Merge pull request #2370 from benzea/cairo-draw-markers

WeatherGod · web-flow · commit 2ceaa9c8bd41 · 2016-06-18T09:33:37.000-04:00
Implement draw_markers in the cairo backend.
diff --git a/lib/matplotlib/backends/backend_cairo.py b/lib/matplotlib/backends/backend_cairo.py
@@ -167,6 +167,49 @@ def draw_path(self, gc, path, transform, rgbFace=None):
 
         self._fill_and_stroke(ctx, rgbFace, gc.get_alpha(), gc.get_forced_alpha())
 
+    def draw_markers(self, gc, marker_path, marker_trans, path, transform, rgbFace=None):
+        ctx = gc.ctx
+
+        ctx.new_path()
+        # Create the path for the marker; it needs to be flipped here already!
+        self.convert_path(ctx, marker_path, marker_trans + Affine2D().scale(1.0, -1.0))
+        marker_path = ctx.copy_path_flat()
+
+        # Figure out whether the path has a fill
+        x1, y1, x2, y2 = ctx.fill_extents()
+        if x1 == 0 and y1 == 0 and x2 == 0 and y2 == 0:
+            filled = False
+            # No fill, just unset this (so we don't try to fill it later on)
+            rgbFace = None
+        else:
+            filled = True
+
+        transform = transform + \
+            Affine2D().scale(1.0, -1.0).translate(0, self.height)
+
+        ctx.new_path()
+        for i, (vertices, codes) in enumerate(path.iter_segments(transform, simplify=False)):
+            if len(vertices):
+                x, y = vertices[-2:]
+                ctx.save()
+
+                # Translate and apply path
+                ctx.translate(x, y)
+                ctx.append_path(marker_path)
+
+                ctx.restore()
+
+                # Slower code path if there is a fill; we need to draw
+                # the fill and stroke for each marker at the same time.
+                # Also flush out the drawing every once in a while to
+                # prevent the paths from getting way too long.
+                if filled or i % 1000 == 0:
+                    self._fill_and_stroke(ctx, rgbFace, gc.get_alpha(), gc.get_forced_alpha())
+
+        # Fast path, if there is no fill, draw everything in one step
+        if not filled:
+            self._fill_and_stroke(ctx, rgbFace, gc.get_alpha(), gc.get_forced_alpha())
+
     def draw_image(self, gc, x, y, im):
         # bbox - not currently used
         if _debug: print('%s.%s()' % (self.__class__.__name__, _fn_name()))
