Bug 1094056 - Use nsCaret::GetGeometryForFrame to determine position of selection carets. r=roc

layout/base/SelectionCarets.cpp

@@ -377,19 +377,6 @@ IsRightToLeft(nsIFrame* aFrame)
     aFrame->StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL;
 }
 
-/*
- * Reduce rect to 1 css pixel width along either left or right edge base on
- * aToRightEdge parameter.
- */
-static void
-ReduceRectToVerticalEdge(nsRect& aRect, bool aToRightEdge)
-{
-  if (aToRightEdge) {
-    aRect.x = aRect.XMost() - AppUnitsPerCSSPixel();
-  }
-  aRect.width = AppUnitsPerCSSPixel();
-}
-
 static nsIFrame*
 FindFirstNodeWithFrame(nsIDocument* aDocument,
                        nsRange* aRange,
@@ -472,16 +459,6 @@ SelectionCarets::UpdateSelectionCarets()
   nsRefPtr<nsRange> firstRange = selection->GetRangeAt(0);
   nsRefPtr<nsRange> lastRange = selection->GetRangeAt(rangeCount - 1);
 
-  nsLayoutUtils::FirstAndLastRectCollector collectorStart;
-  nsRange::CollectClientRects(&collectorStart, firstRange,
-                              firstRange->GetStartParent(), firstRange->StartOffset(),
-                              firstRange->GetEndParent(), firstRange->EndOffset(), true, true);
-
-  nsLayoutUtils::FirstAndLastRectCollector collectorEnd;
-  nsRange::CollectClientRects(&collectorEnd, lastRange,
-                              lastRange->GetStartParent(), lastRange->StartOffset(),
-                              lastRange->GetEndParent(), lastRange->EndOffset(), true, true);
-
   nsIFrame* canvasFrame = mPresShell->GetCanvasFrame();
   nsIFrame* rootFrame = mPresShell->GetRootFrame();
 
@@ -522,17 +499,29 @@ SelectionCarets::UpdateSelectionCarets()
   bool startFrameIsRTL = IsRightToLeft(startFrame);
   bool endFrameIsRTL = IsRightToLeft(endFrame);
 
-  // If start frame is LTR, then place start caret in first rect's leftmost
-  // otherwise put it to first rect's rightmost.
-  ReduceRectToVerticalEdge(collectorStart.mFirstRect, startFrameIsRTL);
+  mPresShell->FlushPendingNotifications(Flush_Layout);
+  nsRect firstRectInRootFrame =
+    nsCaret::GetGeometryForFrame(startFrame, startOffset, nullptr);
+  nsRect lastRectInRootFrame =
+    nsCaret::GetGeometryForFrame(endFrame, endOffset, nullptr);
 
-  // Contrary to start frame, if end frame is LTR, put end caret to last
-  // rect's rightmost position, otherwise, put it to last rect's leftmost.
-  ReduceRectToVerticalEdge(collectorEnd.mLastRect, !endFrameIsRTL);
+  // GetGeometryForFrame may return a rect that outside frame's rect. So
+  // constrain rect inside frame's rect.
+  firstRectInRootFrame = firstRectInRootFrame.ForceInside(startFrame->GetRectRelativeToSelf());
+  lastRectInRootFrame = lastRectInRootFrame.ForceInside(endFrame->GetRectRelativeToSelf());
+  nsRect firstRectInCanvasFrame = firstRectInRootFrame;
+  nsRect lastRectInCanvasFrame =lastRectInRootFrame;
+  nsLayoutUtils::TransformRect(startFrame, rootFrame, firstRectInRootFrame);
+  nsLayoutUtils::TransformRect(endFrame, rootFrame, lastRectInRootFrame);
+  nsLayoutUtils::TransformRect(startFrame, canvasFrame, firstRectInCanvasFrame);
+  nsLayoutUtils::TransformRect(endFrame, canvasFrame, lastRectInCanvasFrame);
+
+  firstRectInRootFrame.Inflate(AppUnitsPerCSSPixel(), 0);
+  lastRectInRootFrame.Inflate(AppUnitsPerCSSPixel(), 0);
 
