core/rendering/InlineTextBox.cpp b/Source/core/rendering/InlineTextBox.cpp
index dcb093c0379302ef922e0d75d88c12ff06442363..02e4ffa0cfd53df1c6f0c46dcf5eb6e784de9b09 100644
--- a/Source/core/rendering/InlineTextBox.cpp
+++ b/Source/core/rendering/InlineTextBox.cpp
@@ -42,6 +42,7 @@
 #include "core/rendering/RenderRubyRun.h"
 #include "core/rendering/RenderRubyText.h"
 #include "core/rendering/RenderTheme.h"
+#include "core/rendering/style/AppliedTextDecorationList.h"
 #include "core/rendering/style/ShadowList.h"
 #include "core/rendering/svg/SVGTextRunRenderingContext.h"
 #include "platform/fonts/FontCache.h"
@@ -751,12 +752,11 @@ void InlineTextBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset,
     }
 
     // Paint decorations
-    TextDecoration textDecorations = styleToUse->textDecorationsInEffect();
-    if (textDecorations != TextDecorationNone && paintInfo.phase != PaintPhaseSelection) {
+    if (styleToUse->hasAppliedTextDecorations() && paintInfo.phase != PaintPhaseSelection) {
         updateGraphicsContext(context, textFillColor, textStrokeColor, textStrokeWidth);
         if (combinedText)
             context->concatCTM(rotation(boxRect, Clockwise));
-        paintDecoration(context, boxOrigin, textDecorations, textShadow);
+        paintDecoration(context, boxOrigin, styleToUse, textShadow);
         if (combinedText)
             context->concatCTM(rotation(boxRect, Counterclockwise));
     }
@@ -916,8 +916,11 @@ static StrokeStyle textDecorationStyleToStrokeStyle(TextDecorationStyle decorati
     return strokeStyle;
 }
 
-static int computeUnderlineOffset(const TextUnderlinePosition underlinePosition, const FontMetrics& fontMetrics, const InlineTextBox* inlineTextBox, const float textDecorationThickness)
+int InlineTextBox::computeUnderlineOffset(RenderStyle* style, const float textDecorationThickness)
 {
+    const TextUnderlinePosition underlinePosition = style->textUnderlinePosition();
+    const FontMetrics& fontMetrics = style->fontMetrics();
+
     // Compute the gap between the font and the underline. Use at least one
     // pixel gap, if underline is thick then use a bigger gap.
     const int gap = std::max<int>(1, ceilf(textDecorationThickness / 2.f));
@@ -928,10 +931,10 @@ static int computeUnderlineOffset(const TextUnderlinePosition underlinePosition,
         return fontMetrics.ascent() + gap; // Position underline near the alphabetic baseline.
     case TextUnderlinePositionUnder: {
         // Position underline relative to the under edge of the lowest element's content box.
-        const float offset = inlineTextBox->root().maxLogicalTop() - inlineTextBox->logicalTop();
+        const float offset = root().maxLogicalTop() - logicalTop();
         if (offset > 0)
-            return inlineTextBox->logicalHeight() + gap + offset;
-        return inlineTextBox->logicalHeight() + gap;
+            return logicalHeight() + gap + offset;
+        return logicalHeight() + gap;
     }
     }
 
@@ -1066,34 +1069,71 @@ static bool shouldSetDecorationAntialias(TextDecorationStyle decorationStyle)
     return decorationStyle == TextDecorationStyleDotted || decorationStyle == TextDecorationStyleDashed;
 }
 
-static bool shouldSetDecorationAntialias(TextDecorationStyle underline, TextDecorationStyle overline, TextDecorationStyle linethrough)
+static void getDecorationMetaData(const AppliedTextDecorationList* decorations, bool& linesAreOpaque, bool& setDecorationAntialias)

[esprehn, 2014/03/31 17:41:24]

I might use a struct instead of all these out params.

 {
-    return shouldSetDecorationAntialias(underline) || shouldSetDecorationAntialias(overline) || shouldSetDecorationAntialias(linethrough);
+    for (size_t i = 0; i < decorations->size(); ++i) {

[esprehn, 2014/03/31 17:41:24]

Pass decorations by reference.

