C++ nsRect::Empty方法代码示例

nsresult 
nsBoxObject::GetOffsetRect(nsRect& aRect)
{
  aRect.x = aRect.y = 0;
  aRect.Empty();
 
  if (!mContent)
    return NS_ERROR_NOT_INITIALIZED;

  nsresult res = NS_OK;
  nsCOMPtr<nsIDocument> doc = mContent->GetDocument();

  if (doc) {
    // Flush all pending notifications so that our frames are uptodate.  Must
    // do this before we get the presshell, since this can destroy presshells.
    doc->FlushPendingNotifications(Flush_Layout);

    // Get Presentation shell 0
    nsIPresShell *presShell = doc->GetShellAt(0);

    if(presShell) {
      // Get the Frame for our content
      nsIFrame* frame = nsnull;
      presShell->GetPrimaryFrameFor(mContent, &frame);
      if(frame != nsnull) {
        // Get its origin
        nsPoint origin = frame->GetPosition();

        // Get the union of all rectangles in this and continuation frames
        nsRect rcFrame;
        nsIFrame* next = frame;
        do {
          rcFrame.UnionRect(rcFrame, next->GetRect());
          next = next->GetNextInFlow();
        } while (nsnull != next);
        

        // Find the frame parent whose content's tagName either matches 
        // the tagName passed in or is the document element.
        nsIContent *docElement = doc->GetRootContent();
        nsIFrame* parent = frame->GetParent();
        while (parent) {
          // If we've hit the document element, break here
          if (parent->GetContent() == docElement) {
            break;
          }

          // Add the parent's origin to our own to get to the
          // right coordinate system
          origin += parent->GetPosition();

          parent = parent->GetParent();
        }
  
        // For the origin, add in the border for the frame
        const nsStyleBorder* border = frame->GetStyleBorder();
        origin.x += border->GetBorderWidth(NS_SIDE_LEFT);
        origin.y += border->GetBorderWidth(NS_SIDE_TOP);

        // And subtract out the border for the parent
        if (parent) {
          const nsStyleBorder* parentBorder = parent->GetStyleBorder();
          origin.x -= parentBorder->GetBorderWidth(NS_SIDE_LEFT);
          origin.y -= parentBorder->GetBorderWidth(NS_SIDE_TOP);
        }

        // Get the Presentation Context from the Shell
        nsPresContext *context = presShell->GetPresContext();
        if (context) {
          // Get the scale from that Presentation Context
          float scale;
          scale = context->TwipsToPixels();
              
          // Convert to pixels using that scale
          aRect.x = NSTwipsToIntPixels(origin.x, scale);
          aRect.y = NSTwipsToIntPixels(origin.y, scale);
          aRect.width = NSTwipsToIntPixels(rcFrame.width, scale);
          aRect.height = NSTwipsToIntPixels(rcFrame.height, scale);
        }
      }
    }
  }
 
  return res;
}

//.........这里部分代码省略.........
      if (mLegendRect.height > border.top) {
        // center the border on the legend
        mLegendSpace = mLegendRect.height - border.top;
      } else {
        mLegendRect.y = (border.top - mLegendRect.height)/2;
      }

      // if the legend space changes then we need to reflow the 
      // content area as well.
      if (mLegendSpace != oldSpace) {
        if (reflowContent == PR_FALSE || reason == eReflowReason_Dirty) {
          reflowContent = PR_TRUE;
          reason = eReflowReason_Resize;
        }
      }

      // if we are contrained then remove the legend from our available height.
      if (NS_INTRINSICSIZE != availSize.height) {
        if (availSize.height >= mLegendSpace)
          availSize.height -= mLegendSpace;
      }
  
      // don't get any smaller than the legend
      if (NS_INTRINSICSIZE != availSize.width) {
        if (availSize.width < mLegendRect.width)
          availSize.width = mLegendRect.width;
      }

      FinishReflowChild(mLegendFrame, aPresContext, &legendReflowState, 
                        legendDesiredSize, 0, 0, NS_FRAME_NO_MOVE_FRAME);    

    }
  } else {
    mLegendRect.Empty();
    mLegendSpace = 0;
  }

  nsRect contentRect;

  // reflow the content frame only if needed
  if (mContentFrame) {
    if (reflowContent) {
      availSize.width = aReflowState.mComputedWidth;

      nsHTMLReflowState kidReflowState(aPresContext, aReflowState, mContentFrame,
                                       availSize, reason);

      nsHTMLReflowMetrics kidDesiredSize(aDesiredSize.mComputeMEW, aDesiredSize.mFlags);
      // Reflow the frame
      ReflowChild(mContentFrame, aPresContext, kidDesiredSize, kidReflowState,
                  borderPadding.left + kidReflowState.mComputedMargin.left,
                  borderPadding.top + mLegendSpace + kidReflowState.mComputedMargin.top,
                  0, aStatus);

      // set the rect. make sure we add the margin back in.
      contentRect.SetRect(borderPadding.left,borderPadding.top + mLegendSpace,kidDesiredSize.width ,kidDesiredSize.height);
      if (aReflowState.mComputedHeight != NS_INTRINSICSIZE &&
          borderPadding.top + mLegendSpace+kidDesiredSize.height > aReflowState.mComputedHeight) {
        kidDesiredSize.height = aReflowState.mComputedHeight-(borderPadding.top + mLegendSpace);
      }

      FinishReflowChild(mContentFrame, aPresContext, &kidReflowState, 
                        kidDesiredSize, contentRect.x, contentRect.y, 0);
      if (aDesiredSize.mComputeMEW) {
        aDesiredSize.mMaxElementWidth = kidDesiredSize.mMaxElementWidth;
        if (eStyleUnit_Coord == aReflowState.mStylePosition->mWidth.GetUnit() &&