Thuban/UI/baserenderer.py

# Copyright (c) 2001, 2002, 2003 by Intevation GmbH
# Authors:
# Bernhard Herzog <[email protected]>
# Jonathan Coles <[email protected]>
# Frank Koormann <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with Thuban for details.

"""Basic rendering logic for Thuban maps

The code in this module is completely independend of wx so that it can
be tested reasonably easily and it could make it easier to write non-wx
renderers.
"""

from __future__ import generators

__version__ = "$Revision$"
# $Source$
# $Id$

import traceback

from Thuban.Model.layer import Layer, RasterLayer
from Thuban.Model.data import SHAPETYPE_ARC, SHAPETYPE_POINT
from Thuban.Model.label import ALIGN_CENTER, ALIGN_TOP, ALIGN_BOTTOM, \
     ALIGN_LEFT, ALIGN_RIGHT

import Thuban.Model.resource

if Thuban.Model.resource.has_gdal_support():
    from gdalwarp import ProjectRasterFile


class BaseRenderer:

    """Basic Renderer Infrastructure for Thuban Maps

    This class can't be used directly to render because it doesn't know
    anything about real DCs such as how to create pens or brushes. That
    functionality has to be provided by derived classes. The reason for
    this is that it makes the BaseRenderer completely independend of wx
    and thus it's quite easy to write test cases for it.
    """
    # If true the render honors the visibility flag of the layers
    honor_visibility = 1

    # Transparent brushes and pens. Derived classes should define these
    # as appropriate.
    TRANSPARENT_PEN = None
    TRANSPARENT_BRUSH = None

    def __init__(self, dc, map, scale, offset, region = None,
                 resolution = 72.0, honor_visibility = None):
        """Inititalize the renderer.

        dc -- the device context to render on.

        scale, offset -- the scale factor and translation to convert
                between projected coordinates and the DC coordinates

        region -- The region to draw as a (x, y, width, height) tuple in
                  the map's coordinate system. Default is None meaning
                  to draw everything.

        resolution -- the assumed resolution of the DC. Used to convert
                absolute lengths like font sizes to DC coordinates. The
                default is 72.0. If given, this parameter must be
                provided as a keyword argument.

        honor_visibility -- boolean. If true, honor the visibility flag
                of the layers, otherwise draw all layers. If None (the
                default), use the renderer's default. If given, this
                parameter must be provided as a keyword argument.
        """
        # resolution in pixel/inch
        self.dc = dc
        self.map = map
        self.scale = scale
        self.offset = offset
        self.region = region
        if honor_visibility is not None:
            self.honor_visibility = honor_visibility
        # store the resolution in pixel/point because it's more useful
        # later.
        self.resolution = resolution / 72.0

    def tools_for_property(self, prop):
        """Return a suitable pen and brush for the property

        This method must be implemented in derived classes. The return
        value should be a tuple (pen, brush).
        """
        raise NotImplementedError

    def render_map(self):
        """Render the map onto the DC.

        Both map and DC are the ones the renderer was instantiated with.

        This method is just a front-end for render_map_incrementally
        which does all rendering in one go. It also calls the dc's
        BeginDrawing and EndDrawing methods before and after calling
        render_map_incrementally.
        """

        self.dc.BeginDrawing()
        try:
            for cont in self.render_map_incrementally():
                pass
        finally:
            self.dc.EndDrawing()

    def render_map_incrementally(self):
        """Render the map incrementally.

        Return an iterator whose next method should be called until it
        returns False. After returning False it will raise StopIteration
        so that you could also use it in a for loop (implementation
        detail: this method is implemented as a generator).

        Iterate through all layers and draw them. Layers containing
        vector data are drawn with the draw_shape_layer method, raster
        layers are drawn with draw_raster_layer. The label layer is
        drawn last with draw_label_layer.

        During execution of this method, the map is bound to self.map so
        that methods especially in derived classes have access to the
        map if necessary.
        """
        # Whether the raster layer has already been drawn. See below for
        # the optimization this is used for
        seenRaster = True

        #
        # 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 self.map.Layers():
                if isinstance(layer, RasterLayer) and layer.Visible():
                    seenRaster = False
                    break

        for layer in self.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:
                    for i in self.draw_shape_layer_incrementally(layer):
                        yield True
                elif isinstance(layer, RasterLayer) \
                    and Thuban.Model.resource.has_gdal_support():
                    self.draw_raster_layer(layer)
                    seenRaster = True
                    yield True

        self.draw_label_layer(self.map.LabelLayer())
        yield False

    def draw_shape_layer_incrementally(self, layer):
        """Draw the shape layer layer onto the map incrementally.

