Changeset 55636 in webkit

Timestamp:

Mar 7, 2010 10:15:02 AM (14 years ago)

Author:

mitz@apple.com

Message:

<rdar://problem/7722008> Column breaking ignores floats
​https://bugs.webkit.org/show_bug.cgi?id=35837

Reviewed by Simon Fraser.

WebCore:

Test: fast/multicol/float-truncation.html

Introduce an earlier column-break if otherwise a float that could fit
inside a single column will be split between columns.

It is still possible for floats to be needlessly broken if initially
they fit in the column, but normal flow truncation then shortens the
column.

• rendering/RenderBlock.cpp:

(WebCore::RenderBlock::visibleTopOfHighestFloatExtendingBelow): Added.
Returns the visible top of the highest descendant float that visibly
extends below the given y offset, ignoring floats that are taller than
the given maximum height.
(WebCore::RenderBlock::layoutColumns): If the initial column height
would cause a float to be split, truncate above the float.

• rendering/RenderBlock.h:

LayoutTests:

• fast/multicol/float-truncation-expected.txt: Added.
• fast/multicol/float-truncation.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/multicol/float-truncation-expected.txt (added)
• LayoutTests/fast/multicol/float-truncation.html (added)
• WebCore/ChangeLog (modified) (1 diff)
• WebCore/rendering/RenderBlock.cpp (modified) (3 diffs)
• WebCore/rendering/RenderBlock.h (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2010-03-07  Dan Bernstein  <mitz@apple.com>
+
+        Reviewed by Simon Fraser.
+
+        <rdar://problem/7722008> Column breaking ignores floats
+        https://bugs.webkit.org/show_bug.cgi?id=35837
+
+        * fast/multicol/float-truncation-expected.txt: Added.
+        * fast/multicol/float-truncation.html: Added.
+
 2010-03-07  Dmitry Titov  <dimich@chromium.org>
 

trunk/WebCore/ChangeLog

@@ +1 @@
+2010-03-07  Dan Bernstein  <mitz@apple.com>
+
+        Reviewed by Simon Fraser.
+
+        <rdar://problem/7722008> Column breaking ignores floats
+        https://bugs.webkit.org/show_bug.cgi?id=35837
+
+        Test: fast/multicol/float-truncation.html
+
+        Introduce an earlier column-break if otherwise a float that could fit
+        inside a single column will be split between columns.
+
+        It is still possible for floats to be needlessly broken if initially
+        they fit in the column, but normal flow truncation then shortens the
+        column.
+
+        * rendering/RenderBlock.cpp:
+        (WebCore::RenderBlock::visibleTopOfHighestFloatExtendingBelow): Added.
+        Returns the visible top of the highest descendant float that visibly
+        extends below the given y offset, ignoring floats that are taller than
+        the given maximum height.
+        (WebCore::RenderBlock::layoutColumns): If the initial column height
+        would cause a float to be split, truncate above the float.
+        * rendering/RenderBlock.h:
+
 2010-03-07  Dmitry Titov  <dimich@chromium.org>
 

trunk/WebCore/rendering/RenderBlock.cpp

@@ -3183 +3183 @@
 }
 
+int RenderBlock::visibleTopOfHighestFloatExtendingBelow(int bottom, int maxHeight) const
+{
+    int top = bottom;
+    if (m_floatingObjects) {
+        FloatingObject* floatingObject;
+        for (DeprecatedPtrListIterator<FloatingObject> it(*m_floatingObjects); (floatingObject = it.current()); ++it) {
+            RenderBox* floatingBox = floatingObject->m_renderer;
+            IntRect visibleOverflow = floatingBox->visibleOverflowRect();
+            visibleOverflow.move(floatingBox->x(), floatingBox->y());
+            if (visibleOverflow.y() < top && visibleOverflow.bottom() > bottom && visibleOverflow.height() <= maxHeight && floatingBox->containingBlock() == this)
+                top = visibleOverflow.y();
+        }
+    }
+
+    if (!childrenInline()) {
+        for (RenderObject* child = firstChild(); child; child = child->nextSibling()) {
+            if (child->isFloatingOrPositioned() || !child->isRenderBlock())
+                continue;
+            RenderBlock* childBlock = toRenderBlock(child);
+            top = min(top, childBlock->y() + childBlock->visibleTopOfHighestFloatExtendingBelow(bottom - childBlock->y(), maxHeight));
+        }
+    }
+
+    return top;
+}
+
 int RenderBlock::getClearDelta(RenderBox* child, int yPos)
 {
@@ -3724 +3750 @@
         // This represents the real column position.
         IntRect colRect(currX, top, desiredColumnWidth, colHeight);
-        
+
+        int truncationPoint = visibleTopOfHighestFloatExtendingBelow(currY + colHeight, colHeight);
+
         // For the simulated paint, we pretend like everything is in one long strip.
-        IntRect pageRect(left, currY, desiredColumnWidth, colHeight);
+        IntRect pageRect(left, currY, desiredColumnWidth, truncationPoint - currY);
         v->setPrintRect(pageRect);
-        v->setTruncatedAt(currY + colHeight);
+        v->setTruncatedAt(truncationPoint);
         GraphicsContext context((PlatformGraphicsContext*)0);
         RenderObject::PaintInfo paintInfo(&context, pageRect, PaintPhaseForeground, false, 0, 0);
@@ -3743 +3771 @@
         int adjustedBottom = v->bestTruncatedAt();
         if (adjustedBottom <= currY)
-            adjustedBottom = currY + colHeight;
+            adjustedBottom = truncationPoint;
         
         colRect.setHeight(adjustedBottom - currY);

trunk/WebCore/rendering/RenderBlock.h

@@ -372 +372 @@
     void calcColumnWidth();
     int layoutColumns(int endOfContent = -1, int requestedColumnHeight = -1);
+    int visibleTopOfHighestFloatExtendingBelow(int bottom, int maxHeight) const;
 
     bool expandsToEncloseOverhangingFloats() const;