Cairo Inkscape Rendering

cario_test_2.py

import wx
import rsvg
import numpy

try:
    import wx.lib.wxcairo
    import cairo
    haveCairo = True
except ImportError:
    haveCairo = False

from lxml import etree as ET

nsmap = {
    'sodipodi': 'http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd',
    'cc': 'http://web.resource.org/cc/',
    'svg': 'http://www.w3.org/2000/svg',
    'dc': 'http://purl.org/dc/elements/1.1/',
    'xlink': 'http://www.w3.org/1999/xlink',
    'rdf': 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
    'inkscape': 'http://www.inkscape.org/namespaces/inkscape'
    }

class ComponentFrame(wx.Frame):
    def __init__(self, parent, id, title, pos, size):
        wx.Frame.__init__(self, parent, id, title, pos, size)

        self.panel = wx.Panel(self)
        vbox = wx.BoxSizer(wx.HORIZONTAL)
        component = SvgComponent(self.panel)
        vbox.Add(component, 1, wx.EXPAND | wx.ALL, 10)
        self.panel.SetSizer(vbox)

        self.Show(True)

class SvgComponent(wx.PyControl):
    def __init__(self, parent, label="",
                 id=wx.ID_ANY,
                 pos=wx.DefaultPosition,
                 size=wx.DefaultSize, style=wx.NO_BORDER, validator=wx.DefaultValidator,
                 name="CustomMeter"):

        wx.PyControl.__init__(self, parent, id, pos, size, style, validator, name)

        self.Bind(wx.EVT_PAINT, self.OnPaint)
        self.Bind(wx.EVT_SIZE, self.OnSize)
        self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)

        if not haveCairo or not wx.GraphicsRenderer.GetCairoRenderer():
            print "Cairo unavailable!"

    def OnPaint(self, event):
        dc = wx.BufferedPaintDC(self)
        dc.Clear()
        self.Draw(dc)

    def Draw(self, dc):
        width, height = self.GetClientSize()
        if not width or not height:
            return

        surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)

        ctx = wx.lib.wxcairo.ContextFromDC(dc)
        ctx.scale(width/300.0, height/300.0)

        with open('demo.svg', 'r') as content_file:
            xml_data = content_file.read()

        xml_data = self.RotateNeedle(xml_data)

        svg = rsvg.Handle(data=xml_data)
        svg.render_cairo(ctx)

    def OnSize(self, event):
        self.Refresh(True)

    def OnEraseBackground(self, event):
        pass

    def DoGetBestSize(self):
        """
        Overridden base class virtual.  Determines the best size of the control
        based on the label size, the bitmap size and the current font.
        """
        best = wx.Size(400, 400)
        self.CacheBestSize(best)
        return best

    def RotateNeedle(self, xml):
        tree = ET.fromstring(xml)
        needle = tree.xpath("//svg:path[@id='needle']", namespaces=nsmap)[0]
        needle_axis = tree.xpath("//svg:path[@id='needle_axis']", namespaces=nsmap)

        #needle.set('transform', 'rotate(90, 161, 885)') manually determined
        print ET.tostring(needle)

        return ET.tostring(tree)

if __name__ == '__main__':
        app = wx.App()
        frame = ComponentFrame(None, wx.ID_ANY, 'test rsvg', (200, 200), (400, 400))
        app.MainLoop()

demo.svg