gecko-dev/gfx/thebes/gfxBlur.cpp
2012-05-21 12:12:37 +01:00

102 lines
3.3 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "gfxBlur.h"
#include "mozilla/gfx/Blur.h"
using namespace mozilla::gfx;
gfxAlphaBoxBlur::gfxAlphaBoxBlur()
: mBlur(nsnull)
{
}
gfxAlphaBoxBlur::~gfxAlphaBoxBlur()
{
delete mBlur;
}
gfxContext*
gfxAlphaBoxBlur::Init(const gfxRect& aRect,
const gfxIntSize& aSpreadRadius,
const gfxIntSize& aBlurRadius,
const gfxRect* aDirtyRect,
const gfxRect* aSkipRect)
{
mozilla::gfx::Rect rect(aRect.x, aRect.y, aRect.width, aRect.height);
IntSize spreadRadius(aSpreadRadius.width, aSpreadRadius.height);
IntSize blurRadius(aBlurRadius.width, aBlurRadius.height);
nsAutoPtr<mozilla::gfx::Rect> dirtyRect;
if (aDirtyRect) {
dirtyRect = new mozilla::gfx::Rect(aDirtyRect->x, aDirtyRect->y, aDirtyRect->width, aDirtyRect->height);
}
nsAutoPtr<mozilla::gfx::Rect> skipRect;
if (aSkipRect) {
skipRect = new mozilla::gfx::Rect(aSkipRect->x, aSkipRect->y, aSkipRect->width, aSkipRect->height);
}
mBlur = new AlphaBoxBlur(rect, spreadRadius, blurRadius, dirtyRect, skipRect);
unsigned char* data = mBlur->GetData();
if (!data)
return nsnull;
IntSize size = mBlur->GetSize();
// Make an alpha-only surface to draw on. We will play with the data after
// everything is drawn to create a blur effect.
mImageSurface = new gfxImageSurface(data, gfxIntSize(size.width, size.height),
mBlur->GetStride(),
gfxASurface::ImageFormatA8);
if (mImageSurface->CairoStatus())
return nsnull;
IntRect irect = mBlur->GetRect();
gfxPoint topleft(irect.TopLeft().x, irect.TopLeft().y);
// Use a device offset so callers don't need to worry about translating
// coordinates, they can draw as if this was part of the destination context
// at the coordinates of rect.
mImageSurface->SetDeviceOffset(-topleft);
mContext = new gfxContext(mImageSurface);
return mContext;
}
void
gfxAlphaBoxBlur::Paint(gfxContext* aDestinationCtx, const gfxPoint& offset)
{
if (!mContext)
return;
mBlur->Blur();
mozilla::gfx::Rect* dirtyrect = mBlur->GetDirtyRect();
// Avoid a semi-expensive clip operation if we can, otherwise
// clip to the dirty rect
if (dirtyrect) {
aDestinationCtx->Save();
aDestinationCtx->NewPath();
gfxRect dirty(dirtyrect->x, dirtyrect->y, dirtyrect->width, dirtyrect->height);
gfxRect imageRect(offset - mImageSurface->GetDeviceOffset(), mImageSurface->GetSize());
dirty.IntersectRect(dirty, imageRect);
aDestinationCtx->Rectangle(dirty);
aDestinationCtx->Clip();
aDestinationCtx->Mask(mImageSurface, offset);
aDestinationCtx->Restore();
} else {
aDestinationCtx->Mask(mImageSurface, offset);
}
}
gfxIntSize gfxAlphaBoxBlur::CalculateBlurRadius(const gfxPoint& aStd)
{
mozilla::gfx::Point std(aStd.x, aStd.y);
IntSize size = AlphaBoxBlur::CalculateBlurRadius(std);
return gfxIntSize(size.width, size.height);
}