        This method is a generator which yields True after every 500
        shapes.
        """
        scale = self.scale
        offx, offy = self.offset

        map_proj = self.map.projection
        layer_proj = layer.projection

        brush = self.TRANSPARENT_BRUSH
        pen   = self.TRANSPARENT_PEN

        old_prop = None
        old_group = None
        lc = layer.GetClassification()
        field = layer.GetClassificationColumn()
        defaultGroup = lc.GetDefaultGroup()
        table = layer.ShapeStore().Table()

        # Determine which render function to use.
        useraw, draw_func, draw_func_param = self.low_level_renderer(layer)

        # Iterate through all shapes that have to be drawn.
        count = 0
        for shape in self.layer_shapes(layer):
            count += 1
            if field is None:
                group = defaultGroup
            else:
                record = table.ReadRowAsDict(shape.ShapeID())
                assert record is not None
                group = lc.FindGroup(record[field])

            if not group.IsVisible():
                continue

            # don't recreate new objects if they are the same as before
            if group is not old_group:
                old_group = group

                prop = group.GetProperties()

                if prop != old_prop:
                    pen, brush = self.tools_for_property(prop)

            if useraw:
                data = shape.RawData()
            else:
                data = shape.Points()
            draw_func(draw_func_param, data, pen, brush)
            if count % 500 == 0:
                yield True

    def layer_shapes(self, layer):
        """Return an iterable over the shapes to be drawn from the given layer.

        The default implementation simply returns all ids in the layer.
        Override in derived classes to be more precise.
        """
        return layer.ShapeStore().AllShapes()

    def low_level_renderer(self, layer):
        """Return the low-level renderer for the layer for draw_shape_layer

        The low level renderer to be returned by this method is a tuple
        (useraw, func, param) where useraw is a boolean indicating
        whether the function uses the raw shape data, func is a callable
        object and param is passed as the first parameter to func. The
        draw_shape_layer method will call func like this:

            func(param, shapedata, pen, brush)

        where shapedata is the return value of the RawData method of the
        shape object if useraw is true or the return value of the Points
        method if it's false. pen and brush are the pen and brush to use
        to draw the shape on the dc.

        The default implementation returns one of
        self.draw_polygon_shape, self.draw_arc_shape or
        self.draw_point_shape as func and layer as param. None of the
        method use the raw shape data. Derived classes can override this
        method to return more efficient low level renderers.
        """
        shapetype = layer.ShapeType()
        if shapetype == SHAPETYPE_POINT:
            func = self.draw_point_shape
        elif shapetype == SHAPETYPE_ARC:
            func = self.draw_arc_shape
        else:
            func = self.draw_polygon_shape
        return False, func, layer

    def make_point(self, x, y):
        """Convert (x, y) to a point object.

        Derived classes must override this method.
        """
        raise NotImplementedError

    def projected_points(self, layer, points):
        """Return the projected coordinates of the points taken from layer.

        Transform all the points in the list of lists of coordinate
        pairs in points.

        The transformation applies the inverse of the layer's projection
        if any, then the map's projection if any and finally applies
        self.scale and self.offset.

        The returned list has the same structure as the one returned the
        shape's Points method.
        """
        proj = self.map.GetProjection()
        if proj is not None:
            forward = proj.Forward
        else:
            forward = None
        proj = layer.GetProjection()
        if proj is not None:
            inverse = proj.Inverse
        else:
            inverse = None
        result = []
        scale = self.scale
        offx, offy = self.offset
        make_point = self.make_point
        for part in points:
            result.append([])
            for x, y in part:
                if inverse:
                    x, y = inverse(x, y)
                if forward:
                    x, y = forward(x, y)
                result[-1].append(make_point(x * scale + offx,
                                             -y * scale + offy))
        return result

    def draw_polygon_shape(self, layer, points, pen, brush):
        """Draw a polygon shape from layer with the given brush and pen

