Alt State Stack.ipynb

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      "\n",
      "\n",
      "\n",
      "\n",
      "Color: ((0,),)\n",
      "Color: ((0.1, 0.2, 0.3, 1.0),) Color: ((0.9, 0.9, 0.9, 1.0),)\n",
      "restore data to  None\n",
      "restore data to  None\n",
      "-- back to normal\n",
      "Color: ((0.1, 0.2, 0.3, 1.0),)\n"
     ]
    }
   ],
   "source": [
    "class RestorableState:\n",
    "    def __init__(self, context, data, cm_raises_exception):\n",
    "        self.data = data\n",
    "        self.restore_data = None\n",
    "        self.context = context\n",
    "        self.cm_raises_exception = cm_raises_exception\n",
    "        \n",
    "    def __enter__(self):\n",
    "        if self.cm_raises_exception:\n",
    "            ex, *args = self.cm_raises_exception\n",
    "            raise ex(*args)\n",
    "        return self.context\n",
    "\n",
    "    def __exit__(self, *args):\n",
    "        print(\"restore data to \", self.restore_data)\n",
    "        self.data = self.restore_data\n",
    "        return False\n",
    "\n",
    "#     def __call__(self, *args):\n",
    "#         print(\"set restore data\")\n",
    "#         self.restore_data = self.data\n",
    "#         self.data = args\n",
    "#         return self #.color\n",
    "\n",
    "    def __repr__(self):\n",
    "        return f\"{self.__class__.__name__}: {self.data}\"\n",
    "\n",
    "    \n",
    "def normalize_color(args):\n",
    "    if args is None:\n",
    "        return None\n",
    "    \n",
    "    if len(args) == 1:\n",
    "        c = args[0]\n",
    "        return (c, c, c, 1)\n",
    "    elif len(args) == 2:\n",
    "        return (args[0], args[1], 1, 1)\n",
    "    elif len(args) == 3:\n",
    "        return (*args, 1)\n",
    "    else:\n",
    "        return args\n",
    "\n",
    "    \n",
    "# class ColorState(RestorableState):\n",
    "#     def __init__(self, context, color, cm_raises_exception=None):\n",
    "#         RestorableState.__init__(self, context, color, cm_raises_exception=cm_raises_exception)\n",
    "        \n",
    "#     def __call__(self, *args):\n",
    "#         color = normalize_color(args)\n",
    "#         return super().__call__(color)\n",
    "\n",
    "\n",
    "class Color(RestorableState):\n",
    "    def __init__(self, context, color, cm_raises_exception=None):\n",
    "        RestorableState.__init__(self, context, color, cm_raises_exception=cm_raises_exception)\n",
    "        \n",
    "    def copy(self, *args):\n",
    "        return Color(self.context, args, self.cm_raises_exception)\n",
    "#     def __call__(self, *args):\n",
    "#         color = normalize_color(args)\n",
    "#         return super().__call__(*color)\n",
    "\n",
    "    \n",
    "\n",
    "IDENTITY_MATRIX = [\n",
    "    [1, 0, 0],\n",
    "    [0, 1, 0],\n",
    "    [0, 0, 1],\n",
    "]\n",
    "    \n",
    "class Transform(RestorableState):\n",
    "    def __init__(self, context, matrix=None):\n",
    "        if matrix is None:\n",
    "            matrix = IDENTITY_MATRIX\n",
    "        RestorableState.__init__(self, context, matrix, cm_raises_exception=False)\n",
    "        \n",
    "    def skew(self, x=0, y=0):\n",
    "        if (x, y) == (0, 0):\n",
    "            return self\n",
    "        return self\n",
    "    \n",
    "    def rotate(self, degrees):\n",
    "        return self\n",
    "    \n",
    "    def push(self, t):\n",
    "        self.__call__(t)\n",
    "        return self.__enter__()\n",
    "    \n",
    "    def pop(self):\n",
    "        return self.__exit__()\n",
    "\n",
    "class Context:\n",
    "    def __init__(self):\n",
    "        self._fill = Color(self, (1, 1, 1, 1))\n",
    "        self._stroke = Color(self, (0, 0, 0, 1))\n",
    "        self._transform = Transform(self)\n",
    "        \n",
    "    def fill(self, *args):\n",
    "        if not len(args):\n",
    "            return self._fill\n",
    "        self._fill = self._fill.copy(args)\n",
    "        return self._fill\n",
    "    \n",
    "    def stroke(self, *args):\n",
    "        return self._stroke.copy(args)\n",
    "        \n",
    "#     def move(self, x, y):\n",
    "#         self.transform.move_to(x, y)\n",
    "    \n",
    "#     def push(self):\n",
    "#         return self.transform.push()\n",
    "    \n",
    "#     def pop(self):\n",
    "#         return self.transform.pop()\n",
    "    \n",
    "#     def skew(self, *args):\n",
    "#         return self.transform.skew(*args)\n",
    "        \n",
    "\n",
    "ctx = Context()\n",
    "\n",
    "print(\"\\n\\n\\n\")\n",
    "ctx.fill(.1, .1, .1, 1)\n",
    "\n",
    "print(ctx.fill(0))\n",
    "with ctx.fill(1, 0, 0, 1), ctx.stroke(0):\n",
    "    print(ctx.fill(.1, .2, .3, 1.), ctx.stroke(.9, .9, .9, 1.))\n",
    "    \n",
    "print(\"-- back to normal\")\n",
    "print(ctx.fill())"
   ]
  }
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