/[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 1926 by bh, Mon Nov 10 16:57:19 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  # $Id$  # $Id$
22    
23    import sys
24  import traceback  import traceback
25    
26  from Thuban.Model.layer import Layer, RasterLayer  from Thuban.Model.layer import Layer, RasterLayer
# Line 31  if Thuban.Model.resource.has_gdal_suppor Line 34  if Thuban.Model.resource.has_gdal_suppor
34      from gdalwarp import ProjectRasterFile      from gdalwarp import ProjectRasterFile
35    
36    
37    #
38    #       Renderer Extensions
39    #
40    # The renderer extensions provide a way to render layer types defined in
41    # Thuban extensions. The renderer extensions are stored as a list with
42    # (layer_class, draw_function) pairs. If the renderer has to draw a
43    # non-builtin layer type, i.e. a layer that is not a subclass of Layer
44    # or RasterLayer, it iterates through that list, tests whether the layer
45    # to be drawin is an instance of layer_class and if so calls
46    # draw_function with the renderer and the layer as arguments. Since
47    # drawing is done incrementally, the draw_function should return an
48    # iterable. The easiest way is to simply implement the draw_function as
49    # a generator and to yield in suitable places, or to return the empty
50    # tuple.
51    #
52    # New renderer extensions should be added with add_renderer_extension().
53    # If necessary the extensions list can be reset with
54    # init_renderer_extensions().
55    
56    _renderer_extensions = []
57    
58    def add_renderer_extension(layer_class, function):
59        """Add a renderer extension for the layer class layer_class
60    
61        When an instance of layer_class is to be drawn by the renderer the
62        renderer will call function with the renderer and the layer_class
63        instance as arguments. Since drawing is done incrementally, the
64        function should return an iterable. The easiest way is to simply
65        implement the draw_function as a generator and to yield True in
66        suitable places, or to return the empty tuple if it's not possible
67        to do the rendering in incrementally.
68        """
69        _renderer_extensions.append((layer_class, function))
70    
71    def init_renderer_extensions():
72        """(Re)initialize the list of renderer extensions
73    
74        Calling this function outside of the test suite is probably not
75        useful.
76        """
77        del _renderer_extensions[:]
78    
79    
80    #
81    #       Base Renderer
82    #
83    
84  class BaseRenderer:  class BaseRenderer:
85    
86      """Basic Renderer Infrastructure for Thuban Maps      """Basic Renderer Infrastructure for Thuban Maps
# Line 49  class BaseRenderer: Line 99  class BaseRenderer:
99      TRANSPARENT_PEN = None      TRANSPARENT_PEN = None
100      TRANSPARENT_BRUSH = None      TRANSPARENT_BRUSH = None
101    
102      def __init__(self, dc, scale, offset, resolution = 72.0,      def __init__(self, dc, map, scale, offset, region = None,
103                   honor_visibility = None):                   resolution = 72.0, honor_visibility = None):
104          """Inititalize the renderer.          """Inititalize the renderer.
105    
106          dc -- the device context to render on.          dc -- the device context to render on.
# Line 58  class BaseRenderer: Line 108  class BaseRenderer:
108          scale, offset -- the scale factor and translation to convert          scale, offset -- the scale factor and translation to convert
109                  between projected coordinates and the DC coordinates                  between projected coordinates and the DC coordinates
110    
111            region -- The region to draw as a (x, y, width, height) tuple in
112                      the map's coordinate system. Default is None meaning
113                      to draw everything.
114    
115          resolution -- the assumed resolution of the DC. Used to convert          resolution -- the assumed resolution of the DC. Used to convert
116                  absolute lengths like font sizes to DC coordinates. The                  absolute lengths like font sizes to DC coordinates. The
117                  defauult is 72.0                  default is 72.0. If given, this parameter must be
118                    provided as a keyword argument.
119    
120          honor_visibility -- boolean. If true, honor the visibility flag          honor_visibility -- boolean. If true, honor the visibility flag
121                  of the layers, otherwise draw all layers. If None (the                  of the layers, otherwise draw all layers. If None (the
122                  default), use the renderer's default.                  default), use the renderer's default. If given, this
123                    parameter must be provided as a keyword argument.
124          """          """
125          # resolution in pixel/inch          # resolution in pixel/inch
   
126          self.dc = dc          self.dc = dc
127            self.map = map
128          self.scale = scale          self.scale = scale
129          self.offset = offset          self.offset = offset
130            self.region = region
131          if honor_visibility is not None:          if honor_visibility is not None:
132              self.honor_visibility = honor_visibility              self.honor_visibility = honor_visibility
133          # 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 142  class BaseRenderer:
142          """          """
143          raise NotImplementedError          raise NotImplementedError
144    
145      def render_map(self, map):      def render_map(self):
146          """Render the map onto the DC the renderer was instantiated with          """Render the map onto the DC.
