gm/localmatriximagefilter.cpp

   1 /*
   2  * Copyright 2015 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.h"
   9 #include "SkCanvas.h"
  10 #include "SkBlurImageFilter.h"
  11 #include "SkColorFilterImageFilter.h"
  12 #include "SkModeColorFilter.h"
  13 #include "SkMorphologyImageFilter.h"
  14 #include "SkOffsetImageFilter.h"
  15 #include "SkSurface.h"
  16
  17 static sk_sp<SkImage> make_image(SkCanvas* rootCanvas) {
  18     SkImageInfo info = SkImageInfo::MakeN32Premul(100, 100);
  19     auto surface(rootCanvas->makeSurface(info));
  20     if (!surface) {
  21         surface = SkSurface::MakeRaster(info);
  22     }
  23
  24     SkPaint paint;
  25     paint.setAntiAlias(true);
  26     paint.setColor(SK_ColorRED);
  27     surface->getCanvas()->drawCircle(50, 50, 50, paint);
  28     return surface->makeImageSnapshot();
  29 }
  30
  31 static void show_image(SkCanvas* canvas, SkImage* image, sk_sp<SkImageFilter> filter) {
  32     SkPaint paint;
  33     paint.setStyle(SkPaint::kStroke_Style);
  34     SkRect r = SkRect::MakeIWH(image->width(), image->height()).makeOutset(SK_ScalarHalf,
  35                                                                            SK_ScalarHalf);
  36     canvas->drawRect(r, paint);
  37
  38     paint.setStyle(SkPaint::kFill_Style);
  39     paint.setImageFilter(filter);
  40     canvas->drawImage(image, 0, 0, &paint);
  41 }
  42
  43 typedef sk_sp<SkImageFilter> (*ImageFilterFactory)();
  44
  45 // +[]{...} did not work on windows (VS)
  46 // (ImageFilterFactory)[]{...} did not work on linux (gcc)
  47 // hence this cast function
  48 template <typename T> ImageFilterFactory IFCCast(T arg) { return arg; }
  49
  50 // Show the effect of localmatriximagefilter with various matrices, on various filters
  51 DEF_SIMPLE_GM(localmatriximagefilter, canvas, 640, 640) {
  52     sk_sp<SkImage> image0(make_image(canvas));
  53
  54     const ImageFilterFactory factories[] = {
  55         IFCCast([]{ return SkBlurImageFilter::Make(8, 8, nullptr); }),
  56         IFCCast([]{ return SkDilateImageFilter::Make(8, 8, nullptr); }),
  57         IFCCast([]{ return SkErodeImageFilter::Make(8, 8, nullptr); }),
  58         IFCCast([]{ return SkOffsetImageFilter::Make(8, 8, nullptr); }),
  59     };
  60
  61     const SkMatrix matrices[] = {
  62         SkMatrix::MakeScale(SK_ScalarHalf, SK_ScalarHalf),
  63         SkMatrix::MakeScale(2, 2),
  64         SkMatrix::MakeTrans(10, 10)
  65     };
  66
  67     const SkScalar spacer = image0->width() * 3.0f / 2;
  68
  69     canvas->translate(40, 40);
  70     for (auto&& factory : factories) {
  71         sk_sp<SkImageFilter> filter(factory());
  72
  73         canvas->save();
  74         show_image(canvas, image0.get(), filter);
  75         for (const auto& matrix : matrices) {
  76             sk_sp<SkImageFilter> localFilter(filter->makeWithLocalMatrix(matrix));
  77             canvas->translate(spacer, 0);
  78             show_image(canvas, image0.get(), std::move(localFilter));
  79         }
  80         canvas->restore();
  81         canvas->translate(0, spacer);
  82     }
  83 }