Bug 56488 - Down scroll arrow hidden, draws behind resize widget when neither Status Bar nor horizontal scrollbar are displayed. r+sr=roc.

layout/generic/nsGfxScrollFrame.cpp

@@ -2497,6 +2497,34 @@ static void LayoutAndInvalidate(nsBoxLayoutState& aState,
     aBox->Invalidate(aBox->GetOverflowRect());
 }
 
+static void AdjustScrollbarRect(nsIView* aView, nsPresContext* aPresContext,
+                                nsRect& aRect, PRBool aVertical)
+{
+  if ((aVertical ? aRect.width : aRect.height) == 0)
+    return;
+
+  nsPoint offset;
+  nsIWidget* widget = aView->GetNearestWidget(&offset);
+
+  nsIntRect widgetRect;
+  if (!widget->ShowsResizeIndicator(&widgetRect))
+    return;
+
+  nsRect resizerRect =
+      nsRect(aPresContext->DevPixelsToAppUnits(widgetRect.x) - offset.x,
+             aPresContext->DevPixelsToAppUnits(widgetRect.y) - offset.y,
+             aPresContext->DevPixelsToAppUnits(widgetRect.width),
+             aPresContext->DevPixelsToAppUnits(widgetRect.height));
+
+  if (!aRect.Intersects(resizerRect))
+    return;
+
+  if (aVertical)
+    aRect.height = PR_MAX(0, resizerRect.y - aRect.y);
+  else
+    aRect.width = PR_MAX(0, resizerRect.x - aRect.x);
+}
+
 void
 nsGfxScrollFrameInner::LayoutScrollbars(nsBoxLayoutState& aState,
                                         const nsRect& aContentArea,
@@ -2506,6 +2534,8 @@ nsGfxScrollFrameInner::LayoutScrollbars(nsBoxLayoutState& aState,
   NS_ASSERTION(!mSupppressScrollbarUpdate,
                "This should have been suppressed");
     
+  nsIView* view = mOuter->GetView();
+  nsPresContext* presContext = mScrolledFrame->PresContext();
   if (mVScrollbarBox) {
     NS_PRECONDITION(mVScrollbarBox->IsBoxFrame(), "Must be a box frame!");
     nsRect vRect(aScrollArea);
@@ -2514,6 +2544,7 @@ nsGfxScrollFrameInner::LayoutScrollbars(nsBoxLayoutState& aState,
     nsMargin margin;
     mVScrollbarBox->GetMargin(margin);
     vRect.Deflate(margin);
+    AdjustScrollbarRect(view, presContext, vRect, PR_TRUE);
     LayoutAndInvalidate(aState, mVScrollbarBox, vRect);
   }
 
@@ -2525,6 +2556,7 @@ nsGfxScrollFrameInner::LayoutScrollbars(nsBoxLayoutState& aState,
     nsMargin margin;
     mHScrollbarBox->GetMargin(margin);
     hRect.Deflate(margin);
+    AdjustScrollbarRect(view, presContext, hRect, PR_FALSE);
     LayoutAndInvalidate(aState, mHScrollbarBox, hRect);
   }
 

widget/public/nsIWidget.h

@@ -41,6 +41,7 @@
 #include "nsISupports.h"
 #include "nsColor.h"
 #include "nsCoord.h"
+#include "nsRect.h"
 
 #include "prthread.h"
 #include "nsEvent.h"
@@ -53,7 +54,6 @@ class   nsIFontMetrics;
 class   nsIRenderingContext;
 class   nsIDeviceContext;
 class   nsIRegion;
-struct  nsRect;
 struct  nsFont;
 class   nsIEventListener;
 class   nsIRollupListener;
@@ -94,10 +94,10 @@ typedef nsEventStatus (*PR_CALLBACK EVENT_CALLBACK)(nsGUIEvent *event);
 #define NS_NATIVE_PLUGIN_PORT_CG    101
 #endif
 
-// 594d22a3-ef2d-4189-9bc1-3c3da586f47a
+// 3d304df2-8e6b-4f09-8782-98bd649c7e96
 #define NS_IWIDGET_IID \
-{ 0x594d22a3, 0xef2d, 0x4189, \
-  { 0x9b, 0xc1, 0x3c, 0x3d, 0xa5, 0x86, 0xf4, 0x7a } }
+{ 0x3d304df2, 0x8e6b, 0x4f09, \
+  { 0x87, 0x82, 0x98, 0xbd, 0x64, 0x9c, 0x7e, 0x96 } }
 
