Changeset 211292 in webkit

Timestamp:

Jan 27, 2017 11:24:26 AM (7 years ago)

Author:

Alan Bujtas

Message:

Simple line layout: Do not bail out on -webkit-line-box-contain: block glyphs unless text overflows vertically.
​https://bugs.webkit.org/show_bug.cgi?id=167481
<rdar://problem/30180150>

Reviewed by Antti Koivisto.

Source/WebCore:

Since -webkit-line-box-contain: glyphs requires variable line height support, we can use simple line layout
only when each line happen to have the same height ('block' property value is set, glyphs do not overflow the block line height).

Test: fast/text/simple-line-layout-line-box-contain-glyphs.html

• rendering/SimpleLineLayout.cpp:

(WebCore::SimpleLineLayout::canUseForText):
(WebCore::SimpleLineLayout::canUseForFontAndText):
(WebCore::SimpleLineLayout::canUseForStyle):
(WebCore::SimpleLineLayout::printReason):

LayoutTests:

• fast/text/simple-line-layout-line-box-contain-glyphs-expected.html: Added.
• fast/text/simple-line-layout-line-box-contain-glyphs.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/text/simple-line-layout-line-box-contain-glyphs-expected.html (added)
• LayoutTests/fast/text/simple-line-layout-line-box-contain-glyphs.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/SimpleLineLayout.cpp (modified) (8 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2017-01-27  Zalan Bujtas  <zalan@apple.com>
+
+        Simple line layout: Do not bail out on -webkit-line-box-contain: block glyphs unless text overflows vertically.
+        https://bugs.webkit.org/show_bug.cgi?id=167481
+        <rdar://problem/30180150>
+
+        Reviewed by Antti Koivisto.
+
+        * fast/text/simple-line-layout-line-box-contain-glyphs-expected.html: Added.
+        * fast/text/simple-line-layout-line-box-contain-glyphs.html: Added.
+
 2017-01-27  Devin Rousso  <dcrousso+webkit@gmail.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2017-01-27  Zalan Bujtas  <zalan@apple.com>
+
+        Simple line layout: Do not bail out on -webkit-line-box-contain: block glyphs unless text overflows vertically.
+        https://bugs.webkit.org/show_bug.cgi?id=167481
+        <rdar://problem/30180150>
+
+        Reviewed by Antti Koivisto.
+
+        Since -webkit-line-box-contain: glyphs requires variable line height support, we can use simple line layout
+        only when each line happen to have the same height ('block' property value is set, glyphs do not overflow the block line height).  
+
+        Test: fast/text/simple-line-layout-line-box-contain-glyphs.html
+
+        * rendering/SimpleLineLayout.cpp:
+        (WebCore::SimpleLineLayout::canUseForText):
+        (WebCore::SimpleLineLayout::canUseForFontAndText):
+        (WebCore::SimpleLineLayout::canUseForStyle):
+        (WebCore::SimpleLineLayout::printReason):
+
 2017-01-27  Chris Dumez  <cdumez@apple.com>
 

trunk/Source/WebCore/rendering/SimpleLineLayout.cpp

@@ -113 +113 @@
     FlowChildIsSelected                   = 1LLU  << 47,
     FlowHasHangingPunctuation             = 1LLU  << 48,
-    EndOfReasons                          = 1LLU  << 49
+    FlowFontHasOverflowGlyph              = 1LLU  << 49,
+    EndOfReasons                          = 1LLU  << 50
 };
 const unsigned NoReason = 0;
@@ -137 +138 @@
 
 template <typename CharacterType>
-static AvoidanceReasonFlags canUseForText(const CharacterType* text, unsigned length, const Font& font, bool textIsJustified, IncludeReasons includeReasons)
+static AvoidanceReasonFlags canUseForText(const CharacterType* text, unsigned length, const Font& font, std::optional<float> lineHeightConstraint,
+    bool textIsJustified, IncludeReasons includeReasons)
 {
     AvoidanceReasonFlags reasons = { };
@@ -167 +169 @@
             SET_REASON_AND_RETURN_IF_NEEDED(FlowTextHasDirectionCharacter, reasons, includeReasons);
 
