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