gm/stroke_rect_shader.cpp

   1 /*
   2  * Copyright 2016 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
  11 namespace skiagm {
  12
  13 // Draw stroked rects (both AA and nonAA) with all the types of joins:
  14 //    bevel, miter, miter-limited-to-bevel, round
  15 // and as a hairline.
  16 DEF_SIMPLE_GM(stroke_rect_shader, canvas, 690, 300) {
  17     constexpr SkRect kRect {0, 0, 100, 100};
  18     constexpr SkPoint kPts[] {{kRect.fLeft, kRect.fTop}, {kRect.fRight, kRect.fBottom}};
  19     constexpr SkColor kColors[] {SK_ColorRED, SK_ColorBLUE};
  20     SkPaint paint;
  21     sk_sp<SkShader> shader = SkGradientShader::MakeLinear(kPts, kColors, nullptr, 2,
  22                                                           SkShader::kClamp_TileMode);
  23     paint.setShader(std::move(shader));
  24     paint.setStyle(SkPaint::kStroke_Style);
  25     // Do a large initial translate so that local coords disagree with device coords significantly
  26     // for the first rect drawn.
  27     canvas->translate(kRect.centerX(), kRect.centerY());
  28     constexpr SkScalar kPad = 20;
  29     for (auto aa : {false, true}) {
  30         paint.setAntiAlias(aa);
  31         canvas->save();
  32
  33         constexpr SkScalar kStrokeWidth = 10;
  34         paint.setStrokeWidth(kStrokeWidth);
  35
  36         paint.setStrokeJoin(SkPaint::kBevel_Join);
  37         canvas->drawRect(kRect, paint);
  38         canvas->translate(kRect.width() + kPad, 0);
  39
  40         paint.setStrokeJoin(SkPaint::kMiter_Join);
  41         canvas->drawRect(kRect, paint);
  42         canvas->translate(kRect.width() + kPad, 0);
  43
  44         // This miter limit should effectively produce a bevel join.
  45         paint.setStrokeMiter(0.01f);
  46         canvas->drawRect(kRect, paint);
  47         canvas->translate(kRect.width() + kPad, 0);
  48
  49         paint.setStrokeJoin(SkPaint::kRound_Join);
  50         canvas->drawRect(kRect, paint);
  51         canvas->translate(kRect.width() + kPad, 0);
  52
  53         paint.setStrokeWidth(0);
  54         canvas->drawRect(kRect, paint);
  55
  56         canvas->restore();
  57         canvas->translate(0, kRect.height() + kPad);
  58     }
  59 }
  60
  61 }