Cairo - Canvas and intermediate output - 2.ipynb

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    "%reload_ext cairo_jupyter"
   ]
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     "text": [
      "ImageSurface\n"
     ]
    },
    {
     "ename": "AttributeError",
     "evalue": "'BufferedCanvas' object has no attribute '_save_png'",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-3-1a91c7801508>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m    118\u001b[0m \u001b[0;31m# intermediate ImageSurface 1\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m    119\u001b[0m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m\"ImageSurface\"\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 120\u001b[0;31m \u001b[0mcanvas\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mdisplay\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mformat\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mFORMAT_PNG\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mdimensions\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;36m128\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0;36m128\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m    121\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m    122\u001b[0m \u001b[0;31m# intermediate SVGSurface to buffer\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;32m<ipython-input-3-1a91c7801508>\u001b[0m in \u001b[0;36mdisplay\u001b[0;34m(self, format, *args, **kwargs)\u001b[0m\n\u001b[1;32m     76\u001b[0m         \u001b[0;32mwith\u001b[0m \u001b[0mBytesIO\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m \u001b[0;32mas\u001b[0m \u001b[0mio\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     77\u001b[0m             \u001b[0;32mif\u001b[0m \u001b[0mformat\u001b[0m \u001b[0;34m==\u001b[0m \u001b[0mFORMAT_PNG\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 78\u001b[0;31m                 \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m_save_png\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mio\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0;34m*\u001b[0m\u001b[0margs\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0;34m**\u001b[0m\u001b[0mkwargs\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m     79\u001b[0m                 \u001b[0m_display\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mImage\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mdata\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mio\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mgetvalue\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     80\u001b[0m             \u001b[0;32melif\u001b[0m \u001b[0mformat\u001b[0m \u001b[0;34m==\u001b[0m \u001b[0mFORMAT_SVG\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;31mAttributeError\u001b[0m: 'BufferedCanvas' object has no attribute '_save_png'"
     ]
    }
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   "source": [
    "import cairo\n",
    "\n",
    "from io import BytesIO\n",
    "from IPython.display import Image, SVG, display\n",
    "from IPython.display import display as _display\n",
    "\n",
    "FORMAT_PS = 'ps'\n",
    "FORMAT_PDF = 'pdf'\n",
    "FORMAT_PNG = 'png'\n",
    "FORMAT_SVG = 'svg'\n",
    "FORMAT_SVG_XML = 'svg_xml'\n",
    "\n",
    "# SURFACE_CLASSES = {\n",
    "#     FORMAT_PS: cairo.PDFSurface,\n",
    "    \n",
    "# }\n",
    "\n",
    "VALID_FORMATS = [FORMAT_PNG, FORMAT_SVG, FORMAT_SVG_XML]\n",
    "\n",
    "class BufferedCanvas:\n",
    "    \"\"\"\n",
    "    Uses a RecordingSurface to keep track of the draw state on the current page,\n",
    "    and allowing it to be copied to various outputs as needed.\n",
    "    \"\"\"\n",
    "    def __init__(self, extents=None):\n",
    "        \"\"\"\n",
    "        :param dimensions: Extents of recording surface, or None for unbounded.\n",
    "        \"\"\"\n",
    "        self.surface = cairo.RecordingSurface(cairo.CONTENT_COLOR_ALPHA, \n",
    "                                              extents\n",
    "                                             ) \n",
    "    \n",
    "    def _copy_to_surface(self, f, surface_t=cairo.ImageSurface, dimensions=None):\n",
    "        if dimensions is None:\n",
    "            extents = self.surface.ink_extents()\n",
    "            dimensions = extents[2], extents[3]\n",
    "        \n",
    "        surface = surface_t(f, *dimensions)\n",
