04-Drawing Images.ipynb

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    "<img src=\"http://akhavanpour.ir/notebook/images/srttu.gif\" alt=\"SRTTU\" style=\"width: 150px;\"/>\n",
    "\n",
    "[![Azure Notebooks](https://notebooks.azure.com/launch.png)](https://notebooks.azure.com/import/gh/Alireza-Akhavan/class.vision)"
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   "cell_type": "markdown",
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   "source": [
    "## <div style=\"direction:rtl;text-align:right;font-family:B Lotus, B Nazanin, Tahoma\">ترسیم تصاویر و اشکال در OpenCV</div>"
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   "source": [
    "import cv2\n",
    "import numpy as np\n",
    "\n",
    "# Create a black image\n",
    "image = np.zeros((512,512,3), np.uint8)\n",
    "\n",
    "# Can we make this in black and white?\n",
    "image_bw = np.zeros((512,512), np.uint8)\n",
    "\n",
    "cv2.imshow(\"Black Rectangle (Color)\", image)\n",
    "cv2.imshow(\"Black Rectangle (B&W)\", image_bw)\n",
    "\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## <div style=\"direction:rtl;text-align:right;font-family:B Lotus, B Nazanin, Tahoma\">ترسیم خط</div>\n",
    "cv2.line(image, starting cordinates, ending cordinates, color, thickness)"
   ]
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   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Draw a diagonal blue line of thickness of 5 pixels\n",
    "image = np.zeros((512,512,3), np.uint8)\n",
    "cv2.line(image, (0,0), (511,511), (255,127,0), 5)\n",
    "cv2.imshow(\"Blue Line\", image)\n",
    "\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
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    "<div class=\"alert alert-warning\">\n",
    "From the documentation, **OpenCV changes its behavior according to the type** of the array:\n",
    "    <ul>\n",
    "    <li>If the image is 8-bit unsigned, it is displayed as is.</li>\n",
    "    <li>If the image is 16-bit unsigned or 32-bit integer, the pixels are divided by 256. That is, the value range [0,255*256] is mapped to [0,255].</li>\n",
    "    <li>If the image is 32-bit floating-point, the pixel values are multiplied by 255. That is, the value range [0,1] is mapped to [0,255].</li>\n",
    "    </ul>\n",
    "    https://stackoverflow.com/questions/23749968/why-datatype-has-to-be-uint8-in-opencv-python-wrapper\n",
    "\n",
    "</div>"
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## <div style=\"direction:rtl;text-align:right;font-family:B Lotus, B Nazanin, Tahoma\">ترسیم مستطیل</div>\n",
    "\n",
    "cv2.rectangle(image, starting vertex, opposite vertex, color, thickness)"
   ]
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  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Draw a Rectangle in\n",
    "image = np.zeros((512,512,3), np.uint8)\n",
    "\n",
    "cv2.rectangle(image, (100,100), (300,250), (0,0,255), 5)\n",
    "cv2.imshow(\"Rectangle\", image)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## <div style=\"direction:rtl;text-align:right;font-family:B Lotus, B Nazanin, Tahoma\">ترسیم دایره</div>\n",
    "\n",
    "cv2.cirlce(image, center, radius, color, thickness)\n",
    "<div style=\"direction:rtl;text-align:right;font-family:Tahoma\">\n",
    "اگر thickness را منفی بدهیم چه میشود؟!\n",
    "</div>"
   ]
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  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "image = np.zeros((512,512,3), np.uint8)\n",
    "\n",
    "cv2.circle(image, (350, 350), 100, (15,75,50), 7) \n",
    "cv2.imshow(\"Circle\", image)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## <div style=\"direction:rtl;text-align:right;font-family:B Lotus, B Nazanin, Tahoma\">ترسیم چند ضلعی</div>\n"
   ]
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   "cell_type": "code",
   "execution_count": 5,
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   "outputs": [],
   "source": [
    "image = np.zeros((512,512,3), np.uint8)\n",
    "\n",
    "# Let's define four points\n",
    "pts = np.array( [[10,50], [400,50], [90,200], [50,500]], np.int32)\n",
    "# Let's now reshape our points in form  required by polylines\n",
    "pts = pts.reshape((-1,1,2))\n",
    "\n",
    "cv2.polylines(image, [pts], True, (0,0,255), 3)\n",
    "cv2.imshow(\"Polygon\", image)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
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    " <div class=\"alert alert-warning\">\n",
    "If third argument is False, you will get a polylines joining all the points, not a closed shape.<br>\n",
    "**cv2.polylines()** can be used to draw multiple lines. Just create a list of all the lines you want to draw and pass it to the function.<br>\n",
    "All lines will be drawn individually. It is a much better and faster way to draw a group of lines than calling **cv2.line()** for each line.\n",
    "<p>https://docs.opencv.org/3.1.0/dc/da5/tutorial_py_drawing_functions.html</p>\n",
    " </div>"
   ]
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## <div style=\"direction:rtl;text-align:right;font-family:B Lotus, B Nazanin, Tahoma\">افزودن نوشته</div>\n",
    "\n",
    "cv2.putText(image, 'Text to Display', bottom left starting point, Font, Font Size, Color, Thickness)\n",
    "\n",
    "- FONT_HERSHEY_SIMPLEX, FONT_HERSHEY_PLAIN\n",
    "- FONT_HERSHEY_DUPLEX,FONT_HERSHEY_COMPLEX \n",
    "- FONT_HERSHEY_TRIPLEX, FONT_HERSHEY_COMPLEX_SMALL\n",
    "- FONT_HERSHEY_SCRIPT_SIMPLEX\n",
    "- FONT_HERSHEY_SCRIPT_COMPLEX"
   ]
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   "cell_type": "code",
   "execution_count": 6,
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   "source": [
    "image = np.zeros((512,512,3), np.uint8)\n",
    "\n",
    "cv2.putText(image, 'Hello World!', (75,290), cv2.FONT_HERSHEY_COMPLEX, 2, (100,170,0), 3)\n",
    "cv2.imshow(\"Hello World!\", image)\n",
    "cv2.waitKey(0)\n",
    "cv2.destroyAllWindows()"
   ]
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   "source": [
    "<div class=\"alert alert-block alert-info\">\n",
    "<div style=\"direction:rtl;text-align:right;font-family:B Lotus, B Nazanin, Tahoma\"> دانشگاه تربیت دبیر شهید رجایی<br>مباحث ویژه - آشنایی با بینایی کامپیوتر<br>علیرضا اخوان پور<br>96-97<br>\n",
    "</div>\n",
    "<a href=\"https://www.srttu.edu/\">SRTTU.edu</a> - <a href=\"http://class.vision\">Class.Vision</a> - <a href=\"http://AkhavanPour.ir\">AkhavanPour.ir</a>\n",
    "</div>"
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