/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/UI/baserenderer.py
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revision 1554 by bh, Wed Aug 6 17:24:30 2003 UTC revision 1918 by bh, Mon Nov 3 17:33:19 2003 UTC
# Line 14  be tested reasonably easily and it could Line 14  be tested reasonably easily and it could
14  renderers.  renderers.
15  """  """
16    
17    from __future__ import generators
18    
19  __version__ = "$Revision$"  __version__ = "$Revision$"
20  # $Source$  # $Source$
21  # $Id$  # $Id$
# Line 49  class BaseRenderer: Line 51  class BaseRenderer:
51      TRANSPARENT_PEN = None      TRANSPARENT_PEN = None
52      TRANSPARENT_BRUSH = None      TRANSPARENT_BRUSH = None
53    
54      def __init__(self, dc, scale, offset, resolution = 72.0,      def __init__(self, dc, map, scale, offset, region = None,
55                   honor_visibility = None):                   resolution = 72.0, honor_visibility = None):
56          """Inititalize the renderer.          """Inititalize the renderer.
57    
58          dc -- the device context to render on.          dc -- the device context to render on.
# Line 58  class BaseRenderer: Line 60  class BaseRenderer:
60          scale, offset -- the scale factor and translation to convert          scale, offset -- the scale factor and translation to convert
61                  between projected coordinates and the DC coordinates                  between projected coordinates and the DC coordinates
62    
63            region -- The region to draw as a (x, y, width, height) tuple in
64                      the map's coordinate system. Default is None meaning
65                      to draw everything.
66    
67          resolution -- the assumed resolution of the DC. Used to convert          resolution -- the assumed resolution of the DC. Used to convert
68                  absolute lengths like font sizes to DC coordinates. The                  absolute lengths like font sizes to DC coordinates. The
69                  defauult is 72.0                  default is 72.0. If given, this parameter must be
70                    provided as a keyword argument.
71    
72          honor_visibility -- boolean. If true, honor the visibility flag          honor_visibility -- boolean. If true, honor the visibility flag
73                  of the layers, otherwise draw all layers. If None (the                  of the layers, otherwise draw all layers. If None (the
74                  default), use the renderer's default.                  default), use the renderer's default. If given, this
75                    parameter must be provided as a keyword argument.
76          """          """
77          # resolution in pixel/inch          # resolution in pixel/inch
   
78          self.dc = dc          self.dc = dc
79            self.map = map
80          self.scale = scale          self.scale = scale
81          self.offset = offset          self.offset = offset
82            self.region = region
83          if honor_visibility is not None:          if honor_visibility is not None:
84              self.honor_visibility = honor_visibility              self.honor_visibility = honor_visibility
85          # store the resolution in pixel/point because it's more useful          # store the resolution in pixel/point because it's more useful
# Line 85  class BaseRenderer: Line 94  class BaseRenderer:
94          """          """
95          raise NotImplementedError          raise NotImplementedError
96    
97      def render_map(self, map):      def render_map(self):
98          """Render the map onto the DC the renderer was instantiated with          """Render the map onto the DC.
99    
100            Both map and DC are the ones the renderer was instantiated with.
101    
102            This method is just a front-end for render_map_incrementally
103            which does all rendering in one go. It also calls the dc's
104            BeginDrawing and EndDrawing methods before and after calling
105            render_map_incrementally.
106            """
107    
108            self.dc.BeginDrawing()
109            try:
110                for cont in self.render_map_incrementally():
111                    pass
112            finally:
113                self.dc.EndDrawing()
114    
115        def render_map_incrementally(self):
116            """Render the map incrementally.
117    
118            Return an iterator whose next method should be called until it
119            returns False. After returning False it will raise StopIteration
120            so that you could also use it in a for loop (implementation
121            detail: this method is implemented as a generator).
122    
123          Iterate through all layers and draw them. Layers containing          Iterate through all layers and draw them. Layers containing
124          vector data are drawn with the draw_shape_layer method, raster          vector data are drawn with the draw_shape_layer method, raster
# Line 97  class BaseRenderer: Line 129  class BaseRenderer:
129          that methods especially in derived classes have access to the          that methods especially in derived classes have access to the
130          map if necessary.          map if necessary.
