gecko-dev/gfx/layers/ThebesLayerBuffer.cpp

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C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* 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 "ThebesLayerBuffer.h"
#include "Layers.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
#include "gfxUtils.h"
#include "nsDeviceContext.h"
#include "sampler.h"
namespace mozilla {
namespace layers {
nsIntRect
ThebesLayerBuffer::GetQuadrantRectangle(XSide aXSide, YSide aYSide)
{
// quadrantTranslation is the amount we translate the top-left
// of the quadrant by to get coordinates relative to the layer
nsIntPoint quadrantTranslation = -mBufferRotation;
quadrantTranslation.x += aXSide == LEFT ? mBufferRect.width : 0;
quadrantTranslation.y += aYSide == TOP ? mBufferRect.height : 0;
return mBufferRect + quadrantTranslation;
}
/**
* @param aXSide LEFT means we draw from the left side of the buffer (which
* is drawn on the right side of mBufferRect). RIGHT means we draw from
* the right side of the buffer (which is drawn on the left side of
* mBufferRect).
* @param aYSide TOP means we draw from the top side of the buffer (which
* is drawn on the bottom side of mBufferRect). BOTTOM means we draw from
* the bottom side of the buffer (which is drawn on the top side of
* mBufferRect).
*/
void
ThebesLayerBuffer::DrawBufferQuadrant(gfxContext* aTarget,
XSide aXSide, YSide aYSide,
float aOpacity,
gfxASurface* aMask,
const gfxMatrix* aMaskTransform)
{
// The rectangle that we're going to fill. Basically we're going to
// render the buffer at mBufferRect + quadrantTranslation to get the
// pixels in the right place, but we're only going to paint within
// mBufferRect
nsIntRect quadrantRect = GetQuadrantRectangle(aXSide, aYSide);
nsIntRect fillRect;
if (!fillRect.IntersectRect(mBufferRect, quadrantRect))
return;
aTarget->NewPath();
aTarget->Rectangle(gfxRect(fillRect.x, fillRect.y,
fillRect.width, fillRect.height),
true);
gfxPoint quadrantTranslation(quadrantRect.x, quadrantRect.y);
nsRefPtr<gfxPattern> pattern = new gfxPattern(mBuffer);
#ifdef MOZ_GFX_OPTIMIZE_MOBILE
gfxPattern::GraphicsFilter filter = gfxPattern::FILTER_NEAREST;
pattern->SetFilter(filter);
#endif
gfxContextMatrixAutoSaveRestore saveMatrix(aTarget);
// Transform from user -> buffer space.
gfxMatrix transform;
transform.Translate(-quadrantTranslation);
pattern->SetMatrix(transform);
aTarget->SetPattern(pattern);
if (aMask) {
if (aOpacity == 1.0) {
aTarget->SetMatrix(*aMaskTransform);
aTarget->Mask(aMask);
} else {
aTarget->PushGroup(gfxASurface::CONTENT_COLOR_ALPHA);
aTarget->Paint(aOpacity);
aTarget->PopGroupToSource();
aTarget->SetMatrix(*aMaskTransform);
aTarget->Mask(aMask);
}
} else {
if (aOpacity == 1.0) {
aTarget->Fill();
} else {
aTarget->Save();
aTarget->Clip();
aTarget->Paint(aOpacity);
aTarget->Restore();
}
}
}
void
ThebesLayerBuffer::DrawBufferWithRotation(gfxContext* aTarget, float aOpacity,
gfxASurface* aMask,
const gfxMatrix* aMaskTransform)
{
SAMPLE_LABEL("ThebesLayerBuffer", "DrawBufferWithRotation");
// Draw four quadrants. We could use REPEAT_, but it's probably better
// not to, to be performance-safe.