+        const AppliedTextDecoration& d = decorations->at(i);
+        linesAreOpaque &= (d.color().alpha() == 255);
+        setDecorationAntialias |= shouldSetDecorationAntialias(d.style());
+    }
 }
 
-static void paintAppliedDecoration(GraphicsContext* context, FloatPoint start, float width, float doubleOffset, int wavyOffsetFactor,
-    RenderObject::AppliedTextDecoration decoration, float thickness, bool antialiasDecoration, bool isPrinting)
+struct PaintAppliedDecorationData {
+    RenderStyle* style;
+    FloatPoint start;
+    float width;
+    float doubleOffset;
+    float thickness;
+    bool antialias;
+    bool isPrinting;
+    int baseline;

[esprehn, 2014/03/31 17:41:24]

Do we need a constructor that zero inits this thing?

+};
+
+static void paintAppliedDecorationStyle(GraphicsContext* context, const AppliedTextDecoration& decoration, const PaintAppliedDecorationData& d, int wavyOffsetFactor)

[esprehn, 2014/03/31 17:41:24]

Don't use single letter variable names.

 {
-    context->setStrokeStyle(textDecorationStyleToStrokeStyle(decoration.style));
-    context->setStrokeColor(decoration.color);
+    context->setStrokeStyle(textDecorationStyleToStrokeStyle(decoration.style()));
+    context->setStrokeColor(decoration.color());
 
-    switch (decoration.style) {
+    switch (decoration.style()) {
     case TextDecorationStyleWavy:
-        strokeWavyTextDecoration(context, start + FloatPoint(0, doubleOffset * wavyOffsetFactor), start + FloatPoint(width, doubleOffset * wavyOffsetFactor), thickness);
+        strokeWavyTextDecoration(context, d.start + FloatPoint(0, d.doubleOffset * wavyOffsetFactor), d.start + FloatPoint(d.width, d.doubleOffset * wavyOffsetFactor), d.thickness);
         break;
     case TextDecorationStyleDotted:
     case TextDecorationStyleDashed:
-        context->setShouldAntialias(antialiasDecoration);
+        context->setShouldAntialias(d.antialias);
         // Fall through
     default:
-        context->drawLineForText(start, width, isPrinting);
+        context->drawLineForText(d.start, d.width, d.isPrinting);
 
-        if (decoration.style == TextDecorationStyleDouble)
-            context->drawLineForText(start + FloatPoint(0, doubleOffset), width, isPrinting);
+        if (decoration.style() == TextDecorationStyleDouble)
+            context->drawLineForText(d.start + FloatPoint(0, d.doubleOffset), d.width, d.isPrinting);
     }
 }
 
-void InlineTextBox::paintDecoration(GraphicsContext* context, const FloatPoint& boxOrigin, TextDecoration deco, const ShadowList* shadowList)
+void InlineTextBox::paintAppliedDecoration(GraphicsContext* context, const AppliedTextDecoration& decoration, const PaintAppliedDecorationData& d)
+{
+    PaintAppliedDecorationData data = d;
+    int wavyOffsetFactor = 1;
+
+    switch (decoration.line()) {
+    case TextDecorationUnderline:
+        data.start += FloatPoint(0, computeUnderlineOffset(d.style, d.thickness));
+        break;
+    case TextDecorationOverline:
+        data.doubleOffset *= -1;
+        break;
+    case TextDecorationLineThrough:
+        data.start += FloatPoint(0, (2 * d.baseline / 3));
+        wavyOffsetFactor = 0;
+        break;
+    default:
+        return;
+    }
+
+    paintAppliedDecorationStyle(context, decoration, data, wavyOffsetFactor);
+}
+
+void InlineTextBox::paintDecoration(GraphicsContext* context, const FloatPoint& boxOrigin, RenderStyle* styleToUse, const ShadowList* shadowList)
 {
     GraphicsContextStateSaver stateSaver(*context);
 
@@ -1109,19 +1149,25 @@ void InlineTextBox::paintDecoration(GraphicsContext* context, const FloatPoint&
             localOrigin.move(m_logicalWidth - width, 0);
     }
 
-    // Get the text decoration colors.
-    RenderObject::AppliedTextDecoration underline, overline, linethrough;
+    const AppliedTextDecorationList* decorations = styleToUse->appliedTextDecorations();
 
