Changeset 199516 in webkit

Timestamp:

Apr 13, 2016 3:11:46 PM (8 years ago)

Author:

Alan Bujtas

Message:

Text on compositing layer with negative letter-spacing is truncated.
​https://bugs.webkit.org/show_bug.cgi?id=156550
<rdar://problem/24212140>

Reviewed by Antti Koivisto.

Negative letter-spacing affects the right edge of content's visual overflow (for both RTL and LTR).
This is similar to how normal line layout adjusts it at InlineFlowBox::addTextBoxVisualOverflow().

Source/WebCore:

Test: fast/text/negative-letter-spacing-visual-overflow.html

• rendering/SimpleLineLayoutFunctions.cpp:

(WebCore::SimpleLineLayout::computeOverflow):
(WebCore::SimpleLineLayout::paintFlow):
(WebCore::SimpleLineLayout::collectFlowOverflow):

LayoutTests:

• fast/text/negative-letter-spacing-visual-overflow-expected.html: Added.
• fast/text/negative-letter-spacing-visual-overflow.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/text/negative-letter-spacing-visual-overflow-expected.html (added)
• LayoutTests/fast/text/negative-letter-spacing-visual-overflow.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/SimpleLineLayoutFunctions.cpp (modified) (4 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2016-04-13  Zalan Bujtas  <zalan@apple.com>
+
+        Text on compositing layer with negative letter-spacing is truncated.
+        https://bugs.webkit.org/show_bug.cgi?id=156550
+        <rdar://problem/24212140>
+
+        Reviewed by Antti Koivisto.
+
+        Negative letter-spacing affects the right edge of content's visual overflow (for both RTL and LTR).
+        This is similar to how normal line layout adjusts it at InlineFlowBox::addTextBoxVisualOverflow().
+
+        * fast/text/negative-letter-spacing-visual-overflow-expected.html: Added.
+        * fast/text/negative-letter-spacing-visual-overflow.html: Added.
+
 2016-04-13  Eric Carlson  <eric.carlson@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2016-04-13  Zalan Bujtas  <zalan@apple.com>
+
+        Text on compositing layer with negative letter-spacing is truncated.
+        https://bugs.webkit.org/show_bug.cgi?id=156550
+        <rdar://problem/24212140>
+
+        Reviewed by Antti Koivisto.
+
+        Negative letter-spacing affects the right edge of content's visual overflow (for both RTL and LTR).
+        This is similar to how normal line layout adjusts it at InlineFlowBox::addTextBoxVisualOverflow().
+
+        Test: fast/text/negative-letter-spacing-visual-overflow.html
+
+        * rendering/SimpleLineLayoutFunctions.cpp:
+        (WebCore::SimpleLineLayout::computeOverflow):
+        (WebCore::SimpleLineLayout::paintFlow):
+        (WebCore::SimpleLineLayout::collectFlowOverflow):
+
 2016-04-13  Eric Carlson  <eric.carlson@apple.com>
 

trunk/Source/WebCore/rendering/SimpleLineLayoutFunctions.cpp

@@ -66 +66 @@
 }
 
+static FloatRect computeOverflow(const RenderBlockFlow& flow, const FloatRect& layoutRect)
+{
+    auto overflowRect = layoutRect;
+    auto strokeOverflow = std::ceil(flow.style().textStrokeWidth());
+    overflowRect.inflate(strokeOverflow);
+
+    auto letterSpacing = flow.style().fontCascade().letterSpacing();
+    if (letterSpacing >= 0)
+        return overflowRect;
+    // Last letter's negative spacing shrinks layout rect. Push it to visual overflow.
+    overflowRect.expand(-letterSpacing, 0);
+    return overflowRect;
+}
+
 void paintFlow(const RenderBlockFlow& flow, const Layout& layout, PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
@@ -95 +109 @@
 
     auto resolver = runResolver(flow, layout);
-    float strokeOverflow = std::ceil(flow.style().textStrokeWidth());
     float deviceScaleFactor = flow.document().deviceScaleFactor();
     for (auto run : resolver.rangeForRect(paintRect)) {
@@ -102 +115 @@
 
         FloatRect rect = run.rect();
-        FloatRect visualOverflowRect = rect;
-        visualOverflowRect.inflate(strokeOverflow);
+        FloatRect visualOverflowRect = computeOverflow(flow, rect);
         if (paintRect.y() > visualOverflowRect.maxY() || paintRect.maxY() < visualOverflowRect.y())
             continue;
@@ -152 +164 @@
 void collectFlowOverflow(RenderBlockFlow& flow, const Layout& layout)
 {
-    float strokeOverflow = std::ceil(flow.style().textStrokeWidth());
-    for (FloatRect lineRect : lineResolver(flow, layout)) {
-        LayoutRect inflatedLineRect(lineRect);
-        inflatedLineRect.inflate(strokeOverflow);
-        flow.addLayoutOverflow(inflatedLineRect);
-        flow.addVisualOverflow(inflatedLineRect);
+    for (auto lineRect : lineResolver(flow, layout)) {
+        LayoutRect visualOverflowRect = LayoutRect(computeOverflow(flow, lineRect));
+        flow.addLayoutOverflow(LayoutRect(lineRect));
+        flow.addVisualOverflow(visualOverflowRect);
     }
 }