Untitled10.ipynb

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     "text": [
      "Context(stroke=Color({'mode': 'rgba', 'value': ((0, 0, 0, 1),)}) fill=Color({'mode': 'rgba', 'value': ((1, 1, 1, 1),)}))\n",
      "Context(stroke=Color({'mode': 'rgba', 'value': ((0, 0, 0, 1),)}) fill=Color({'mode': 'rgba', 'value': ((1, 1, 1, 1),)}))\n",
      "Context(stroke=Color({'mode': 'rgba', 'value': ((0, 0, 0, 1),)}) fill=Color({'mode': 'rgba', 'value': ((1, 1, 1, 1),)}))\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "TransformStack(['Affine(0.8090169943749475, 0.5877852522924731, 0.0,\\n       0.5877852522924731, -0.8090169943749475, 0.0)'])"
      ]
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     "execution_count": 39,
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   "source": [
    "import math\n",
    "\n",
    "from affine import Affine\n",
    "\n",
    "class Color:\n",
    "    def __init__(self, context, *args, cm_restore=None):\n",
    "        self._state = {\"mode\": \"rgba\", \"value\": args}\n",
    "        self._cm_restore = cm_restore\n",
    "        self._context = context\n",
    "       \n",
    "    def __enter__(self):\n",
    "        return self._context\n",
    "    \n",
    "    def __exit__(self, *args):\n",
    "        \"\"\"\n",
    "        If any values were saved in cm_restore then add\n",
    "        them back to context.\n",
    "        \"\"\"\n",
    "        if self._cm_restore:\n",
    "            attr, value = self._cm_restore\n",
    "            setattr(self._context, attr, value)\n",
    "    \n",
    "    def __repr__(self):\n",
    "        return f\"{self.__class__.__name__}({self._state})\"\n",
    "\n",
    "\n",
    "class TransformStack:\n",
    "    def __init__(self, context, cm_restore=None):\n",
    "        # TODO - having cm_restore here looks like a bug !\n",
    "        self._context = context\n",
    "        self._cm_restore = cm_restore\n",
    "        self._matrix = Affine.identity()\n",
    "        self._stack = [self._matrix]\n",
    "\n",
    "    def push(self, matrix):\n",
    "        self._stack[-1] = self._matrix\n",
    "        self._stack.append(matrix)\n",
    "        self._matrix = matrix\n",
    "        \n",
    "    def pop(self):\n",
    "        del self._stack[-1]\n",
    "        self._matrix = self._stack[-1]\n",
    "        \n",
    "    def __enter__(self):\n",
    "        return self._context\n",
    "    \n",
    "    def __exit__(self, *args):\n",
    "        \"\"\"\n",
    "        If any values were saved in cm_restore then add\n",
    "        them back to context.\n",
    "        \"\"\"\n",
    "        if self._cm_restore:\n",
    "            attr, value = self._cm_restore\n",
    "            setattr(self._context, attr, value)\n",
    "    \n",
    "    def rotate(self, degrees=None, radians=None):\n",
    "        if degrees is not None:\n",
    "            radians = degrees * math.tau\n",
    "            \n",
    "        cos_theta = math.cos(radians)\n",
    "        sin_theta = math.sin(radians)\n",
    "        \n",
    "        self._matrix *= Affine(cos_theta, sin_theta, 0,\\\n",
    "                               sin_theta, -cos_theta, 0)\n",
    "        self._stack[-1] = self._matrix\n",
    "        return self\n",
    "\n",
    "    def skew(self, xoff=0., yoff=0.):\n",
    "        self._matrix *= Affine.skew(xoff, yoff)\n",
    "        self._stack[-1] = self._matrix\n",
    "        return self\n",
    "    \n",
    "    def translate(self, x=0., y=0.):\n",
    "        self._matrix *= Affine.translation(x, y)\n",
    "        self._stack[-1] = self._matrix\n",
    "        return self\n",
    "        \n",
    "    def __repr__(self):\n",
    "        return f'TransformStack({[repr(matrix) for matrix in self._stack]})'\n",
    "\n",
    "\n",
    "class Context:\n",
    "    _state_vars = [\"_fill\", \"_stroke, _transform\"]\n",
    "    \n",
    "    def __init__(self):\n",
    "        self._fill = Color(self, (1, 1, 1, 1))\n",
    "        self._stroke = Color(self, (0, 0, 0, 1))\n",
    "        self._path = None\n",
    "        self._transform = TransformStack(self)\n",
    "        self._position = (0, 0)\n",
    "\n",
    "    def rotate(self, *args, **kwargs):\n",
    "        # TODO save current transform in cm_restore to\n",
    "        # enable context manager.\n",
    "        return self._transform.rotate(*args, **kwargs)\n",
    "    \n",
    "    def skew(self, *args, **kwargs):\n",
    "        # TODO save current transform in cm_restore to\n",
    "        # enable context manager.\n",
    "        return self._transform.skew(*args, **kwargs)\n",
    "\n",
    "    def translate(self, *args, **kwargs):\n",
    "        # TODO save current transform in cm_restore to\n",
    "        # enable context manager.\n",
    "        return self._transform.translate(*args, **kwargs)\n",
    "    \n",
    "    def rect(self, width, height):\n",
    "        pass\n",
    "    \n",
    "    def fill(self, *args):\n",
    "        if not len(args):\n",
    "            return self._fill\n",
    "        #  Store current fill in cm_restore so Color can be used as context manager,\n",
    "        #  then return it.\n",
    "        self._fill = Color(self, *args, cm_restore=(\"_fill\", self._fill))\n",
    "        return self._fill\n",
    "    \n",
    "    def stroke(self, *args):\n",
    "        if not len(args):\n",
    "            return self._stroke\n",
    "        #  Store current fill in cm_restore so Color can be used as context manager,\n",
    "        #  then return it.\n",
    "        self._stroke = Color(self, *args, cm_restore=(\"_stroke\", self._stroke))\n",
    "        return self._stroke\n",
    "    \n",
    "    def __repr__(self):\n",
    "        return f\"{self.__class__.__name__}(stroke={self._stroke} fill={self._fill})\"\n",
    "\n",
    "    \n",
    "ctx = Context()\n",
    "print(ctx)\n",
    "\n",
    "# with ctx.fill(1, 1, 0, 1), ctx.stroke(0, 0, 1, 1) as c:\n",
    "#     print(ctx)\n",
    "    \n",
    "with ctx.rotate(.1):\n",
    "    print(ctx)\n",
    "\n",
    "print(ctx)\n",
    "\n",
    "ctx.translate(0, 0)"
   ]
  }
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