gm/patch.cpp

   1 /*
   2  * Copyright 2014 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 "SkGradientShader.h"
  10 #include "SkPatchUtils.h"
  11
  12 static sk_sp<SkShader> make_shader() {
  13     const SkColor colors[] = {
  14         SK_ColorRED, SK_ColorCYAN, SK_ColorGREEN, SK_ColorWHITE, SK_ColorMAGENTA, SK_ColorBLUE,
  15         SK_ColorYELLOW,
  16     };
  17     const SkPoint pts[] = { { 100.f / 4.f, 0.f }, { 3.f * 100.f / 4.f, 100.f } };
  18
  19     return SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
  20                                         SkShader::kMirror_TileMode);
  21 }
  22
  23 static void draw_control_points(SkCanvas* canvas, const SkPoint cubics[12]) {
  24     //draw control points
  25     SkPaint paint;
  26     SkPoint bottom[SkPatchUtils::kNumPtsCubic];
  27     SkPatchUtils::GetBottomCubic(cubics, bottom);
  28     SkPoint top[SkPatchUtils::kNumPtsCubic];
  29     SkPatchUtils::GetTopCubic(cubics, top);
  30     SkPoint left[SkPatchUtils::kNumPtsCubic];
  31     SkPatchUtils::GetLeftCubic(cubics, left);
  32     SkPoint right[SkPatchUtils::kNumPtsCubic];
  33     SkPatchUtils::GetRightCubic(cubics, right);
  34
  35     paint.setColor(SK_ColorBLACK);
  36     paint.setStrokeWidth(0.5f);
  37     SkPoint corners[4] = { bottom[0], bottom[3], top[0], top[3] };
  38     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, bottom, paint);
  39     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, bottom + 1, paint);
  40     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, top, paint);
  41     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, left, paint);
  42     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, right, paint);
  43
  44     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, top + 1, paint);
  45     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, left + 1, paint);
  46     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, right + 1, paint);
  47
  48     paint.setStrokeWidth(2);
  49
  50     paint.setColor(SK_ColorRED);
  51     canvas->drawPoints(SkCanvas::kPoints_PointMode, 4, corners, paint);
  52
  53     paint.setColor(SK_ColorBLUE);
  54     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, bottom + 1, paint);
  55
  56     paint.setColor(SK_ColorCYAN);
  57     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, top + 1, paint);
  58
  59     paint.setColor(SK_ColorYELLOW);
  60     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, left + 1, paint);
  61
  62     paint.setColor(SK_ColorGREEN);
  63     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, right + 1, paint);
  64 }
  65
  66 DEF_SIMPLE_GM(patch_primitive, canvas, 1500, 1100) {
  67         SkPaint paint;
  68
  69         // The order of the colors and points is clockwise starting at upper-left corner.
  70         const SkPoint cubics[SkPatchUtils::kNumCtrlPts] = {
  71             //top points
  72             {100,100},{150,50},{250,150}, {300,100},
  73             //right points
  74             {250, 150},{350,250},
  75             //bottom points
  76             {300,300},{250,250},{150,350},{100,300},
  77             //left points
  78             {50,250},{150,150}
  79         };
  80
  81         const SkColor colors[SkPatchUtils::kNumCorners] = {
  82             SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorCYAN
  83         };
  84         const SkPoint texCoords[SkPatchUtils::kNumCorners] = {
  85             {0.0f, 0.0f}, {100.0f, 0.0f}, {100.0f,100.0f}, {0.0f, 100.0f}}
  86         ;
  87
  88         const SkBlendMode modes[] = {
  89             SkBlendMode::kSrc,
  90             SkBlendMode::kDst,
  91             SkBlendMode::kModulate,
  92         };
  93
  94         sk_sp<SkShader> shader(make_shader());
  95
  96         canvas->save();
  97         for (int y = 0; y < 3; y++) {
  98             for (int x = 0; x < 4; x++) {
  99                 canvas->save();
 100                 canvas->translate(x * 350.0f, y * 350.0f);
 101                 switch (x) {
 102                     case 0:
 103                         canvas->drawPatch(cubics, nullptr, nullptr, modes[y], paint);
 104                         break;
 105                     case 1:
 106                         canvas->drawPatch(cubics, colors, nullptr, modes[y], paint);
 107                         break;
 108                     case 2:
 109                         paint.setShader(shader);
 110                         canvas->drawPatch(cubics, nullptr, texCoords, modes[y], paint);
 111                         paint.setShader(nullptr);
 112                         break;
 113                     case 3:
 114                         paint.setShader(shader);
 115                         canvas->drawPatch(cubics, colors, texCoords, modes[y], paint);
 116                         paint.setShader(nullptr);
 117                         break;
 118                     default:
 119                         break;
 120                 }
 121
 122                 draw_control_points(canvas, cubics);
 123                 canvas->restore();
 124             }
 125         }
 126         canvas->restore();
 127 }