 // Hide the native window systems real window type so as to avoid
 // including native window system types and APIs. This is necessary
@@ -1045,6 +1045,17 @@ class nsIWidget : public nsISupports {
      *                windows.
      */
     NS_IMETHOD SetWindowTitlebarColor(nscolor aColor, PRBool aActive) = 0;
+    
+    /*
+     * Determine whether the widget shows a resize widget. If it does,
+     * aResizerRect returns the resizer's rect.
+     *
+     * Returns false on any platform that does not support it.
+     *
+     * @param aResizerRect The resizer's rect in device pixels.
+     * @return Whether a resize widget is shown.
+     */
+    virtual PRBool ShowsResizeIndicator(nsIntRect* aResizerRect) = 0;
 
     /**
      * Get the Thebes surface associated with this widget.

widget/src/cocoa/nsChildView.h

@@ -304,6 +304,7 @@ public:
   NS_IMETHOD              ScreenToWidget(const nsRect& aOldRect, nsRect& aNewRect);
   NS_IMETHOD              BeginResizingChildren(void);
   NS_IMETHOD              EndResizingChildren(void);
+  virtual PRBool          ShowsResizeIndicator(nsIntRect* aResizerRect);
 
   static  PRBool          ConvertStatus(nsEventStatus aStatus)
                           { return aStatus == nsEventStatus_eConsumeNoDefault; }

widget/src/cocoa/nsChildView.mm

@@ -1158,6 +1158,29 @@ NS_IMETHODIMP nsChildView::EndResizingChildren(void)
 }
 
 
+static const PRInt32 resizeIndicatorWidth = 15;
+static const PRInt32 resizeIndicatorHeight = 15;
+PRBool nsChildView::ShowsResizeIndicator(nsIntRect* aResizerRect)
+{
+  NSView *topLevelView = mView, *superView = nil;
+  while (superView = [topLevelView superview])
+    topLevelView = superView;
+
+  if (![[topLevelView window] showsResizeIndicator])
+    return PR_FALSE;
+
+  if (aResizerRect) {
+    NSSize bounds = [topLevelView bounds].size;
+    NSPoint corner = NSMakePoint(bounds.width, [topLevelView isFlipped] ? bounds.height : 0);
+    corner = [topLevelView convertPoint:corner toView:mView];
+    aResizerRect->SetRect(NSToIntRound(corner.x) - resizeIndicatorWidth,
+                          NSToIntRound(corner.y) - resizeIndicatorHeight,
+                          resizeIndicatorWidth, resizeIndicatorHeight);
+  }
+  return PR_TRUE;
+}
+
+
 NS_IMETHODIMP nsChildView::GetPluginClipRect(nsRect& outClipRect, nsPoint& outOrigin, PRBool& outWidgetVisible)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

widget/src/xpwidgets/nsBaseWidget.cpp

@@ -862,6 +862,12 @@ nsBaseWidget::SetWindowTitlebarColor(nscolor aColor, PRBool aActive)
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+PRBool
+nsBaseWidget::ShowsResizeIndicator(nsIntRect* aResizerRect)
+{
+  return PR_FALSE;
+}
+
 
 /**
  * Modifies aFile to point at an icon file with the given name and suffix.  The

widget/src/xpwidgets/nsBaseWidget.h

@@ -133,6 +133,7 @@ public:
   NS_IMETHOD              BeginSecureKeyboardInput();
   NS_IMETHOD              EndSecureKeyboardInput();
   NS_IMETHOD              SetWindowTitlebarColor(nscolor aColor, PRBool aActive);
+  virtual PRBool          ShowsResizeIndicator(nsIntRect* aResizerRect);
   virtual void            ConvertToDeviceCoordinates(nscoord  &aX,nscoord &aY) {}
   virtual void            FreeNativeData(void * data, PRUint32 aDataType) {}
   NS_IMETHOD              BeginResizeDrag(nsGUIEvent* aEvent, PRInt32 aHorizontal, PRInt32 aVertical);