        The shape is given by points argument which is a the return
        value of the shape's Points() method. The coordinates in the
        DC's coordinate system are determined with
        self.projected_points.
        """
        points = self.projected_points(layer, points)

        if brush is not self.TRANSPARENT_BRUSH:
            polygon = []
            for part in points:
                polygon.extend(part)

            insert_index = len(polygon)
            for part in points[:-1]:
                polygon.insert(insert_index, part[0])

            self.dc.SetBrush(brush)
            self.dc.SetPen(self.TRANSPARENT_PEN)
            self.dc.DrawPolygon(polygon)

        if pen is not self.TRANSPARENT_PEN:
            # At last draw the boundarys of the simple polygons
            self.dc.SetBrush(self.TRANSPARENT_BRUSH)
            self.dc.SetPen(pen)
            for part in points:
                self.dc.DrawLines(part)

    def draw_arc_shape(self, layer, points, pen, brush):
        """Draw an arc shape from layer with the given brush and pen

        The shape is given by points argument which is a the return
        value of the shape's Points() method. The coordinates in the
        DC's coordinate system are determined with
        self.projected_points.
        """
        points = self.projected_points(layer, points)
        self.dc.SetBrush(brush)
        self.dc.SetPen(pen)
        for part in points:
            self.dc.DrawLines(part)

    def draw_point_shape(self, layer, points, pen, brush):
        """Draw a point shape from layer with the given brush and pen

        The shape is given by points argument which is a the return
        value of the shape's Points() method. The coordinates in the
        DC's coordinate system are determined with
        self.projected_points.

        The point is drawn as a circle centered on the point.
        """
        points = self.projected_points(layer, points)
        if not points:
            return

        radius = self.resolution * 5
        self.dc.SetBrush(brush)
        self.dc.SetPen(pen)
        for part in points:
            for p in part:
                self.dc.DrawEllipse(p.x - radius, p.y - radius,
                                    2 * radius, 2 * radius)

    def draw_raster_layer(self, layer):
        """Draw the raster layer

        This implementation does the projection and scaling of the data
        as required by the layer's and map's projections and the scale
        and offset of the renderer and then hands the transformed data
        to self.draw_raster_data() which has to be implemented in
        derived classes.
        """
        offx, offy = self.offset
        width, height = self.dc.GetSizeTuple()

        in_proj = ""
        proj = layer.GetProjection()
        if proj is not None:
            for p in proj.GetAllParameters():
                in_proj += "+" + p + " "

        out_proj = ""
        proj = self.map.GetProjection()
        if proj is not None:
            for p in proj.GetAllParameters():
                out_proj += "+" + p + " "

        xmin = (0 - offx) / self.scale
        ymin = (offy - height) / self.scale
        xmax = (width - offx) / self.scale
        ymax = (offy - 0) / self.scale

        try:
            data = ProjectRasterFile(layer.GetImageFilename(),
                                     in_proj, out_proj,
                                     (xmin, ymin, xmax, ymax), "",
                                     (width, height))
        except (IOError, AttributeError, ValueError):
            # Why does this catch AttributeError and ValueError?
            # FIXME: The exception should be communicated to the user
            # better.
            traceback.print_exc()
        else:
            self.draw_raster_data(data)

    def draw_raster_data(self, data):
        """Draw the raster image in data onto the DC

        The raster image data is a string holding the data in BMP
        format. The data is exactly the size of the dc and covers it
        completely.

        This method has to be implemented by derived classes.
        """
        raise NotImplementedError

    def label_font(self):
        """Return the font object for the label layer"""
        raise NotImplementedError

    def draw_label_layer(self, layer):
        """Draw the label layer

        All labels are draw in the font returned by self.label_font().
        """
        scale = self.scale
        offx, offy = self.offset

        self.dc.SetFont(self.label_font())

        map_proj = self.map.projection
        if map_proj is not None:
            forward = map_proj.Forward
        else:
            forward = None

