efficiently dash very large rectangles and very long lines

Speed up dashing when lines and rects are absurdly large.

Prior to this CL, only horizontal lines were detected.

The onOnceBeforeDraw changes are there to make debugging easier.

Also folded in a change to handle dashing of zero length lines.

R=reed@google.com, egdaniel@google.com
Bug: skia:7311
Change-Id: Ia16fb124c7a78a5cc639e612fae29c879a37da1a
Reviewed-on: https://skia-review.googlesource.com/84862
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Mike Reed <reed@google.com>

2 files changed, 12 insertions, 7 deletions

diff --git a/samplecode/SampleAARects.cpp b/samplecode/SampleAARects.cpp
index 942242b02e..c50c39f5af 100644
--- a/samplecode/SampleAARects.cpp
+++ b/samplecode/SampleAARects.cpp
@@ -39,14 +39,16 @@ class AARectView : public SampleView {
     };
 public:
     AARectView() {
-        fBitmap = createBitmap(N);
+    }
 
+protected:
+    void onOnceBeforeDraw() override {
+        fBitmap = createBitmap(N);
         fWidth = N;
     }
 
-protected:
     // overrides from SkEventSink
-    virtual bool onQuery(SkEvent* evt) {
+    bool onQuery(SkEvent* evt) override {
         if (SampleCode::TitleQ(*evt)) {
             SampleCode::TitleR(evt, "AA Rects");
             return true;
@@ -54,7 +56,7 @@ protected:
         return this->INHERITED::onQuery(evt);
     }
 
-    virtual void onDrawContent(SkCanvas* canvas) {
+    void onDrawContent(SkCanvas* canvas) override {
         canvas->translate(SkIntToScalar(10), SkIntToScalar(10));
 
         SkPaint bluePaint;
diff --git a/samplecode/SampleDither.cpp b/samplecode/SampleDither.cpp
index fbe25ddcaa..79adc629fa 100644
--- a/samplecode/SampleDither.cpp
+++ b/samplecode/SampleDither.cpp
@@ -109,6 +109,10 @@ public:
     SkScalar fAngle;
 
     DitherView() {
+    }
+
+protected:
+    void onOnceBeforeDraw() override {
         make_bm(&fBM);
         make_bm(&fBMPreDither);
         pre_dither(fBMPreDither);
@@ -119,9 +123,8 @@ public:
         this->setBGColor(0xFF181818);
     }
 
-protected:
     // overrides from SkEventSink
-    virtual bool onQuery(SkEvent* evt) {
+    bool onQuery(SkEvent* evt) override {
         if (SampleCode::TitleQ(*evt)) {
             SampleCode::TitleR(evt, "Dither");
             return true;
@@ -129,7 +132,7 @@ protected:
         return this->INHERITED::onQuery(evt);
     }
 
-    virtual void onDrawContent(SkCanvas* canvas) {
+    void onDrawContent(SkCanvas* canvas) override {
         SkPaint paint;
         SkScalar x = SkIntToScalar(10);
         SkScalar y = SkIntToScalar(10);