用C# 实现 已知旋转矩形左上角点点和宽高以及角度，计算旋转矩形4点坐标

以下是用C#实现已知旋转矩形左上角点、宽高和角度，计算旋转矩形4点坐标的代码：

public static PointF[] GetRotatedRectPoints(PointF leftTop, float width, float height, float angle)
{
    PointF[] points = new PointF[4];

    // 计算中心点
    float centerX = leftTop.X + width / 2;
    float centerY = leftTop.Y + height / 2;

    // 计算旋转后的4个点坐标
    float sin = (float)Math.Sin(angle);
    float cos = (float)Math.Cos(angle);
    float x1 = -width / 2;
    float y1 = -height / 2;
    float x2 = width / 2;
    float y2 = -height / 2;
    float x3 = width / 2;
    float y3 = height / 2;
    float x4 = -width / 2;
    float y4 = height / 2;

    points[0] = new PointF(centerX + x1 * cos - y1 * sin, centerY + x1 * sin + y1 * cos);
    points[1] = new PointF(centerX + x2 * cos - y2 * sin, centerY + x2 * sin + y2 * cos);
    points[2] = new PointF(centerX + x3 * cos - y3 * sin, centerY + x3 * sin + y3 * cos);
    points[3] = new PointF(centerX + x4 * cos - y4 * sin, centerY + x4 * sin + y4 * cos);

    return points;
}

其中，leftTop为左上角点坐标，width和height为宽和高，angle为旋转角度，函数返回值为旋转后的4个点坐标。