initial implementation of patheffect for collections

Author: leejjoon

examples/pylab_examples/patheffect_demo.py

@@ -28,6 +28,12 @@
     arr = np.arange(25).reshape((5,5))
     ax2.imshow(arr)
     cntr = ax2.contour(arr, colors="k")
+
+    plt.setp(cntr.collections,
+             path_effects=[PathEffects.withStroke(linewidth=3,
+                                                  foreground="w")])
+
+
     clbls = ax2.clabel(cntr, fmt="%2.0f", use_clabeltext=True)
     plt.setp(clbls,
              path_effects=[PathEffects.withStroke(linewidth=3,

lib/matplotlib/collections.py

@@ -91,6 +91,7 @@ def __init__(self,
                  urls=None,
                  offset_position='screen',
                  zorder=1,
+                 path_effects=None,
                  **kwargs
                  ):
         """
@@ -123,6 +124,7 @@ def __init__(self,
             else:
                 self._uniform_offsets = offsets
 
+        self._path_effects = None
         self.update(kwargs)
         self._paths = None
 
@@ -258,11 +260,21 @@ def draw(self, renderer):
         if self._hatch:
             gc.set_hatch(self._hatch)
 
-        renderer.draw_path_collection(
-            gc, transform.frozen(), paths, self.get_transforms(),
-            offsets, transOffset, self.get_facecolor(), self.get_edgecolor(),
-            self._linewidths, self._linestyles, self._antialiaseds, self._urls,
-            self._offset_position)
+        if self.get_path_effects():
+            #from patheffects import PathEffectsRenderer
+            for pe in self.get_path_effects():
+                pe.draw_path_collection(renderer,
+                    gc, transform.frozen(), paths, self.get_transforms(),
+                    offsets, transOffset, self.get_facecolor(), self.get_edgecolor(),
+                    self._linewidths, self._linestyles, self._antialiaseds, self._urls,
+                    self._offset_position)
+        else:
+
+            renderer.draw_path_collection(
+                gc, transform.frozen(), paths, self.get_transforms(),
+                offsets, transOffset, self.get_facecolor(), self.get_edgecolor(),
+                self._linewidths, self._linestyles, self._antialiaseds, self._urls,
+                self._offset_position)
 
         gc.restore()
         renderer.close_group(self.__class__.__name__)
@@ -642,6 +654,17 @@ def update_from(self, other):
         self.cmap = other.cmap
         # self.update_dict = other.update_dict # do we need to copy this? -JJL
 
+    def set_path_effects(self, path_effects):
+        """
+        set path_effects, which should be a list of instances of
+        matplotlib.patheffect._Base class or its derivatives.
+        """
+        self._path_effects = path_effects
+
+    def get_path_effects(self):
+        return self._path_effects
+
+
 # these are not available for the object inspector until after the
 # class is built so we define an initial set here for the init
 # function and they will be overridden after object defn

lib/matplotlib/patheffects.py

@@ -53,6 +53,46 @@ def draw_path(self, renderer, gc, tpath, affine, rgbFace):
         """
         renderer.draw_path(gc, tpath, affine, rgbFace)
 
+    def draw_path_collection(self, renderer,
+                             gc, master_transform, paths, all_transforms,
+                             offsets, offsetTrans, facecolors, edgecolors,
+                             linewidths, linestyles, antialiaseds, urls,
+                             offset_position):
+        """
+        Draws a collection of paths selecting drawing properties from
+        the lists *facecolors*, *edgecolors*, *linewidths*,
+        *linestyles* and *antialiaseds*. *offsets* is a list of
+        offsets to apply to each of the paths.  The offsets in
+        *offsets* are first transformed by *offsetTrans* before being
+        applied.  *offset_position* may be either "screen" or "data"
+        depending on the space that the offsets are in.
+
+        This provides a fallback implementation of
+        :meth:`draw_path_collection` that makes multiple calls to
+        :meth:`draw_path`.  Some backends may want to override this in
+        order to render each set of path data only once, and then
+        reference that path multiple times with the different offsets,
+        colors, styles etc.  The generator methods
+        :meth:`_iter_collection_raw_paths` and
+        :meth:`_iter_collection` are provided to help with (and
+        standardize) the implementation across backends.  It is highly
+        recommended to use those generators, so that changes to the
+        behavior of :meth:`draw_path_collection` can be made globally.
+        """
+        path_ids = []
+        for path, transform in renderer._iter_collection_raw_paths(
+            master_transform, paths, all_transforms):
+            path_ids.append((path, transform))
+
+        for xo, yo, path_id, gc0, rgbFace in renderer._iter_collection(
+            gc, master_transform, all_transforms, path_ids, offsets,
+            offsetTrans, facecolors, edgecolors, linewidths, linestyles,
+            antialiaseds, urls, offset_position):
+            path, transform = path_id
+            transform = transforms.Affine2D(transform.get_matrix()).translate(xo, yo)
+            self.draw_path(renderer, gc0, path, transform, rgbFace)
+
+
     def draw_tex(self, renderer, gc, x, y, s, prop, angle, ismath='TeX!'):
         self._draw_text_as_path(renderer, gc, x, y, s, prop, angle, ismath="TeX")
 
@@ -101,21 +141,6 @@ def draw_markers(self, renderer, gc, marker_path, marker_trans, path, trans, rgb
                                marker_trans + transforms.Affine2D().translate(x, y),
                                rgbFace)
 
-#     def draw_path_collection(self, renderer,
-#                              gc, master_transform, paths, all_transforms,
-#                              offsets, offsetTrans, facecolors, edgecolors,
-#                              linewidths, linestyles, antialiaseds, urls):
-#         path_ids = []
-#         for path, transform in renderer._iter_collection_raw_paths(
-#             master_transform, paths, all_transforms):
-#             path_ids.append((path, transform))
-
-#         for xo, yo, path_id, gc0, rgbFace in renderer._iter_collection(
-#             gc, path_ids, offsets, offsetTrans, facecolors, edgecolors,
-#             linewidths, linestyles, antialiaseds, urls):
-#             path, transform = path_id
-#             transform = transforms.Affine2D(transform.get_matrix()).translate(xo, yo)
-#             self.draw_path(renderer, gc0, path, transform, rgbFace)
 
 class ProxyRenderer(object):
     def __init__(self, path_effect, renderer):
@@ -138,6 +163,17 @@ def draw_markers(self, gc, marker_path, marker_trans, path, trans, rgbFace=None)
                                        gc, marker_path, marker_trans, path, trans,
                                        rgbFace=rgbFace)
 
+    def draw_path_collection(self, gc, master_transform, paths, all_transforms,
+                             offsets, offsetTrans, facecolors, edgecolors,
+                             linewidths, linestyles, antialiaseds, urls,
+                             offset_position):
+        pe = self._path_effect
+        pe.draw_path_collection(self._renderer,
+                                gc, master_transform, paths, all_transforms,
+                                offsets, offsetTrans, facecolors, edgecolors,
+                                linewidths, linestyles, antialiaseds, urls,
+                                offset_position)
+
 
 class Normal(_Base):
     """