147    
148            Both map and DC are the ones the renderer was instantiated with.
149    
150            This method is just a front-end for render_map_incrementally
151            which does all rendering in one go. It also calls the dc's
152            BeginDrawing and EndDrawing methods before and after calling
153            render_map_incrementally.
154            """
155    
156            self.dc.BeginDrawing()
157            try:
158                for cont in self.render_map_incrementally():
159                    pass
160            finally:
161                self.dc.EndDrawing()
162    
163        def render_map_incrementally(self):
164            """Render the map incrementally.
165    
166            Return an iterator whose next method should be called until it
167            returns False. After returning False it will raise StopIteration
168            so that you could also use it in a for loop (implementation
169            detail: this method is implemented as a generator).
170    
171          Iterate through all layers and draw them. Layers containing          Iterate through all layers and draw them. Layers containing
172          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 177  class BaseRenderer:
177          that methods especially in derived classes have access to the          that methods especially in derived classes have access to the
178          map if necessary.          map if necessary.
179          """          """
         # Some method have to have access to the map so we store it in  
         # self.map.  
         self.map = map  
   
180          # Whether the raster layer has already been drawn. See below for          # Whether the raster layer has already been drawn. See below for
181          # the optimization this is used for          # the optimization this is used for
182          seenRaster = True          seenRaster = True
183    
184          self.dc.BeginDrawing()          #
185            # This is only a good optimization if there is only one
186          try:          # raster layer and the image covers the entire window (as
187              #          # it currently does). We note if there is a raster layer
188              # This is only a good optimization if there is only one          # and only begin drawing layers once we have drawn it.
189              # raster layer and the image covers the entire window (as          # That way we avoid drawing layers that won't be seen.
190              # it currently does). We note if there is a raster layer          #
191              # and only begin drawing layers once we have drawn it.          if Thuban.Model.resource.has_gdal_support():
192              # That way we avoid drawing layers that won't be seen.              for layer in self.map.Layers():
193              #                  if isinstance(layer, RasterLayer) and layer.Visible():
194              if Thuban.Model.resource.has_gdal_support():                      seenRaster = False
195                  for layer in map.Layers():                      break
196                      if isinstance(layer, RasterLayer) and layer.Visible():  
197                          seenRaster = False          for layer in self.map.Layers():
198                          break              # if honor_visibility is true, only draw visible layers,
199                # otherwise draw all layers
200              for layer in map.Layers():              if not self.honor_visibility or layer.Visible():
201                  # if honor_visibility is true, only draw visible layers,                  if isinstance(layer, Layer) and seenRaster:
202                  # otherwise draw all layers                      for i in self.draw_shape_layer_incrementally(layer):
203                  if not self.honor_visibility or layer.Visible():                          yield True
204                      if isinstance(layer, Layer) and seenRaster:                  elif isinstance(layer, RasterLayer) \
205                          self.draw_shape_layer(layer)                      and Thuban.Model.resource.has_gdal_support():
206                      elif isinstance(layer, RasterLayer) \                      self.draw_raster_layer(layer)
207                          and Thuban.Model.resource.has_gdal_support():                      seenRaster = True
208                          self.draw_raster_layer(layer)                      yield True
209                          seenRaster = True                  else:
210                        # look it up in the renderer extensions
211                        for cls, func in _renderer_extensions:
212                            if isinstance(layer, cls):
213                                for i in func(self, layer):
214                                    yield True
215                                break
216                        else:
217                            # No renderer found. Print a message about it
218                            print >>sys.stderr, ("Drawing layer %r not supported"
219                                                 % layer)
220                yield True
221    
222              self.draw_label_layer(map.LabelLayer())          self.draw_label_layer(self.map.LabelLayer())
223          finally:          yield False
             self.dc.EndDrawing()  
224    
225      def draw_shape_layer(self, layer):      def draw_shape_layer_incrementally(self, layer):
226          """Draw the shape layer layer onto the map.          """Draw the shape layer layer onto the map incrementally.
227    
228          Automatically called by render_map. Iterate through all shapes          This method is a generator which yields True after every 500
229          as indicated by self.layer_ids() and draw them, using low-level          shapes.
         renderers returned by self.low_level_renderer().  
230          """          """
231          scale = self.scale          scale = self.scale
232          offx, offy = self.offset          offx, offy = self.offset
# Line 159  class BaseRenderer: Line 244  class BaseRenderer:
244          defaultGroup = lc.GetDefaultGroup()          defaultGroup = lc.GetDefaultGroup()
245          table = layer.ShapeStore().Table()          table = layer.ShapeStore().Table()
246    
247            if lc.GetNumGroups() == 0:
248                # There's only the default group, so we can pretend that
249                # there is no field to classifiy on which makes things
250                # faster since we don't need the attribute information at
251                # all.
