java - 在矩形内创建椭圆/圆形

Question

我正在尝试在矩形内创建一个椭圆形/圆形。我正在尝试在 Canvas 上对位图图像执行此操作。这是我的代码:

int x = (int) (midpoint.x*xRatio);
int y = (int) (midpoint.y*yRatio);
int radius = (int) (distance/2);
int left =  x - radius;
int right = x + radius;
int top = y - radius;

canvas.drawRect(left, top, right, bottom, paint);

现在我想在这个矩形内创建一个椭圆形/圆形。我尝试了这个，但尝试了几个小时却无法让它工作:

RectF ovalBounds = new RectF();
//ovalBounds.set(x, y,  (right - left)/2, (bottom-top)/2);
ovalBounds.set(x, y-radius, radius * 2, radius * 2);
canvas.drawOval(ovalBounds, paint);                 

有人可以帮我解决这个问题吗？这是帮助我实现目标的视觉效果:

Answer 1

您应该使用与绘制矩形相同的边界:

RectF rect = new RectF(left, top, right, bottom);
canvas.drawRect(rect, paint);
canvas.drawOval(rect, paint);