python微信跳一跳系列之棋子定位像素遍历

def find_piece_and_board(im):
 #寻找关键坐标
 w, h = im.size

 piece_x_sum = 0
 piece_x_c = 0
 piece_y_max = 0
 board_x = 0
 board_y = 0
 scan_x_border = int(w / 8) # 扫描棋子时的左右边界
 scan_start_y = 0 # 扫描的起始 y 坐标
 im_pixel = im.load()
 # 以 50px 步长，尝试探测 scan_start_y
 for i in range(int(h / 3), int(h*2 / 3), 50):
 last_pixel = im_pixel[0, i]
 for j in range(1, w):
  pixel = im_pixel[j, i]
  # 不是纯色的线，则记录 scan_start_y 的值，准备跳出循环
  if pixel != last_pixel:
  scan_start_y = i - 50
  break
 if scan_start_y:
  break
 print('scan_start_y: {}'.format(scan_start_y))

 # 从 scan_start_y 开始往下扫描，棋子应位于屏幕上半部分，这里暂定不超过 2/3
 for i in range(scan_start_y, int(h * 2 / 3)):
 # 横坐标方面也减少了一部分扫描开销
 for j in range(scan_x_border, w - scan_x_border):
  pixel = im_pixel[j, i]
  # 根据棋子的最低行的颜色判断，找最后一行那些点的平均值，这个颜
  # 色这样应该 OK，暂时不提出来
  if (50 < pixel[0] < 60) \
   and (53 < pixel[1] < 63) \
   and (95 < pixel[2] < 110):
  piece_x_sum += j
  piece_x_c += 1
  piece_y_max = max(i, piece_y_max)

 if not all((piece_x_sum, piece_x_c)):
 return 0, 0, 0, 0
 piece_x = int(piece_x_sum / piece_x_c)
 piece_y = piece_y_max - piece_base_height_1_2 # 上移棋子底盘高度的一半