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/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkRecordOpts.h"
#include "SkRecordPattern.h"
#include "SkRecords.h"
#include "SkTDArray.h"
using namespace SkRecords;
void SkRecordOptimize(SkRecord* record) {
// TODO(mtklein): fuse independent optimizations to reduce number of passes?
SkRecordNoopSaveRestores(record);
SkRecordNoopSaveLayerDrawRestores(record);
SkRecordAnnotateCullingPairs(record);
SkRecordReduceDrawPosTextStrength(record); // Helpful to run this before BoundDrawPosTextH.
SkRecordBoundDrawPosTextH(record);
}
// Most of the optimizations in this file are pattern-based. These are all defined as structs with:
// - a Pattern typedef
// - a bool onMatch(SkRceord*, Pattern*, unsigned begin, unsigned end) method,
// which returns true if it made changes and false if not.
// Run a pattern-based optimization once across the SkRecord, returning true if it made any changes.
// It looks for spans which match Pass::Pattern, and when found calls onMatch() with the pattern,
// record, and [begin,end) span of the commands that matched.
template <typename Pass>
static bool apply(Pass* pass, SkRecord* record) {
typename Pass::Pattern pattern;
bool changed = false;
unsigned begin, end = 0;
while (pattern.search(record, &begin, &end)) {
changed |= pass->onMatch(record, &pattern, begin, end);
}
return changed;
}
// Turns the logical NoOp Save and Restore in Save-Draw*-Restore patterns into actual NoOps.
struct SaveOnlyDrawsRestoreNooper {
typedef Pattern3<Is<Save>,
Star<Or<Is<NoOp>, IsDraw> >,
Is<Restore> >
Pattern;
bool onMatch(SkRecord* record, Pattern* pattern, unsigned begin, unsigned end) {
record->replace<NoOp>(begin); // Save
record->replace<NoOp>(end-1); // Restore
return true;
}
};
// Turns logical no-op Save-[non-drawing command]*-Restore patterns into actual no-ops.
struct SaveNoDrawsRestoreNooper {
// Star matches greedily, so we also have to exclude Save and Restore.
typedef Pattern3<Is<Save>,
Star<Not<Or3<Is<Save>,
Is<Restore>,
IsDraw> > >,
Is<Restore> >
Pattern;
bool onMatch(SkRecord* record, Pattern* pattern, unsigned begin, unsigned end) {
// If restore doesn't revert both matrix and clip, this isn't safe to noop away.
if (pattern->first<Save>()->flags != SkCanvas::kMatrixClip_SaveFlag) {
return false;
}
// The entire span between Save and Restore (inclusively) does nothing.
for (unsigned i = begin; i < end; i++) {
record->replace<NoOp>(i);
}
return true;
}
};
void SkRecordNoopSaveRestores(SkRecord* record) {
SaveOnlyDrawsRestoreNooper onlyDraws;
SaveNoDrawsRestoreNooper noDraws;
// Run until they stop changing things.
while (apply(&onlyDraws, record) || apply(&noDraws, record));
}
// For some SaveLayer-[drawing command]-Restore patterns, merge the SaveLayer's alpha into the
// draw, and no-op the SaveLayer and Restore.
struct SaveLayerDrawRestoreNooper {
typedef Pattern3<Is<SaveLayer>, IsDraw, Is<Restore> > Pattern;
bool onMatch(SkRecord* record, Pattern* pattern, unsigned begin, unsigned end) {
SaveLayer* saveLayer = pattern->first<SaveLayer>();
if (saveLayer->bounds != NULL) {
// SaveLayer with bounds is too tricky for us.
return false;
}
SkPaint* layerPaint = saveLayer->paint;
if (NULL == layerPaint) {
// There wasn't really any point to this SaveLayer at all.
return KillSaveLayerAndRestore(record, begin);
}
SkPaint* drawPaint = pattern->second<SkPaint>();
if (drawPaint == NULL) {
// We can just give the draw the SaveLayer's paint.
// TODO(mtklein): figure out how to do this clearly
return false;
}
const uint32_t layerColor = layerPaint->getColor();
const uint32_t drawColor = drawPaint->getColor();
if (!IsOnlyAlpha(layerColor) || !IsOpaque(drawColor) || HasAnyEffect(*layerPaint)) {
// Too fancy for us. Actually, as long as layerColor is just an alpha
// we can blend it into drawColor's alpha; drawColor doesn't strictly have to be opaque.
return false;
}
drawPaint->setColor(SkColorSetA(drawColor, SkColorGetA(layerColor)));
return KillSaveLayerAndRestore(record, begin);
}
static bool KillSaveLayerAndRestore(SkRecord* record, unsigned saveLayerIndex) {
record->replace<NoOp>(saveLayerIndex); // SaveLayer
record->replace<NoOp>(saveLayerIndex+2); // Restore
return true;
}
static bool HasAnyEffect(const SkPaint& paint) {
return paint.getPathEffect() ||
paint.getShader() ||
paint.getXfermode() ||
paint.getMaskFilter() ||
paint.getColorFilter() ||
paint.getRasterizer() ||
paint.getLooper() ||
paint.getImageFilter();
}
static bool IsOpaque(SkColor color) {
return SkColorGetA(color) == SK_AlphaOPAQUE;
}
static bool IsOnlyAlpha(SkColor color) {
return SK_ColorTRANSPARENT == SkColorSetA(color, SK_AlphaTRANSPARENT);
}
};
void SkRecordNoopSaveLayerDrawRestores(SkRecord* record) {
SaveLayerDrawRestoreNooper pass;
apply(&pass, record);
}
// Replaces DrawPosText with DrawPosTextH when all Y coordinates are equal.
struct StrengthReducer {
typedef Pattern1<Is<DrawPosText> > Pattern;
bool onMatch(SkRecord* record, Pattern* pattern, unsigned begin, unsigned end) {
SkASSERT(end == begin + 1);
DrawPosText* draw = pattern->first<DrawPosText>();
const unsigned points = draw->paint.countText(draw->text, draw->byteLength);
if (points == 0) {
return false; // No point (ha!).