131          """          """
         # Some method have to have access to the map so we store it in  
         # self.map.  
         self.map = map  
   
132          # Whether the raster layer has already been drawn. See below for          # Whether the raster layer has already been drawn. See below for
133          # the optimization this is used for          # the optimization this is used for
134          seenRaster = True          seenRaster = True
135    
136          self.dc.BeginDrawing()          #
137            # This is only a good optimization if there is only one
138            # raster layer and the image covers the entire window (as
139            # it currently does). We note if there is a raster layer
140            # and only begin drawing layers once we have drawn it.
141            # That way we avoid drawing layers that won't be seen.
142            #
143            if Thuban.Model.resource.has_gdal_support():
144                for layer in self.map.Layers():
145                    if isinstance(layer, RasterLayer) and layer.Visible():
146                        seenRaster = False
147                        break
148    
149            for layer in self.map.Layers():
150                # if honor_visibility is true, only draw visible layers,
151                # otherwise draw all layers
152                if not self.honor_visibility or layer.Visible():
153                    if isinstance(layer, Layer) and seenRaster:
154                        for i in self.draw_shape_layer_incrementally(layer):
155                            yield True
156                    elif isinstance(layer, RasterLayer) \
157                        and Thuban.Model.resource.has_gdal_support():
158                        self.draw_raster_layer(layer)
159                        seenRaster = True
160                        yield True
161    
162          try:          self.draw_label_layer(self.map.LabelLayer())
163              #          yield False
             # This is only a good optimization if there is only one  
             # raster layer and the image covers the entire window (as  
             # it currently does). We note if there is a raster layer  
             # and only begin drawing layers once we have drawn it.  
             # That way we avoid drawing layers that won't be seen.  
             #  
             if Thuban.Model.resource.has_gdal_support():  
                 for layer in map.Layers():  
                     if isinstance(layer, RasterLayer) and layer.Visible():  
                         seenRaster = False  
                         break  
   
             for layer in map.Layers():  
                 # if honor_visibility is true, only draw visible layers,  
                 # otherwise draw all layers  
                 if not self.honor_visibility or layer.Visible():  
                     if isinstance(layer, Layer) and seenRaster:  
                         self.draw_shape_layer(layer)  
                     elif isinstance(layer, RasterLayer) \  
                         and Thuban.Model.resource.has_gdal_support():  
                         self.draw_raster_layer(layer)  
                         seenRaster = True  
164    
165              self.draw_label_layer(map.LabelLayer())      def draw_shape_layer_incrementally(self, layer):
166          finally:          """Draw the shape layer layer onto the map incrementally.
             self.dc.EndDrawing()  
   
     def draw_shape_layer(self, layer):  
         """Draw the shape layer layer onto the map.  
167    
168          Automatically called by render_map. Iterate through all shapes          This method is a generator which yields True after every 500
169          as indicated by self.layer_ids() and draw them, using low-level          shapes.
         renderers returned by self.low_level_renderer().  
170          """          """
171          scale = self.scale          scale = self.scale
172          offx, offy = self.offset          offx, offy = self.offset
# Line 159  class BaseRenderer: Line 184  class BaseRenderer:
184          defaultGroup = lc.GetDefaultGroup()          defaultGroup = lc.GetDefaultGroup()
185          table = layer.ShapeStore().Table()          table = layer.ShapeStore().Table()
186    
187            if lc.GetNumGroups() == 0:
188                # There's only the default group, so we can pretend that
189                # there is no field to classifiy on which makes things
190                # faster since we don't need the attribute information at
191                # all.
192                field = None
193    
194          # Determine which render function to use.          # Determine which render function to use.
195          draw_func, draw_func_param = self.low_level_renderer(layer)          useraw, draw_func, draw_func_param = self.low_level_renderer(layer)
196    
197            #
198          # Iterate through all shapes that have to be drawn.          # Iterate through all shapes that have to be drawn.
