Mapnik-with-wxPython.md

+<!-- Name: IntegrateWithWxPython -->
+<!-- Version: 5 -->
+<!-- Last-Modified: 2008/12/13 22:15:55 -->
+<!-- Author: victorlin -->
+
+
+# Mapnik with wxPython
+
+Here's a sample application integrating Mapnik with [wxPython](http://wxpython.org/)
+
+```python
+    """
+    This is a simple wxPython application demonstrates how to
+    integrate mapnik, it do nothing but draw the map from the World Poplulation XML
+    example:
+    https://github.com/mapnik/mapnik/wiki/GettingStartedInXML
+    
+    Victor Lin. (bornstub@gmail.com)
+    Blog http://blog.ez2learn.com
+    
+    """
+    
+    import wx
+    import mapnik
+    
+    class Frame(wx.Frame):
+        def __init__(self, *args, **kwargs):
+            wx.Frame.__init__(self, size=(800, 500) ,*args, **kwargs)
+            self.Bind(wx.EVT_PAINT, self.onPaint)
+    
+            self.mapfile = "population.xml"
+            self.width = 800
+            self.height = 500
+            self.createMap()
+            self.drawBmp()
+    
+        def createMap(self):
+            """Create mapnik object
+    
+            """
+            self.map = mapnik.Map(self.width, self.height)
+            mapnik.load_map(self.map, self.mapfile)
+            bbox = mapnik.Envelope(mapnik.Coord(-180.0, -75.0), mapnik.Coord(180.0, 90.0))
+            self.map.zoom_to_box(bbox)
+    
+        def drawBmp(self):
+            """Draw map to Bitmap object
+    
+            """
+            # create a Image32 object
+            image = mapnik.Image(self.width, self.height)
+            # render map to Image32 object
+            mapnik.render(self.map, image)
+            # load raw data from Image32 to bitmap
+            self.bmp = wx.BitmapFromBufferRGBA(self.width, self.height, image.tostring())
+    
+        def onPaint(self, event):
+            dc = wx.PaintDC(self)
+            memoryDC = wx.MemoryDC(self.bmp)
+            # draw map to dc
+            dc.Blit(0, 0, self.width, self.height, memoryDC, 0, 0)
+    
+    if __name__ == '__main__':
+        app = wx.App()
+        frame = Frame(None, title="wxPython Mapnik Demo By Victor Lin")
+        frame.Show()
+        app.MainLoop()
+```
+
+The key point of this program is this:
+
+
+```python
+    # create a Image32 object
+    image = mapnik.Image(self.width, self.height)
+    # render map to Image32 object
+    mapnik.render(self.map, image)
+    # load raw data from Image32 to bitmap
+    self.bmp = wx.BitmapFromBufferRGBA(self.width, self.height, image.tostring())
+```
+
+We create an Image32 object, and render map on to that image, then load raw data of image into wxPython's Bitmap object. That's it! Now you can use your memory dc to do whatever you like
+
+
+```python
+    memoryDC = wx.MemoryDC(self.bmp)
+    # draw map to dc
+    dc.Blit(0, 0, self.width, self.height, memoryDC, 0, 0)
+```
+
+Screenshots
+
+[[/images/wxMapnikScreenshot.png]]
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