}
const SkScalar firstY = draw->pos[0].fY;
for (unsigned i = 1; i < points; i++) {
if (draw->pos[i].fY != firstY) {
return false; // Needs full power of DrawPosText.
}
}
// All ys are the same. We can replace DrawPosText with DrawPosTextH.
// draw->pos is points SkPoints, [(x,y),(x,y),(x,y),(x,y), ... ].
// We're going to squint and look at that as 2*points SkScalars, [x,y,x,y,x,y,x,y, ...].
// Then we'll rearrange things so all the xs are in order up front, clobbering the ys.
SK_COMPILE_ASSERT(sizeof(SkPoint) == 2 * sizeof(SkScalar), SquintingIsNotSafe);
SkScalar* scalars = &draw->pos[0].fX;
for (unsigned i = 0; i < 2*points; i += 2) {
scalars[i/2] = scalars[i];
}
// Extend lifetime of draw to the end of the loop so we can copy its paint.
Adopted<DrawPosText> adopted(draw);
SkNEW_PLACEMENT_ARGS(record->replace<DrawPosTextH>(begin, adopted),
DrawPosTextH,
(draw->text, draw->byteLength, scalars, firstY, draw->paint));
return true;
}
};
void SkRecordReduceDrawPosTextStrength(SkRecord* record) {
StrengthReducer pass;
apply(&pass, record);
}
// Tries to replace DrawPosTextH with BoundedDrawPosTextH, which knows conservative upper and lower
// bounds to use with SkCanvas::quickRejectY.
struct TextBounder {
typedef Pattern1<Is<DrawPosTextH> > Pattern;
bool onMatch(SkRecord* record, Pattern* pattern, unsigned begin, unsigned end) {
SkASSERT(end == begin + 1);
DrawPosTextH* draw = pattern->first<DrawPosTextH>();
// If we're drawing vertical text, none of the checks we're about to do make any sense.
// We'll need to call SkPaint::computeFastBounds() later, so bail if that's not possible.
if (draw->paint.isVerticalText() || !draw->paint.canComputeFastBounds()) {
return false;
}
// Rather than checking the top and bottom font metrics, we guess. Actually looking up the
// top and bottom metrics is slow, and this overapproximation should be good enough.
const SkScalar buffer = draw->paint.getTextSize() * 1.5f;
SkDEBUGCODE(SkPaint::FontMetrics metrics;)
SkDEBUGCODE(draw->paint.getFontMetrics(&metrics);)
SkASSERT(-buffer <= metrics.fTop);
SkASSERT(+buffer >= metrics.fBottom);
// Let the paint adjust the text bounds. We don't care about left and right here, so we use
// 0 and 1 respectively just so the bounds rectangle isn't empty.
SkRect bounds;
bounds.set(0, draw->y - buffer, SK_Scalar1, draw->y + buffer);
SkRect adjusted = draw->paint.computeFastBounds(bounds, &bounds);
Adopted<DrawPosTextH> adopted(draw);
SkNEW_PLACEMENT_ARGS(record->replace<BoundedDrawPosTextH>(begin, adopted),
BoundedDrawPosTextH,
(&adopted, adjusted.fTop, adjusted.fBottom));
return true;
}
};
void SkRecordBoundDrawPosTextH(SkRecord* record) {
TextBounder pass;
apply(&pass, record);
}
// Replaces PushCull with PairedPushCull, which lets us skip to the paired PopCull when the canvas
// can quickReject the cull rect.
// There's no efficient way (yet?) to express this one as a pattern, so we write a custom pass.
class CullAnnotator {
public:
// Do nothing to most ops.
template <typename T> void operator()(T*) {}
void operator()(PushCull* push) {
Pair pair = { fIndex, push };
fPushStack.push(pair);
}
void operator()(PopCull* pop) {
Pair push = fPushStack.top();
fPushStack.pop();
SkASSERT(fIndex > push.index);
unsigned skip = fIndex - push.index;
Adopted<PushCull> adopted(push.command);
SkNEW_PLACEMENT_ARGS(fRecord->replace<PairedPushCull>(push.index, adopted),
PairedPushCull, (&adopted, skip));
}
void apply(SkRecord* record) {
for (fRecord = record, fIndex = 0; fIndex < record->count(); fIndex++) {
fRecord->mutate<void>(fIndex, *this);
}
}
private:
struct Pair {
unsigned index;
PushCull* command;
};
SkTDArray<Pair> fPushStack;
SkRecord* fRecord;
unsigned fIndex;
};
void SkRecordAnnotateCullingPairs(SkRecord* record) {
CullAnnotator pass;
pass.apply(record);
}
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