Should be able to compute decoration overflow without InlineIterator:…

…:TextBoxIterator

https://bugs.webkit.org/show_bug.cgi?id=241490

Reviewed by Antti Koivisto.

This patch enables IFC codebase to compute visual overflow for decoration (even when TextBoxIterator is not available).

* Source/WebCore/rendering/style/RenderStyle.cpp:
(WebCore::RenderStyle::changeAffectsVisualOverflow const):
* Source/WebCore/style/InlineTextBoxStyle.cpp:
(WebCore::visualOverflowForDecorations):
* Source/WebCore/style/InlineTextBoxStyle.h:

Canonical link: https://commits.webkit.org/251461@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@295455 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/rendering/style/RenderStyle.cpp

@@ -685,7 +685,7 @@ inline bool RenderStyle::changeAffectsVisualOverflow(const RenderStyle& other) c
         // is specified. We can take an early out here.
         if (textUnderlinePosition() == TextUnderlinePosition::Under || other.textUnderlinePosition() == TextUnderlinePosition::Under)
             return true;
-        return visualOverflowForDecorations(*this, { }) != visualOverflowForDecorations(other, { });
+        return visualOverflowForDecorations(*this) != visualOverflowForDecorations(other);
     }
 
     auto hasOutlineInVisualOverflow = this->hasOutlineInVisualOverflow();

Source/WebCore/style/InlineTextBoxStyle.cpp

@@ -172,22 +172,20 @@ WavyStrokeParameters getWavyStrokeParameters(float fontSize)
     return result;
 }
 
-GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const InlineIterator::TextBoxIterator& textRun)
+GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, std::optional<float> underlineOffset)
 {
-    ASSERT(!textRun || textRun->style() == lineStyle);
-
     auto decoration = lineStyle.textDecorationsInEffect();
     if (decoration.isEmpty())
         return GlyphOverflow();
 
     float strokeThickness = lineStyle.textDecorationThickness().resolve(lineStyle.computedFontSize(), lineStyle.metricsOfPrimaryFont());
     WavyStrokeParameters wavyStrokeParameters;
     float wavyOffset = 0;
-        
+
     TextDecorationStyle decorationStyle = lineStyle.textDecorationStyle();
     float height = lineStyle.fontCascade().metricsOfPrimaryFont().floatHeight();
     GlyphOverflow overflowResult;
-    
+
     if (decorationStyle == TextDecorationStyle::Wavy) {
         wavyStrokeParameters = getWavyStrokeParameters(lineStyle.computedFontPixelSize());
         wavyOffset = wavyOffsetFromDecoration();
@@ -198,27 +196,13 @@ GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const I
     // These metrics must match where underlines get drawn.
     // FIXME: Share the code in TextDecorationPainter::paintBackgroundDecorations() so we can just query it for the painted geometry.
     if (decoration & TextDecorationLine::Underline) {
-        // Compensate for the integral ceiling in GraphicsContext::computeLineBoundsAndAntialiasingModeForText()
-        int underlineOffset = 1;
-        float textDecorationBaseFontSize = 16;
-        auto defaultGap = lineStyle.computedFontSize() / textDecorationBaseFontSize;
-        // FIXME: RenderStyle calls us with empty textRun but only when TextUnderlinePosition is not Under.
-        ASSERT(textRun || lineStyle.textUnderlinePosition() != TextUnderlinePosition::Under);
-        if (!textRun)
-            underlineOffset += computeUnderlineOffset({ lineStyle, defaultGap });
-        else {
-            underlineOffset += computeUnderlineOffset({ lineStyle
-                , defaultGap
-                , UnderlineOffsetArguments::TextUnderlinePositionUnder { textRun->lineBox()->baselineType(), textRun->logicalBottom() - textRun->logicalTop(), textRunLogicalOffsetFromLineBottom(textRun) }
-            });
-        }
-
+        ASSERT(underlineOffset);
         if (decorationStyle == TextDecorationStyle::Wavy) {
-            overflowResult.extendBottom(underlineOffset + wavyOffset + wavyStrokeParameters.controlPointDistance + strokeThickness - height);
-            overflowResult.extendTop(-(underlineOffset + wavyOffset - wavyStrokeParameters.controlPointDistance - strokeThickness));
+            overflowResult.extendBottom(*underlineOffset + wavyOffset + wavyStrokeParameters.controlPointDistance + strokeThickness - height);
+            overflowResult.extendTop(-(*underlineOffset + wavyOffset - wavyStrokeParameters.controlPointDistance - strokeThickness));
         } else {
-            overflowResult.extendBottom(underlineOffset + strokeThickness - height);
-            overflowResult.extendTop(-underlineOffset);
+            overflowResult.extendBottom(*underlineOffset + strokeThickness - height);
+            overflowResult.extendTop(-*underlineOffset);
         }
     }
     if (decoration & TextDecorationLine::Overline) {
@@ -250,5 +234,34 @@ GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const I
     }
     return overflowResult;
 }
+
+GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const InlineIterator::TextBoxIterator& textRun)
+{
+    ASSERT(!textRun || textRun->style() == lineStyle);
+
+    if (!lineStyle.textDecorationsInEffect().contains(TextDecorationLine::Underline))
+        return visualOverflowForDecorations(lineStyle, std::optional<float> { });
+
+    // Compensate for the integral ceiling in GraphicsContext::computeLineBoundsAndAntialiasingModeForText()
+    int underlineOffset = 1;
+    float textDecorationBaseFontSize = 16;
+    auto defaultGap = lineStyle.computedFontSize() / textDecorationBaseFontSize;
+    // FIXME: RenderStyle calls us with empty textRun but only when TextUnderlinePosition is not Under.
+    ASSERT(textRun || lineStyle.textUnderlinePosition() != TextUnderlinePosition::Under);
+    if (!textRun)
+        underlineOffset += computeUnderlineOffset({ lineStyle, defaultGap });
+    else {
+        underlineOffset += computeUnderlineOffset({ lineStyle
+            , defaultGap
+            , UnderlineOffsetArguments::TextUnderlinePositionUnder { textRun->lineBox()->baselineType(), textRun->logicalBottom() - textRun->logicalTop(), textRunLogicalOffsetFromLineBottom(textRun) }
+        });
+    }
+    return visualOverflowForDecorations(lineStyle, underlineOffset);
+}
+
+GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle)
+{
+    return visualOverflowForDecorations(lineStyle, InlineIterator::TextBoxIterator { });
+}
 
 }

Source/WebCore/style/InlineTextBoxStyle.h

@@ -53,7 +53,9 @@ struct WavyStrokeParameters {
     float step { 0 };
 };
 WavyStrokeParameters getWavyStrokeParameters(float fontSize);
+GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle);
 GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const InlineIterator::TextBoxIterator&);
+GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, std::optional<float> underlineOffset);
 
 struct UnderlineOffsetArguments {
     const RenderStyle& lineStyle;