03-Direct-Drawing-with-Mouse.ipynb

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    "<a href=\"https://www.pieriandata.com\"><img src=\"../DATA/Logo.jpg\"></a>"
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   "source": [
    "# Direct Drawing with Mouse\n",
    "\n",
    "## NOTE: THESE SHOULD ALL BE RUN AS A .py SCRIPT. View video for full details."
   ]
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  {
   "cell_type": "markdown",
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   "source": [
    "## SCRIPT 1: Connecting a Function for Drawing"
   ]
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    "import cv2\n",
    "import numpy as np\n",
    "# Create a function based on a CV2 Event (Left button click)\n",
    "def draw_circle(event,x,y,flags,param):\n",
    "    if event == cv2.EVENT_LBUTTONDOWN:\n",
    "        cv2.circle(img,(x,y),100,(0,255,0),-1)\n",
    "\n",
    "# Create a black image\n",
    "img = np.zeros((512,512,3), np.uint8)\n",
    "# This names the window so we can reference it \n",
    "cv2.namedWindow(winname='my_drawing')\n",
    "# Connects the mouse button to our callback function\n",
    "cv2.setMouseCallback('my_drawing',draw_circle)\n",
    "\n",
    "while True: #Runs forever until we break with Esc key on keyboard\n",
    "    # Shows the image window\n",
    "    cv2.imshow('my_drawing',img)\n",
    "    # EXPLANATION FOR THIS LINE OF CODE:\n",
    "    # https://stackoverflow.com/questions/35372700/whats-0xff-for-in-cv2-waitkey1/39201163\n",
    "    if cv2.waitKey(20) & 0xFF == 27:\n",
    "        break\n",
    "# Once script is done, its usually good practice to call this line\n",
    "# It closes all windows (just in case you have multiple windows called)\n",
    "cv2.destroyAllWindows()\n"
   ]
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## SCRIPT 2: Adding Functionality with Event Choices"
   ]
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   "source": [
    "---------"
   ]
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   "source": [
    "import cv2\n",
    "import numpy as np\n",
    "\n",
    "\n",
    "# Create a function based on a CV2 Event (Left button click)\n",
    "def draw_circle(event,x,y,flags,param):\n",
    "    if event == cv2.EVENT_LBUTTONDOWN:\n",
    "        cv2.circle(img,(x,y),100,(0,255,0),-1)\n",
    "    elif event == cv2.EVENT_RBUTTONDOWN:\n",
    "        cv2.circle(img,(x,y),100,(0,0,255),-1)\n",
    "        \n",
    "\n",
    "# Create a black image\n",
    "img = np.zeros((512,512,3), np.uint8)\n",
    "# This names the window so we can reference it \n",
    "cv2.namedWindow(winname='my_drawing')\n",
    "# Connects the mouse button to our callback function\n",
    "cv2.setMouseCallback('my_drawing',draw_circle)\n",
    "\n",
    "while True: #Runs forever until we break with Esc key on keyboard\n",
    "    # Shows the image window\n",
    "    cv2.imshow('my_drawing',img)\n",
    "    # EXPLANATION FOR THIS LINE OF CODE:\n",
    "    # https://stackoverflow.com/questions/35372700/whats-0xff-for-in-cv2-waitkey1/39201163\n",
    "    if cv2.waitKey(20) & 0xFF == 27:\n",
    "        break\n",
    "# Once script is done, its usually good practice to call this line\n",
    "# It closes all windows (just in case you have multiple windows called)\n",
    "cv2.destroyAllWindows()\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# SCRIPT 3: Dragging with Mouse"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import cv2\n",
    "import numpy as np\n",
    "\n",
    "\n",
    "# Create a function based on a CV2 Event (Left button click)\n",
    "drawing = False # True if mouse is pressed\n",
    "ix,iy = -1,-1\n",
    "\n",
    "# mouse callback function\n",
    "def draw_rectangle(event,x,y,flags,param):\n",
    "    global ix,iy,drawing,mode\n",
    "\n",
    "    if event == cv2.EVENT_LBUTTONDOWN:\n",
    "        # When you click DOWN with left mouse button drawing is set to True\n",
    "        drawing = True\n",
    "        # Then we take note of where that mouse was located\n",
    "        ix,iy = x,y\n",
    "\n",
    "    elif event == cv2.EVENT_MOUSEMOVE:\n",
    "        # Now the mouse is moving\n",
    "        if drawing == True:\n",
    "            # If drawing is True, it means you've already clicked on the left mouse button\n",
    "            # We draw a rectangle from the previous position to the x,y where the mouse is\n",
    "            cv2.rectangle(img,(ix,iy),(x,y),(0,255,0),-1)\n",
    "           \n",
    "\n",
    "    elif event == cv2.EVENT_LBUTTONUP:\n",
    "        # Once you lift the mouse button, drawing is False\n",
    "        drawing = False\n",
    "        # we complete the rectangle.\n",
    "        cv2.rectangle(img,(ix,iy),(x,y),(0,255,0),-1)\n",
    "        \n",
    "        \n",
    "\n",
    "# Create a black image\n",
    "img = np.zeros((512,512,3), np.uint8)\n",
    "# This names the window so we can reference it \n",
    "cv2.namedWindow(winname='my_drawing')\n",
    "# Connects the mouse button to our callback function\n",
    "cv2.setMouseCallback('my_drawing',draw_rectangle)\n",
    "\n",
    "while True: #Runs forever until we break with Esc key on keyboard\n",
    "    # Shows the image window\n",
    "    cv2.imshow('my_drawing',img)\n",
    "    # EXPLANATION FOR THIS LINE OF CODE:\n",
    "    # https://stackoverflow.com/questions/35372700/whats-0xff-for-in-cv2-waitkey1/39201163\n",
    "    \n",
    "    # CHECK TO SEE IF ESC WAS PRESSED ON KEYBOARD\n",
    "    if cv2.waitKey(1) & 0xFF == 27:\n",
    "        break\n",
    "# Once script is done, its usually good practice to call this line\n",
    "# It closes all windows (just in case you have multiple windows called)\n",
    "cv2.destroyAllWindows()"
   ]
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