C++ nsRenderingContext::PushState方法代码示例

//------------------------------------------------------------------------------
void
nsSimplePageSequenceFrame::PaintPageSequence(nsRenderingContext& aRenderingContext,
                                             const nsRect&        aDirtyRect,
                                             nsPoint              aPt) {
  nsRect rect = aDirtyRect;
  float scale = PresContext()->GetPrintPreviewScale();
  aRenderingContext.PushState();
  nsPoint framePos = aPt;
  aRenderingContext.Translate(framePos);
  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);
    nsLayoutUtils::PaintFrame(&aRenderingContext, child,
                              nsRegion(rect - pt), NS_RGBA(0,0,0,0),
                              nsLayoutUtils::PAINT_SYNC_DECODE_IMAGES);
    aRenderingContext.PopState();
    child = child->GetNextSibling();
  }

  aRenderingContext.PopState();
}

void
nsFieldSetFrame::PaintBorderBackground(nsRenderingContext& aRenderingContext,
    nsPoint aPt, const nsRect& aDirtyRect, uint32_t aBGFlags)
{
  // if the border is smaller than the legend. Move the border down
  // to be centered on the legend. 
  // FIXME: This means border-radius clamping is incorrect; we should
  // override nsIFrame::GetBorderRadii.
  nsRect rect = VisualBorderRectRelativeToSelf();
  nscoord yoff = rect.y;
  rect += aPt;
  nsPresContext* presContext = PresContext();

  nsCSSRendering::PaintBackground(presContext, aRenderingContext, this,
                                  aDirtyRect, rect, aBGFlags);

  nsCSSRendering::PaintBoxShadowInner(presContext, aRenderingContext,
                                      this, rect, aDirtyRect);

   if (nsIFrame* legend = GetLegend()) {
     nscoord topBorder = StyleBorder()->GetComputedBorderWidth(NS_SIDE_TOP);

    // Use the rect of the legend frame, not mLegendRect, so we draw our
    // border under the legend's left and right margins.
    nsRect legendRect = legend->GetRect() + aPt;
    
    // we should probably use PaintBorderEdges to do this but for now just use clipping
    // to achieve the same effect.

    // draw left side
    nsRect clipRect(rect);
    clipRect.width = legendRect.x - rect.x;
    clipRect.height = topBorder;

    aRenderingContext.PushState();
    aRenderingContext.IntersectClip(clipRect);
    nsCSSRendering::PaintBorder(presContext, aRenderingContext, this,
                                aDirtyRect, rect, mStyleContext);

    aRenderingContext.PopState();


    // draw right side
    clipRect = rect;
    clipRect.x = legendRect.XMost();
    clipRect.width = rect.XMost() - legendRect.XMost();
    clipRect.height = topBorder;

    aRenderingContext.PushState();
    aRenderingContext.IntersectClip(clipRect);
    nsCSSRendering::PaintBorder(presContext, aRenderingContext, this,
                                aDirtyRect, rect, mStyleContext);

    aRenderingContext.PopState();

    
    // draw bottom
    clipRect = rect;
    clipRect.y += topBorder;
    clipRect.height = mRect.height - (yoff + topBorder);
    
    aRenderingContext.PushState();
    aRenderingContext.IntersectClip(clipRect);
    nsCSSRendering::PaintBorder(presContext, aRenderingContext, this,
                                aDirtyRect, rect, mStyleContext);

    aRenderingContext.PopState();
  } else {

    nsCSSRendering::PaintBorder(presContext, aRenderingContext, this,
                                aDirtyRect,
                                nsRect(aPt, mRect.Size()),
                                mStyleContext);
  }
}

// Draw a header or footer string
// @param aRenderingContext - rendering context to draw into
// @param aHeaderFooter - indicates whether it is a header or footer
// @param aJust - indicates where the string is located within the header/footer
// @param aStr - the string to be drawn
// @param aRect - the rect of the page
// @param aHeight - the height of the font
// @param aAscent - the ascent of the font
// @param aWidth - available width for the string
void
nsPageFrame::DrawHeaderFooter(nsRenderingContext& aRenderingContext,
                              nsHeaderFooterEnum   aHeaderFooter,
                              int32_t              aJust,
                              const nsString&      aStr,
                              const nsRect&        aRect,
                              nscoord              aAscent,
                              nscoord              aHeight,
                              nscoord              aWidth)
{

  nscoord contentWidth = aWidth - (mPD->mEdgePaperMargin.left + mPD->mEdgePaperMargin.right);

  if ((aHeaderFooter == eHeader && aHeight < mPD->mReflowMargin.top) ||
      (aHeaderFooter == eFooter && aHeight < mPD->mReflowMargin.bottom)) {
    nsAutoString str;
    ProcessSpecialCodes(aStr, str);

    int32_t indx;
    int32_t textWidth = 0;
    const PRUnichar* text = str.get();

    int32_t len = (int32_t)str.Length();
    if (len == 0) {
      return; // bail is empty string
    }
    // find how much text fits, the "position" is the size of the available area
    if (nsLayoutUtils::BinarySearchForPosition(&aRenderingContext, text, 0, 0, 0, len,
                                int32_t(contentWidth), indx, textWidth)) {
      if (indx < len-1 ) {
        // we can't fit in all the text
        if (indx > 3) {
          // But we can fit in at least 4 chars.  Show all but 3 of them, then
          // an ellipsis.
          // XXXbz for non-plane0 text, this may be cutting things in the
          // middle of a codepoint!  Also, we have no guarantees that the three
          // dots will fit in the space the three chars we removed took up with
          // these font metrics!
          str.Truncate(indx-3);
          str.AppendLiteral("...");
        } else {
          // We can only fit 3 or fewer chars.  Just show nothing
          str.Truncate();
        }
      }
    } else { 
      return; // bail if couldn't find the correct length
    }
    
    if (HasRTLChars(str)) {
      PresContext()->SetBidiEnabled();
    }

    // cacl the x and y positions of the text
    nscoord x = GetXPosition(aRenderingContext, aRect, aJust, str);
    nscoord y;
    if (aHeaderFooter == eHeader) {
      y = aRect.y + mPD->mExtraMargin.top + mPD->mEdgePaperMargin.top;
    } else {
      y = aRect.YMost() - aHeight - mPD->mExtraMargin.bottom - mPD->mEdgePaperMargin.bottom;
    }

    // set up new clip and draw the text
    aRenderingContext.PushState();
    aRenderingContext.SetColor(NS_RGB(0,0,0));
    aRenderingContext.IntersectClip(aRect);
    nsLayoutUtils::DrawString(this, &aRenderingContext, str.get(), str.Length(), nsPoint(x, y + aAscent));
    aRenderingContext.PopState();
  }
}