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      1 /*
      2  * Copyright 2011 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 "SampleCode.h"
      9 #include "SkCanvas.h"
     10 #include "SkPaint.h"
     11 #include "SkPath.h"
     12 #include "SkView.h"
     13 
     14 // ensure that we don't accidentally screw up the bounds when the oval is
     15 // fractional, and the impl computes the center and radii, and uses them to
     16 // reconstruct the edges of the circle.
     17 // see bug# 1504910
     18 static void test_circlebounds(SkCanvas*) {
     19     SkRect r = { 1.39999998f, 1, 21.3999996f, 21 };
     20     SkPath p;
     21     p.addOval(r);
     22     SkASSERT(r == p.getBounds());
     23 }
     24 
     25 class CircleView : public SampleView {
     26 public:
     27     static const SkScalar ANIM_DX;
     28     static const SkScalar ANIM_DY;
     29     static const SkScalar ANIM_RAD;
     30     SkScalar fDX, fDY, fRAD;
     31 
     32     CircleView() {
     33         fDX = fDY = fRAD = 0;
     34         fN = 3;
     35     }
     36 
     37 protected:
     38     // overrides from SkEventSink
     39     virtual bool onQuery(SkEvent* evt) {
     40         if (SampleCode::TitleQ(*evt)) {
     41             SampleCode::TitleR(evt, "Circles");
     42             return true;
     43         }
     44         return this->INHERITED::onQuery(evt);
     45     }
     46 
     47     void circle(SkCanvas* canvas, int width, bool aa) {
     48         SkPaint paint;
     49 
     50         paint.setAntiAlias(aa);
     51         if (width < 0) {
     52             paint.setStyle(SkPaint::kFill_Style);
     53         } else {
     54             paint.setStyle(SkPaint::kStroke_Style);
     55             paint.setStrokeWidth(SkIntToScalar(width));
     56         }
     57         canvas->drawCircle(0, 0, SkIntToScalar(9) + fRAD, paint);
     58         if (false) { // avoid bit rot, suppress warning
     59             test_circlebounds(canvas);
     60         }
     61     }
     62 
     63     void drawSix(SkCanvas* canvas, SkScalar dx, SkScalar dy) {
     64         for (int width = -1; width <= 1; width++) {
     65             canvas->save();
     66             circle(canvas, width, false);
     67             canvas->translate(0, dy);
     68             circle(canvas, width, true);
     69             canvas->restore();
     70             canvas->translate(dx, 0);
     71         }
     72     }
     73 
     74     static void make_poly(SkPath* path, int n) {
     75         if (n <= 0) {
     76             return;
     77         }
     78         path->incReserve(n + 1);
     79         path->moveTo(SK_Scalar1, 0);
     80         SkScalar step = SK_ScalarPI * 2 / n;
     81         SkScalar angle = 0;
     82         for (int i = 1; i < n; i++) {
     83             angle += step;
     84             SkScalar c, s = SkScalarSinCos(angle, &c);
     85             path->lineTo(c, s);
     86         }
     87         path->close();
     88     }
     89 
     90     virtual void onDrawContent(SkCanvas* canvas) {
     91         SkPaint paint;
     92         paint.setAntiAlias(true);
     93         paint.setStyle(SkPaint::kStroke_Style);
     94         SkMatrix matrix;
     95         matrix.setScale(SkIntToScalar(100), SkIntToScalar(100));
     96         matrix.postTranslate(SkIntToScalar(200), SkIntToScalar(200));
     97         canvas->concat(matrix);
     98         for (int n = 3; n < 20; n++) {
     99             SkPath path;
    100             make_poly(&path, n);
    101             SkAutoCanvasRestore acr(canvas, true);
    102             canvas->rotate(SkIntToScalar(10) * (n - 3));
    103             canvas->translate(-SK_Scalar1, 0);
    104             canvas->drawPath(path, paint);
    105         }
    106     }
    107 
    108 private:
    109     int fN;
    110     typedef SampleView INHERITED;
    111 };
    112 
    113 const SkScalar CircleView::ANIM_DX(SK_Scalar1 / 67);
    114 const SkScalar CircleView::ANIM_DY(SK_Scalar1 / 29);
    115 const SkScalar CircleView::ANIM_RAD(SK_Scalar1 / 19);
    116 
    117 //////////////////////////////////////////////////////////////////////////////
    118 
    119 static SkView* MyFactory() { return new CircleView; }
    120 static SkViewRegister reg(MyFactory);
    121