Android通过手势实现的缩放处理(2)

51             float dx = metrics.widthPixels * dxi / (float) dyit;
52             float dy = metrics.heightPixels * dyi / (float) dyit;
53  
54             x1 = event.getX();
55             y1 = event.getY();
56  
57             x2 = x1 + dx;
58             y2 = y1 + dy;
59  
60             invalidate();
61  
62             return true;
63         }
64  
65         @Override
66         protected void onDraw(Canvas canvas) {
67             // TODO Auto-generated method stub
68             super.onDraw(canvas);
69  
70             float r = (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2)
71                     * (y1 - y2)) / 2;
72             r = 50 >= r ? 50 : r;
73  
74             Paint paint = new Paint();
75             paint.setColor(Color.BLUE);
76             canvas.drawCircle(x1, y1, r, paint);
77  
78         }
79  
80     }
81  
82 }
 

作者“ljbal”