Merge pull request matplotlib#20524 from anntzer/lo

Dedupe some box anchoring code between legend.py and offsetbox.py.

Author: QuLogic

lib/matplotlib/legend.py

@@ -28,7 +28,7 @@
 import numpy as np
 
 import matplotlib as mpl
-from matplotlib import _api, docstring, colors
+from matplotlib import _api, docstring, colors, offsetbox
 from matplotlib.artist import Artist, allow_rasterization
 from matplotlib.cbook import silent_list
 from matplotlib.font_manager import FontProperties
@@ -40,10 +40,11 @@
     PolyCollection, RegularPolyCollection)
 from matplotlib.transforms import Bbox, BboxBase, TransformedBbox
 from matplotlib.transforms import BboxTransformTo, BboxTransformFrom
-
-from matplotlib.offsetbox import HPacker, VPacker, TextArea, DrawingArea
-from matplotlib.offsetbox import DraggableOffsetBox
-
+from matplotlib.offsetbox import (
+    AnchoredOffsetbox, DraggableOffsetBox,
+    HPacker, VPacker,
+    DrawingArea, TextArea,
+)
 from matplotlib.container import ErrorbarContainer, BarContainer, StemContainer
 from . import legend_handler
 
@@ -280,21 +281,10 @@ def _update_bbox_to_anchor(self, loc_in_canvas):
 class Legend(Artist):
     """
     Place a legend on the axes at location loc.
-
     """
-    codes = {'best':         0,  # only implemented for axes legends
-             'upper right':  1,
-             'upper left':   2,
-             'lower left':   3,
-             'lower right':  4,
-             'right':        5,
-             'center left':  6,
-             'center right': 7,
-             'lower center': 8,
-             'upper center': 9,
-             'center':       10,
-             }
 
+    # 'best' is only implemented for axes legends
+    codes = {'best': 0, **AnchoredOffsetbox.codes}
     zorder = 5
 
     def __str__(self):
@@ -1014,29 +1004,10 @@ def _get_anchored_bbox(self, loc, bbox, parentbbox, renderer):
             bbox to be placed, in display coordinates.
         parentbbox : `~matplotlib.transforms.Bbox`
             A parent box which will contain the bbox, in display coordinates.
-
         """
-        assert loc in range(1, 11)  # called only internally
-
-        BEST, UR, UL, LL, LR, R, CL, CR, LC, UC, C = range(11)
-
-        anchor_coefs = {UR: "NE",
-                        UL: "NW",
-                        LL: "SW",
-                        LR: "SE",
-                        R: "E",
-                        CL: "W",
-                        CR: "E",
-                        LC: "S",
-                        UC: "N",
-                        C: "C"}
-
-        c = anchor_coefs[loc]
-
-        fontsize = renderer.points_to_pixels(self._fontsize)
-        container = parentbbox.padded(-self.borderaxespad * fontsize)
-        anchored_box = bbox.anchored(c, container=container)
-        return anchored_box.x0, anchored_box.y0
+        return offsetbox._get_anchored_bbox(
+            loc, bbox, parentbbox,
+            self.borderaxespad * renderer.points_to_pixels(self._fontsize))
 
     def _find_best_position(self, width, height, renderer, consider=None):
         """

lib/matplotlib/offsetbox.py

@@ -1098,17 +1098,14 @@ def _update_offset_func(self, renderer, fontsize=None):
         """
         if fontsize is None:
             fontsize = renderer.points_to_pixels(
-                            self.prop.get_size_in_points())
+                self.prop.get_size_in_points())
 
-        def _offset(w, h, xd, yd, renderer, fontsize=fontsize, self=self):
+        def _offset(w, h, xd, yd, renderer):
             bbox = Bbox.from_bounds(0, 0, w, h)
             borderpad = self.borderpad * fontsize
             bbox_to_anchor = self.get_bbox_to_anchor()
-
-            x0, y0 = self._get_anchored_bbox(self.loc,
-                                             bbox,
-                                             bbox_to_anchor,
-                                             borderpad)
+            x0, y0 = _get_anchored_bbox(
+                self.loc, bbox, bbox_to_anchor, borderpad)
             return x0 + xd, y0 + yd
 
         self.set_offset(_offset)
@@ -1139,31 +1136,18 @@ def draw(self, renderer):
         self.get_child().draw(renderer)
         self.stale = False
 
-    def _get_anchored_bbox(self, loc, bbox, parentbbox, borderpad):
-        """
-        Return the position of the bbox anchored at the parentbbox
-        with the loc code, with the borderpad.
-        """
-        assert loc in range(1, 11)  # called only internally
-
-        BEST, UR, UL, LL, LR, R, CL, CR, LC, UC, C = range(11)
 
-        anchor_coefs = {UR: "NE",
-                        UL: "NW",
-                        LL: "SW",
-                        LR: "SE",
-                        R: "E",
-                        CL: "W",
-                        CR: "E",
-                        LC: "S",
-                        UC: "N",
-                        C: "C"}
-
-        c = anchor_coefs[loc]
-
-        container = parentbbox.padded(-borderpad)
-        anchored_box = bbox.anchored(c, container=container)
-        return anchored_box.x0, anchored_box.y0
+def _get_anchored_bbox(loc, bbox, parentbbox, borderpad):
+    """
+    Return the (x, y) position of the *bbox* anchored at the *parentbbox* with
+    the *loc* code with the *borderpad*.
+    """
+    # This is only called internally and *loc* should already have been
+    # validated.  If 0 (None), we just let ``bbox.anchored`` raise.
+    c = [None, "NE", "NW", "SW", "SE", "E", "W", "E", "S", "N", "C"][loc]
+    container = parentbbox.padded(-borderpad)
+    anchored_box = bbox.anchored(c, container=container)
+    return anchored_box.x0, anchored_box.y0
 
 
 class AnchoredText(AnchoredOffsetbox):