-    renderer().getTextDecorations(deco, underline, overline, linethrough, true);
-    if (isFirstLineStyle())
-        renderer().getTextDecorations(deco, underline, overline, linethrough, true, true);
+    // If appliedTextUnderline() is true, we must paint an extra underline
+    // before painting the other decorations.
+    AppliedTextDecoration underline;
+    if (styleToUse->appliedTextUnderline()) {
+        Color color = renderer().getUnderlineColor(true, isFirstLineStyle());

[esprehn, 2014/03/31 17:41:24]

this boolean argument is confusing, can we use an enum or something?

+        underline = AppliedTextDecoration(TextDecorationUnderline, TextDecorationStyleSolid, color);
+    }
 
     // Use a special function for underlines to get the positioning exactly right.
     bool isPrinting = textRenderer().document().printing();
 
-    bool linesAreOpaque = !isPrinting && (!(deco & TextDecorationUnderline) || underline.color.alpha() == 255) && (!(deco & TextDecorationOverline) || overline.color.alpha() == 255) && (!(deco & TextDecorationLineThrough) || linethrough.color.alpha() == 255);
+    bool linesAreOpaque = !isPrinting;
+    bool setDecorationAntialias = false;
+
+    if (decorations)
+        getDecorationMetaData(decorations, linesAreOpaque, setDecorationAntialias);
 
-    RenderStyle* styleToUse = renderer().style(isFirstLineStyle());
     int baseline = styleToUse->fontMetrics().ascent();
 
     size_t shadowCount = shadowList ? shadowList->shadows().size() : 0;
@@ -1136,8 +1182,7 @@ void InlineTextBox::paintDecoration(GraphicsContext* context, const FloatPoint&
 
     context->setStrokeThickness(textDecorationThickness);
 
-    bool antialiasDecoration = shouldSetDecorationAntialias(overline.style, underline.style, linethrough.style)
-        && RenderBoxModelObject::shouldAntialiasLines(context);
+    bool antialiasDecoration = setDecorationAntialias && RenderBoxModelObject::shouldAntialiasLines(context);
 
     float extraOffset = 0;
     if (!linesAreOpaque && shadowCount > 1) {
@@ -1171,20 +1216,23 @@ void InlineTextBox::paintDecoration(GraphicsContext* context, const FloatPoint&
             context->setShadow(FloatSize(shadowX, shadowY - extraOffset), shadow.blur(), shadow.color());
         }
 
+        PaintAppliedDecorationData data;
+        data.style = styleToUse;
+        data.start = localOrigin;
+        data.width = width;
         // Offset between lines - always non-zero, so lines never cross each other.
-        float doubleOffset = textDecorationThickness + 1.f;
-
-        if (deco & TextDecorationUnderline) {
-            const int underlineOffset = computeUnderlineOffset(styleToUse->textUnderlinePosition(), styleToUse->fontMetrics(), this, textDecorationThickness);
-            paintAppliedDecoration(context, localOrigin + FloatPoint(0, underlineOffset), width, doubleOffset, 1, underline, textDecorationThickness, antialiasDecoration, isPrinting);
-        }
-        if (deco & TextDecorationOverline) {
-            paintAppliedDecoration(context, localOrigin, width, -doubleOffset, 1, overline, textDecorationThickness, antialiasDecoration, isPrinting);
-        }
-        if (deco & TextDecorationLineThrough) {
-            const float lineThroughOffset = 2 * baseline / 3;
-            paintAppliedDecoration(context, localOrigin + FloatPoint(0, lineThroughOffset), width, doubleOffset, 0, linethrough, textDecorationThickness, antialiasDecoration, isPrinting);
-        }
+        data.doubleOffset = textDecorationThickness + 1.f;
+        data.thickness = textDecorationThickness;
+        data.antialias = antialiasDecoration;
+        data.isPrinting = isPrinting;
+        data.baseline = baseline;
+
+        if (styleToUse->appliedTextUnderline())
+            paintAppliedDecoration(context, underline, data);
+
+        if (decorations)
+            for (size_t i = 0; i < decorations->size(); ++i)
+                paintAppliedDecoration(context, decorations->at(i), data);
     }
 }