submodule/skia/samplecode/SampleStringArt.cpp

   1 /*
   2  * Copyright 2013 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 "include/core/SkCanvas.h"
   9 #include "include/core/SkPath.h"
  10 #include "samplecode/Sample.h"
  11
  12 // Reproduces https://code.google.com/p/chromium/issues/detail?id=279014
  13
  14 // Renders a string art shape.
  15 // The particular shape rendered can be controlled by clicking horizontally, thereby
  16 // generating an angle from 0 to 1.
  17
  18 class StringArtView : public Sample {
  19 public:
  20     StringArtView() : fAngle(0.305f) {}
  21
  22 protected:
  23     SkString name() override { return SkString("StringArt"); }
  24
  25     void onDrawContent(SkCanvas* canvas) override {
  26         SkScalar angle = fAngle*SK_ScalarPI + SkScalarHalf(SK_ScalarPI);
  27
  28         SkPoint center = SkPoint::Make(SkScalarHalf(this->width()), SkScalarHalf(this->height()));
  29         SkScalar length = 5;
  30         SkScalar step = angle;
  31
  32         SkPath path;
  33         path.moveTo(center);
  34
  35         while (length < (SkScalarHalf(std::min(this->width(), this->height())) - 10.f))
  36         {
  37             SkPoint rp = SkPoint::Make(length*SkScalarCos(step) + center.fX,
  38                                        length*SkScalarSin(step) + center.fY);
  39             path.lineTo(rp);
  40             length += angle / SkScalarHalf(SK_ScalarPI);
  41             step += angle;
  42         }
  43         path.close();
  44
  45         SkPaint paint;
  46         paint.setAntiAlias(true);
  47         paint.setStyle(SkPaint::kStroke_Style);
  48         paint.setColor(0xFF007700);
  49
  50         canvas->drawPath(path, paint);
  51     }
  52
  53     Sample::Click* onFindClickHandler(SkScalar x, SkScalar y, skui::ModifierKey) override {
  54         fAngle = x/width();
  55         return nullptr;
  56     }
  57 private:
  58
  59     SkScalar fAngle;
  60     using INHERITED = Sample;
  61 };
  62
  63 //////////////////////////////////////////////////////////////////////////////
  64
  65 DEF_SAMPLE( return new StringArtView(); )