252                field = None
253    
254          # Determine which render function to use.          # Determine which render function to use.
255          draw_func, draw_func_param = self.low_level_renderer(layer)          useraw, draw_func, draw_func_param = self.low_level_renderer(layer)
256    
257            #
258          # Iterate through all shapes that have to be drawn.          # Iterate through all shapes that have to be drawn.
259          for i in self.layer_ids(layer):          #
260    
261            # Count the shapes drawn so that we can yield every few hundred
262            # shapes
263            count = 0
264    
265            # Cache the tools (pens and brushes) for the classification
266            # groups. This is a mapping from the group's ids to the a tuple
267            # (pen, brush)
268            tool_cache = {}
269    
270            for shape in self.layer_shapes(layer):
271                count += 1
272              if field is None:              if field is None:
273                  group = defaultGroup                  group = defaultGroup
274              else:              else:
275                  record = table.ReadRowAsDict(i)                  value = table.ReadValue(shape.ShapeID(), field)
276                  assert record is not None                  group = lc.FindGroup(value)
                 group = lc.FindGroup(record[field])  
277    
278              if not group.IsVisible():              if not group.IsVisible():
279                  continue                  continue
280    
281              # don't recreate new objects if they are the same as before              try:
282              if group is not old_group:                  pen, brush = tool_cache[id(group)]
283                  old_group = group              except KeyError:
284                    pen, brush = tool_cache[id(group)] \
285                                 = self.tools_for_property(group.GetProperties())
286    
287                  prop = group.GetProperties()              if useraw:
288                    data = shape.RawData()
289                  if prop != old_prop:              else:
290                      pen, brush = self.tools_for_property(prop)                  data = shape.Points()
291                draw_func(draw_func_param, data, pen, brush)
292              draw_func(draw_func_param, i, pen, brush)              if count % 500 == 0:
293                    yield True
294    
295      def layer_ids(self, layer):      def layer_shapes(self, layer):
296          """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.
297    
298          The default implementation simply returns all ids in the layer.          The default implementation simply returns all ids in the layer.
299          Override in derived classes to be more precise.          Override in derived classes to be more precise.
300          """          """
301          return range(layer.NumShapes())          return layer.ShapeStore().AllShapes()
302    
303      def low_level_renderer(self, layer):      def low_level_renderer(self, layer):
304          """Return the low-level renderer for the layer for draw_shape_layer          """Return the low-level renderer for the layer for draw_shape_layer
305    
306          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
307          (func, param) where func is a callable object and param is          (useraw, func, param) where useraw is a boolean indicating
308          passed as the first parameter to func. The draw_shape_layer          whether the function uses the raw shape data, func is a callable
309          method will call func like this:          object and param is passed as the first parameter to func. The
310            draw_shape_layer method will call func like this:
311              func(param, rawshape, pen, brush)  
312                func(param, shapedata, pen, brush)
313          where rawshape is currently the shapeid. pen and brush are the  
314          pen and brush to use to draw the shape on the dc.          where shapedata is the return value of the RawData method of the
315            shape object if useraw is true or the return value of the Points
316            method if it's false. pen and brush are the pen and brush to use
317            to draw the shape on the dc.
318    
319          The default implementation returns one of          The default implementation returns one of
320          self.draw_polygon_shape, self.draw_arc_shape or          self.draw_polygon_shape, self.draw_arc_shape or
321          self.draw_point_shape as func and layer as param. Derived          self.draw_point_shape as func and layer as param. None of the
322          classes can override this method to return more efficient low          method use the raw shape data. Derived classes can override this
323          level renderers.          method to return more efficient low level renderers.
324          """          """
325          shapetype = layer.ShapeType()          shapetype = layer.ShapeType()
326          if shapetype == SHAPETYPE_POINT:          if shapetype == SHAPETYPE_POINT:
# Line 220  class BaseRenderer: Line 329  class BaseRenderer:
329              func = self.draw_arc_shape              func = self.draw_arc_shape
330          else:          else:
331              func = self.draw_polygon_shape              func = self.draw_polygon_shape
332          return func, layer          return False, func, layer
333    
334      def make_point(self, x, y):      def make_point(self, x, y):
335          """Convert (x, y) to a point object.          """Convert (x, y) to a point object.
# Line 229  class BaseRenderer: Line 338  class BaseRenderer:
338          """          """
339          raise NotImplementedError          raise NotImplementedError
340    
341      def projected_points(self, layer, shapeid):      def projected_points(self, layer, points):
342          """Return the projected coordinates of shape shapeid in layer.          """Return the projected coordinates of the points taken from layer.
343    
344          Read the shape from the layer through its Shape method and          Transform all the points in the list of lists of coordinate
345          transform all the points in the list of lists of coordinate          pairs in points.
         pairs returned by the shape's Points method.  