DrawBufferQuadrant(aTarget, LEFT, TOP, aOpacity, aMask, aMaskTransform);
DrawBufferQuadrant(aTarget, RIGHT, TOP, aOpacity, aMask, aMaskTransform);
DrawBufferQuadrant(aTarget, LEFT, BOTTOM, aOpacity, aMask, aMaskTransform);
DrawBufferQuadrant(aTarget, RIGHT, BOTTOM, aOpacity, aMask, aMaskTransform);
}
already_AddRefed<gfxContext>
ThebesLayerBuffer::GetContextForQuadrantUpdate(const nsIntRect& aBounds)
{
nsRefPtr<gfxContext> ctx = new gfxContext(mBuffer);
// Figure out which quadrant to draw in
PRInt32 xBoundary = mBufferRect.XMost() - mBufferRotation.x;
PRInt32 yBoundary = mBufferRect.YMost() - mBufferRotation.y;
XSide sideX = aBounds.XMost() <= xBoundary ? RIGHT : LEFT;
YSide sideY = aBounds.YMost() <= yBoundary ? BOTTOM : TOP;
nsIntRect quadrantRect = GetQuadrantRectangle(sideX, sideY);
NS_ASSERTION(quadrantRect.Contains(aBounds), "Messed up quadrants");
ctx->Translate(-gfxPoint(quadrantRect.x, quadrantRect.y));
return ctx.forget();
}
static void
WrapRotationAxis(PRInt32* aRotationPoint, PRInt32 aSize)
{
if (*aRotationPoint < 0) {
*aRotationPoint += aSize;
} else if (*aRotationPoint >= aSize) {
*aRotationPoint -= aSize;
}
}
ThebesLayerBuffer::PaintState
ThebesLayerBuffer::BeginPaint(ThebesLayer* aLayer, ContentType aContentType,
PRUint32 aFlags)
{
PaintState result;
// We need to disable rotation if we're going to be resampled when
// drawing, because we might sample across the rotation boundary.
bool canHaveRotation = !(aFlags & (PAINT_WILL_RESAMPLE | PAINT_NO_ROTATION));
nsIntRegion validRegion = aLayer->GetValidRegion();
ContentType contentType;
nsIntRegion neededRegion;
bool canReuseBuffer;
nsIntRect destBufferRect;
while (true) {
contentType = aContentType;
neededRegion = aLayer->GetVisibleRegion();
canReuseBuffer = mBuffer && BufferSizeOkFor(neededRegion.GetBounds().Size());
if (canReuseBuffer) {
if (mBufferRect.Contains(neededRegion.GetBounds())) {
// We don't need to adjust mBufferRect.
destBufferRect = mBufferRect;
} else if (neededRegion.GetBounds().Size() <= mBufferRect.Size()) {
// The buffer's big enough but doesn't contain everything that's
// going to be visible. We'll move it.
destBufferRect = nsIntRect(neededRegion.GetBounds().TopLeft(), mBufferRect.Size());
} else {
destBufferRect = neededRegion.GetBounds();
}
} else {
destBufferRect = neededRegion.GetBounds();
}
if ((aFlags & PAINT_WILL_RESAMPLE) &&
(!neededRegion.GetBounds().IsEqualInterior(destBufferRect) ||
neededRegion.GetNumRects() > 1)) {
// The area we add to neededRegion might not be painted opaquely
contentType = gfxASurface::CONTENT_COLOR_ALPHA;
// We need to validate the entire buffer, to make sure that only valid
// pixels are sampled
neededRegion = destBufferRect;
}
if (mBuffer && contentType != mBuffer->GetContentType()) {
// We're effectively clearing the valid region, so we need to draw
// the entire needed region now.
result.mRegionToInvalidate = aLayer->GetValidRegion();
validRegion.SetEmpty();
Clear();
// Restart decision process with the cleared buffer. We can only go
// around the loop one more iteration, since mBuffer is null now.
continue;
}
break;
}
NS_ASSERTION(destBufferRect.Contains(neededRegion.GetBounds()),
"Destination rect doesn't contain what we need to paint");
result.mRegionToDraw.Sub(neededRegion, validRegion);
if (result.mRegionToDraw.IsEmpty())
return result;
nsIntRect drawBounds = result.mRegionToDraw.GetBounds();
nsRefPtr<gfxASurface> destBuffer;
PRUint32 bufferFlags = canHaveRotation ? ALLOW_REPEAT : 0;
if (canReuseBuffer) {
nsIntRect keepArea;
if (keepArea.IntersectRect(destBufferRect, mBufferRect)) {
// Set mBufferRotation so that the pixels currently in mBuffer
// will still be rendered in the right place when mBufferRect
// changes to destBufferRect.
