1. 三个点:圆心A,半径r,度数0的点B,任意点C.
先计算∠BAC的度数(弧度)。
public double calculatorDegree(float x1, float y1, float x2, float y2, float x3, float y3) { double radian = 0; double ab = getDistance(x1, y1, x2, y2); double ac = getDistance(x1, y1, x3, y3); double bc = getDistance(x2, y2, x3, y3); double value = (ab * ab + ac * ac - (bc * bc)) / (2 * ab * ac); radian = Math.acos(value); return radian; } public double getDistance(float x1, float y1, float x2, float y2) { double distance = 0; distance = Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)); return distance; }
2. 根据弧度计算度数并且计算AC距离。
float x = event.getX(); float y = event.getY(); double radian = calculatorDegree(width / 2, height / 2, width / 2 + radius, height / 2, x, y); double degree = (180 / Math.PI * radian); double distance = getDistance(width / 2, height / 2, x, y);
3,根据度数和距离计算。
使用度数前先判断是否用补角。
计算扇型弧线起始点坐标:
(float) (center_X + r * Math.cos(startAngle * Math.PI / 180)),(float) (center_Y + r * Math.sin(startAngle * Math.PI / 180))
扫描二维码关注公众号,回复:
607708 查看本文章