Added dashing fast path
https://codereview.appspot.com/6844067/
git-svn-id: http://skia.googlecode.com/svn/trunk@6585 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/dashing.cpp b/gm/dashing.cpp
index 2f1f026..e09df5f 100644
--- a/gm/dashing.cpp
+++ b/gm/dashing.cpp
@@ -171,9 +171,87 @@
//////////////////////////////////////////////////////////////////////////////
+// Test out the on/off line dashing Chrome if fond of
+class Dashing3GM : public skiagm::GM {
+public:
+ Dashing3GM() {}
+
+protected:
+ SkString onShortName() {
+ return SkString("dashing3");
+ }
+
+ SkISize onISize() { return skiagm::make_isize(640, 480); }
+
+ // Draw a 100x100 block of dashed lines. The horizontal ones are BW
+ // while the vertical ones are AA.
+ void drawDashedLines(SkCanvas* canvas, SkScalar length, SkScalar phase) {
+ SkPaint p;
+ p.setColor(SK_ColorBLACK);
+ p.setStyle(SkPaint::kStroke_Style);
+ p.setStrokeWidth(SK_Scalar1);
+
+ SkScalar intervals[2] = { SK_Scalar1, SK_Scalar1 };
+
+ p.setPathEffect(new SkDashPathEffect(intervals, 2, phase, false));
+
+ SkPoint pts[2];
+
+ for (int y = 0; y < 100; y += 5) {
+ pts[0].set(0, SkIntToScalar(y));
+ pts[1].set(length, SkIntToScalar(y));
+
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 2, pts, p);
+ }
+
+ p.setAntiAlias(true);
+
+ for (int x = 0; x < 100; x += 7) {
+ pts[0].set(SkIntToScalar(x), 0);
+ pts[1].set(SkIntToScalar(x), length);
+
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 2, pts, p);
+ }
+ }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ // fast path should work on this run
+ canvas->save();
+ this->drawDashedLines(canvas, 100, SK_Scalar1);
+ canvas->restore();
+
+ // non-1 phase should break the fast path
+ canvas->save();
+ canvas->translate(110, 0);
+ this->drawDashedLines(canvas, 100, SK_ScalarHalf);
+ canvas->restore();
+
+ // non-integer length should break the fast path
+ canvas->save();
+ canvas->translate(220, 0);
+ this->drawDashedLines(canvas, 99.5, SK_ScalarHalf);
+ canvas->restore();
+
+ // rotation should break the fast path
+ canvas->save();
+ canvas->translate(110+SK_ScalarRoot2Over2*100, 110+SK_ScalarRoot2Over2*100);
+ canvas->rotate(45);
+ canvas->translate(-50, -50);
+
+ this->drawDashedLines(canvas, 100, SK_Scalar1);
+ canvas->restore();
+
+ }
+
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
static skiagm::GM* F0(void*) { return new DashingGM; }
static skiagm::GM* F1(void*) { return new Dashing2GM; }
+static skiagm::GM* F2(void*) { return new Dashing3GM; }
static skiagm::GMRegistry gR0(F0);
static skiagm::GMRegistry gR1(F1);
+static skiagm::GMRegistry gR2(F2);
diff --git a/include/core/SkPathEffect.h b/include/core/SkPathEffect.h
index 5d9b68a..44056a9 100644
--- a/include/core/SkPathEffect.h
+++ b/include/core/SkPathEffect.h
@@ -12,6 +12,10 @@
#include "SkFlattenable.h"
#include "SkPaint.h"
+#include "SkPath.h"
+#include "SkPoint.h"
+#include "SkRect.h"
+#include "SkTDArray.h"
class SkPath;
@@ -129,6 +133,47 @@
*/
virtual void computeFastBounds(SkRect* dst, const SkRect& src);
+ /** \class PointData
+
+ PointData aggregates all the information needed to draw the point
+ primitives returned by an 'asPoints' call.
+ */
+ class PointData {
+ public:
+ PointData()
+ : fFlags(0) {
+ fSize.set(SK_Scalar1, SK_Scalar1);
+ // 'asPoints' needs to initialize/fill-in 'fClipRect' if it sets
+ // the kUseClip flag
+ };
+ ~PointData() {};
+
+ // TODO: consider using passed-in flags to limit the work asPoints does.
+ // For example, a kNoPath flag could indicate don't bother generating
+ // stamped solutions.
+
+ // Currently none of these flags are supported.
+ enum PointFlags {
+ kCircles_PointFlag = 0x01, // draw points as circles (instead of rects)
+ kUsePath_PointFlag = 0x02, // draw points as stamps of the returned path
+ kUseClip_PointFlag = 0x04, // apply 'fClipRect' before drawing the points
+ };
+
+ uint32_t fFlags; // flags that impact the drawing of the points
+ // TODO: consider replacing the TDArray with either SkData or a ptr/len field
+ SkTDArray<SkPoint> fPoints; // the center point of each generated point
+ SkVector fSize; // the size to draw the points
+ SkRect fClipRect; // clip required to draw the points (if kUseClip is set)
+ SkPath fPath; // 'stamp' to be used at each point (if kUsePath is set)
+ };
+
+ /**
+ * Does applying this path effect to 'src' yield a set of points? If so,
+ * optionally return the points in 'results'.
