dashing asPoints could draw excessively long first dash

https://codereview.appspot.com/7098054/

Will require rebaselining of dashing gm.



git-svn-id: http://skia.googlecode.com/svn/trunk@7177 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 24 insertions, 16 deletions

diff --git a/debugger/SkDrawCommand.cpp b/debugger/SkDrawCommand.cpp
index 4b39fac587..5f33eb1f39 100644
--- a/debugger/SkDrawCommand.cpp
+++ b/debugger/SkDrawCommand.cpp
@@ -316,6 +316,7 @@ DrawPoints::DrawPoints(SkCanvas::PointMode mode, size_t count,
     this->fInfo.push(SkObjectParser::ScalarToString(SkIntToScalar(count),
                                                     "Points: "));
     this->fInfo.push(SkObjectParser::PointModeToString(mode));
+    this->fInfo.push(SkObjectParser::PaintToString(paint));
 }
 
 void DrawPoints::execute(SkCanvas* canvas) {
diff --git a/gm/dashing.cpp b/gm/dashing.cpp
index 914824d885..37ea285024 100644
--- a/gm/dashing.cpp
+++ b/gm/dashing.cpp
@@ -248,6 +248,12 @@ protected:
             this->drawDashedLines(canvas, 99.5f, SK_ScalarHalf, SK_Scalar1, 1, false);
         canvas->restore();
 
+        // 255on/255off 1x1 squares with phase of 0 - rects fast path
+        canvas->save();
+            canvas->translate(446, 0);
+            this->drawDashedLines(canvas, 100, 0, SkIntToScalar(255), 1, false);
+        canvas->restore();
+
         // 1on/1off 3x3 squares with phase of 0 - points fast path
         canvas->save();
             canvas->translate(2, 110);
diff --git a/src/effects/SkDashPathEffect.cpp b/src/effects/SkDashPathEffect.cpp
index 58d746b3b9..ef10ca5e8c 100644
--- a/src/effects/SkDashPathEffect.cpp
+++ b/src/effects/SkDashPathEffect.cpp
@@ -320,6 +320,7 @@ bool SkDashPathEffect::asPoints(PointData* results,
 
     if (NULL != results) {
         results->fFlags = 0;
+        SkScalar clampedInitialDashLength = SkMinScalar(length, fInitialDashLength);
 
         if (SkPaint::kRound_Cap == rec.getCap()) {
             results->fFlags |= PointData::kCircles_PointFlag;
@@ -328,22 +329,22 @@ bool SkDashPathEffect::asPoints(PointData* results,
         results->fNumPoints = 0;
         SkScalar len2 = length;
         bool partialFirst = false;
-        if (fInitialDashLength > 0 || 0 == fInitialDashIndex) {
-            SkASSERT(len2 >= fInitialDashLength);
+        if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
+            SkASSERT(len2 >= clampedInitialDashLength);
             if (0 == fInitialDashIndex) {
-                if (fInitialDashLength > 0) {
+                if (clampedInitialDashLength > 0) {
                     partialFirst = true;
-                    if (fInitialDashLength >= fIntervals[0]) {
+                    if (clampedInitialDashLength >= fIntervals[0]) {
                         ++results->fNumPoints;  // partial first dash
                     }
-                    len2 -= fInitialDashLength;
+                    len2 -= clampedInitialDashLength;
                 }
                 len2 -= fIntervals[1];  // also skip first space
                 if (len2 < 0) {
                     len2 = 0;
                 }
             } else {
-                len2 -= fInitialDashLength; // skip initial partial empty
+                len2 -= clampedInitialDashLength; // skip initial partial empty
             }
         }
         int numMidPoints = SkScalarFloorToInt(SkScalarDiv(len2, fIntervalLength));
@@ -364,24 +365,24 @@ bool SkDashPathEffect::asPoints(PointData* results,
         SkScalar    distance = 0;
         int         curPt = 0;
 
-        if (fInitialDashLength > 0 || 0 == fInitialDashIndex) {
-            SkASSERT(fInitialDashLength <= length);
+        if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
+            SkASSERT(clampedInitialDashLength <= length);
 
             if (0 == fInitialDashIndex) {
-                if (fInitialDashLength > 0) {
+                if (clampedInitialDashLength > 0) {
                     // partial first block
                     SkASSERT(SkPaint::kRound_Cap != rec.getCap()); // can't handle partial circles
-                    SkScalar x = pts[0].fX + SkScalarMul(tangent.fX, SkScalarHalf(fInitialDashLength));
-                    SkScalar y = pts[0].fY + SkScalarMul(tangent.fY, SkScalarHalf(fInitialDashLength));
+                    SkScalar x = pts[0].fX + SkScalarMul(tangent.fX, SkScalarHalf(clampedInitialDashLength));
+                    SkScalar y = pts[0].fY + SkScalarMul(tangent.fY, SkScalarHalf(clampedInitialDashLength));
                     SkScalar halfWidth, halfHeight;
                     if (isXAxis) {
-                        halfWidth = SkScalarHalf(fInitialDashLength);
+                        halfWidth = SkScalarHalf(clampedInitialDashLength);
                         halfHeight = SkScalarHalf(rec.getWidth());
                     } else {
                         halfWidth = SkScalarHalf(rec.getWidth());
-                        halfHeight = SkScalarHalf(fInitialDashLength);
+                        halfHeight = SkScalarHalf(clampedInitialDashLength);
                     }
-                    if (fInitialDashLength < fIntervals[0]) {
+                    if (clampedInitialDashLength < fIntervals[0]) {
                         // This one will not be like the others
                         results->fFirst.addRect(x - halfWidth, y - halfHeight,
                                                 x + halfWidth, y + halfHeight);
@@ -391,12 +392,12 @@ bool SkDashPathEffect::asPoints(PointData* results,
                         ++curPt;
                     }
 
-                    distance += fInitialDashLength;
+                    distance += clampedInitialDashLength;
                 }
 
                 distance += fIntervals[1];  // skip over the next blank block too
             } else {
-                distance += fInitialDashLength;
+                distance += clampedInitialDashLength;
             }
         }