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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 "SkDevice.h"
     11 #include "SkPaint.h"
     12 #include "SkPath.h"
     13 #include "SkView.h"
     14 
     15 // ensure that we don't accidentally screw up the bounds when the oval is
     16 // fractional, and the impl computes the center and radii, and uses them to
     17 // reconstruct the edges of the circle.
     18 // see bug# 1504910
     19 static void test_circlebounds(SkCanvas*) {
     20     SkRect r = { 1.39999998f, 1, 21.3999996f, 21 };
     21     SkPath p;
     22     p.addOval(r);
     23     SkASSERT(r == p.getBounds());
     24 }
     25 
     26 class CircleView : public SampleView {
     27 public:
     28     static const SkScalar ANIM_DX;
     29     static const SkScalar ANIM_DY;
     30     static const SkScalar ANIM_RAD;
     31     SkScalar fDX, fDY, fRAD;
     32 
     33     CircleView() {
     34         fDX = fDY = fRAD = 0;
     35         fN = 3;
     36     }
     37 
     38 protected:
     39     // overrides from SkEventSink
     40     virtual bool onQuery(SkEvent* evt) {
     41         if (SampleCode::TitleQ(*evt)) {
     42             SampleCode::TitleR(evt, "Circles");
     43             return true;
     44         }
     45         return this->INHERITED::onQuery(evt);
     46     }
     47 
     48     void circle(SkCanvas* canvas, int width, bool aa) {
     49         SkPaint paint;
     50 
     51         paint.setAntiAlias(aa);
     52         if (width < 0) {
     53             paint.setStyle(SkPaint::kFill_Style);
     54         } else {
     55             paint.setStyle(SkPaint::kStroke_Style);
     56             paint.setStrokeWidth(SkIntToScalar(width));
     57         }
     58         canvas->drawCircle(0, 0, SkIntToScalar(9) + fRAD, paint);
     59         if (false) { // avoid bit rot, suppress warning
     60             test_circlebounds(canvas);
     61         }
     62     }
     63 
     64     void drawSix(SkCanvas* canvas, SkScalar dx, SkScalar dy) {
     65         for (int width = -1; width <= 1; width++) {
     66             canvas->save();
     67             circle(canvas, width, false);
     68             canvas->translate(0, dy);
     69             circle(canvas, width, true);
     70             canvas->restore();
     71             canvas->translate(dx, 0);
     72         }
     73     }
     74 
     75     static void make_poly(SkPath* path, int n) {
     76         if (n <= 0) {
     77             return;
     78         }
     79         path->incReserve(n + 1);
     80         path->moveTo(SK_Scalar1, 0);
     81         SkScalar step = SK_ScalarPI * 2 / n;
     82         SkScalar angle = 0;
     83         for (int i = 1; i < n; i++) {
     84             angle += step;
     85             SkScalar c, s = SkScalarSinCos(angle, &c);
     86             path->lineTo(c, s);
     87         }
     88         path->close();
     89     }
     90 
     91     static void rotate(SkCanvas* canvas, SkScalar angle, SkScalar px, SkScalar py) {
     92         canvas->translate(-px, -py);
     93         canvas->rotate(angle);
     94         canvas->translate(px, py);
     95     }
     96 
     97     virtual void onDrawContent(SkCanvas* canvas) {
     98         SkPaint paint;
     99         paint.setAntiAlias(true);
    100         paint.setStyle(SkPaint::kStroke_Style);
    101 //        canvas->drawCircle(250, 250, 220, paint);
    102         SkMatrix matrix;
    103         matrix.setScale(SkIntToScalar(100), SkIntToScalar(100));
    104         matrix.postTranslate(SkIntToScalar(200), SkIntToScalar(200));
    105         canvas->concat(matrix);
    106         for (int n = 3; n < 20; n++) {
    107             SkPath path;
    108             make_poly(&path, n);
    109             SkAutoCanvasRestore acr(canvas, true);
    110             canvas->rotate(SkIntToScalar(10) * (n - 3));
    111             canvas->translate(-SK_Scalar1, 0);
    112             canvas->drawPath(path, paint);
    113         }
    114     }
    115 
    116 private:
    117     int fN;
    118     typedef SampleView INHERITED;
    119 };
    120 
    121 const SkScalar CircleView::ANIM_DX(SK_Scalar1 / 67);
    122 const SkScalar CircleView::ANIM_DY(SK_Scalar1 / 29);
    123 const SkScalar CircleView::ANIM_RAD(SK_Scalar1 / 19);
    124 
    125 //////////////////////////////////////////////////////////////////////////////
    126 
    127 static SkView* MyFactory() { return new CircleView; }
    128 static SkViewRegister reg(MyFactory);
    129