static bool
GetInsetBoxShadowRects(const Margin& aBlurMargin,
const Margin& aInnerMargin,
const Rect& aShadowClipRect,
const Rect& aDestinationRect,
Rect& aOutWhitespaceRect,
Rect& aOutOuterRect)
{
// We always copy (2 * blur radius) + corner radius worth of data to the destination rect
// This covers the blend of the path + the actual blur
// Need +1 so that we copy the edges correctly as we'll copy
// over the min box shadow corners then the +1 for the edges between
// Note, the (x,y) coordinates are from the blur margin
// since the frame outside the whitespace rect is 1 blur radius extra space.
Rect insideWhiteSpace(aBlurMargin.left,
aBlurMargin.top,
aInnerMargin.LeftRight() + 1,
aInnerMargin.TopBottom() + 1);
// If the inner white space rect is larger than the shadow clip rect
// our approach does not work as we'll just copy one corner
// and cover the destination. In those cases, fallback to the destination rect
bool useDestRect = (aShadowClipRect.width <= aInnerMargin.LeftRight()) ||
(aShadowClipRect.height <= aInnerMargin.TopBottom());
if (useDestRect) {
aOutWhitespaceRect = aShadowClipRect;
aOutOuterRect = aDestinationRect;
} else {
aOutWhitespaceRect = insideWhiteSpace;
aOutOuterRect = aOutWhitespaceRect;
aOutOuterRect.Inflate(aBlurMargin);
}
return useDestRect;
}
static void
ComputeRectsForInsetBoxShadow(gfxIntSize aBlurRadius,
gfxIntSize aSpreadRadius,
const Rect& aDestRect,
const Rect& aShadowClipRect,
Rect& aOutOuterRect,
Rect& aOutInnerRect,
Margin& aOutPathMargins)
{
gfxIntSize marginSize = aBlurRadius + aSpreadRadius;
// The sizes we're given for aBlurRadius/aSpreadRadius are radius'.
// We actually want to paint the whole blur, so we need the diameter.
// We render both the outer / inner blur portions of a blur,
// Then we clip out the outer portion later.
aOutPathMargins.SizeTo(marginSize.height, marginSize.width, marginSize.height, marginSize.width);
aOutPathMargins += aOutPathMargins;
aOutOuterRect.x = 0;
aOutInnerRect.x = marginSize.width;
aOutOuterRect.y = 0;
aOutInnerRect.y = marginSize.height;
// + 1 for the middle edges so we can sample them
aOutInnerRect.width = aOutPathMargins.LeftRight() + 1;
aOutInnerRect.height = aOutPathMargins.TopBottom() + 1;
// The outer path rect needs to be 1 blur radius past the inner edges
aOutOuterRect.width = aOutInnerRect.XMost() + marginSize.width;
aOutOuterRect.height = aOutInnerRect.YMost() + marginSize.height;
if ((aOutOuterRect.width >= aDestRect.width) ||
(aOutOuterRect.height >= aDestRect.height) ||
(aOutInnerRect.width >= aShadowClipRect.width) ||
(aOutInnerRect.height >= aShadowClipRect.height))
{
aOutOuterRect.width = aDestRect.width;
aOutOuterRect.height = aDestRect.height;
aOutInnerRect.width = aShadowClipRect.width;
aOutInnerRect.height = aShadowClipRect.height;
aOutPathMargins.SizeTo(0, 0, 0, 0);
}
}
