Added virtual paint

Author: mehabhalodiya

Virtual Paint/README.md

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+# Project Description
+About: "Detecting Color and using colored marker to draw virtually."
+
+It is an OpenCV application that can track an object’s movement, using which a user can draw on the screen by moving the object around — I call it Webcam Paint.
+
+## Code Explanation
+
+### Step 1: Initialize Some Stuff
+Firstly, I need to import the necessary libraries.
+
+Then I initialize variables that are used in the following steps.
+
+The *lower* and the *upper* numpy arrays help us in finding the colored cap. The *myColors* and *myColorValues* are used to create list of colors. The *myPoints* helps to set the coordinates of each of the color.
+
+### Step 2: Start Reading The Video (Frame by Frame)
+Now I use the OpenCV function **cv2.VideoCapture()** method to read a video, frame by frame (using a while loop), either from a video file or from a webcam in real-time. In this case, I pass 0 to the method to read from a webcam.
+
+### Step 3: Find The Contour-Of-Interest
+Once I start reading the webcam feed, I constantly look for a color object in the frames with the help of **cv2.inRange()** method and use the *upper* and *lower* variables initialized in Step 1. Once I find the contour(the if condition passes when a contour is found), I do a series of image operations and make it smooth. I use the center of the contour to draw on the screen as it moves. The **cv2.circle()** method draws a circle around it.
+
+### Step 4: Start Drawing And Store The Drawings
+Now I start tracking coordinates of each and every point the center of the contour touches on the screen, along with its color.
+
+I have created a *drawOnCanvas()* function to store the points in its respective color.
+
+### Step 5: Show The Drawings On The Screen
+So far I stored all the points in their respective color. Now I just join all the points in each and every frame with a line and put it on a window we created using **cv2.imshow()** method and it all fits perfectly to work!
+
+That’s it! I have successfully used a bunch of basic image processing tools and operations in OpenCV!

Virtual Paint/virtual_paint.py

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+import cv2
+import numpy as np
+
+frameWidth = 640
+frameHeight = 480
+cap = cv2.VideoCapture(0)
+cap.set(3, frameWidth)
+cap.set(4, frameHeight)
+cap.set(10, 150)
+
+myColors = [[5, 107, 0, 19, 255, 255],  # orange
+            [133, 56, 0, 159, 156, 255],  # purple
+            [57, 76, 0, 100, 255, 255],  # green
+            [90, 48, 0, 118, 255, 255]]  # blue
+
+myColorValues = [[51, 153, 255],  # BGR
+                 [255, 0, 255],
+                 [0, 255, 0],
+                 [255, 0, 0]]
+
+myPoints = []  ## [x , y , colorId ]
+
+
+def findColor(img, myColors, myColorValues):
+    imgHSV = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
+    count = 0
+    newPoints = []
+    for color in myColors:
+        lower = np.array(color[0:3])
+        upper = np.array(color[3:6])
+        mask = cv2.inRange(imgHSV, lower, upper)
+        x, y = getContours(mask)
+        cv2.circle(imgResult, (x, y), 15, myColorValues[count], cv2.FILLED)
+        if x != 0 and y != 0:
+            newPoints.append([x, y, count])
+        count += 1
+        # cv2.imshow(str(color[0]),mask)
+    return newPoints
+
+
+def getContours(img):
+    contours, hierarchy = cv2.findContours(img, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
+    x, y, w, h = 0, 0, 0, 0
+    for cnt in contours:
+        area = cv2.contourArea(cnt)
+        if area > 500:
+            # cv2.drawContours(imgResult, cnt, -1, (255, 0, 0), 3)
+            peri = cv2.arcLength(cnt, True)
+            approx = cv2.approxPolyDP(cnt, 0.02 * peri, True)
+            x, y, w, h = cv2.boundingRect(approx)
+    return x + w // 2, y
+
+
+def drawOnCanvas(myPoints, myColorValues):
+    for point in myPoints:
+        cv2.circle(imgResult, (point[0], point[1]), 10, myColorValues[point[2]], cv2.FILLED)
+
+
+while True:
+    success, img = cap.read()
+    imgResult = img.copy()
+    newPoints = findColor(img, myColors, myColorValues)
+    if len(newPoints) != 0:
+        for newP in newPoints:
+            myPoints.append(newP)
+    if len(myPoints) != 0:
+        drawOnCanvas(myPoints, myColorValues)
+
+    cv2.imshow("Result", imgResult)
+    if cv2.waitKey(1) & 0xFF == ord('q'):
+        break