        for label in layer.Labels():
            x = label.x
            y = label.y
            text = label.text
            if forward:
                x, y = forward(x, y)
            x = x * scale + offx
            y = -y * scale + offy
            width, height = self.dc.GetTextExtent(text)
            if label.halign == ALIGN_LEFT:
                # nothing to be done
                pass
            elif label.halign == ALIGN_RIGHT:
                x = x - width
            elif label.halign == ALIGN_CENTER:
                x = x - width/2
            if label.valign == ALIGN_TOP:
                # nothing to be done
                pass
            elif label.valign == ALIGN_BOTTOM:
                y = y - height
            elif label.valign == ALIGN_CENTER:
                y = y - height/2
            self.dc.DrawText(text, x, y)
1	# Copyright (c) 2001, 2002, 2003 by Intevation GmbH
2	# Authors:
3	# Bernhard Herzog <[email protected]>
4	# Jonathan Coles <[email protected]>
5	# Frank Koormann <[email protected]>
6	#
7	# This program is free software under the GPL (>=v2)
8	# Read the file COPYING coming with Thuban for details.
9
10	"""Basic rendering logic for Thuban maps
11
12	The code in this module is completely independend of wx so that it can
13	be tested reasonably easily and it could make it easier to write non-wx
14	renderers.
15	"""
16
17	from __future__ import generators
18
19	__version__ = "$Revision$"
20	# $Source$
21	# $Id$
22
23	import traceback
24
25	from Thuban.Model.layer import Layer, RasterLayer
26	from Thuban.Model.data import SHAPETYPE_ARC, SHAPETYPE_POINT
27	from Thuban.Model.label import ALIGN_CENTER, ALIGN_TOP, ALIGN_BOTTOM, \
28	ALIGN_LEFT, ALIGN_RIGHT
29
30	import Thuban.Model.resource
31
32	if Thuban.Model.resource.has_gdal_support():
33	from gdalwarp import ProjectRasterFile
34
35
36	class BaseRenderer:
37
38	"""Basic Renderer Infrastructure for Thuban Maps
39
40	This class can't be used directly to render because it doesn't know
41	anything about real DCs such as how to create pens or brushes. That
42	functionality has to be provided by derived classes. The reason for
43	this is that it makes the BaseRenderer completely independend of wx
44	and thus it's quite easy to write test cases for it.
45	"""
46	# If true the render honors the visibility flag of the layers
47	honor_visibility = 1
48
49	# Transparent brushes and pens. Derived classes should define these
50	# as appropriate.
51	TRANSPARENT_PEN = None
52	TRANSPARENT_BRUSH = None
53
54	def __init__(self, dc, map, scale, offset, region = None,
55	resolution = 72.0, honor_visibility = None):
56	"""Inititalize the renderer.
57
58	dc -- the device context to render on.
59
60	scale, offset -- the scale factor and translation to convert
61	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
68	absolute lengths like font sizes to DC coordinates. The
69	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
73	of the layers, otherwise draw all layers. If None (the
74	default), use the renderer's default. If given, this
75	parameter must be provided as a keyword argument.
76	"""
77	# resolution in pixel/inch
78	self.dc = dc
79	self.map = map
80	self.scale = scale
81	self.offset = offset
82	self.region = region
83	if honor_visibility is not None:
84	self.honor_visibility = honor_visibility
85	# store the resolution in pixel/point because it's more useful
86	# later.
87	self.resolution = resolution / 72.0
88
89	def tools_for_property(self, prop):
90	"""Return a suitable pen and brush for the property
91
92	This method must be implemented in derived classes. The return
93	value should be a tuple (pen, brush).
94	"""
95	raise NotImplementedError
96
97	def render_map(self):
98	"""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
124	vector data are drawn with the draw_shape_layer method, raster
125	layers are drawn with draw_raster_layer. The label layer is
126	drawn last with draw_label_layer.
127
128	During execution of this method, the map is bound to self.map so
129	that methods especially in derived classes have access to the
130	map if necessary.
131	"""
132	# Whether the raster layer has already been drawn. See below for
133	# the optimization this is used for
134	seenRaster = True
135
136	#
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	self.draw_label_layer(self.map.LabelLayer())
163	yield False
164
165	def draw_shape_layer_incrementally(self, layer):
166	"""Draw the shape layer layer onto the map incrementally.
167
168	This method is a generator which yields True after every 500
