如何在python中将图像裁剪成多边形

Question

我正在尝试制作一个图形用户界面，帮助我裁剪人脸，并根据他们的情绪（如愤怒、悲伤、高兴等）对其进行折叠。我的代码看起来工作正常，但当我裁剪图像时，它会保存图像的其余部分。我真的不知道怎么才能做到！！ 我的裁剪功能：

    def on_mouse(self, event, x, y, buttons, user_param):
    # Mouse callback that gets called for every mouse event (i.e. moving, clicking, etc.)

    if self.done: # Nothing more to do
        return

    if event == cv2.EVENT_MOUSEMOVE:
        # We want to be able to draw the line-in-progress, so update current mouse position
        self.current = (x, y)
    elif event == cv2.EVENT_LBUTTONDOWN:
        # Left click means adding a point at current position to the list of points
        print("Adding point #%d with position(%d,%d)" % (len(self.points), x, y))
        self.points.append((x, y))
    elif event == cv2.EVENT_RBUTTONDOWN:
        # Right click means we're done
        print("Completing polygon with %d points." % len(self.points))
        self.done = True


def run(self, image):
    # Let's create our working window and set a mouse callback to handle events
    cv2.namedWindow(self.window_name, flags=cv2.WINDOW_AUTOSIZE)
    cv2.imshow(self.window_name, image)
    cv2.waitKey(1)
    cv2.setMouseCallback(self.window_name, self.on_mouse)

    while(not self.done):
        # This is our drawing loop, we just continuously draw new images
        # and show them in the named window
        if (len(self.points) > 0):
            # Draw all the current polygon segments
            cv2.polylines(image, np.array([self.points]), False, FINAL_LINE_COLOR, 1)
            # And  also show what the current segment would look like
            cv2.line(image, self.points[-1], self.current, WORKING_LINE_COLOR)
        # Update the window
        cv2.imshow(self.window_name, image)
        # And wait 50ms before next iteration (this will pump window messages meanwhile)
        if cv2.waitKey(50) == 27: # ESC hit
            self.done = True

    # User finised entering the polygon points, so let's make the final drawing
    # of a filled polygon
    if (len(self.points) > 0):
        cv2.fillPoly(image, np.array([self.points]), FINAL_LINE_COLOR)
    # And show it
    cv2.imshow(self.window_name, image)
    # Waiting for the user to press any key
    cv2.waitKey()

    cv2.destroyWindow(self.window_name)
    return image

I added the whole code here if you need

编辑：当我在open函数中更改这行时：

^{pr2}$

为此：

im = Image.open(fileName).convert("RGBA")
imArray = numpy.asarray(im)
real_image = imageViewer.run(imArray)

它给了我这样的错误： 已连接到pydev调试器（内部版本162.1967.10） JPEG数据损坏：数据段过早结束 回溯（最近一次呼叫）： 文件“C:/Users/ASUS/Desktop/cgg/gui/template2.py”，第156行，打开 im=图像.打开（文件名）.convert（“RGBA”） 文件“C:\Python27\lib\site packages\PIL\图像.py“，第1956行，开放式 前缀=fp.读取（十六） AttributeError:“QString”对象没有属性“read”

顺便说一下，我用这些代码行得到了文件名

fileName = QtGui.QFileDialog.getOpenFileName(self, "Open File",
            QtCore.QDir.currentPath())
if fileName:
   image = QtGui.QImage(fileName)
   if image.isNull():
      QtGui.QMessageBox.information(self, "Image Viewer",
                    "Cannot load %s." % fileName)
            return