Python-判断矩形与多边形相交

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判断矩形与不规则多边形相交。

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borderPoints = [(100, 100), (250, 100), (250, 250), (100, 250)]
def rectInRegion(x1, y1, x2 ,y2):
    global borderPoints
    rectPoints = [(x1, y1), (x1, y2), (x2, y1), (x2, y2)]
    pointsLen = len(borderPoints)
    for x, y in rectPoints:
        winding = 0
        for i in range(pointsLen):
            p1x, p1y = borderPoints[i]
            p2x, p2y = borderPoints[(i + 1) % pointsLen]
            cv2.rectangle(canvas, (p1x, p1y), (p2x, p2y), (255, 0, 0), 2)
            if p1y <= y:
                if p2y > y:
                    if ((p2x - p1x) * (y - p1y) - (x -  p1x) * (p2y - p1y)) > 0:
                        winding += 1
            else:
                if p2y <= y:
                    if ((p2x - p1x) * (y - p1y) - (x -  p1x) * (p2y - p1y)) < 0:
                        winding -= 1
        if winding != 0:
            return True
    return False