matplotlib · jinshifen33 · Mar 7, 2018 · Mar 8, 2018 · Mar 8, 2018 · Mar 8, 2018
diff --git a/lib/matplotlib/legend.py b/lib/matplotlib/legend.py
@@ -244,12 +244,23 @@ def _update_bbox_to_anchor(self, loc_in_canvas):
     Default is ``None``, which will take the value from
     :rc:`legend.labelspacing`.
 
+scalehandlebox : None or bool
+    Control whether to scale each individual handlebox up to fit it's handle.
+    Default is ``None``, which will take the value from
+    :rc:`legend.scalehandlebox`.
+
 handlelength : float or None
     The length of the legend handles.
     Measured in font-size units.
     Default is ``None``, which will take the value from
     :rc:`legend.handlelength`.
 
+handleheight : float or None
+    The height of the legend handles.
+    Measured in font-size units.
+    Default is ``None``, which will take the value from
+    :rc:`legend.handleheight`.
+
 handletextpad : float or None
     The pad between the legend handle and text.
     Measured in font-size units.
@@ -317,6 +328,7 @@ def __init__(self, parent, handles, labels,
                  borderpad=None,      # the whitespace inside the legend border
                  labelspacing=None,   # the vertical space between the legend
                                       # entries
+                 scalehandlebox=None,  # scale handlebox to fit handle
                  handlelength=None,   # the length of the legend handles
                  handleheight=None,   # the height of the legend handles
                  handletextpad=None,  # the pad between the legend handle
@@ -404,9 +416,9 @@ def __init__(self, parent, handles, labels,
 
         locals_view = locals()
         for name in ["numpoints", "markerscale", "shadow", "columnspacing",
-                     "scatterpoints", "handleheight", 'borderpad',
-                     'labelspacing', 'handlelength', 'handletextpad',
-                     'borderaxespad']:
+                     "scatterpoints", "scalehandlebox", "handleheight",
+                     'handlelength', 'borderpad', 'labelspacing',
+                     'handletextpad', 'borderaxespad']:
             if locals_view[name] is None:
                 value = rcParams["legend." + name]
             else:
@@ -746,6 +758,7 @@ def _init_legend_box(self, handles, labels, markerfirst=True):
         descent = 0.35 * self._approx_text_height() * (self.handleheight - 0.7)
         # 0.35 and 0.7 are just heuristic numbers and may need to be improved.
         height = self._approx_text_height() * self.handleheight - descent
+        width = self.handlelength * fontsize
         # each handle needs to be drawn inside a box of (x, y, w, h) =
         # (0, -descent, width, height).  And their coordinates should
         # be given in the display coordinates.
@@ -773,7 +786,7 @@ def _init_legend_box(self, handles, labels, markerfirst=True):
                 textbox = TextArea(lab, textprops=label_prop,
                                    multilinebaseline=True,
                                    minimumdescent=True)
-                handlebox = DrawingArea(width=self.handlelength * fontsize,
+                handlebox = DrawingArea(width=width,
                                         height=height,
                                         xdescent=0., ydescent=descent)
 

diff --git a/lib/matplotlib/legend_handler.py b/lib/matplotlib/legend_handler.py
@@ -84,6 +84,58 @@ def adjust_drawing_area(self, legend, orig_handle,
         height = height - self._ypad * fontsize
         return xdescent, ydescent, width, height
 
+    def _scale_dimensions(self, legend, handlebox, orig_handle):
+        '''
+        Scales up handlebox dimensions to fit orig_handle
+
+        Parameters
+        ----------
+        legend : :class:`matplotlib.legend.Legend` instance
+            The legend that will contain the orig_handle
+        handlebox: :class:`matplotlib.offsetbox.DrawingArea`
+            The drawing area that is to be scaled
+        orig_handle : :class:`matplotlib.artist.Artist` or similar
+            The object that the output width and height must be large
+            enough to fit.
+
+        '''
+        width = max(handlebox.width, self.handle_width(legend, orig_handle))
+        height = max(handlebox.height, self.handle_height(legend, orig_handle))
+        handlebox.set_width(width)
+        handlebox.set_height(height)
+
+    def handle_width(self, legend, orig_handle):
+        '''
+        Overriden in children classes if orig_handle could be larger
+        than the default DrawingArea height, returns the height of orig_handle.
+
+        Parameters
+        ----------
+        legend : :class:`matplotlib.legend.Legend` instance
+            The legend that will contain the orig_handle.
+        orig_handle : :class:`matplotlib.artist.Artist` or similar
+            The object that the output width and height must be large
+            enough to fit.
+
+        '''
+        return -1
+
+    def handle_height(self, legend, orig_handle):
+        '''
+        Overriden in children classes if orig_handle could be larger
+        than the default DrawingArea height, returns the height of orig_handle.
+
+        Parameters
+        ----------
+        legend : :class:`matplotlib.legend.Legend` instance
+            The legend that will contain the orig_handle.
+        orig_handle : :class:`matplotlib.artist.Artist` or similar
+            The object that the output width and height must be large
+            enough to fit.
+
+        '''
+        return -1
+
     def legend_artist(self, legend, orig_handle,
                       fontsize, handlebox):
         """
@@ -105,6 +157,8 @@ def legend_artist(self, legend, orig_handle,
             be added to this handlebox inside this method.
 