199          for i in self.layer_ids(layer):          #
200    
201            # Count the shapes drawn so that we can yield every few hundred
202            # shapes
203            count = 0
204    
205            # Cache the tools (pens and brushes) for the classification
206            # groups. This is a mapping from the group's ids to the a tuple
207            # (pen, brush)
208            tool_cache = {}
209    
210            for shape in self.layer_shapes(layer):
211                count += 1
212              if field is None:              if field is None:
213                  group = defaultGroup                  group = defaultGroup
214              else:              else:
215                  record = table.ReadRowAsDict(i)                  value = table.ReadValue(shape.ShapeID(), field)
216                  assert record is not None                  group = lc.FindGroup(value)
                 group = lc.FindGroup(record[field])  
217    
218              if not group.IsVisible():              if not group.IsVisible():
219                  continue                  continue
220    
221              # don't recreate new objects if they are the same as before              try:
222              if group is not old_group:                  pen, brush = tool_cache[id(group)]
223                  old_group = group              except KeyError:
224                    pen, brush = tool_cache[id(group)] \
225                  prop = group.GetProperties()                               = self.tools_for_property(group.GetProperties())
226    
227                  if prop != old_prop:              if useraw:
228                      pen, brush = self.tools_for_property(prop)                  data = shape.RawData()
229                else:
230              draw_func(draw_func_param, i, pen, brush)                  data = shape.Points()
231                draw_func(draw_func_param, data, pen, brush)
232                if count % 500 == 0:
233                    yield True
234    
235      def layer_ids(self, layer):      def layer_shapes(self, layer):
236          """Return the shape ids of the given layer that have to be drawn.          """Return an iterable over the shapes to be drawn from the given layer.
237    
238          The default implementation simply returns all ids in the layer.          The default implementation simply returns all ids in the layer.
239          Override in derived classes to be more precise.          Override in derived classes to be more precise.
240          """          """
241          return range(layer.NumShapes())          return layer.ShapeStore().AllShapes()
242    
243      def low_level_renderer(self, layer):      def low_level_renderer(self, layer):
244          """Return the low-level renderer for the layer for draw_shape_layer          """Return the low-level renderer for the layer for draw_shape_layer
245    
246          The low level renderer to be returned by this method is a tuple          The low level renderer to be returned by this method is a tuple
247          (func, param) where func is a callable object and param is          (useraw, func, param) where useraw is a boolean indicating
248          passed as the first parameter to func. The draw_shape_layer          whether the function uses the raw shape data, func is a callable
249          method will call func like this:          object and param is passed as the first parameter to func. The
250            draw_shape_layer method will call func like this:
251              func(param, rawshape, pen, brush)  
252                func(param, shapedata, pen, brush)
253          where rawshape is currently the shapeid. pen and brush are the  
254          pen and brush to use to draw the shape on the dc.          where shapedata is the return value of the RawData method of the
255            shape object if useraw is true or the return value of the Points
256            method if it's false. pen and brush are the pen and brush to use
257            to draw the shape on the dc.
258    
259          The default implementation returns one of          The default implementation returns one of
260          self.draw_polygon_shape, self.draw_arc_shape or          self.draw_polygon_shape, self.draw_arc_shape or
261          self.draw_point_shape as func and layer as param. Derived          self.draw_point_shape as func and layer as param. None of the
262          classes can override this method to return more efficient low          method use the raw shape data. Derived classes can override this
263          level renderers.          method to return more efficient low level renderers.
264          """          """
265          shapetype = layer.ShapeType()          shapetype = layer.ShapeType()
266          if shapetype == SHAPETYPE_POINT:          if shapetype == SHAPETYPE_POINT:
# Line 220  class BaseRenderer: Line 269  class BaseRenderer:
269              func = self.draw_arc_shape              func = self.draw_arc_shape
270          else:          else:
271              func = self.draw_polygon_shape              func = self.draw_polygon_shape
272          return func, layer          return False, func, layer
273    
274      def make_point(self, x, y):      def make_point(self, x, y):
275          """Convert (x, y) to a point object.          """Convert (x, y) to a point object.
# Line 229  class BaseRenderer: Line 278  class BaseRenderer:
278          """          """
279          raise NotImplementedError          raise NotImplementedError
280    
281      def projected_points(self, layer, shapeid):      def projected_points(self, layer, points):
282          """Return the projected coordinates of shape shapeid in layer.          """Return the projected coordinates of the points taken from layer.
