Another attempt at getting pixel markers to work correctly.

Author: mdboom

lib/matplotlib/lines.py

@@ -547,8 +547,11 @@ def draw(self, renderer):
                 marker_path = marker.get_path()
                 marker_trans = marker.get_transform()
                 w = renderer.points_to_pixels(self._markersize)
-                if marker.get_marker() != ',': # Don't scale for pixels
+                if marker.get_marker() != ',':
+                    # Don't scale for pixels, and don't stroke them
                     marker_trans = marker_trans.scale(w)
+                else:
+                    gc.set_linewidth(0)
                 renderer.draw_markers(
                     gc, marker_path, marker_trans, subsampled, affine.frozen(),
                     rgbFace)

lib/matplotlib/markers.py

@@ -280,10 +280,8 @@ def _set_circle(self, reduction = 1.0):
 
     def _set_pixel(self):
         self._path = Path.unit_rectangle()
-        self._transform = Affine2D().translate(-0.5, -0.5) \
-                          .scale(0.5, 0.5).translate(0.5, 0.5)
+        self._transform = Affine2D().translate(-0.49999, -0.50001)
         self._snap_threshold = False
-        self._joinstyle = 'miter'
 
     def _set_point(self):
         self._set_circle(reduction = self._point_size_reduction)

src/_backend_agg.cpp

@@ -660,7 +660,7 @@ RendererAgg::draw_markers(const Py::Tuple& args)
     // Deal with the difference in y-axis direction
     marker_trans *= agg::trans_affine_scaling(1.0, -1.0);
     trans *= agg::trans_affine_scaling(1.0, -1.0);
-    trans *= agg::trans_affine_translation(0.5, (double)height+0.5);
+    trans *= agg::trans_affine_translation(0.0, (double)height);
 
     PathIterator       marker_path(marker_path_obj);
     transformed_path_t marker_path_transformed(marker_path, marker_trans);