07_trackbar_brightness_contrast.ipynb

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    "import numpy as np\n",
    "import cv2\n",
    "import time\n",
    "from tqdm import tqdm\n",
    "\n",
    "ESCAPE_KEY_ASCII = 27\n",
    "\n",
    "def onChange(value):\n",
    "    #print(\"valor alterado\", value)\n",
    "    pass\n",
    "\n",
    "#imagem carregada e sua cópia\n",
    "img = cv2.imread(\"pirula.jpg\")\n",
    "copyimg = img.copy()\n",
    "\n",
    "#cria janela gráfica para inserir a imagem\n",
    "windowTitle = \"Ajuste de Brilho e Contraste\"\n",
    "cv2.namedWindow(windowTitle)\n",
    "\n",
    "#cria trackbar\n",
    "cv2.createTrackbar(\"contraste\", windowTitle, 100, 100, onChange)\n",
    "cv2.createTrackbar(\"brilho\", windowTitle, 0, 200, onChange)\n",
    "\n",
    "before_contrast = 100\n",
    "update_contrast = False\n",
    "\n",
    "before_brightness = 0\n",
    "update_brightness = False\n",
    "\n",
    "counter_time = 0\n",
    "\n",
    "while True:\n",
    "    current_contrast = cv2.getTrackbarPos(\"contraste\", windowTitle)\n",
    "    current_brightness = cv2.getTrackbarPos(\"brilho\", windowTitle)\n",
    "    \n",
    "    #valor de contraste do trackbar foi alterado pelo usuário\n",
    "    if before_contrast != current_contrast:\n",
    "        update_contrast = True\n",
    "        counter_time = time.time()\n",
    "        before_contrast = current_contrast\n",
    "        \n",
    "    #valor de brilho do trackbar foi alterado pelo usuário\n",
    "    if before_brightness != current_brightness:\n",
    "        update_brightness = True\n",
    "        counter_time = time.time()\n",
    "        before_brightness = current_brightness\n",
    "\n",
    "    #se tiver passado 1 segundo desde que o usuário mexeu em algum trackbar\n",
    "    if time.time() - counter_time > 1:\n",
    "        #se tiver sido marcado que é pra atualizar contraste ou brilho\n",
    "        if update_contrast == True or update_brightness == True:\n",
    "            \n",
    "            #fazemos uma cópia da imagem original\n",
    "            '''\n",
    "            copyimg = img.copy()\n",
    "\n",
    "            height, width, channels = img.shape\n",
    "\n",
    "            #para cada informação de cor, de cada pixel, atualizamos o contraste\n",
    "            for y in tqdm(range(height)):\n",
    "                for x in range(width):\n",
    "                    for c in range(channels):\n",
    "                        newColorValue = copyimg[y][x][c] * (current_contrast / 100) + current_brightness\n",
    "                        copyimg[y][x][c] = np.clip(newColorValue, 0, 255)\n",
    "            '''\n",
    "            copyimg = cv2.convertScaleAbs(img, alpha=current_contrast / 100, beta=current_brightness)\n",
    "\n",
    "            update_contrast = False\n",
    "            update_brightness = False\n",
    "        \n",
    "    cv2.imshow(windowTitle, copyimg)\n",
    "    \n",
    "    keyPressed = cv2.waitKey(1) & 0xFF #cv2.waitKey(1) & 111111\n",
    "    if keyPressed == ESCAPE_KEY_ASCII:\n",
    "        break\n",
    "        \n",
    "cv2.destroyAllWindows()"
   ]
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