gecko-dev/gfx/thebes/gfxUtils.cpp

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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* ***** 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):
* Vladimir Vukicevic <vladimir@pobox.com>
*
* 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 "gfxUtils.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
#include "gfxDrawable.h"
#include "nsRegion.h"
#if defined(XP_WIN) || defined(WINCE)
#include "gfxWindowsPlatform.h"
#endif
static PRUint8 sUnpremultiplyTable[256*256];
static PRUint8 sPremultiplyTable[256*256];
static PRBool sTablesInitialized = PR_FALSE;
static const PRUint8 PremultiplyValue(PRUint8 a, PRUint8 v) {
return sPremultiplyTable[a*256+v];
}
static const PRUint8 UnpremultiplyValue(PRUint8 a, PRUint8 v) {
return sUnpremultiplyTable[a*256+v];
}
static void
CalculateTables()
{
// It's important that the array be indexed first by alpha and then by rgb
// value. When we unpremultiply a pixel, we're guaranteed to do three
// lookups with the same alpha; indexing by alpha first makes it likely that
// those three lookups will be close to one another in memory, thus
// increasing the chance of a cache hit.
// Unpremultiply table
// a == 0 case
for (PRUint32 c = 0; c <= 255; c++) {
sUnpremultiplyTable[c] = c;
}
for (int a = 1; a <= 255; a++) {
for (int c = 0; c <= 255; c++) {
sUnpremultiplyTable[a*256+c] = (PRUint8)((c * 255) / a);
}
}
// Premultiply table
for (int a = 0; a <= 255; a++) {
for (int c = 0; c <= 255; c++) {
sPremultiplyTable[a*256+c] = (a * c + 254) / 255;
}
}
sTablesInitialized = PR_TRUE;
}
void
gfxUtils::PremultiplyImageSurface(gfxImageSurface *aSourceSurface,
gfxImageSurface *aDestSurface)
{
if (!aDestSurface)
aDestSurface = aSourceSurface;
NS_ASSERTION(aSourceSurface->Format() == aDestSurface->Format() &&
aSourceSurface->Width() == aDestSurface->Width() &&
aSourceSurface->Height() == aDestSurface->Height() &&
aSourceSurface->Stride() == aDestSurface->Stride(),
"Source and destination surfaces don't have identical characteristics");
NS_ASSERTION(aSourceSurface->Stride() == aSourceSurface->Width() * 4,
"Source surface stride isn't tightly packed");
// Only premultiply ARGB32
if (aSourceSurface->Format() != gfxASurface::ImageFormatARGB32) {
if (aDestSurface != aSourceSurface) {
memcpy(aDestSurface->Data(), aSourceSurface->Data(),
aSourceSurface->Stride() * aSourceSurface->Height());
}
return;
}
if (!sTablesInitialized)
CalculateTables();
PRUint8 *src = aSourceSurface->Data();
PRUint8 *dst = aDestSurface->Data();
PRUint32 dim = aSourceSurface->Width() * aSourceSurface->Height();
for (PRUint32 i = 0; i < dim; ++i) {
#ifdef IS_LITTLE_ENDIAN
PRUint8 b = *src++;
PRUint8 g = *src++;
PRUint8 r = *src++;
PRUint8 a = *src++;
*dst++ = PremultiplyValue(a, b);
*dst++ = PremultiplyValue(a, g);
*dst++ = PremultiplyValue(a, r);
*dst++ = a;
#else
PRUint8 a = *src++;
PRUint8 r = *src++;
PRUint8 g = *src++;
PRUint8 b = *src++;
*dst++ = a;
*dst++ = PremultiplyValue(a, r);
*dst++ = PremultiplyValue(a, g);
*dst++ = PremultiplyValue(a, b);
#endif
}
}
void
gfxUtils::UnpremultiplyImageSurface(gfxImageSurface *aSourceSurface,
gfxImageSurface *aDestSurface)
{
if (!aDestSurface)
aDestSurface = aSourceSurface;
