Source Code for Package visgraph.renderers

 1  ''' 
 2  Home of the code which knows how to actually *draw* a graph which 
 3  has been layed out. 
 4  ''' 
 5   
 6 -class GraphRenderer: 
 7      ''' 
 8      Only a "renderer" knows how big each node will end up based on metadata 
 9      in the graph which is specific to the renderer. 
10   
11      All renderers should be able to set the (x,y) "size" tuple 
12      ''' 
13 -    def __init__(self, graph): 
14          self._vg_graph = graph 
15          self._vg_layout = None 
16   
17          self._vg_rendering = False 
18          self._vg_canvas_width = 0 
19          self._vg_canvas_height = 0 
20   
21 -    def beginRender(self, width, height): 
22          self._vg_rendering = True 
23          self._vg_canvas_width = width 
24          self._vg_canvas_height = height 
25   
26 -    def endRender(self): 
27          self._vg_rendering = False 
28   
29 -    def setNodeSizes(self, graph): 
30          ''' 
31          Calculate the sizes for each node based on graph metadata (or defaults) 
32          ''' 
33          raise Exception('%s must implement setNodeSizes!' % self.__class__.__name__) 
34   
35 -    def renderNode(self, nid, ninfo, xpos, ypos): 
36          ''' 
37          Render the given node at the specified position. 
38          ''' 
39          raise Exception('%s must implement renderNode!' % self.__class__.__name__) 
40   
41 -    def renderEdge(self, eid, einfo, points): 
42          ''' 
43          Render an edge in the graph by drawing lines between all the listed 
44          points (as (x,y) tuples...) 
45          ''' 
46          raise Exception('%s must implement renderNode!' % self.__class__.__name__) 
47