         """
+        if legend.scalehandlebox:
+            self._scale_dimensions(legend, handlebox, orig_handle)
         xdescent, ydescent, width, height = self.adjust_drawing_area(
                  legend, orig_handle,
                  handlebox.xdescent, handlebox.ydescent,
@@ -113,7 +167,6 @@ def legend_artist(self, legend, orig_handle,
         artists = self.create_artists(legend, orig_handle,
                                       xdescent, ydescent, width, height,
                                       fontsize, handlebox.get_transform())
-
         # create_artists will return a list of artists.
         for a in artists:
             handlebox.add_artist(a)
@@ -224,6 +277,54 @@ def __init__(self, marker_pad=0.3, numpoints=None, **kw):
         HandlerNpoints.__init__(self, marker_pad=marker_pad,
                                 numpoints=numpoints, **kw)
 
+    def handle_width(self, legend, orig_handle):
+        '''
+        If *orig_handle* contains a marker, returns markersize multiplied by
+        legend.marker_scale, if the marker is not significantly
+        larger in width, do nothing.
+
+        Parameters
+        ----------
+        legend : :class:`matplotlib.legend.Legend` instance
+            The legend that will contain the orig_handle.
+        orig_handle : :class:`matplotlib.artist.Artist` or similar
+            The object that the output width and height must be large
+            enough to fit.
+
+        '''
+
+        marker = orig_handle.get_marker()
+        marker_size = orig_handle.get_markersize()
+        if marker and marker_size > 0:
+            if legend.markerscale != 1:
+                marker_size = marker_size * legend.markerscale
+            return marker_size
+        return -1
+
+    def handle_height(self, legend, orig_handle):
+        '''
+        If *orig_handle* contains a marker, returns markersize multiplied by
+        legend.marker_scale, if the marker is not significantly
+        larger in height, do nothing.
+
+        Parameters
+        ----------
+        legend : :class:`matplotlib.legend.Legend` instance
+            The legend that will contain the orig_handle.
+        orig_handle : :class:`matplotlib.artist.Artist` or similar
+            The object that the output width and height must be large
+            enough to fit.
+
+        '''
+
+        marker = orig_handle.get_marker()
+        marker_size = orig_handle.get_markersize()
+        if marker and marker_size > 0:
+            if legend.markerscale != 1:
+                marker_size = marker_size * legend.markerscale
+            return marker_size
+        return -1
+
     def create_artists(self, legend, orig_handle,
                        xdescent, ydescent, width, height, fontsize,
                        trans):
@@ -305,6 +406,12 @@ class HandlerLineCollection(HandlerLine2D):
     """
     Handler for `.LineCollection` instances.
     """
+    def handle_width(self, legend, orig_handle):
+        return -1
+
+    def handle_height(self, legend, orig_handle):
+        return -1
+
     def get_numpoints(self, legend):
         if self._numpoints is None:
             return legend.scatterpoints
@@ -437,6 +544,12 @@ class HandlerErrorbar(HandlerLine2D):
     """
     Handler for Errorbars.
     """
+    def handle_width(self, legend, orig_handle):
+        return -1
+
+    def handle_height(self, legend, orig_handle):
+        return -1
+
     def __init__(self, xerr_size=0.5, yerr_size=None,
                  marker_pad=0.3, numpoints=None, **kw):
 
@@ -499,8 +612,8 @@ def create_artists(self, legend, orig_handle,
         handle_caplines = []
 
         if orig_handle.has_xerr:
-            verts = [ ((x - xerr_size, y), (x + xerr_size, y))
-                      for x, y in zip(xdata_marker, ydata_marker)]
+            verts = [((x - xerr_size, y), (x + xerr_size, y))
+                     for x, y in zip(xdata_marker, ydata_marker)]
             coll = mcoll.LineCollection(verts)
             self.update_prop(coll, barlinecols[0], legend)
             handle_barlinecols.append(coll)
@@ -517,8 +630,8 @@ def create_artists(self, legend, orig_handle,
                 handle_caplines.append(capline_right)
 
         if orig_handle.has_yerr:
-            verts = [ ((x, y - yerr_size), (x, y + yerr_size))
-                      for x, y in zip(xdata_marker, ydata_marker)]
+            verts = [((x, y - yerr_size), (x, y + yerr_size))
+                     for x, y in zip(xdata_marker, ydata_marker)]
             coll = mcoll.LineCollection(verts)
             self.update_prop(coll, barlinecols[0], legend)
             handle_barlinecols.append(coll)
@@ -652,6 +765,48 @@ def __init__(self, ndivide=1, pad=None, **kwargs):
         self._pad = pad
         HandlerBase.__init__(self, **kwargs)
 
