你可以简单地以弧度计算角度as

You can simply calculate the angle in radians as

double rads = atan2(y2 - y1, x2 - x1);

然后你得到如下坐标：

double x3 = x2 + gapSize * cos(rads);
double y3 = y2 + gapSize * sin(rads);

这是你的意思吗？