NS_ASSERTION(aSourceSurface->Format() == aDestSurface->Format() &&
aSourceSurface->Width() == aDestSurface->Width() &&
aSourceSurface->Height() == aDestSurface->Height() &&
aSourceSurface->Stride() == aDestSurface->Stride(),
"Source and destination surfaces don't have identical characteristics");
NS_ASSERTION(aSourceSurface->Stride() == aSourceSurface->Width() * 4,
"Source surface stride isn't tightly packed");
// Only premultiply ARGB32
if (aSourceSurface->Format() != gfxASurface::ImageFormatARGB32) {
if (aDestSurface != aSourceSurface) {
memcpy(aDestSurface->Data(), aSourceSurface->Data(),
aSourceSurface->Stride() * aSourceSurface->Height());
}
return;
}
if (!sTablesInitialized)
CalculateTables();
PRUint8 *src = aSourceSurface->Data();
PRUint8 *dst = aDestSurface->Data();
PRUint32 dim = aSourceSurface->Width() * aSourceSurface->Height();
for (PRUint32 i = 0; i < dim; ++i) {
#ifdef IS_LITTLE_ENDIAN
PRUint8 b = *src++;
PRUint8 g = *src++;
PRUint8 r = *src++;
PRUint8 a = *src++;
*dst++ = UnpremultiplyValue(a, b);
*dst++ = UnpremultiplyValue(a, g);
*dst++ = UnpremultiplyValue(a, r);
*dst++ = a;
#else
PRUint8 a = *src++;
PRUint8 r = *src++;
PRUint8 g = *src++;
PRUint8 b = *src++;
*dst++ = a;
*dst++ = UnpremultiplyValue(a, r);
*dst++ = UnpremultiplyValue(a, g);
*dst++ = UnpremultiplyValue(a, b);
#endif
}
}
static PRBool
IsSafeImageTransformComponent(gfxFloat aValue)
{
return aValue >= -32768 && aValue <= 32767;
}
/**
* This returns the fastest operator to use for solid surfaces which have no
* alpha channel or their alpha channel is uniformly opaque.
* This differs per render mode.
*/
static gfxContext::GraphicsOperator
OptimalFillOperator()
{
#ifdef XP_WIN
if (gfxWindowsPlatform::GetPlatform()->GetRenderMode() ==
gfxWindowsPlatform::RENDER_DIRECT2D) {
// D2D -really- hates operator source.
return gfxContext::OPERATOR_OVER;
} else {
#endif
return gfxContext::OPERATOR_SOURCE;
#ifdef XP_WIN
}
#endif
}
// EXTEND_PAD won't help us here; we have to create a temporary surface to hold
// the subimage of pixels we're allowed to sample.
static already_AddRefed<gfxDrawable>
CreateSamplingRestrictedDrawable(gfxDrawable* aDrawable,
gfxContext* aContext,
const gfxMatrix& aUserSpaceToImageSpace,
const gfxRect& aSourceRect,
const gfxRect& aSubimage,
const gfxImageSurface::gfxImageFormat aFormat)
{
gfxRect userSpaceClipExtents = aContext->GetClipExtents();
// This isn't optimal --- if aContext has a rotation then GetClipExtents
// will have to do a bounding-box computation, and TransformBounds might
// too, so we could get a better result if we computed image space clip
// extents in one go --- but it doesn't really matter and this is easier
// to understand.
gfxRect imageSpaceClipExtents =
aUserSpaceToImageSpace.TransformBounds(userSpaceClipExtents);
// Inflate by one pixel because bilinear filtering will sample at most
// one pixel beyond the computed image pixel coordinate.
imageSpaceClipExtents.Outset(1.0);
gfxRect needed = imageSpaceClipExtents.Intersect(aSourceRect);
needed = needed.Intersect(aSubimage);
needed.RoundOut();
// if 'needed' is empty, nothing will be drawn since aFill
// must be entirely outside the clip region, so it doesn't
// matter what we do here, but we should avoid trying to
// create a zero-size surface.
