Changeset 176470 in webkit

Timestamp:

Nov 21, 2014, 1:08:55 PM (12 years ago)

Author:

Alan Bujtas

Message:

REGRESSION(r175259) Simple line layout text measuring behavior changed.
​https://bugs.webkit.org/show_bug.cgi?id=138947
rdar://problem/19050653

Reviewed by Antti Koivisto.

In certain cases, when block flow needs to compute the preferred width of a particular text
renderer, we use the non-simple line layout text measuring.
However, the same text renderer might end up at simple line layout later.
Complex line layout measures text including the trailing space and it subtracts
(the constant value of) space width afterwards, while simple line layout measures
runs without the extra space.
In such cases, this may result different word widths and produce unexpected line breaking. (preferred width != final width)
In long term, any text renderer qualified for simple line layout should go through the simple
text measuring code path. (​https://bugs.webkit.org/show_bug.cgi?id=138973)
For now, just copy complex line layout behaviour. This also matches the previous simple line layout line breaking implementation.

Source/WebCore:

Test: fast/text/simple-line-text-measuring-with-trailing-space.html

• rendering/SimpleLineLayoutFlowContents.cpp:

(WebCore::SimpleLineLayout::FlowContents::textWidth):

LayoutTests:

• fast/text/simple-line-text-measuring-with-trailing-space-expected.html: Added.
• fast/text/simple-line-text-measuring-with-trailing-space.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/text/simple-line-text-measuring-with-trailing-space-expected.html (added)
• LayoutTests/fast/text/simple-line-text-measuring-with-trailing-space.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/SimpleLineLayoutFlowContents.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2014-11-21  Zalan Bujtas  <zalan@apple.com>
+
+        REGRESSION(r175259) Simple line layout text measuring behavior changed.
+        https://bugs.webkit.org/show_bug.cgi?id=138947
+        rdar://problem/19050653
+
+        Reviewed by Antti Koivisto.
+
+        In certain cases, when block flow needs to compute the preferred width of a particular text
+        renderer, we use the non-simple line layout text measuring.
+        However, the same text renderer might end up at simple line layout later.
+        Complex line layout measures text including the trailing space and it subtracts
+        (the constant value of) space width afterwards, while simple line layout measures
+        runs without the extra space.
+        In such cases, this may result different word widths and produce unexpected line breaking. (preferred width != final width)
+        In long term, any text renderer qualified for simple line layout should go through the simple
+        text measuring code path. (https://bugs.webkit.org/show_bug.cgi?id=138973)
+        For now, just copy complex line layout behaviour. This also matches the previous simple line layout line breaking implementation.
+
+        * fast/text/simple-line-text-measuring-with-trailing-space-expected.html: Added.
+        * fast/text/simple-line-text-measuring-with-trailing-space.html: Added.
+
 2014-11-21  Chris Dumez  <cdumez@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2014-11-21  Zalan Bujtas  <zalan@apple.com>
+
+        REGRESSION(r175259) Simple line layout text measuring behavior changed.
+        https://bugs.webkit.org/show_bug.cgi?id=138947
+        rdar://problem/19050653
+
+        Reviewed by Antti Koivisto.
+
+        In certain cases, when block flow needs to compute the preferred width of a particular text
+        renderer, we use the non-simple line layout text measuring.
+        However, the same text renderer might end up at simple line layout later.
+        Complex line layout measures text including the trailing space and it subtracts
+        (the constant value of) space width afterwards, while simple line layout measures
+        runs without the extra space.
+        In such cases, this may result different word widths and produce unexpected line breaking. (preferred width != final width)
+        In long term, any text renderer qualified for simple line layout should go through the simple
+        text measuring code path. (https://bugs.webkit.org/show_bug.cgi?id=138973)
+        For now, just copy complex line layout behaviour. This also matches the previous simple line layout line breaking implementation.
+
+        Test: fast/text/simple-line-text-measuring-with-trailing-space.html
+
+        * rendering/SimpleLineLayoutFlowContents.cpp:
+        (WebCore::SimpleLineLayout::FlowContents::textWidth):
+
 2014-11-21  Anders Carlsson  <andersca@apple.com>
 

trunk/Source/WebCore/rendering/SimpleLineLayoutFlowContents.cpp

@@ -181 +181 @@
     ASSERT(from < to);
     String string = renderer.text();
+    bool measureWithEndSpace = m_style.collapseWhitespace && to < string.length() && string[to] == ' ';
+    if (measureWithEndSpace)
+        ++to;
     TextRun run(string.characters8() + from, to - from);
     run.setXPos(xPosition);
     run.setTabSize(!!m_style.tabWidth, m_style.tabWidth);
-    return m_style.font.width(run);
+    float width = m_style.font.width(run);
+    if (measureWithEndSpace)
+        width -= m_style.spaceWidth;
+    return width;
 }