if direction == 'vertical':
for y in range(height):
for x in range(width):
线性渐变,从上到下
mask[y, x] = int(255 * (y / height))
elif direction == 'horizontal':
for y in range(height):
for x in range(width):
线性渐变,从左到右
mask[y, x] = int(255 * (x / width))
应用渐变蒙版到图像
result = cv2.applyColorMap(img, cv2.COLORMAP_JET, mask)