long rect dash with guards

check dash fix back in with
guards against changing
chrome layout test results

original CL: skia-review.googlesource.com/c/skia/+/84862

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.

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

TBR=egdaniel@google.com
Bug: skia:7311
Change-Id: I139b10f676e7ae06ad83aaf2a35d49cf06280a67
Reviewed-on: https://skia-review.googlesource.com/87760
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@skia.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/gm/strokes.cpp b/gm/strokes.cpp
index ed13d090ff..df632dc269 100644
--- a/gm/strokes.cpp
+++ b/gm/strokes.cpp
@@ -533,3 +533,34 @@ DEF_SIMPLE_GM(zerolinedash, canvas, 256, 256) {
 
     canvas->drawLine(100, 100, 100, 100, paint);
 }
+
+#define PDF_IS_FIXED_SO_THIS_DOESNT_BREAK_IT
+#ifdef PDF_IS_FIXED_SO_THIS_DOESNT_BREAK_IT
+DEF_SIMPLE_GM(longrect_dash, canvas, 250, 250) {
+    canvas->clear(SK_ColorWHITE);
+
+    SkPaint paint;
+    paint.setColor(SkColorSetARGB(255, 0, 0, 0));
+    paint.setStrokeWidth(5);
+    paint.setStrokeCap(SkPaint::kRound_Cap);
+    paint.setStrokeJoin(SkPaint::kBevel_Join);
+    paint.setStyle(SkPaint::kStroke_Style);
+    SkScalar dash_pattern[] = {1, 5};
+    paint.setPathEffect(SkDashPathEffect::Make(dash_pattern, 2, 0));
+    // try all combinations of stretching bounds
+    for (auto left : { 20.f, -100001.f } ) {
+        for (auto top : { 20.f, -100001.f } ) {
+            for (auto right : { 40.f, 100001.f } ) {
+                for (auto bottom : { 40.f, 100001.f } ) {
+                    canvas->save();
+                    canvas->clipRect({10, 10, 50, 50});
+                    canvas->drawRect({left, top, right, bottom}, paint);
+                    canvas->restore();
+                    canvas->translate(60, 0);
+               }
+            }
+            canvas->translate(-60 * 4, 60);
+        }
+    }
+}
+#endif