283    
284          Read the shape from the layer through its Shape method and          Transform all the points in the list of lists of coordinate
285          transform all the points in the list of lists of coordinate          pairs in points.
         pairs returned by the shape's Points method.  
286    
287          The transformation applies the inverse of the layer's projection          The transformation applies the inverse of the layer's projection
288          if any, then the map's projection if any and finally applies          if any, then the map's projection if any and finally applies
# Line 253  class BaseRenderer: Line 301  class BaseRenderer:
301              inverse = proj.Inverse              inverse = proj.Inverse
302          else:          else:
303              inverse = None              inverse = None
304          shape = layer.Shape(shapeid)          result = []
         points = []  
305          scale = self.scale          scale = self.scale
306          offx, offy = self.offset          offx, offy = self.offset
307          make_point = self.make_point          make_point = self.make_point
308          for part in shape.Points():          for part in points:
309              points.append([])              result.append([])
310              for x, y in part:              for x, y in part:
311                  if inverse:                  if inverse:
312                      x, y = inverse(x, y)                      x, y = inverse(x, y)
313                  if forward:                  if forward:
314                      x, y = forward(x, y)                      x, y = forward(x, y)
315                  points[-1].append(make_point(x * scale + offx,                  result[-1].append(make_point(x * scale + offx,
316                                               -y * scale + offy))                                               -y * scale + offy))
317          return points          return result
318    
319      def draw_polygon_shape(self, layer, index, pen, brush):      def draw_polygon_shape(self, layer, points, pen, brush):
320          """Draw a polygon shape with the given brush and pen          """Draw a polygon shape from layer with the given brush and pen
321    
322          The shape is indicated by its id (index) and the layer. The          The shape is given by points argument which is a the return
323          coordinates in the DC's coordinate system are determined with          value of the shape's Points() method. The coordinates in the
324            DC's coordinate system are determined with
325          self.projected_points.          self.projected_points.
326          """          """
327          points = self.projected_points(layer, index)          points = self.projected_points(layer, points)
328    
329          if brush is not self.TRANSPARENT_BRUSH:          if brush is not self.TRANSPARENT_BRUSH:
330              polygon = []              polygon = []
# Line 298  class BaseRenderer: Line 346  class BaseRenderer:
346              for part in points:              for part in points:
347                  self.dc.DrawLines(part)                  self.dc.DrawLines(part)
348    
349      def draw_arc_shape(self, layer, index, pen, brush):      def draw_arc_shape(self, layer, points, pen, brush):
350          """Draw an arc shape with the given brush and pen          """Draw an arc shape from layer with the given brush and pen
351    
352          The shape is indicated by its id (index) and the layer. The          The shape is given by points argument which is a the return
353          coordinates in the DC's coordinate system are determined with          value of the shape's Points() method. The coordinates in the
354            DC's coordinate system are determined with
355          self.projected_points.          self.projected_points.
356          """          """
357          points = self.projected_points(layer, index)          points = self.projected_points(layer, points)
358          self.dc.SetBrush(brush)          self.dc.SetBrush(brush)
359          self.dc.SetPen(pen)          self.dc.SetPen(pen)
360          for part in points:          for part in points:
361              self.dc.DrawLines(part)              self.dc.DrawLines(part)
362    
363      def draw_point_shape(self, layer, index, pen, brush):      def draw_point_shape(self, layer, points, pen, brush):
364          """Draw a point shape with the given brush and pen          """Draw a point shape from layer with the given brush and pen
365    
366          The shape is indicated by its id (index) and the layer. The          The shape is given by points argument which is a the return
367          coordinates in the DC's coordinate system are determined with          value of the shape's Points() method. The coordinates in the
368            DC's coordinate system are determined with
369          self.projected_points.          self.projected_points.
370    
371          The point is drawn as a circle centered on the point.          The point is drawn as a circle centered on the point.
372          """          """
373          points = self.projected_points(layer, index)          points = self.projected_points(layer, points)
374          if not points:          if not points:
375              return              return
376    
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