用2点和圆心绘制圆弧 [英] Draw arc with 2 points and center of the circle

问题描述

我有两个圆圈和圆圈的中心。我想在这些点之间画一条弧。方法 drawArc 很简单，不符合我的目的。
有人帮忙吗？

I have two points of circle and center of this circle. I want to draw an arc between these points. Method drawArc is to simple and doesn't fit my purpose. Anybody help?

推荐答案

你可以使用Canvas.drawArc，但你必须计算它需要的参数：

You can use Canvas.drawArc, but you must compute the arguments it needs:

假设圆的中心是（x0，y0）并且弧包含你的两个点（x1，y1）和（x2，y2）。然后半径为：r = sqrt（（x1-x0）（x1-x0）+（y1-y0）（y1-y0））。所以：

Lets say that the center of the circle is (x0, y0) and that the arc contains your two points (x1, y1) and (x2, y2). Then the radius is: r=sqrt((x1-x0)(x1-x0) + (y1-y0)(y1-y0)). So:

int r = (int)Math.sqrt((x1-x0)*(x1-x0) + (y1-y0)*(y1-y0));
int x = x0-r;
int y = y0-r;
int width = 2*r;
int height = 2*r;
int startAngle = (int) (180/Math.PI*atan2(y1-y0, x1-x0));
int endAngle = (int) (180/Math.PI*atan2(y2-y0, x2-x0));
canvas.drawArc(x, y, width, height, startAngle, endAngle);

祝你好运！

这篇关于用2点和圆心绘制圆弧的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！