C++ nsIRenderingContext::Scale方法代码示例

//------------------------------------------------------------------------------
void
nsSimplePageSequenceFrame::PaintPageSequence(nsIRenderingContext& aRenderingContext,
                                             const nsRect&        aDirtyRect,
                                             nsPoint              aPt) {
  nsRect rect = aDirtyRect;
  float scale = PresContext()->GetPrintPreviewScale();
  aRenderingContext.PushState();
  nsPoint framePos = aPt;
  aRenderingContext.Translate(framePos.x, framePos.y);
  rect -= framePos;
  aRenderingContext.Scale(scale, scale);
  rect.ScaleRoundOut(1.0f / scale);

  // Now the rect and the rendering coordinates are are relative to this frame.
  // Loop over the pages and paint them.
  nsIFrame* child = GetFirstChild(nsnull);
  while (child) {
    nsPoint pt = child->GetPosition();
    // The rendering context has to be translated before each call to PaintFrame
    aRenderingContext.PushState();
    aRenderingContext.Translate(pt.x, pt.y);
    nsLayoutUtils::PaintFrame(&aRenderingContext, child,
                              nsRegion(rect - pt), NS_RGBA(0,0,0,0));
    aRenderingContext.PopState();
    child = child->GetNextSibling();
  }

  aRenderingContext.PopState();
}

//------------------------------------------------------------------------------
void
nsPageFrame::PaintPageContent(nsIRenderingContext& aRenderingContext,
                              const nsRect&        aDirtyRect,
                              nsPoint              aPt) {
  nsIFrame* pageContentFrame  = mFrames.FirstChild();
  nsRect rect = aDirtyRect;
  float scale = PresContext()->GetPageScale();
  aRenderingContext.PushState();
  nsPoint framePos = aPt + pageContentFrame->GetOffsetTo(this);
  aRenderingContext.Translate(framePos.x, framePos.y);
  // aPt translates to coords relative to this, then margins translate to
  // pageContentFrame's coords
  rect -= framePos;
  aRenderingContext.Scale(scale, scale);
  rect.ScaleRoundOut(1.0f / scale);
  // Make sure we don't draw where we aren't supposed to draw, especially
  // when printing selection
  nsRect clipRect(nsPoint(0, 0), pageContentFrame->GetSize());
  // Note: this computation matches how we compute maxSize.height
  // in nsPageFrame::Reflow
  nscoord expectedPageContentHeight = 
    NSToCoordCeil((GetSize().height - mPD->mReflowMargin.TopBottom()) / scale);
  if (clipRect.height > expectedPageContentHeight) {
    // We're doing print-selection, with one long page-content frame.
    // Clip to the appropriate page-content slice for the current page.
    NS_ASSERTION(mPageNum > 0, "page num should be positive");
    // Note: The pageContentFrame's y-position has been set such that a zero
    // y-value matches the top edge of the current page.  So, to clip to the
    // current page's content (in coordinates *relative* to the page content
    // frame), we just negate its y-position and add the top margin.
    clipRect.y = NSToCoordCeil((-pageContentFrame->GetRect().y + 
                                mPD->mReflowMargin.top) / scale);
    clipRect.height = expectedPageContentHeight;
    NS_ASSERTION(clipRect.y < pageContentFrame->GetSize().height,
                 "Should be clipping to region inside the page content bounds");
  }
  aRenderingContext.SetClipRect(clipRect, nsClipCombine_kIntersect);

  nsRect backgroundRect = nsRect(nsPoint(0, 0), pageContentFrame->GetSize());
  nsCSSRendering::PaintBackground(PresContext(), aRenderingContext, this,
                                  rect, backgroundRect,
                                  nsCSSRendering::PAINTBG_SYNC_DECODE_IMAGES);

  nsLayoutUtils::PaintFrame(&aRenderingContext, pageContentFrame,
                            nsRegion(rect), NS_RGBA(0,0,0,0),
                            nsLayoutUtils::PAINT_SYNC_DECODE_IMAGES);

  aRenderingContext.PopState();
}

//------------------------------------------------------------------------------
void
nsPageFrame::PaintPageContent(nsIRenderingContext& aRenderingContext,
                              const nsRect&        aDirtyRect,
                              nsPoint              aPt) {
  nsIFrame* pageContentFrame  = mFrames.FirstChild();
  nsRect rect = aDirtyRect;
  float scale = PresContext()->GetPageScale();
  aRenderingContext.PushState();
  nsPoint framePos = aPt + pageContentFrame->GetOffsetTo(this);
  aRenderingContext.Translate(framePos.x, framePos.y);
  // aPt translates to coords relative to this, then margins translate to
  // pageContentFrame's coords
  rect -= framePos;
  aRenderingContext.Scale(scale, scale);
  rect.ScaleRoundOut(1.0f / scale);
  // Make sure we don't draw where we aren't supposed to draw, especially
  // when printing selection
  nsRect clipRect(nsPoint(0, 0), pageContentFrame->GetSize());
  // Note: this computation matches how we compute maxSize.height
  // in nsPageFrame::Reflow
  nscoord expectedPageContentHeight = 
    NSToCoordCeil((GetSize().height - mPD->mReflowMargin.TopBottom()) / scale);
  if (clipRect.height > expectedPageContentHeight) {
    // We're doing print-selection, with one long page-content frame.
    // Clip to the appropriate page-content slice for the current page.
    NS_ASSERTION(mPageNum > 0, "page num should be positive");
    clipRect.y =  expectedPageContentHeight * (mPageNum - 1);
    clipRect.height = expectedPageContentHeight;
    NS_ASSERTION(clipRect.y < pageContentFrame->GetSize().height,
                 "Should be clipping to region inside the page content bounds");
  }
  aRenderingContext.SetClipRect(clipRect, nsClipCombine_kIntersect);

  const nsStyleBorder* border = GetStyleBorder();
  const nsStylePadding* padding = GetStylePadding();
  nsRect backgroundRect = nsRect(nsPoint(0, 0), pageContentFrame->GetSize());
  nsCSSRendering::PaintBackground(PresContext(), aRenderingContext, this,
                                  rect, backgroundRect, *border, *padding,
                                  PR_TRUE);

  nsLayoutUtils::PaintFrame(&aRenderingContext, pageContentFrame,
                            nsRegion(rect), NS_RGBA(0,0,0,0));

  aRenderingContext.PopState();
}