Changeset 50869 in webkit

Timestamp:

Nov 12, 2009 12:15:48 AM (14 years ago)

Author:

hamaji@chromium.org

Message:

2009-11-12 Yuta Kitamura <​yutak@chromium.org>

Reviewed by Eric Seidel.

Prevent text inside a multi-column block from being split into columns.

If the tentative height of a multi-column block was too small, we need to
expand the block height and try to layout again, in order to prevent text
from being split into different columns.

CSS Multicolumn text is split awkwardly
​https://bugs.webkit.org/show_bug.cgi?id=22249

• fast/multicol/single-line.html: Added.
• fast/multicol/single-line-expected.checksum: Added.
• fast/multicol/single-line-expected.png: Added.
• fast/multicol/single-line-expected.txt: Added.

2009-11-12 Yuta Kitamura <​yutak@chromium.org>

Reviewed by Eric Seidel.

Prevent text inside a multi-column block from being split into columns.

If the tentative height of a multi-column block was too small, we need to
expand the block height and try to layout again, in order to prevent text
from being split into different columns.

CSS Multicolumn text is split awkwardly
​https://bugs.webkit.org/show_bug.cgi?id=22249

Test: fast/multicol/single-line.html

• rendering/RenderBlock.cpp: (WebCore::RenderBlock::layoutColumns):
• rendering/RenderBlock.h:
• rendering/RenderLineBoxList.cpp: (WebCore::RenderLineBoxList::paint):
• rendering/RenderView.h: (WebCore::RenderView::setTruncatedAt): (WebCore::RenderView::setMinimumColumnHeight): (WebCore::RenderView::minimumColumnHeight):

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/multicol/single-line-expected.checksum (added)
• LayoutTests/fast/multicol/single-line-expected.png (added)
• LayoutTests/fast/multicol/single-line-expected.txt (added)
• LayoutTests/fast/multicol/single-line.html (added)
• WebCore/ChangeLog (modified) (1 diff)
• WebCore/rendering/RenderBlock.cpp (modified) (5 diffs)
• WebCore/rendering/RenderBlock.h (modified) (1 diff)
• WebCore/rendering/RenderLineBoxList.cpp (modified) (1 diff)
• WebCore/rendering/RenderView.h (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2009-11-12  Yuta Kitamura  <yutak@chromium.org>
+
+        Reviewed by Eric Seidel.
+
+        Prevent text inside a multi-column block from being split into columns.
+        
+        If the tentative height of a multi-column block was too small, we need to
+        expand the block height and try to layout again, in order to prevent text
+        from being split into different columns.
+
+        CSS Multicolumn text is split awkwardly
+        https://bugs.webkit.org/show_bug.cgi?id=22249
+
+        * fast/multicol/single-line.html: Added.
+        * fast/multicol/single-line-expected.checksum: Added.
+        * fast/multicol/single-line-expected.png: Added.
+        * fast/multicol/single-line-expected.txt: Added.
+
 2009-11-11  Kent Tamura  <tkent@chromium.org>
 

trunk/WebCore/ChangeLog

@@ +1 @@
+2009-11-12  Yuta Kitamura  <yutak@chromium.org>
+
+        Reviewed by Eric Seidel.
+
+        Prevent text inside a multi-column block from being split into columns.
+        
+        If the tentative height of a multi-column block was too small, we need to
+        expand the block height and try to layout again, in order to prevent text
+        from being split into different columns.
+
+        CSS Multicolumn text is split awkwardly
+        https://bugs.webkit.org/show_bug.cgi?id=22249
+
+        Test: fast/multicol/single-line.html
+
+        * rendering/RenderBlock.cpp:
+        (WebCore::RenderBlock::layoutColumns):
+        * rendering/RenderBlock.h:
+        * rendering/RenderLineBoxList.cpp:
+        (WebCore::RenderLineBoxList::paint):
+        * rendering/RenderView.h:
+        (WebCore::RenderView::setTruncatedAt):
+        (WebCore::RenderView::setMinimumColumnHeight):
+        (WebCore::RenderView::minimumColumnHeight):
+
 2009-11-11  Kent Tamura  <tkent@chromium.org>
 

trunk/WebCore/rendering/RenderBlock.cpp

@@ -3618 +3618 @@
 }
 
-int RenderBlock::layoutColumns(int endOfContent)
+int RenderBlock::layoutColumns(int endOfContent, int requestedColumnHeight)
 {
     // Don't do anything if we have no columns
@@ -3631 +3631 @@
     bool computeIntrinsicHeight = (endOfContent == -1);
 
