In SkDraw::drawRect, use SkPath for huge rects.

gm/bigrect.cpp

Index: gm/bigrect.cpp
diff --git a/gm/bigrect.cpp b/gm/bigrect.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..9773d379086aac79fc6e56e00efcffe5ef3a4ea3
--- /dev/null
+++ b/gm/bigrect.cpp
@@ -0,0 +1,104 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+
+// Draws big rects with clip (0, 0, 35, 35). The size of the rects is given by big.
+void DrawBigRect(SkCanvas* canvas, SkScalar big, const SkPaint& rectPaint) {
+    // Looks like this:
+    // +-+-+--+-+------+
+    // | | |  | |  +---+
+    // | +-+  | |  +---+
+    // |      | |      |
+    // +------+-+------+
+    // +------+-+------+
+    // |      | |      |
+    // +---+  | |  +-+ |
+    // +---+  | |  | | |
+    // +------+-+--+-+-+
+
+    canvas->clipRect({0, 0, 35, 35});
+
+    // Align to pixel boundaries.
+    canvas->translate(0.5, 0.5);
+
+    SkRect tl = SkRect::MakeLTRB(5, -big, 10, 10);
+    canvas->drawRect(tl, rectPaint);
+
+    SkRect tr = SkRect::MakeLTRB(25, 5, big, 10);
+    canvas->drawRect(tr, rectPaint);
+
+    SkRect br = SkRect::MakeLTRB(25, 25, 30, big);
+    canvas->drawRect(br, rectPaint);
+
+    SkRect bl = SkRect::MakeLTRB(-big, 25, 10, 30);
+    canvas->drawRect(bl, rectPaint);
+
+    SkRect horiz = SkRect::MakeLTRB(-big, 15, big, 20);
+    canvas->drawRect(horiz, rectPaint);
+
+    SkRect vert = SkRect::MakeLTRB(15, -big, 20, big);
+    canvas->drawRect(vert, rectPaint);
+
+    SkRect leftBorder = SkRect::MakeLTRB(-2, -1, 0, 35);
+    canvas->drawRect(leftBorder, rectPaint);
+
+    SkRect topBorder = SkRect::MakeLTRB(-1, -2, 35, 0);
+    canvas->drawRect(topBorder, rectPaint);
+
+    SkRect rightBorder = SkRect::MakeLTRB(34, -1, 36, 35);
+    canvas->drawRect(rightBorder, rectPaint);
+
+    SkRect bottomBorder = SkRect::MakeLTRB(-1, 34, 35, 36);
+    canvas->drawRect(bottomBorder, rectPaint);
+
+    SkPaint outOfBoundsPaint;
+    outOfBoundsPaint.setColor(SK_ColorRED);
+    outOfBoundsPaint.setStyle(SkPaint::kStroke_Style);
+    outOfBoundsPaint.setStrokeWidth(0);
+
+    SkRect outOfBounds = SkRect::MakeLTRB(-1, -1, 35, 35);
+    canvas->drawRect(outOfBounds, outOfBoundsPaint);
+}
+
+DEF_SIMPLE_GM(bigrect, canvas, 325, 125) {
+    // Test with sizes:
+    //   - reasonable size (for comparison),
+    //   - outside the range of int32, and
+    //   - outside the range of SkFixed.
+    static const SkScalar sizes[] = {SkIntToScalar(100), 5e10f, 1e6f};
+
+    for (int i = 0; i < 8; i++) {
+        for (int j = 0; j < 3; j++) {
+            canvas->save();
+            canvas->translate(SkIntToScalar(i*40+5), SkIntToScalar(j*40+5));
+
+            SkPaint paint;
+            paint.setColor(SK_ColorBLUE);
+            // These are the three parameters that affect the behavior of SkDraw::drawRect.
+            if (i & 1) {
+                paint.setStyle(SkPaint::kFill_Style);
+            } else {
+                paint.setStyle(SkPaint::kStroke_Style);
+            }
+            if (i & 2) {
+                paint.setStrokeWidth(1);
+            } else {
+                paint.setStrokeWidth(0);
+            }
+            if (i & 4) {
+                paint.setAntiAlias(true);
+            } else {
+                paint.setAntiAlias(false);
+            }
+
+            const SkScalar big = SkFloatToScalar(sizes[j]);
+            DrawBigRect(canvas, big, paint);
+            canvas->restore();
+        }
+    }
+}