C++ Rect::IsEqualInterior方法代码示例

/* static */ void
gfxAlphaBoxBlur::BlurRectangle(gfxContext* aDestinationCtx,
                               const gfxRect& aRect,
                               RectCornerRadii* aCornerRadii,
                               const gfxPoint& aBlurStdDev,
                               const gfxRGBA& aShadowColor,
                               const gfxRect& aDirtyRect,
                               const gfxRect& aSkipRect)
{
  DrawTarget& destDrawTarget = *aDestinationCtx->GetDrawTarget();
  IntSize blurRadius = CalculateBlurRadius(aBlurStdDev);

  IntRect rect = RoundedToInt(ToRect(aRect));
  IntMargin extendDestBy;
  IntMargin slice;

  RefPtr<SourceSurface> boxShadow = GetBlur(destDrawTarget,
                                            rect.Size(), blurRadius,
                                            aCornerRadii, aShadowColor,
                                            extendDestBy, slice);
  if (!boxShadow) {
    return;
  }

  destDrawTarget.PushClipRect(ToRect(aDirtyRect));

  // Copy the right parts from boxShadow into destDrawTarget. The middle parts
  // will be stretched, border-image style.

  Rect srcOuter(Point(), Size(boxShadow->GetSize()));
  Rect srcInner = srcOuter;
  srcInner.Deflate(Margin(slice));

  rect.Inflate(extendDestBy);
  Rect dstOuter(rect);
  Rect dstInner(rect);
  dstInner.Deflate(Margin(slice));

  Rect skipRect = ToRect(aSkipRect);

  if (srcInner.IsEqualInterior(srcOuter)) {
    MOZ_ASSERT(dstInner.IsEqualInterior(dstOuter));
    // The target rect is smaller than the minimal size so just draw the surface
    destDrawTarget.DrawSurface(boxShadow, dstInner, srcInner);
  } else {
    DrawBoxShadows(destDrawTarget, boxShadow, dstOuter, dstInner,
                   srcOuter, srcInner, skipRect);

    // Middle part
    RepeatOrStretchSurface(destDrawTarget, boxShadow,
                           RectWithEdgesTRBL(dstInner.Y(), dstInner.XMost(),
                                             dstInner.YMost(), dstInner.X()),
                           RectWithEdgesTRBL(srcInner.Y(), srcInner.XMost(),
                                             srcInner.YMost(), srcInner.X()),
                           skipRect);
  }

  // A note about anti-aliasing and seems between adjacent parts:
  // We don't explicitly disable anti-aliasing in the DrawSurface calls above,
  // so if there's a transform on destDrawTarget that is not pixel-aligned,
  // there will be seams between adjacent parts of the box-shadow. It's hard to
  // avoid those without the use of an intermediate surface.
  // You might think that we could avoid those by just turning of AA, but there
  // is a problem with that: Box-shadow rendering needs to clip out the
  // element's border box, and we'd like that clip to have anti-aliasing -
  // especially if the element has rounded corners! So we can't do that unless
  // we have a way to say "Please anti-alias the clip, but don't antialias the
  // destination rect of the DrawSurface call".
  // On OS X there is an additional problem with turning off AA: CoreGraphics
  // will not just fill the pixels that have their pixel center inside the
  // filled shape. Instead, it will fill all the pixels which are partially
  // covered by the shape. So for pixels on the edge between two adjacent parts,
  // all those pixels will be painted to by both parts, which looks very bad.

  destDrawTarget.PopClip();
}