3_drawing_functions.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import cv2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "img = np.zeros((320,320,3),dtype=np.uint8) # a black image"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "line_img = cv2.line(img,(0,0),(250,250),(255,0,0),4) # Draw a line from top right to bottom left, (0,0) is the  top left screen with a thickness of 4"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "cv2.imshow('image_line',line_img)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "rectangle_img = cv2.rectangle(line_img,(0,0),(250,250),(0,255,0),4) # recatngle from top left to bottom right\n",
    "cv2.imshow('image_line',rectangle_img)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "circle_img = cv2.circle(rectangle_img,(250,250),50,(0,0,255),4) #circle with center and radius\n",
    "cv2.imshow('image_line',circle_img)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [],
   "source": [
    "ellipse_img = cv2.ellipse(img,(100,100),(100,50),0,0,360,255,4)#drawing an ellipse\n",
    "cv2.imshow('image_line',ellipse_img)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [],
   "source": [
    "poly  = np.array(([20,30],[20,70],[175,100],[250,200]),np.int32)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "poly = poly.reshape(-1,1,2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [],
   "source": [
    "poly_img  = cv2.polylines(ellipse_img,[poly],True,(0,255,255),1)#draw a polygon and always the shape of vertices in (rows,1,2)\n",
    "cv2.imshow('image_line',poly_img)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [],
   "source": [
    "font = cv2.FONT_HERSHEY_SIMPLEX # type of font\n",
    "text_img = cv2.putText(poly_img,'Hello World !!',(50,275),font,1,(255,255,255),3) #display text on the image\n",
    "cv2.imshow('image_line',text_img)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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