169	shapes.
170	"""
171	scale = self.scale
172	offx, offy = self.offset
173
174	map_proj = self.map.projection
175	layer_proj = layer.projection
176
177	brush = self.TRANSPARENT_BRUSH
178	pen = self.TRANSPARENT_PEN
179
180	old_prop = None
181	old_group = None
182	lc = layer.GetClassification()
183	field = layer.GetClassificationColumn()
184	defaultGroup = lc.GetDefaultGroup()
185	table = layer.ShapeStore().Table()
186
187	# Determine which render function to use.
188	useraw, draw_func, draw_func_param = self.low_level_renderer(layer)
189
190	# Iterate through all shapes that have to be drawn.
191	count = 0
192	for shape in self.layer_shapes(layer):
193	count += 1
194	if field is None:
195	group = defaultGroup
196	else:
197	record = table.ReadRowAsDict(shape.ShapeID())
198	assert record is not None
199	group = lc.FindGroup(record[field])
200
201	if not group.IsVisible():
202	continue
203
204	# don't recreate new objects if they are the same as before
205	if group is not old_group:
206	old_group = group
207
208	prop = group.GetProperties()
209
210	if prop != old_prop:
211	pen, brush = self.tools_for_property(prop)
212
213	if useraw:
214	data = shape.RawData()
215	else:
216	data = shape.Points()
217	draw_func(draw_func_param, data, pen, brush)
218	if count % 500 == 0:
219	yield True
220
221	def layer_shapes(self, layer):
222	"""Return an iterable over the shapes to be drawn from the given layer.
223
224	The default implementation simply returns all ids in the layer.
225	Override in derived classes to be more precise.
226	"""
227	return layer.ShapeStore().AllShapes()
228
229	def low_level_renderer(self, layer):
230	"""Return the low-level renderer for the layer for draw_shape_layer
231
232	The low level renderer to be returned by this method is a tuple
233	(useraw, func, param) where useraw is a boolean indicating
234	whether the function uses the raw shape data, func is a callable
235	object and param is passed as the first parameter to func. The
236	draw_shape_layer method will call func like this:
237
238	func(param, shapedata, pen, brush)
239
240	where shapedata is the return value of the RawData method of the
241	shape object if useraw is true or the return value of the Points
242	method if it's false. pen and brush are the pen and brush to use
243	to draw the shape on the dc.
244
245	The default implementation returns one of
246	self.draw_polygon_shape, self.draw_arc_shape or
247	self.draw_point_shape as func and layer as param. None of the
248	method use the raw shape data. Derived classes can override this
249	method to return more efficient low level renderers.
250	"""
251	shapetype = layer.ShapeType()
252	if shapetype == SHAPETYPE_POINT:
253	func = self.draw_point_shape
254	elif shapetype == SHAPETYPE_ARC:
255	func = self.draw_arc_shape
256	else:
257	func = self.draw_polygon_shape
258	return False, func, layer
259
260	def make_point(self, x, y):
261	"""Convert (x, y) to a point object.
262
263	Derived classes must override this method.
264	"""
265	raise NotImplementedError
266
267	def projected_points(self, layer, points):
268	"""Return the projected coordinates of the points taken from layer.
269
270	Transform all the points in the list of lists of coordinate
271	pairs in points.
272
273	The transformation applies the inverse of the layer's projection
274	if any, then the map's projection if any and finally applies
275	self.scale and self.offset.
276
277	The returned list has the same structure as the one returned the
278	shape's Points method.
279	"""
280	proj = self.map.GetProjection()
281	if proj is not None:
282	forward = proj.Forward
283	else:
284	forward = None
285	proj = layer.GetProjection()
286	if proj is not None:
287	inverse = proj.Inverse
288	else:
289	inverse = None
290	result = []
291	scale = self.scale
292	offx, offy = self.offset
293	make_point = self.make_point
294	for part in points:
295	result.append([])
296	for x, y in part:
297	if inverse:
298	x, y = inverse(x, y)
299	if forward:
300	x, y = forward(x, y)
301	result[-1].append(make_point(x * scale + offx,
302	-y * scale + offy))
303	return result
304
305	def draw_polygon_shape(self, layer, points, pen, brush):
306	"""Draw a polygon shape from layer with the given brush and pen
307
308	The shape is given by points argument which is a the return
309	value of the shape's Points() method. The coordinates in the
310	DC's coordinate system are determined with
311	self.projected_points.
312	"""
313	points = self.projected_points(layer, points)
314
