diff options
| -rw-r--r-- | tests/ClipperTest.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/tests/ClipperTest.cpp b/tests/ClipperTest.cpp index 7bb225417e..607561d752 100644 --- a/tests/ClipperTest.cpp +++ b/tests/ClipperTest.cpp @@ -10,6 +10,43 @@ #include "SkLineClipper.h" #include "SkEdgeClipper.h" +#include "SkCanvas.h" +static void test_hairclipping(skiatest::Reporter* reporter) { + SkBitmap bm; + bm.setConfig(SkBitmap::kARGB_8888_Config, 4, 4); + bm.allocPixels(); + bm.eraseColor(SK_ColorWHITE); + + SkPaint paint; + paint.setAntiAlias(true); + + SkCanvas canvas(bm); + canvas.clipRect(SkRect::MakeWH(4, 2)); + canvas.drawLine(1.5, 1.5, 3.5, 3.5, paint); + + /** + * We had a bug where we misinterpreted the bottom of the clip, and + * would draw another pixel (to the right in this case) on the same + * last scanline. i.e. we would draw to [2,1], even though this hairline + * should just draw to [1,1], [2,2], [3,3] modulo the clip. + * + * The result of this entire draw should be that we only draw to [1,1] + * + * Fixed in rev. 3366 + */ + for (int y = 0; y < 4; ++y) { + for (int x = 0; x < 4; ++x) { + bool nonWhite = (1 == y) && (1 == x); + SkPMColor c = *bm.getAddr32(x, y); + if (nonWhite) { + REPORTER_ASSERT(reporter, 0xFFFFFFFF != c); + } else { + REPORTER_ASSERT(reporter, 0xFFFFFFFF == c); + } + } + } +} + static void test_edgeclipper(skiatest::Reporter* reporter) { SkEdgeClipper clipper; @@ -109,6 +146,7 @@ static void test_intersectline(skiatest::Reporter* reporter) { void TestClipper(skiatest::Reporter* reporter) { test_intersectline(reporter); test_edgeclipper(reporter); + test_hairclipping(reporter); } #include "TestClassDef.h" |