if (needed.IsEmpty())
return nsnull;
gfxIntSize size(PRInt32(needed.Width()), PRInt32(needed.Height()));
nsRefPtr<gfxASurface> temp =
gfxPlatform::GetPlatform()->CreateOffscreenSurface(size, gfxASurface::ContentFromFormat(aFormat));
if (!temp || temp->CairoStatus())
return nsnull;
nsRefPtr<gfxContext> tmpCtx = new gfxContext(temp);
tmpCtx->SetOperator(OptimalFillOperator());
aDrawable->Draw(tmpCtx, needed - needed.pos, PR_TRUE,
gfxPattern::FILTER_FAST, gfxMatrix().Translate(needed.pos));
nsRefPtr<gfxPattern> resultPattern = new gfxPattern(temp);
if (!resultPattern)
return nsnull;
nsRefPtr<gfxDrawable> drawable =
new gfxSurfaceDrawable(temp, size, gfxMatrix().Translate(-needed.pos));
return drawable.forget();
}
// working around cairo/pixman bug (bug 364968)
// Our device-space-to-image-space transform may not be acceptable to pixman.
struct NS_STACK_CLASS AutoCairoPixmanBugWorkaround
{
AutoCairoPixmanBugWorkaround(gfxContext* aContext,
const gfxMatrix& aDeviceSpaceToImageSpace,
const gfxRect& aFill,
const gfxASurface::gfxSurfaceType& aSurfaceType)
: mContext(aContext), mSucceeded(PR_TRUE), mPushedGroup(PR_FALSE)
{
// Quartz's limits for matrix are much larger than pixman
if (aSurfaceType == gfxASurface::SurfaceTypeQuartz)
return;
if (!IsSafeImageTransformComponent(aDeviceSpaceToImageSpace.xx) ||
!IsSafeImageTransformComponent(aDeviceSpaceToImageSpace.xy) ||
!IsSafeImageTransformComponent(aDeviceSpaceToImageSpace.yx) ||
!IsSafeImageTransformComponent(aDeviceSpaceToImageSpace.yy)) {
NS_WARNING("Scaling up too much, bailing out");
mSucceeded = PR_FALSE;
return;
}
if (IsSafeImageTransformComponent(aDeviceSpaceToImageSpace.x0) &&
IsSafeImageTransformComponent(aDeviceSpaceToImageSpace.y0))
return;
// We'll push a group, which will hopefully reduce our transform's
// translation so it's in bounds.
gfxMatrix currentMatrix = mContext->CurrentMatrix();
mContext->Save();
// Clip the rounded-out-to-device-pixels bounds of the
// transformed fill area. This is the area for the group we
// want to push.