315	if brush is not self.TRANSPARENT_BRUSH:
316	polygon = []
317	for part in points:
318	polygon.extend(part)
319
320	insert_index = len(polygon)
321	for part in points[:-1]:
322	polygon.insert(insert_index, part[0])
323
324	self.dc.SetBrush(brush)
325	self.dc.SetPen(self.TRANSPARENT_PEN)
326	self.dc.DrawPolygon(polygon)
327
328	if pen is not self.TRANSPARENT_PEN:
329	# At last draw the boundarys of the simple polygons
330	self.dc.SetBrush(self.TRANSPARENT_BRUSH)
331	self.dc.SetPen(pen)
332	for part in points:
333	self.dc.DrawLines(part)
334
335	def draw_arc_shape(self, layer, points, pen, brush):
336	"""Draw an arc shape from layer with the given brush and pen
337
338	The shape is given by points argument which is a the return
339	value of the shape's Points() method. The coordinates in the
340	DC's coordinate system are determined with
341	self.projected_points.
342	"""
343	points = self.projected_points(layer, points)
344	self.dc.SetBrush(brush)
345	self.dc.SetPen(pen)
346	for part in points:
347	self.dc.DrawLines(part)
348
349	def draw_point_shape(self, layer, points, pen, brush):
350	"""Draw a point shape from layer with the given brush and pen
351
352	The shape is given by points argument which is a the return
353	value of the shape's Points() method. The coordinates in the
354	DC's coordinate system are determined with
355	self.projected_points.
356
357	The point is drawn as a circle centered on the point.
358	"""
359	points = self.projected_points(layer, points)
360	if not points:
361	return
362
363	radius = self.resolution * 5
364	self.dc.SetBrush(brush)
365	self.dc.SetPen(pen)
366	for part in points:
367	for p in part:
368	self.dc.DrawEllipse(p.x - radius, p.y - radius,
369	2 * radius, 2 * radius)
370
371	def draw_raster_layer(self, layer):
372	"""Draw the raster layer
373
374	This implementation does the projection and scaling of the data
375	as required by the layer's and map's projections and the scale
376	and offset of the renderer and then hands the transformed data
377	to self.draw_raster_data() which has to be implemented in
378	derived classes.
379	"""
380	offx, offy = self.offset
381	width, height = self.dc.GetSizeTuple()
382
383	in_proj = ""
384	proj = layer.GetProjection()
385	if proj is not None:
386	for p in proj.GetAllParameters():
387	in_proj += "+" + p + " "
388
389	out_proj = ""
390	proj = self.map.GetProjection()
391	if proj is not None:
392	for p in proj.GetAllParameters():
393	out_proj += "+" + p + " "
394
395	xmin = (0 - offx) / self.scale
396	ymin = (offy - height) / self.scale
397	xmax = (width - offx) / self.scale
398	ymax = (offy - 0) / self.scale
399
400	try:
401	data = ProjectRasterFile(layer.GetImageFilename(),
402	in_proj, out_proj,
403	(xmin, ymin, xmax, ymax), "",
404	(width, height))
405	except (IOError, AttributeError, ValueError):
406	# Why does this catch AttributeError and ValueError?
407	# FIXME: The exception should be communicated to the user
408	# better.
409	traceback.print_exc()
410	else:
411	self.draw_raster_data(data)
412
413	def draw_raster_data(self, data):
414	"""Draw the raster image in data onto the DC
415
416	The raster image data is a string holding the data in BMP
417	format. The data is exactly the size of the dc and covers it
418	completely.
419
420	This method has to be implemented by derived classes.
421	"""
422	raise NotImplementedError
423
424	def label_font(self):
425	"""Return the font object for the label layer"""
426	raise NotImplementedError
427
428	def draw_label_layer(self, layer):
429	"""Draw the label layer
430
431	All labels are draw in the font returned by self.label_font().
432	"""
433	scale = self.scale
434	offx, offy = self.offset
435
436	self.dc.SetFont(self.label_font())
437
438	map_proj = self.map.projection
439	if map_proj is not None:
440	forward = map_proj.Forward
441	else:
442	forward = None
443
444	for label in layer.Labels():
445	x = label.x
446	y = label.y
447	text = label.text
448	if forward:
449	x, y = forward(x, y)
450	x = x * scale + offx
451	y = -y * scale + offy
452	width, height = self.dc.GetTextExtent(text)
453	if label.halign == ALIGN_LEFT:
454	# nothing to be done
455	pass
456	elif label.halign == ALIGN_RIGHT:
457	x = x - width
458	elif label.halign == ALIGN_CENTER:
459	x = x - width/2
460	if label.valign == ALIGN_TOP:
461	# nothing to be done
462	pass
463	elif label.valign == ALIGN_BOTTOM:
464	y = y - height
465	elif label.valign == ALIGN_CENTER:
466	y = y - height/2
467	self.dc.DrawText(text, x, y)
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