| /* |
| * Copyright 2017 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "gm/gm.h" |
| #include "include/core/SkCanvas.h" |
| #include "include/core/SkColor.h" |
| #include "include/core/SkImage.h" |
| #include "include/core/SkMatrix.h" |
| #include "include/core/SkPaint.h" |
| #include "include/core/SkRect.h" |
| #include "include/core/SkRefCnt.h" |
| #include "include/core/SkShader.h" |
| #include "include/core/SkSurface.h" |
| #include "include/core/SkTileMode.h" |
| |
| // This GM reproduces skia:6783, which demonstrated a bug in repeat and mirror |
| // image sampling tiling modes as implemented in software. We want to tile to |
| // [0,limit), and the old incorrect logic was: |
| // |
| // limit = ulp_before(limit) |
| // val = val - floor(val/limit)*limit (This is repeat; mirror is similar.) |
| // |
| // while the correct logic is more like: |
| // |
| // val = val - floor(val/limit)*limit |
| // val = min(val, ulp_before(limit)) |
| // |
| // You would see ugly jaggies on the blue/yellow edge near the bottom left if |
| // the bug were still present. All stripes should now look roughly the same. |
| |
| DEF_SIMPLE_GM(bug6783, canvas, 500, 500) { |
| sk_sp<SkSurface> surface = SkSurfaces::Raster(SkImageInfo::MakeN32Premul(100, 100)); |
| |
| SkPaint p; |
| p.setColor(SK_ColorYELLOW); |
| surface->getCanvas()->drawPaint(p); |
| p.setColor(SK_ColorBLUE); |
| surface->getCanvas()->drawRect(SkRect::MakeWH(50, 100), p); |
| |
| sk_sp<SkImage> img = surface->makeImageSnapshot(); |
| |
| SkMatrix m = SkMatrix::Translate(25, 214) * SkMatrix::Scale(2, 2); |
| m.preSkew(0.5f, 0.5f); |
| |
| // The bug was present at all filter levels, but you might not notice it at nearest. |
| SkSamplingOptions sampling(SkFilterMode::kLinear); |
| |
| // It's only important to repeat or mirror in x to show off the bug. |
| p.setShader(img->makeShader(SkTileMode::kRepeat, SkTileMode::kClamp, sampling, m)); |
| canvas->drawPaint(p); |
| } |