# Contours/shape detection

import cv2 as cv
import numpy as np

def stackImages(scale,imgArray):
    rows = len(imgArray)
    cols = len(imgArray[0])
    rowsAvailable = isinstance(imgArray[0], list)
    width = imgArray[0][0].shape[1]
    height = imgArray[0][0].shape[0]
    if rowsAvailable:
        for x in range ( 0, rows):
            for y in range(0, cols):
                if imgArray[x][y].shape[:2] == imgArray[0][0].shape [:2]:
                    imgArray[x][y] = cv.resize(imgArray[x][y], (0, 0), None, scale, scale)
                else:
                    imgArray[x][y] = cv.resize(imgArray[x][y], (imgArray[0][0].shape[1], imgArray[0][0].shape[0]), None, scale, scale)
                if len(imgArray[x][y].shape) == 2: imgArray[x][y]= cv.cvtColor( imgArray[x][y], cv.COLOR_GRAY2BGR)
        imageBlank = np.zeros((height, width, 3), np.uint8)
        hor = [imageBlank]*rows
        hor_con = [imageBlank]*rows
        for x in range(0, rows):
            hor[x] = np.hstack(imgArray[x])
        ver = np.vstack(hor)
    else:
        for x in range(0, rows):
            if imgArray[x].shape[:2] == imgArray[0].shape[:2]:
                imgArray[x] = cv.resize(imgArray[x], (0, 0), None, scale, scale)
            else:
                imgArray[x] = cv.resize(imgArray[x], (imgArray[0].shape[1], imgArray[0].shape[0]), None,scale, scale)
            if len(imgArray[x].shape) == 2: imgArray[x] = cv.cvtColor(imgArray[x], cv.COLOR_GRAY2BGR)
        hor= np.hstack(imgArray)
        ver = hor
    return ver

def getContours(img):
    contours,hierarchy = cv.findContours(img,cv.RETR_EXTERNAL,cv.CHAIN_APPROX_NONE)
    for cnt in contours:
        area = cv.contourArea(cnt)
        print(area)
        if area > 500:
            cv.drawContours(imgContour,cnt,-1,(255,0,0),3)
            peri = cv.arcLength(cnt,True)
            # print(peri)
            approx = cv.approxPolyDP(cnt,0.02*peri,True)
            # print(len(approx))
            objCor = len(approx)
            x, y, w, h = cv.boundingRect(approx)

            if objCor == 3:
                objectType = "Tri"
            elif objCor == 4:
                aspRatio = w/float(h)
                if aspRatio > 0.9 and aspRatio < 1.05:
                    objectType = "Square"
                else:
                    objectType = "rectangle"
            elif objCor > 4:
                objectType = "Circle"
            else:
                objectType="None"

            cv.rectangle(imgContour,(x,y),(x+w,y+h),(0,255,0),2)
            cv.putText(imgContour,objectType,(x+(w//2)-10,y+(h//2)-10),cv.FONT_HERSHEY_COMPLEX,0.7,
            (0,0,0),2)


img = cv.imread("shapes.png")
imgContour = img.copy()

imgGray = cv.cvtColor(img,cv.COLOR_BGR2GRAY)
imgBlur = cv.GaussianBlur(imgGray,(7,7),1)
imgCann = cv.Canny(imgBlur,50,50)
getContours(imgCann)

imgBlank = np.zeros_like(img)
imgStack = stackImages(0.8,([img,imgGray,imgBlur],[imgCann,imgContour,imgBlank]))

cv.imshow('Stack',imgStack)
cv.waitKey(0)