nsIntPoint newRotation = mBufferRotation +
(destBufferRect.TopLeft() - mBufferRect.TopLeft());
WrapRotationAxis(&newRotation.x, mBufferRect.width);
WrapRotationAxis(&newRotation.y, mBufferRect.height);
NS_ASSERTION(nsIntRect(nsIntPoint(0,0), mBufferRect.Size()).Contains(newRotation),
"newRotation out of bounds");
PRInt32 xBoundary = destBufferRect.XMost() - newRotation.x;
PRInt32 yBoundary = destBufferRect.YMost() - newRotation.y;
if ((drawBounds.x < xBoundary && xBoundary < drawBounds.XMost()) ||
(drawBounds.y < yBoundary && yBoundary < drawBounds.YMost()) ||
(newRotation != nsIntPoint(0,0) && !canHaveRotation)) {
// The stuff we need to redraw will wrap around an edge of the
// buffer, so move the pixels we can keep into a position that
// lets us redraw in just one quadrant.
if (mBufferRotation == nsIntPoint(0,0)) {
nsIntRect srcRect(nsIntPoint(0, 0), mBufferRect.Size());
nsIntPoint dest = mBufferRect.TopLeft() - destBufferRect.TopLeft();
mBuffer->MovePixels(srcRect, dest);
result.mDidSelfCopy = true;
// Don't set destBuffer; we special-case self-copies, and
// just did the necessary work above.
mBufferRect = destBufferRect;
} else {
// We can't do a real self-copy because the buffer is rotated.
// So allocate a new buffer for the destination.
destBufferRect = neededRegion.GetBounds();
destBuffer = CreateBuffer(contentType, destBufferRect.Size(), bufferFlags);
if (!destBuffer)
return result;
}
} else {
mBufferRect = destBufferRect;
mBufferRotation = newRotation;
}
} else {
// No pixels are going to be kept. The whole visible region
// will be redrawn, so we don't need to copy anything, so we don't
// set destBuffer.
mBufferRect = destBufferRect;
mBufferRotation = nsIntPoint(0,0);
}
} else {
// The buffer's not big enough, so allocate a new one
destBuffer = CreateBuffer(contentType, destBufferRect.Size(), bufferFlags);
if (!destBuffer)
return result;
}
NS_ASSERTION(!(aFlags & PAINT_WILL_RESAMPLE) || destBufferRect == neededRegion.GetBounds(),
"If we're resampling, we need to validate the entire buffer");
// If we have no buffered data already, then destBuffer will be a fresh buffer
// and we do not need to clear it below.
bool isClear = mBuffer == nsnull;
if (destBuffer) {
if (mBuffer) {
// Copy the bits
nsRefPtr<gfxContext> tmpCtx = new gfxContext(destBuffer);
nsIntPoint offset = -destBufferRect.TopLeft();
tmpCtx->SetOperator(gfxContext::OPERATOR_SOURCE);
tmpCtx->Translate(gfxPoint(offset.x, offset.y));
DrawBufferWithRotation(tmpCtx, 1.0);
}
mBuffer = destBuffer.forget();
mBufferRect = destBufferRect;
mBufferRotation = nsIntPoint(0,0);
}
NS_ASSERTION(canHaveRotation || mBufferRotation == nsIntPoint(0,0),
"Rotation disabled, but we have nonzero rotation?");
nsIntRegion invalidate;
invalidate.Sub(aLayer->GetValidRegion(), destBufferRect);
result.mRegionToInvalidate.Or(result.mRegionToInvalidate, invalidate);
result.mContext = GetContextForQuadrantUpdate(drawBounds);
gfxUtils::ClipToRegionSnapped(result.mContext, result.mRegionToDraw);
if (contentType == gfxASurface::CONTENT_COLOR_ALPHA && !isClear) {
result.mContext->SetOperator(gfxContext::OPERATOR_CLEAR);
result.mContext->Paint();
result.mContext->SetOperator(gfxContext::OPERATOR_OVER);
}
return result;
}
}
}