mContext->IdentityMatrix();
gfxRect bounds = currentMatrix.TransformBounds(aFill);
bounds.RoundOut();
mContext->Clip(bounds);
mContext->SetMatrix(currentMatrix);
mContext->PushGroup(gfxASurface::CONTENT_COLOR_ALPHA);
mContext->SetOperator(gfxContext::OPERATOR_OVER);
mPushedGroup = PR_TRUE;
}
~AutoCairoPixmanBugWorkaround()
{
if (mPushedGroup) {
mContext->PopGroupToSource();
mContext->Paint();
mContext->Restore();
}
}
PRBool PushedGroup() { return mPushedGroup; }
PRBool Succeeded() { return mSucceeded; }
private:
gfxContext* mContext;
PRPackedBool mSucceeded;
PRPackedBool mPushedGroup;
};
static gfxMatrix
DeviceToImageTransform(gfxContext* aContext,
const gfxMatrix& aUserSpaceToImageSpace)
{
gfxFloat deviceX, deviceY;
nsRefPtr<gfxASurface> currentTarget =
aContext->CurrentSurface(&deviceX, &deviceY);
gfxMatrix currentMatrix = aContext->CurrentMatrix();
gfxMatrix deviceToUser = gfxMatrix(currentMatrix).Invert();
deviceToUser.Translate(-gfxPoint(-deviceX, -deviceY));
return gfxMatrix(deviceToUser).Multiply(aUserSpaceToImageSpace);
}
/* static */ void
gfxUtils::DrawPixelSnapped(gfxContext* aContext,
gfxDrawable* aDrawable,
const gfxMatrix& aUserSpaceToImageSpace,
const gfxRect& aSubimage,
const gfxRect& aSourceRect,
const gfxRect& aImageRect,
const gfxRect& aFill,
const gfxImageSurface::gfxImageFormat aFormat,
const gfxPattern::GraphicsFilter& aFilter)
{
PRBool doTile = !aImageRect.Contains(aSourceRect);
nsRefPtr<gfxASurface> currentTarget = aContext->CurrentSurface();
gfxASurface::gfxSurfaceType surfaceType = currentTarget->GetType();
gfxMatrix deviceSpaceToImageSpace =
DeviceToImageTransform(aContext, aUserSpaceToImageSpace);
AutoCairoPixmanBugWorkaround workaround(aContext, deviceSpaceToImageSpace,
aFill, surfaceType);
if (!workaround.Succeeded())
return;
nsRefPtr<gfxDrawable> drawable = aDrawable;
// OK now, the hard part left is to account for the subimage sampling
// restriction. If all the transforms involved are just integer
// translations, then we assume no resampling will occur so there's
// nothing to do.
// XXX if only we had source-clipping in cairo!
if (aContext->CurrentMatrix().HasNonIntegerTranslation() ||
aUserSpaceToImageSpace.HasNonIntegerTranslation()) {
if (doTile || !aSubimage.Contains(aImageRect)) {
nsRefPtr<gfxDrawable> restrictedDrawable =
CreateSamplingRestrictedDrawable(aDrawable, aContext,
aUserSpaceToImageSpace, aSourceRect,
aSubimage, aFormat);
if (restrictedDrawable) {
drawable.swap(restrictedDrawable);
}
}
// We no longer need to tile: Either we never needed to, or we already
// filled a surface with the tiled pattern; this surface can now be
// drawn without tiling.
doTile = PR_FALSE;
}
gfxContext::GraphicsOperator op = aContext->CurrentOperator();
if ((op == gfxContext::OPERATOR_OVER || workaround.PushedGroup()) &&
aFormat == gfxASurface::ImageFormatRGB24) {
aContext->SetOperator(OptimalFillOperator());
}
drawable->Draw(aContext, aFill, doTile, aFilter, aUserSpaceToImageSpace);
aContext->SetOperator(op);
}
/* static */ int
gfxUtils::ImageFormatToDepth(gfxASurface::gfxImageFormat aFormat)
{
switch (aFormat) {
case gfxASurface::ImageFormatARGB32:
return 32;
case gfxASurface::ImageFormatRGB24:
return 24;
case gfxASurface::ImageFormatRGB16_565:
return 16;
default:
break;
}
return 0;
}
static void
ClipToRegionInternal(gfxContext* aContext, const nsIntRegion& aRegion,
PRBool aSnap)
{
aContext->NewPath();
nsIntRegionRectIterator iter(aRegion);
const nsIntRect* r;
while ((r = iter.Next()) != nsnull) {
aContext->Rectangle(gfxRect(r->x, r->y, r->width, r->height), aSnap);
}
aContext->Clip();
}
/*static*/ void
gfxUtils::ClipToRegion(gfxContext* aContext, const nsIntRegion& aRegion)
{
ClipToRegionInternal(aContext, aRegion, PR_FALSE);
}
/*static*/ void
gfxUtils::ClipToRegionSnapped(gfxContext* aContext, const nsIntRegion& aRegion)
{
ClipToRegionInternal(aContext, aRegion, PR_TRUE);
}