gecko/gfx/layers/ThebesLayerBuffer.cpp

421 lines
16 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Corporation code.
*
* The Initial Developer of the Original Code is Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Robert O'Callahan <robert@ocallahan.org>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "ThebesLayerBuffer.h"
#include "Layers.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
#include "gfxUtils.h"
#include "nsDeviceContext.h"
namespace mozilla {
namespace layers {
static nsIntSize
ScaledSize(const nsIntSize& aSize, float aXScale, float aYScale)
{
if (aXScale == 1.0 && aYScale == 1.0) {
return aSize;
}
gfxRect rect(0, 0, aSize.width, aSize.height);
rect.Scale(aXScale, aYScale);
rect.RoundOut();
return nsIntSize(rect.Width(), rect.Height());
}
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,
float aXRes, float aYRes)
{
// 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),
PR_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.Scale(aXRes, aYRes);
transform.Translate(-quadrantTranslation);
// in common cases the matrix after scaling by 1/aRes is close to 1.0,
// so we want to make it 1.0 in both cases
transform.Scale(1.0 / aXRes, 1.0 / aYRes);
transform.NudgeToIntegers();
gfxMatrix ctxMatrix = aTarget->CurrentMatrix();
ctxMatrix.Scale(1.0 / aXRes, 1.0 / aYRes);
ctxMatrix.NudgeToIntegers();
aTarget->SetMatrix(ctxMatrix);
pattern->SetMatrix(transform);
aTarget->SetPattern(pattern);
if (aOpacity != 1.0) {
aTarget->Save();
aTarget->Clip();
aTarget->Paint(aOpacity);
aTarget->Restore();
} else {
aTarget->Fill();
}
}
void
ThebesLayerBuffer::DrawBufferWithRotation(gfxContext* aTarget, float aOpacity,
float aXRes, float aYRes)
{
// Draw four quadrants. We could use REPEAT_, but it's probably better
// not to, to be performance-safe.
DrawBufferQuadrant(aTarget, LEFT, TOP, aOpacity, aXRes, aYRes);
DrawBufferQuadrant(aTarget, RIGHT, TOP, aOpacity, aXRes, aYRes);
DrawBufferQuadrant(aTarget, LEFT, BOTTOM, aOpacity, aXRes, aYRes);
DrawBufferQuadrant(aTarget, RIGHT, BOTTOM, aOpacity, aXRes, aYRes);
}
already_AddRefed<gfxContext>
ThebesLayerBuffer::GetContextForQuadrantUpdate(const nsIntRect& aBounds,
float aXResolution,
float aYResolution)
{
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->Scale(aXResolution, aYResolution);
ctx->Translate(-gfxPoint(quadrantRect.x, quadrantRect.y));
return ctx.forget();
}
// Move the pixels in aBuffer specified by |aSourceRect| to |aDest|.
// |aSourceRect| and |aDest| are in the space of |aBuffer|, but
// unscaled by the resolution. This helper does the scaling.
static void
MovePixels(gfxASurface* aBuffer,
const nsIntRect& aSourceRect, const nsIntPoint& aDest,
float aXResolution, float aYResolution)
{
gfxRect src(aSourceRect.x, aSourceRect.y, aSourceRect.width, aSourceRect.height);
gfxRect dest(aDest.x, aDest.y, aSourceRect.width, aSourceRect.height);
src.Scale(aXResolution, aYResolution);
dest.Scale(aXResolution, aYResolution);
#ifdef DEBUG
// If we're doing a self-copy, enforce that the rects we're copying
// were computed in order to round to device pixels. If the rects
// we're moving *weren't* computed to round, then glitches like
// seaming are likely. Assume that the precision of these
// computations is 1 app unit, and toss in a fudge factor of 2.0.
static const gfxFloat kPrecision =
1.0 / gfxFloat(nsDeviceContext::AppUnitsPerCSSPixel());
// FIXME/bug 637852: we've decided to live with transient glitches
// during fast-panning for the time being.
NS_WARN_IF_FALSE(
src.WithinEpsilonOfIntegerPixels(2.0 * kPrecision * aXResolution) &&
dest.WithinEpsilonOfIntegerPixels(2.0 * kPrecision * aXResolution),
"Rects don't round to device pixels within precision; glitches likely to follow");
#endif
src.Round();
dest.Round();
aBuffer->MovePixels(nsIntRect(src.X(), src.Y(),
src.Width(), src.Height()),
nsIntPoint(dest.X(), dest.Y()));
}
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,
float aXResolution, float aYResolution,
PRUint32 aFlags)
{
PaintState result;
result.mDidSelfCopy = PR_FALSE;
float curXRes = aLayer->GetXResolution();
float curYRes = aLayer->GetYResolution();
// If we have non-identity resolution then mBufferRotation might not fall
// on a buffer pixel boundary, in which case that row of pixels will contain
// a mix of two completely different rows of the layer, which would be
// a catastrophe. So disable rotation in that case.
// We also need to disable rotation if we're going to be resampled when
// drawing, because we might sample across the rotation boundary.
PRBool canHaveRotation =
!(aFlags & PAINT_WILL_RESAMPLE) && aXResolution == 1.0 && aYResolution == 1.0;
nsIntRegion validRegion = aLayer->GetValidRegion();
ContentType contentType;
nsIntRegion neededRegion;
nsIntSize destBufferDims;
PRBool canReuseBuffer;
nsIntRect destBufferRect;
while (PR_TRUE) {
contentType = aContentType;
neededRegion = aLayer->GetVisibleRegion();
destBufferDims = ScaledSize(neededRegion.GetBounds().Size(),
aXResolution, aYResolution);
canReuseBuffer = mBuffer && BufferSizeOkFor(destBufferDims);
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;
destBufferDims = ScaledSize(neededRegion.GetBounds().Size(),
aXResolution, aYResolution);
}
if (mBuffer &&
(contentType != mBuffer->GetContentType() ||
aXResolution != curXRes || aYResolution != curYRes)) {
// We're effectively clearing the valid region, so we need to draw
// the entire needed region now.
//
// XXX/cjones: a possibly worthwhile optimization to keep in mind
// is to re-use buffers when the resolution and visible region
// have changed in such a way that the buffer size stays the same.
// It might make even more sense to allocate buffers from a
// recyclable pool, so that we could keep this logic simple and
// still get back the same buffer.
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;
PRBool bufferDimsChanged = PR_FALSE;
PRUint32 bufferFlags = canHaveRotation ? ALLOW_REPEAT : 0;
if (canReuseBuffer) {
NS_ASSERTION(curXRes == aXResolution && curYRes == aYResolution,
"resolution changes must Clear()!");
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();
MovePixels(mBuffer, srcRect, dest, curXRes, curYRes);
result.mDidSelfCopy = PR_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();
bufferDimsChanged = PR_TRUE;
destBuffer = CreateBuffer(contentType, destBufferDims, 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
bufferDimsChanged = PR_TRUE;
destBuffer = CreateBuffer(contentType, destBufferDims, 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.
PRBool 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->Scale(aXResolution, aYResolution);
tmpCtx->Translate(gfxPoint(offset.x, offset.y));
NS_ASSERTION(curXRes == aXResolution && curYRes == aYResolution,
"resolution changes must Clear()!");
DrawBufferWithRotation(tmpCtx, 1.0, aXResolution, aYResolution);
}
mBuffer = destBuffer.forget();
mBufferRect = destBufferRect;
mBufferRotation = nsIntPoint(0,0);
}
if (bufferDimsChanged) {
mBufferDims = destBufferDims;
}
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,
aXResolution, aYResolution);
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;
}
}
}