346    
347          The transformation applies the inverse of the layer's projection          The transformation applies the inverse of the layer's projection
348          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 361  class BaseRenderer:
361              inverse = proj.Inverse              inverse = proj.Inverse
362          else:          else:
363              inverse = None              inverse = None
364          shape = layer.Shape(shapeid)          result = []
         points = []  
365          scale = self.scale          scale = self.scale
366          offx, offy = self.offset          offx, offy = self.offset
367          make_point = self.make_point          make_point = self.make_point
368          for part in shape.Points():          for part in points:
369              points.append([])              result.append([])
370              for x, y in part:              for x, y in part:
371                  if inverse:                  if inverse:
372                      x, y = inverse(x, y)                      x, y = inverse(x, y)
373                  if forward:                  if forward:
374                      x, y = forward(x, y)                      x, y = forward(x, y)
375                  points[-1].append(make_point(x * scale + offx,                  result[-1].append(make_point(x * scale + offx,
376                                               -y * scale + offy))                                               -y * scale + offy))
377          return points          return result
378    
379      def draw_polygon_shape(self, layer, index, pen, brush):      def draw_polygon_shape(self, layer, points, pen, brush):
380          """Draw a polygon shape with the given brush and pen          """Draw a polygon shape from layer with the given brush and pen
381    
382          The shape is indicated by its id (index) and the layer. The          The shape is given by points argument which is a the return
383          coordinates in the DC's coordinate system are determined with          value of the shape's Points() method. The coordinates in the
384            DC's coordinate system are determined with
385          self.projected_points.          self.projected_points.
386          """          """
387          points = self.projected_points(layer, index)          points = self.projected_points(layer, points)
388    
389          if brush is not self.TRANSPARENT_BRUSH:          if brush is not self.TRANSPARENT_BRUSH:
390              polygon = []              polygon = []
# Line 298  class BaseRenderer: Line 406  class BaseRenderer:
406              for part in points:              for part in points:
407                  self.dc.DrawLines(part)                  self.dc.DrawLines(part)
408    
409      def draw_arc_shape(self, layer, index, pen, brush):      def draw_arc_shape(self, layer, points, pen, brush):
410          """Draw an arc shape with the given brush and pen          """Draw an arc shape from layer with the given brush and pen
411    
412          The shape is indicated by its id (index) and the layer. The          The shape is given by points argument which is a the return
413          coordinates in the DC's coordinate system are determined with          value of the shape's Points() method. The coordinates in the
414            DC's coordinate system are determined with
415          self.projected_points.          self.projected_points.
416          """          """
417          points = self.projected_points(layer, index)          points = self.projected_points(layer, points)
418          self.dc.SetBrush(brush)          self.dc.SetBrush(brush)
419          self.dc.SetPen(pen)          self.dc.SetPen(pen)
420          for part in points:          for part in points:
421              self.dc.DrawLines(part)              self.dc.DrawLines(part)
422    
423      def draw_point_shape(self, layer, index, pen, brush):      def draw_point_shape(self, layer, points, pen, brush):
424          """Draw a point shape with the given brush and pen          """Draw a point shape from layer with the given brush and pen
425    
426          The shape is indicated by its id (index) and the layer. The          The shape is given by points argument which is a the return
427          coordinates in the DC's coordinate system are determined with          value of the shape's Points() method. The coordinates in the
428            DC's coordinate system are determined with
429          self.projected_points.          self.projected_points.
430    
431          The point is drawn as a circle centered on the point.          The point is drawn as a circle centered on the point.
432          """          """
433          points = self.projected_points(layer, index)          points = self.projected_points(layer, points)
434          if not points:          if not points:
435              return              return
436    
# Line 372  class BaseRenderer: Line 482  class BaseRenderer:
482              # better.              # better.
483              traceback.print_exc()              traceback.print_exc()
484          else:          else:
485              self.draw_raster_data(data)              self.draw_raster_data(data, "BMP")
486    
487      def draw_raster_data(self, data):      def draw_raster_data(self, data, format="BMP"):
488          """Draw the raster image in data onto the DC          """Draw the raster image in data onto the DC
489    
490          The raster image data is a string holding the data in BMP          The raster image data is a string holding the data in the format
491          format. The data is exactly the size of the dc and covers it          indicated by the format parameter. The image is assumed to be
492          completely.          exactly the size of the dc and to cover it completely.
493    
494            The format parameter is a string with the name of the format.
495            The following format names should be used:
496    
497              'BMP' -- Windows Bitmap
498              'JPEG' -- Jpeg
499    
500            The default format is 'bmp'.
501    
502          This method has to be implemented by derived classes.          This method has to be implemented by derived classes. The
503            implementation in the derived class should try to support at
504            least the formats specified above and may support more.
505          """          """
506          raise NotImplementedError          raise NotImplementedError
507    
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