Changeset 142042 in webkit

Timestamp:

Feb 6, 2013 3:08:59 PM (11 years ago)

Author:

leviw@chromium.org

Message:

Negative text indents can break RenderBlock's inline maximum preferred width calculation
​https://bugs.webkit.org/show_bug.cgi?id=108973

Reviewed by Emil A Eklund.

Source/WebCore:

Change two quirks about to how we calculate a block's inline preferred width with
text-indent.

First, re-use text-indent that's first applied to floats on text that follows it.
This matches Layout, as otherwise we can prematurely wrap text when there's a negative
margin on a block starting with a float. This also matches FireFox.

Second, correct how the max preferred width is calculated in the presence of a negative
text-indent. If the text-indent is more negative than the first text line break, we
update the value to be the remainder. Previously, we added this remaining negative value
to subsequent minimum and maximum preferred width calculations (until the remainder was
gone). This is wrong for the max preferred width, as we're adding the negative value more
than once, and leads to a max preferred width that's smaller than our line.

Test: fast/css/negative-text-indent-in-inline-block.html

• rendering/RenderBlock.cpp:

(WebCore::RenderBlock::computeInlinePreferredLogicalWidths):

LayoutTests:

• fast/css/negative-text-indent-in-inline-block-expected.html: Added.
• fast/css/negative-text-indent-in-inline-block.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/css/negative-text-indent-in-inline-block-expected.html (added)
• LayoutTests/fast/css/negative-text-indent-in-inline-block.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderBlock.cpp (modified) (3 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2013-02-06  Levi Weintraub  <leviw@chromium.org>
+
+        Negative text indents can break RenderBlock's inline maximum preferred width calculation
+        https://bugs.webkit.org/show_bug.cgi?id=108973
+
+        Reviewed by Emil A Eklund.
+
+        * fast/css/negative-text-indent-in-inline-block-expected.html: Added.
+        * fast/css/negative-text-indent-in-inline-block.html: Added.
+
 2013-02-06  Zan Dobersek  <zdobersek@igalia.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-02-06  Levi Weintraub  <leviw@chromium.org>
+
+        Negative text indents can break RenderBlock's inline maximum preferred width calculation
+        https://bugs.webkit.org/show_bug.cgi?id=108973
+
+        Reviewed by Emil A Eklund.
+
+        Change two quirks about to how we calculate a block's inline preferred width with
+        text-indent.
+
+        First, re-use text-indent that's first applied to floats on text that follows it.
+        This matches Layout, as otherwise we can prematurely wrap text when there's a negative
+        margin on a block starting with a float. This also matches FireFox.
+
+        Second, correct how the max preferred width is calculated in the presence of a negative
+        text-indent. If the text-indent is more negative than the first text line break, we
+        update the value to be the remainder. Previously, we added this remaining negative value
+        to subsequent minimum and maximum preferred width calculations (until the remainder was
+        gone). This is wrong for the max preferred width, as we're adding the negative value more
+        than once, and leads to a max preferred width that's smaller than our line.
+
+        Test: fast/css/negative-text-indent-in-inline-block.html
+
+        * rendering/RenderBlock.cpp:
+        (WebCore::RenderBlock::computeInlinePreferredLogicalWidths):
+
 2013-02-06  Mark Lam  <mark.lam@apple.com>
 

trunk/Source/WebCore/rendering/RenderBlock.cpp

@@ -5871 +5871 @@
 
     InlineMinMaxIterator childIterator(this);
-    bool addedTextIndent = false; // Only gets added in once.
+
+    // Only gets added to the max preffered width once.
+    bool addedTextIndent = false;
+    // Signals the text indent was more negative than the min preferred width
+    bool hasRemainingNegativeTextIndent = false;
+
     LayoutUnit textIndent = minimumValueForLength(styleToUse->textIndent(), cw, view());
     RenderObject* prevFloat = 0;
@@ -5977 +5982 @@
                 // Add in text-indent.  This is added in only once.
                 LayoutUnit ti = 0;
-                if (!addedTextIndent) {
+                if (!addedTextIndent && !child->isFloating()) {
                     ti = textIndent;
                     childMin += ti.ceilToFloat();
@@ -6057 +6062 @@
                 // Add in text-indent.  This is added in only once.
                 float ti = 0;
-                if (!addedTextIndent) {
+                if (!addedTextIndent || hasRemainingNegativeTextIndent) {
                     ti = textIndent.ceilToFloat();
+                    childMin += ti;
+                    beginMin += ti;
                     
-                    childMin += ti;
-                    childMax += ti;
-                    beginMin += ti;
-                    beginMax += ti;
+                    // It the text indent negative and larger than the child minimum, we re-use the remainder
+                    // in future minimum calculations, but using the negative value again on the maximum
+                    // will lead to under-counting the max pref width.
+                    if (!addedTextIndent) {
+                        childMax += ti;
+                        beginMax += ti;
+                        addedTextIndent = true;
+                    }
                     
-                    if (childMin < 0)
+                    if (childMin < 0) {
                         textIndent = childMin;
-                    else
-                        addedTextIndent = true;
+                        hasRemainingNegativeTextIndent = true;
+                    }
                 }