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 #include "SampleCode.h"
   8 #include "SkCanvas.h"
   9
  10 // Reproduces https://code.google.com/p/chromium/issues/detail?id=279014
  11
  12 // Renders a string art shape.
  13 // The particular shape rendered can be controlled by clicking horizontally, thereby
  14 // generating an angle from 0 to 1.
  15
  16 class StringArtView : public SampleView {
  17 public:
  18     StringArtView() : fAngle(0.305f) {}
  19
  20 protected:
  21     // overrides from SkEventSink
  22     bool onQuery(SkEvent* evt) SK_OVERRIDE {
  23         if (SampleCode::TitleQ(*evt)) {
  24             SampleCode::TitleR(evt, "StringArt");
  25             return true;
  26         }
  27         return this->INHERITED::onQuery(evt);
  28     }
  29
  30     void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {
  31         SkScalar angle = fAngle*SK_ScalarPI + SkScalarHalf(SK_ScalarPI);
  32
  33         SkPoint center = SkPoint::Make(SkScalarHalf(this->width()), SkScalarHalf(this->height()));
  34         SkScalar length = 5;
  35         SkScalar step = angle;
  36
  37         SkPath path;
  38         path.moveTo(center);
  39
  40         while (length < (SkScalarHalf(SkMinScalar(this->width(), this->height())) - 10.f))
  41         {
  42             SkPoint rp = SkPoint::Make(length*SkScalarCos(step) + center.fX,
  43                                        length*SkScalarSin(step) + center.fY);
  44             path.lineTo(rp);
  45             length += SkScalarDiv(angle, SkScalarHalf(SK_ScalarPI));
  46             step += angle;
  47         }
  48         path.close();
  49
  50         SkPaint paint;
  51         paint.setAntiAlias(true);
  52         paint.setStyle(SkPaint::kStroke_Style);
  53         paint.setColor(0xFF007700);
  54
  55         canvas->drawPath(path, paint);
  56     }
  57
  58     SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned) SK_OVERRIDE {
  59         fAngle = x/width();
  60         this->inval(NULL);
  61         return NULL;
  62     }
  63 private:
  64
  65     SkScalar fAngle;
  66     typedef SampleView INHERITED;
  67 };
  68
  69 //////////////////////////////////////////////////////////////////////////////
  70
  71 static SkView* MyFactory() { return new StringArtView; }
  72 static SkViewRegister reg(MyFactory);