+ */
+ virtual bool asPoints(PointData* results, const SkPath& src,
+ const SkStrokeRec&, const SkMatrix&) const;
+
protected:
SkPathEffect(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {}
diff --git a/include/effects/SkDashPathEffect.h b/include/effects/SkDashPathEffect.h
index 0397466..52557c6 100644
--- a/include/effects/SkDashPathEffect.h
+++ b/include/effects/SkDashPathEffect.h
@@ -41,6 +41,9 @@
virtual bool filterPath(SkPath* dst, const SkPath& src, SkStrokeRec*) SK_OVERRIDE;
+ virtual bool asPoints(PointData* results, const SkPath& src,
+ const SkStrokeRec&, const SkMatrix&) const SK_OVERRIDE;
+
// overrides for SkFlattenable
// This method is not exported to java.
virtual Factory getFactory();
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index 3c1b72d..f4487af 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -635,6 +635,39 @@
break;
}
case SkCanvas::kLines_PointMode:
+#ifndef SK_DISABLE_DASHING_OPTIMIZATION
+ if (2 == count && NULL != paint.getPathEffect()) {
+ // most likely a dashed line - see if it is one of the ones
+ // we can accelerate
+ SkStrokeRec rec(paint);
+ SkPathEffect::PointData dst;
+
+ SkPath path;
+ path.moveTo(pts[0]);
+ path.lineTo(pts[1]);
+
+ if (paint.getPathEffect()->asPoints(&dst, path, rec, *fMatrix) &&
+ SK_Scalar1 == dst.fSize.fX && SK_Scalar1 == dst.fSize.fY &&
+ !(SkPathEffect::PointData::kUsePath_PointFlag & dst.fFlags)) {
+ SkPaint newP(paint);
+ newP.setPathEffect(NULL);
+
+ if (SkPathEffect::PointData::kCircles_PointFlag & dst.fFlags) {
+ newP.setStrokeCap(SkPaint::kRound_Cap);
+ } else {
+ newP.setStrokeCap(SkPaint::kButt_Cap);
+ }
+
+ this->drawPoints(SkCanvas::kPoints_PointMode,
+ dst.fPoints.count(),
+ dst.fPoints.begin(),
+ newP,
+ forceUseDevice);
+ break;
+ }
+ }
+#endif // DISABLE_DASHING_OPTIMIZATION
+ // couldn't take fast path so fall through!
case SkCanvas::kPolygon_PointMode: {
count -= 1;
SkPath path;
diff --git a/src/core/SkPathEffect.cpp b/src/core/SkPathEffect.cpp
index d706e8d..a64ebc7 100644
--- a/src/core/SkPathEffect.cpp
+++ b/src/core/SkPathEffect.cpp
@@ -116,6 +116,11 @@
*dst = src;
}
+bool SkPathEffect::asPoints(PointData* results, const SkPath& src,
+ const SkStrokeRec&, const SkMatrix&) const {
+ return false;
+}
+
///////////////////////////////////////////////////////////////////////////////
SkPairPathEffect::SkPairPathEffect(SkPathEffect* pe0, SkPathEffect* pe1)
diff --git a/src/effects/SkDashPathEffect.cpp b/src/effects/SkDashPathEffect.cpp
index 3add0d7..03330f0 100644
--- a/src/effects/SkDashPathEffect.cpp
+++ b/src/effects/SkDashPathEffect.cpp
@@ -227,6 +227,82 @@
return true;
}
+// Currently asPoints is more restrictive then it needs to be. In the future
+// we need to:
+// allow kRound_Cap capping (could allow rotations in the matrix with this)
+// loosen restriction on initial dash length
+// allow cases where (stroke width == interval[0]) and return size
+// allow partial first and last pixels
+bool SkDashPathEffect::asPoints(PointData* results,
+ const SkPath& src,
+ const SkStrokeRec& rec,
+ const SkMatrix& matrix) const {
+ if (rec.isFillStyle() || fInitialDashLength < 0 || SK_Scalar1 != rec.getWidth()) {
+ return false;
+ }
+
+ if (fIntervalLength != 2 || SK_Scalar1 != fIntervals[0] || SK_Scalar1 != fIntervals[1]) {
+ return false;
+ }
+
+ if (fScaleToFit || 0 != fInitialDashLength) {
+ return false;
+ }
+
+ SkPoint pts[2];
+
+ if (rec.isHairlineStyle() || !src.isLine(pts)) {
+ return false;
+ }
+
+ if (SkPaint::kButt_Cap != rec.getCap()) {
+ return false;
+ }
+
+ if (!matrix.rectStaysRect()) {
+ return false;
+ }
+
+ SkPathMeasure meas(src, false);
+ SkScalar length = meas.getLength();
+
+ if (!SkScalarIsInt(length)) {
+ return false;
+ }
+
+ if (NULL != results) {
+ results->fFlags = 0; // don't use clip rect & draw rects
+ results->fSize.set(SK_Scalar1, SK_Scalar1);
+
+ SkVector tangent = pts[1] - pts[0];
+ if (tangent.isZero()) {
+ return false;
+ }
+
+ tangent.scale(SkScalarInvert(length));
+
+ SkScalar ptCount = SkScalarDiv(length, SkIntToScalar(2));
+ results->fPoints.setReserve(SkScalarCeilToInt(ptCount));
+
+ // +1 b.c. fInitialDashLength is zero so the initial segment will be skipped
+ int index = fInitialDashIndex+1;
+
+ for (SkScalar distance = SK_ScalarHalf; distance < length; distance += SK_Scalar1) {
+ SkASSERT(index <= fCount);
+
+ if (0 == index) {
+ SkScalar x0 = pts[0].fX + SkScalarMul(tangent.fX, distance);
+ SkScalar y0 = pts[0].fY + SkScalarMul(tangent.fY, distance);
+ results->fPoints.append()->set(x0, y0);
+ }
+
+ index ^= 1; // 0 -> 1 -> 0 ...
+ }
+ }
+
+ return true;
+}
+
SkFlattenable::Factory SkDashPathEffect::getFactory() {
return fInitialDashLength < 0 ? NULL : CreateProc;
}