+    def handle_width(self, legend, orig_handle):
+        '''
+        Returns width of largest handle in *orig_handle* tuple.
+
+        Parameters
+        ----------
+        legend : :class:`matplotlib.legend.Legend` instance
+            The legend that will contain the orig_handle.
+        orig_handle : :class:`matplotlib.artist.Artist` or similar
+            The object that the output width and height must be large
+            enough to fit.
+
+        '''
+        handler_map = legend.get_legend_handler_map()
+        largest_width = -1
+        for handle1 in orig_handle:
+            handler = legend.get_legend_handler(handler_map, handle1)
+            largest_width = max(largest_width,
+                                handler.handle_width(legend, handle1))
+        return largest_width
+
+    def handle_height(self, legend, orig_handle):
+        '''
+        Returns width of largest handle in *orig_handle* tuple.
+
+        Parameters
+        ----------
+        legend : :class:`matplotlib.legend.Legend` instance
+            The legend that will contain the orig_handle.
+        orig_handle : :class:`matplotlib.artist.Artist` or similar
+            The object that the output width and height must be large
+            enough to fit.
+
+        '''
+        handler_map = legend.get_legend_handler_map()
+        largest_height = -1
+        for handle1 in orig_handle:
+            handler = legend.get_legend_handler(handler_map, handle1)
+            largest_height = max(largest_height,
+                                 handler.handle_height(legend, handle1))
+        return largest_height
+
     def create_artists(self, legend, orig_handle,
                        xdescent, ydescent, width, height, fontsize,
                        trans):

diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -1247,6 +1247,8 @@ def _validate_linestyle(ls):
     'legend.borderpad': [0.4, validate_float],  # units are fontsize
     # the vertical space between the legend entries
     'legend.labelspacing': [0.5, validate_float],
+    # whether or not to scale handlebox to fit handle
+    'legend.scalehandlebox': [True, validate_bool],
     # the length of the legend lines
     'legend.handlelength': [2., validate_float],
     # the length of the legend lines

diff --git a/lib/matplotlib/tests/baseline_images/test_cycles/marker_cycle.png b/lib/matplotlib/tests/baseline_images/test_cycles/marker_cycle.png
diff --git a/lib/matplotlib/tests/baseline_images/test_legend/legend_large_marker_in_tuple.png b/lib/matplotlib/tests/baseline_images/test_legend/legend_large_marker_in_tuple.png
diff --git a/lib/matplotlib/tests/baseline_images/test_legend/legend_large_markers.png b/lib/matplotlib/tests/baseline_images/test_legend/legend_large_markers.png
diff --git a/lib/matplotlib/tests/baseline_images/test_legend/legend_large_markerscale.png b/lib/matplotlib/tests/baseline_images/test_legend/legend_large_markerscale.png
diff --git a/lib/matplotlib/tests/test_legend.py b/lib/matplotlib/tests/test_legend.py
@@ -488,3 +488,38 @@ def test_legend_title_empty():
     leg = ax.legend()
     assert leg.get_title().get_text() == ""
     assert leg.get_title().get_visible() is False
+
+
+@image_comparison(baseline_images=['legend_large_markers'],
+                  extensions=['png'], style='mpl20')
+def test_large_markers():
+    # test that legend scales to fit markers with large markersize
+    plt.figure()
+    a, = plt.plot([1], [1], 's', markersize=40.)
+    b, = plt.plot([2], [1], '*', markersize=40.)
+    plt.xticks([], [])
+    plt.yticks([], [])
+    plt.legend([a, b], ["big square", "big star"], loc=2, numpoints=1)
+
+
+@image_comparison(baseline_images=['legend_large_markerscale'],
+                  extensions=['png'], style='mpl20')
+def test_large_markerscale():
+    # test that legend scales to fit markers with large markerscale
+    plt.figure()
+    a, = plt.plot([1], [1], 's')
+    plt.xticks([], [])
+    plt.yticks([], [])
+    plt.legend([a], ["big markerscale"], markerscale=20., loc=2, numpoints=1)
+
+
+@image_comparison(baseline_images=['legend_large_marker_in_tuple'],
+                  extensions=['png'], style='mpl20')
+def test_large_marker_in_tuple():
+    # test that legend scales to fit large markers in tuple
+    plt.figure()
+    a, = plt.plot([1], [1], "ro", c="green", markersize=15)
+    b, = plt.plot([1], [1], "w+", c="red", markeredgewidth=3, markersize=40)
+    plt.xticks([], [])
+    plt.yticks([], [])
+    plt.legend([(a, b)], ["a and b"], loc=2, numpoints=1)
diff --git a/matplotlibrc.template b/matplotlibrc.template
@@ -416,6 +416,7 @@ backend      : $TEMPLATE_BACKEND
 ## Dimensions as fraction of fontsize:
 #legend.borderpad     : 0.4      ## border whitespace
 #legend.labelspacing  : 0.5      ## the vertical space between the legend entries
+#legend.scalehandlebox : True     ## whether or not to scale handlebox to fit handle
 #legend.handlelength  : 2.0      ## the length of the legend lines
 #legend.handleheight  : 0.7      ## the height of the legend handle
 #legend.handletextpad : 0.8      ## the space between the legend line and legend text