   nsAutoTArray<nsIFrame*, 16> hitFramesInFirstRect;
   nsLayoutUtils::GetFramesForArea(rootFrame,
-    collectorStart.mFirstRect,
+    firstRectInRootFrame,
     hitFramesInFirstRect,
     nsLayoutUtils::IGNORE_PAINT_SUPPRESSION |
       nsLayoutUtils::IGNORE_CROSS_DOC |
@@ -540,7 +529,7 @@ SelectionCarets::UpdateSelectionCarets()
 
   nsAutoTArray<nsIFrame*, 16> hitFramesInLastRect;
   nsLayoutUtils::GetFramesForArea(rootFrame,
-    collectorEnd.mLastRect,
+    lastRectInRootFrame,
     hitFramesInLastRect,
     nsLayoutUtils::IGNORE_PAINT_SUPPRESSION |
       nsLayoutUtils::IGNORE_CROSS_DOC |
@@ -549,11 +538,8 @@ SelectionCarets::UpdateSelectionCarets()
   SetStartFrameVisibility(hitFramesInFirstRect.Contains(startFrame));
   SetEndFrameVisibility(hitFramesInLastRect.Contains(endFrame));
 
-  nsLayoutUtils::TransformRect(rootFrame, canvasFrame, collectorStart.mFirstRect);
-  nsLayoutUtils::TransformRect(rootFrame, canvasFrame, collectorEnd.mLastRect);
-
-  SetStartFramePos(collectorStart.mFirstRect.BottomLeft());
-  SetEndFramePos(collectorEnd.mLastRect.BottomRight());
+  SetStartFramePos(firstRectInCanvasFrame.BottomLeft());
+  SetEndFramePos(lastRectInCanvasFrame.BottomRight());
   SetVisibility(true);
 
   // If range select only one character, append tilt class name to it.

layout/base/nsCaret.h

@@ -149,6 +149,9 @@ class nsCaret MOZ_FINAL : public nsISelectionListener
                                                uint8_t aBidiLevel,
                                                nsIFrame** aReturnFrame,
                                                int32_t* aReturnOffset);
+    static nsRect GetGeometryForFrame(nsIFrame* aFrame,
+                                      int32_t   aFrameOffset,
+                                      nscoord*  aBidiIndicatorSize);
 
     size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 
@@ -168,9 +171,6 @@ protected:
     };
     static Metrics ComputeMetrics(nsIFrame* aFrame, int32_t aOffset,
                                   nscoord aCaretHeight);
-    static nsRect GetGeometryForFrame(nsIFrame* aFrame,
-                                      int32_t   aFrameOffset,
-                                      nscoord*  aBidiIndicatorSize);
 
     void          ComputeCaretRects(nsIFrame* aFrame, int32_t aFrameOffset,
                                     nsRect* aCaretRect, nsRect* aHookRect);

layout/base/nsLayoutUtils.cpp

@@ -3400,20 +3400,6 @@ void nsLayoutUtils::RectListBuilder::AddRect(const nsRect& aRect) {
   mRectList->Append(rect);
 }
 
-nsLayoutUtils::FirstAndLastRectCollector::FirstAndLastRectCollector()
-  : mSeenFirstRect(false)
-{
-}
-
-void nsLayoutUtils::FirstAndLastRectCollector::AddRect(const nsRect& aRect) {
-  if (!mSeenFirstRect) {
-    mSeenFirstRect = true;
-    mFirstRect = aRect;
-  }
-
-  mLastRect = aRect;
-}
-
 nsIFrame* nsLayoutUtils::GetContainingBlockForClientRect(nsIFrame* aFrame)
 {
   return aFrame->PresContext()->PresShell()->GetRootFrame();

layout/base/nsLayoutUtils.h

@@ -1026,21 +1026,6 @@ public:
     virtual void AddRect(const nsRect& aRect);
   };
 
-  /**
-   * SelectionCaret draws carets base on range. The carets are at begin
-   * and end position of range's client rects. This class help us to
-   * collect first and last rect for drawing carets.
-   */
-  struct FirstAndLastRectCollector : public RectCallback {
-    nsRect mFirstRect;
-    nsRect mLastRect;
-    bool mSeenFirstRect;
-
-    FirstAndLastRectCollector();
-
-    virtual void AddRect(const nsRect& aRect);
-  };
-
   static nsIFrame* GetContainingBlockForClientRect(nsIFrame* aFrame);
 
   enum {