-        if (!font.glyphForCharacter(character))
+        auto glyph = font.glyphForCharacter(character);
+        if (!glyph)
             SET_REASON_AND_RETURN_IF_NEEDED(FlowFontIsMissingGlyph, reasons, includeReasons);
+        if (lineHeightConstraint && font.boundsForGlyph(glyph).height() > *lineHeightConstraint)
+            SET_REASON_AND_RETURN_IF_NEEDED(FlowFontHasOverflowGlyph, reasons, includeReasons);
     }
     return reasons;
 }
 
-static AvoidanceReasonFlags canUseForText(const RenderText& textRenderer, const Font& font, bool textIsJustified, IncludeReasons includeReasons)
+static AvoidanceReasonFlags canUseForText(const RenderText& textRenderer, const Font& font, std::optional<float> lineHeightConstraint, bool textIsJustified, IncludeReasons includeReasons)
 {
     if (textRenderer.is8Bit())
-        return canUseForText(textRenderer.characters8(), textRenderer.textLength(), font, false, includeReasons);
-    return canUseForText(textRenderer.characters16(), textRenderer.textLength(), font, textIsJustified, includeReasons);
+        return canUseForText(textRenderer.characters8(), textRenderer.textLength(), font, lineHeightConstraint, false, includeReasons);
+    return canUseForText(textRenderer.characters16(), textRenderer.textLength(), font, lineHeightConstraint, textIsJustified, includeReasons);
 }
 
@@ -188 +193 @@
     if (primaryFont.isLoading())
         SET_REASON_AND_RETURN_IF_NEEDED(FlowIsMissingPrimaryFont, reasons, includeReasons);
-
+    std::optional<float> lineHeightConstraint;
+    if (style.lineBoxContain() & LineBoxContainGlyphs)
+        lineHeightConstraint = lineHeightFromFlow(flow).toFloat();
     bool flowIsJustified = style.textAlign() == JUSTIFY;
     for (const auto& textRenderer : childrenOfType<RenderText>(flow)) {
@@ -204 +211 @@
             SET_REASON_AND_RETURN_IF_NEEDED(FlowFontIsNotSimple, reasons, includeReasons);
 
-        auto textReasons = canUseForText(textRenderer, primaryFont, flowIsJustified, includeReasons);
+        auto textReasons = canUseForText(textRenderer, primaryFont, lineHeightConstraint, flowIsJustified, includeReasons);
         if (textReasons != NoReason)
             SET_REASON_AND_RETURN_IF_NEEDED(textReasons, reasons, includeReasons);
@@ -223 +230 @@
     if (!style.isLeftToRightDirection())
         SET_REASON_AND_RETURN_IF_NEEDED(FlowIsNotLTR, reasons, includeReasons);
-    if (style.lineBoxContain() != RenderStyle::initialLineBoxContain())
+    if (!(style.lineBoxContain() & LineBoxContainBlock))
         SET_REASON_AND_RETURN_IF_NEEDED(FlowHasLineBoxContainProperty, reasons, includeReasons);
     if (style.writingMode() != TopToBottomWritingMode)
@@ -978 +985 @@
         break;
     case FlowHasLineBoxContainProperty:
-        stream << "line-box-contain property";
+        stream << "line-box-contain value indicates variable line height";
         break;
     case FlowIsNotTopToBottom:
@@ -1060 +1067 @@
     case FlowChildIsSelected:
         stream << "selected content";
+        break;
+    case FlowFontHasOverflowGlyph:
+        stream << "-webkit-line-box-contain: glyphs with overflowing text.";
         break;
     case FlowTextIsEmpty: