// 点到直线的最短距离的判断 点（x0,y0） 到由两点组成的线段（x1,y1） ,( x2,y2 )private double pointToLine(int x1, int y1, int x2, int y2, int x0,int y0) {double space = 0;double a, b, c;a = lineSpace(x1, y1, x2, y2);// 线段的长度b = lineSpace(x1, y1, x0, y0);// (x1,y1)到点的距离c = lineSpace(x2, y2, x0, y0);// (x2,y2)到点的距离if (c <= 0.000001 || b <= 0.000001) {space = 0;return space;}if (a <= 0.000001) {space = b;return space;}if (c * c >= a * a + b * b) {space = b;return space;}if (b * b >= a * a + c * c) {space = c;return space;}double p = (a + b + c) / 2;// 半周长double s = Math.sqrt(p * (p - a) * (p - b) * (p - c));// 海伦公式求面积space = 2 * s / a;// 返回点到线的距离（利用三角形面积公式求高）return space;}// 计算两点之间的距离private double lineSpace(int x1, int y1, int x2, int y2) {double lineLength = 0;lineLength = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2)* (y1 - y2));return lineLength;}