-    // Fill the columns in to the available height.  Attempt to balance the height of the columns
-    int availableHeight = contentHeight();
-    int colHeight = computeIntrinsicHeight ? availableHeight / desiredColumnCount : availableHeight;
-    
+    // Fill the columns in to the available height.  Attempt to balance the height of the columns.
     // Add in half our line-height to help with best-guess initial balancing.
     int columnSlop = lineHeight(false) / 2;
     int remainingSlopSpace = columnSlop * desiredColumnCount;
-
-    if (computeIntrinsicHeight)
-        colHeight += columnSlop;
-                                                                            
+    int availableHeight = contentHeight();
+    int colHeight;
+    if (computeIntrinsicHeight && requestedColumnHeight >= 0)
+        colHeight = requestedColumnHeight;
+    else if (computeIntrinsicHeight)
+        colHeight = availableHeight / desiredColumnCount + columnSlop;
+    else
+        colHeight = availableHeight;
+    int originalColHeight = colHeight;
+
     int colGap = columnGap();
 
@@ -3657 +3660 @@
     unsigned colCount = desiredColumnCount;
     int maxColBottom = borderTop() + paddingTop();
-    int contentBottom = top + availableHeight; 
+    int contentBottom = top + availableHeight;
+    int minimumColumnHeight = -1;
     for (unsigned i = 0; i < colCount; i++) {
         // If we aren't constrained, then the last column can just get all the remaining space.
@@ -3676 +3680 @@
         paintObject(paintInfo, 0, 0);
         setHasColumns(true);
+
+        if (computeIntrinsicHeight && v->minimumColumnHeight() > originalColHeight) {
+            // The initial column height was too small to contain one line of text.
+            minimumColumnHeight = max(minimumColumnHeight, v->minimumColumnHeight());
+        }
 
         int adjustedBottom = v->bestTruncatedAt();
@@ -3711 +3720 @@
         if (currY < endOfContent && i == colCount - 1 && (computeIntrinsicHeight || contentHeight()))
             colCount++;
+    }
+
+    if (minimumColumnHeight >= 0) {
+        // If originalColHeight was too small, we need to try to layout again.
+        return layoutColumns(endOfContent, minimumColumnHeight);
     }
 

trunk/WebCore/rendering/RenderBlock.h

@@ -369 +369 @@
 
     void calcColumnWidth();
-    int layoutColumns(int endOfContent = -1);
+    int layoutColumns(int endOfContent = -1, int requestedColumnHeight = -1);
 
     bool expandsToEncloseOverhangingFloats() const;

trunk/WebCore/rendering/RenderLineBoxList.cpp

@@ -200 +200 @@
         h = bottom - top;
         yPos = ty + top;
+        v->setMinimumColumnHeight(h);
         if (yPos < info.rect.bottom() && yPos + h > info.rect.y())
             curr->paint(info, tx, ty);

trunk/WebCore/rendering/RenderView.h

@@ -76 +76 @@
     void setPrintImages(bool enable) { m_printImages = enable; }
     bool printImages() const { return m_printImages; }
-    void setTruncatedAt(int y) { m_truncatedAt = y; m_bestTruncatedAt = m_truncatorWidth = 0; m_forcedPageBreak = false; }
+    void setTruncatedAt(int y) { m_truncatedAt = y; m_bestTruncatedAt = m_truncatorWidth = 0; m_minimumColumnHeight = 0; m_forcedPageBreak = false; }
     void setBestTruncatedAt(int y, RenderBoxModelObject* forRenderer, bool forcedBreak = false);
+    void setMinimumColumnHeight(int height) { m_minimumColumnHeight = height; }
     int bestTruncatedAt() const { return m_bestTruncatedAt; }
+    int minimumColumnHeight() const { return m_minimumColumnHeight; }
 
     int truncatedAt() const { return m_truncatedAt; }
@@ -196 +198 @@
     int m_bestTruncatedAt;
     int m_truncatorWidth;
+    int m_minimumColumnHeight;
     bool m_forcedPageBreak;
     LayoutState* m_layoutState;