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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 "SkRecordDraw.h"
namespace {
// This is an SkRecord visitor that will draw that SkRecord to an SkCanvas.
class Draw : SkNoncopyable {
public:
explicit Draw(SkCanvas* canvas) : fCanvas(canvas), fIndex(0), fClipEmpty(false) {}
unsigned index() const { return fIndex; }
void next() { ++fIndex; }
template <typename T> void operator()(const T& r) {
if (!this->canSkip(r)) {
this->draw(r);
this->updateClip<T>();
}
}
private:
// Can we skip this command right now?
template <typename T> bool canSkip(const T&) const {
// We can skip most commands if the clip is empty. Exceptions are specialized below.
return fClipEmpty;
}
// No base case, so we'll be compile-time checked that we implemented all possibilities below.
template <typename T> void draw(const T&);
// Update fClipEmpty if necessary.
template <typename T> void updateClip() {
// Most commands don't change the clip. Exceptions are specialized below.
}
SkCanvas* fCanvas;
unsigned fIndex;
bool fClipEmpty;
};
// These commands may change the clip.
#define UPDATE_CLIP(T) template <> void Draw::updateClip<SkRecords::T>() \
{ fClipEmpty = fCanvas->isClipEmpty(); }
UPDATE_CLIP(Restore);
UPDATE_CLIP(SaveLayer);
UPDATE_CLIP(ClipPath);
UPDATE_CLIP(ClipRRect);
UPDATE_CLIP(ClipRect);
UPDATE_CLIP(ClipRegion);
#undef UPDATE_CLIP
// These commands must always run.
#define CAN_SKIP(T) template <> bool Draw::canSkip(const SkRecords::T&) const { return false; }
CAN_SKIP(Restore);
CAN_SKIP(Save);
CAN_SKIP(SaveLayer);
CAN_SKIP(Clear);
CAN_SKIP(PushCull);
CAN_SKIP(PopCull);
#undef CAN_SKIP
// We can skip these commands if they're intersecting with a clip that's already empty.
#define CAN_SKIP(T) template <> bool Draw::canSkip(const SkRecords::T& r) const \
{ return fClipEmpty && SkRegion::kIntersect_Op == r.op; }
CAN_SKIP(ClipPath);
CAN_SKIP(ClipRRect);
CAN_SKIP(ClipRect);
CAN_SKIP(ClipRegion);
#undef CAN_SKIP
static bool can_skip_text(const SkCanvas& c, const SkPaint& p, SkScalar minY, SkScalar maxY) {
// If we're drawing vertical text, none of the checks we're about to do make any sense.
// We use canComputeFastBounds as a proxy for "is this text going to be rectangular?".
if (p.isVerticalText() || !p.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 = p.getTextSize() * 1.5f;
SkDEBUGCODE(SkPaint::FontMetrics metrics;)
SkDEBUGCODE(p.getFontMetrics(&metrics);)
SkASSERT(-buffer <= metrics.fTop);
SkASSERT(+buffer >= metrics.fBottom);
return c.quickRejectY(minY - buffer, maxY + buffer);
}
template <> bool Draw::canSkip(const SkRecords::DrawPosTextH& r) const {
return fClipEmpty || can_skip_text(*fCanvas, r.paint, r.y, r.y);
}
template <> bool Draw::canSkip(const SkRecords::DrawPosText& r) const {
if (fClipEmpty) {
return true;
}
// TODO(mtklein): may want to move this minY/maxY calculation into a one-time pass
const unsigned points = r.paint.countText(r.text, r.byteLength);
if (points == 0) {
return true;
}
SkScalar minY = SK_ScalarInfinity, maxY = SK_ScalarNegativeInfinity;
for (unsigned i = 0; i < points; i++) {
minY = SkTMin(minY, r.pos[i].fY);
maxY = SkTMax(maxY, r.pos[i].fY);
}
return can_skip_text(*fCanvas, r.paint, minY, maxY);
}
#define DRAW(T, call) template <> void Draw::draw(const SkRecords::T& r) { fCanvas->call; }
DRAW(Restore, restore());
DRAW(Save, save(r.flags));
DRAW(SaveLayer, saveLayer(r.bounds, r.paint, r.flags));
DRAW(PopCull, popCull());
DRAW(Clear, clear(r.color));
DRAW(Concat, concat(r.matrix));
DRAW(SetMatrix, setMatrix(r.matrix));
DRAW(ClipPath, clipPath(r.path, r.op, r.doAA));
DRAW(ClipRRect, clipRRect(r.rrect, r.op, r.doAA));
DRAW(ClipRect, clipRect(r.rect, r.op, r.doAA));
DRAW(ClipRegion, clipRegion(r.region, r.op));
DRAW(DrawBitmap, drawBitmap(r.bitmap, r.left, r.top, r.paint));
DRAW(DrawBitmapMatrix, drawBitmapMatrix(r.bitmap, r.matrix, r.paint));
DRAW(DrawBitmapNine, drawBitmapNine(r.bitmap, r.center, r.dst, r.paint));
DRAW(DrawBitmapRectToRect, drawBitmapRectToRect(r.bitmap, r.src, r.dst, r.paint, r.flags));
DRAW(DrawDRRect, drawDRRect(r.outer, r.inner, r.paint));
DRAW(DrawOval, drawOval(r.oval, r.paint));
DRAW(DrawPaint, drawPaint(r.paint));
DRAW(DrawPath, drawPath(r.path, r.paint));
DRAW(DrawPoints, drawPoints(r.mode, r.count, r.pts, r.paint));
DRAW(DrawPosText, drawPosText(r.text, r.byteLength, r.pos, r.paint));
DRAW(DrawPosTextH, drawPosTextH(r.text, r.byteLength, r.xpos, r.y, r.paint));
DRAW(DrawRRect, drawRRect(r.rrect, r.paint));
DRAW(DrawRect, drawRect(r.rect, r.paint));
DRAW(DrawSprite, drawSprite(r.bitmap, r.left, r.top, r.paint));
DRAW(DrawText, drawText(r.text, r.byteLength, r.x, r.y, r.paint));
DRAW(DrawTextOnPath, drawTextOnPath(r.text, r.byteLength, r.path, r.matrix, r.paint));
DRAW(DrawVertices, drawVertices(r.vmode, r.vertexCount, r.vertices, r.texs, r.colors,
r.xmode.get(), r.indices, r.indexCount, r.paint));
#undef DRAW
// PushCull is a bit of a oddball. We might be able to just skip until just past its popCull.
template <> void Draw::draw(const SkRecords::PushCull& r) {
if (r.popOffset != SkRecords::kUnsetPopOffset && fCanvas->quickReject(r.rect)) {
fIndex += r.popOffset;
} else {
fCanvas->pushCull(r.rect);
}
}
} // namespace
void SkRecordDraw(const SkRecord& record, SkCanvas* canvas) {
for (Draw draw(canvas); draw.index() < record.count(); draw.next()) {
record.visit(draw.index(), draw);
}
}
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