#!/usr/bin/env python
# encoding: utf-8
 
import numpy as np
 
'''
函數說明：計算兩個框的重疊面積
輸入：
rec1 第一個框xmin ymin xmax ymax
rec2 第二個框xmin ymin xmax ymax
輸出：
iouv 重疊比例 0 沒有
'''
def compute_iou(rec1, rec2):
   
  # computing area of each rectangles
  S_rec1 = (rec1[2] - rec1[0]) * (rec1[3] - rec1[1]) # H1*W1
  S_rec2 = (rec2[2] - rec2[0]) * (rec2[3] - rec2[1]) # H2*W2
  
  # computing the sum_area
  sum_area = S_rec1 + S_rec2 #總面積
  
  # find the each edge of intersect rectangle
  left_line = max(rec1[0], rec2[0])
  right_line = min(rec1[2], rec2[2])
  top_line = max(rec1[1], rec2[1])
  bottom_line = min(rec1[3], rec2[3])
  
  # judge if there is an intersect
  if left_line >= right_line or top_line >= bottom_line:
    #print("沒有重合區域")
    return 0
  else:
  #print("有重合區域")
    intersect = (right_line - left_line) * (bottom_line - top_line)
    iouv=(float(intersect) / float(sum_area - intersect))*1.0
 
    return iouv
 
'''
函數說明：獲取兩組匹配結果
輸入：
rectA 車位
rectB 車輛
threod 重疊面積最小數值界限 默認0.6
輸出：
CarUse 一維數組保存是否占用 1 占用 0 沒有
 
'''
def TestCarUse(rectA,rectB,threod=0.6，debug=0):
  #threod=0.8#設定最小值
  ALength=len(rectA)
  BLength=len(rectB)
 
  #創建保存匹配結果的矩陣
  recIOU=np.zeros((ALength,BLength),dtype=float,order='C')
  #用于記錄車位能夠使否占用  
  CarUse=np.zeros((1,ALength),dtype=int,order='C')
 
  for i in range(0,ALength):
    for j in range(0,BLength):
      iou = compute_iou(rectA[i], rectB[j])
      recIOU[i][j]=format(iou,'.3f')
      if iou>=threod:    
        CarUse[0,i]=1 #有一個超過匹配認為車位i被占用
  if debug==1:
    print('----匹配矩陣----')
    print(recIOU)
    '''
    print('----車位占用情況----')
    for i in range(0,ALength):
    msg='車位'+str(i)+"-"+str(CarUse[0][i])
    print(msg)
    '''
  return CarUse
 
 
  
if __name__=='__main__':
  #A代表車位
  rectA1 = (30, 10, 70, 20)
  rectA2 = (70, 10, 80, 20)
  rectA =[rectA1,rectA2]
  #B代表檢測車輛
  rectB1 = (20, 10, 35, 20)
  rectB2 = (30, 15, 70, 25)
  rectB3 = (70, 10, 80, 20)
  rectB =[rectB1,rectB2,rectB3]
   
  #獲取車位占用情況 rectA車位 rectB車輛 0.6占面積最小比
  CarUse=TestCarUse(rectA,rectB,0.6,1)
 
  print('----車位占用情況----')
  for i in range(0,len(CarUse)+1):
  msg='車位'+str(i)+"-"+str(CarUse[0][i])
    print(msg)