    "        \n",
    "        # Draw self.surface onto surface\n",
    "        cr = cairo.Context(surface)\n",
    "        cr.set_source_surface(self.surface)\n",
    "        cr.paint()\n",
    "        del cr\n",
    "\n",
    "    def _to_svg(self, f, dimensions=None):\n",
    "        surface = self._draw_to_surface(f, cairo.SVGSurface, dimensions)\n",
    "\n",
    "        # Output SVG surface to file or buffer\n",
    "        surface.finish()\n",
    "    \n",
    "    def _to_png(self, f, dimensions=None):\n",
    "        \"\"\"\n",
    "        \n",
    "        \"\"\"\n",
    "        surface = self._draw_to_surface(f, cairo.ImageSurface, dimensions)\n",
    "        surface.write_to_png(f)\n",
    "\n",
    "\n",
    "#         if dimensions is None:\n",
    "#             extents = self.surface.ink_extents()\n",
    "#             dimensions = int(extents[2]), int(extents[3])\n",
    "\n",
    "#         surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, *dimensions)\n",
    "        \n",
    "#         # Draw self.surface onto surface\n",
    "#         cr = cairo.Context(surface)\n",
    "#         cr.set_source_surface(self.surface)\n",
    "#         cr.paint()\n",
    "#         del cr\n",
    "        \n",
    "        \n",
    "    def save(self, io, format=FORMAT_PNG, *args, **kwargs):\n",
    "        # TODO - is this needed, can it be used with display() ... ?\n",
    "        if format == FORMAT_PNG:\n",
    "            self._save_png(io, *args, **kwargs)\n",
    "        elif format in (FORMAT_SVG, FORMAT_SVG_XML):\n",
    "            self._save_svg(io, *args, **kwargs)\n",
    "        else:\n",
    "            raise ValueError(\"Format must be FORMAT_PNG, FORMAT_SVG or FORMAT_SVG_XML\")\n",
    "\n",
    "    def display(self, format=FORMAT_PNG, *args, **kwargs):\n",
    "        with BytesIO() as io:\n",
    "            if format == FORMAT_PNG:\n",
    "                self._save_png(io, *args, **kwargs)\n",
    "                _display(Image(data=io.getvalue()))\n",
    "            elif format == FORMAT_SVG:\n",
    "                self._save_svg(io, *args, **kwargs)\n",
    "                _display(SVG(io.getvalue()))\n",
    "            elif format == FORMAT_SVG_XML:\n",
    "                try:\n",
    "                    from display_xml import XML\n",
    "                except ImportError:\n",
    "                    raise ImportError('Install display_xml to output as XML:  $ pip3 install display_xml')\n",
    "\n",
    "                self.save_svg(io, *args, **kwargs)\n",
    "                _display(XML(io.getvalue()))\n",
    "            else:\n",
    "                raise ValueError(\"Format must be FORMAT_PNG, FORMAT_SVG or FORMAT_SVG_XML\")\n",
    "        \n",
    "    \n",
    "class ShoebotRunner:\n",
    "    def __init__(self):\n",
    "        self.canvas = BufferedCanvas()\n",
    "    \n",
    "    def run_once(self, code):\n",
    "        # During first frame canvas is already cleared.\n",
    "        \n",
    "        # ?\n",
    "        # with canvas.page():\n",
    "        #    blah\n",
    "        #    blah\n",
    "        \n",
    "        # During subsequent frames if canvas should be cleared use show_page, otherwise copy_page\n",
    "        # for outputs.\n",
    "        pass\n",
    "\n",
    "# Draw on surface\n",
    "canvas = BufferedCanvas()\n",
    "ctx = cairo.Context(canvas.surface)\n",
    "ctx.set_source_rgb(.5, .5, 1.)\n",
    "ctx.rectangle(10, 10, 90, 90)\n",
    "ctx.fill()\n",
    "\n",
    "# intermediate ImageSurface 1\n",
    "print(\"ImageSurface\")\n",
    "canvas.display(format=FORMAT_PNG, dimensions=(128, 128))\n",
    "\n",
    "# intermediate SVGSurface to buffer\n",
    "print(\"SVG to buffer\")\n",
    "canvas.display(format=FORMAT_SVG)\n",
    "canvas.display(format=FORMAT_SVG_XML)\n",
    "\n",
    "\n",
    "# continue drawing\n",
    "print(\"continue drawing...\")\n",
    "ctx.set_source_rgb(1., .5, .5)\n",
    "ctx.rectangle(100, 10, 90, 90)\n",
    "ctx.fill()\n",
    "\n",
    "del ctx\n",
    "\n",
    "print(\"Display final surface\")\n",
    "\n",
    "canvas.surface.ink_extents()\n",
    "\n",
    "print(\"Canvas display as bitmap\")\n",
    "canvas.display(FORMAT_PNG, dimensions=(180, 40))\n",
    "\n",
    "print(\"Canvas display svg\")\n",
    "canvas.display(FORMAT_SVG)"
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