Use device-space stroke width for SkDraw::drawRect() quick-reject

tests/RectTest.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBitmap.h"
+#include "SkCanvas.h"
+#include "SkRect.h"
+#include "Test.h"
+
+static bool has_green_pixels(const SkBitmap& bm) {
+    for (int j = 0; j < bm.height(); ++j) {
+        for (int i = 0; i < bm.width(); ++i) {
+            if (SkColorGetG(bm.getColor(i, j))) {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
+static void test_stroke_width_clipping(skiatest::Reporter* reporter) {
+    SkBitmap bm;
+    bm.allocN32Pixels(100, 10);
+    bm.eraseColor(SK_ColorTRANSPARENT);
+
+    SkCanvas canvas(bm);
+    SkPaint paint;
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setStrokeWidth(10);
+    paint.setColor(0xff00ff00);
+
+    // clip out the left half of our canvas
+    canvas.clipRect(SkRect::MakeXYWH(51, 0, 49, 100));
+
+    // no stroke bleed should be visible
+    canvas.drawRect(SkRect::MakeWH(44, 100), paint);
+    REPORTER_ASSERT(reporter, !has_green_pixels(bm));
+
+    // right stroke edge should bleed into the visible area
+    canvas.scale(2, 2);
+    canvas.drawRect(SkRect::MakeWH(22, 50), paint);
+    REPORTER_ASSERT(reporter, has_green_pixels(bm));
+}
+
+DEF_TEST(Rect, reporter) {
+    test_stroke_width_clipping(reporter);
+}