submodule/skia/gm/bicubic.cpp

   1 /*
   2  * Copyright 2020 Google Inc.
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #include "gm/gm.h"
   9 #include "include/core/SkCanvas.h"
  10 #include "include/core/SkSurface.h"
  11
  12 DEF_SIMPLE_GM(bicubic, canvas, 300, 320) {
  13     canvas->clear(SK_ColorBLACK);
  14
  15     const SkSamplingOptions gSamplings[] = {
  16         SkSamplingOptions(SkFilterMode::kNearest),
  17         SkSamplingOptions(SkFilterMode::kLinear),
  18         SkSamplingOptions(SkCubicResampler::Mitchell()),
  19     };
  20
  21     auto make_img = []() {
  22         auto surf = SkSurface::MakeRasterN32Premul(7, 7);
  23         surf->getCanvas()->drawColor(SK_ColorBLACK);
  24
  25         SkPaint paint;
  26         paint.setColor(SK_ColorWHITE);
  27         surf->getCanvas()->drawLine(3.5f, 0, 3.5f, 8, paint);
  28         return surf->makeImageSnapshot();
  29     };
  30
  31     auto img = make_img();
  32
  33     canvas->scale(40, 8);
  34     for (const auto& s : gSamplings) {
  35         canvas->drawImage(img, 0, 0, s, nullptr);
  36         canvas->translate(0, img->height() + 1.0f);
  37     }
  38
  39     const SkRect r = SkRect::MakeIWH(img->width(), img->height());
  40     SkPaint paint;
  41
  42     SkImage::CubicResampler cubics[] = {
  43         SkCubicResampler::CatmullRom(),
  44         SkCubicResampler::Mitchell(),
  45     };
  46     for (auto c : cubics) {
  47         paint.setShader(img->makeShader(SkTileMode::kClamp, SkTileMode::kClamp,
  48                                         SkSamplingOptions(c)));
  49         canvas->drawRect(r, paint);
  50         canvas->translate(0, img->height() + 1.0f);
  51     }
  52 }