@@ -753,6 +753,212 @@ def text(self, x, y, s, fontdict=None, **kwargs):
753753 self ._add_text (t )
754754 return t
755755
756+ def label_lines (self , * args , ** kwargs ):
757+ """
758+ Place labels at the end of lines on the chart.
759+
760+ Call signatures::
761+
762+ label_lines()
763+ label_lines(labels)
764+ label_lines(handles, labels)
765+
766+ The call signatures correspond to three different ways of how to use
767+ this method.
768+
769+ The simplest way to use line_labels is without parameters. After the
770+ lines are created with their labels, the user can call this function
771+ which automatically applies the stored labels by the corresponding
772+ lines. This would be most effectively used after the complete creation
773+ of the line chart.
774+
775+ The second way to call this method is by specifying the first parameter
776+ which is labels. In doing so you would be able to name the lines if
777+ they lack names, or rename them as needed. This process occurs in the
778+ order in which the lines were added to the chart.
779+
780+ The Final way to use this method is specifying both the handles and the
781+ labels. In doing so you can specify names for select lines leaving the
782+ rest blank. This would be useful when users would want to specify
783+ select pieces of data to monitor when data clumps occur.
784+
785+ Parameters
786+ ----------
787+ handles : sequence of `.Artist`, optional
788+ A list of Artists (lines) to be added to the line labels.
789+ Use this together with *labels*, if you need full control on what
790+ is shown in the line labels and the automatic mechanism described
791+ above is not sufficient.
792+
793+ The length of handles and labels should be the same in this
794+ case. If they are not, they are truncated to the smaller length.
795+
796+ labels : list of str, optional
797+ A list of labels to show next to the artists.
798+ Use this together with *handles*, if you need full control on what
799+ is shown in the line labels and the automatic mechanism described
800+ above is not sufficient.
801+
802+ Returns
803+ -------
804+ None
805+
806+ Notes
807+ -----
808+ Only line handles are supported by this method.
809+
810+ Examples
811+ --------
812+ .. plot:: gallery/text_labels_and_annotations/label_lines.py
813+ """
814+ handles , labels , extra_args , kwargs = mlegend ._parse_legend_args (
815+ [self ],
816+ * args ,
817+ ** kwargs )
818+ if len (extra_args ):
819+ raise TypeError (
820+ 'label_lines only accepts two nonkeyword arguments' )
821+
822+ self ._line_labels = []
823+
824+ def get_last_data_point (handle ):
825+ last_x = handle .get_xdata ()[- 1 ]
826+ last_y = handle .get_ydata ()[- 1 ]
827+ return last_x , last_y
828+
829+ # Get last data point for each handle
830+ xys = np .array ([get_last_data_point (x ) for x in handles ])
831+
832+ # Find the largest last x and y value
833+ data_maxx , data_maxy = np .max (xys , axis = 0 )
834+ # Find the smallest last y value
835+ data_miny = np .min (xys , axis = 0 )[1 ]
836+
837+ # Get the figure width and height in pixels
838+ fig_dpi_transform = self .figure .dpi_scale_trans .inverted ()
839+ fig_bbox = self .get_window_extent ().transformed (fig_dpi_transform )
840+ fig_width_px = fig_bbox .width * self .figure .dpi
841+ fig_height_px = fig_bbox .height * self .figure .dpi
842+
843+ # Get the figure width and height in points
844+ fig_minx , fig_maxx = self .get_xbound ()
845+ fig_miny , fig_maxy = self .get_ybound ()
846+ fig_width_pt = abs (fig_maxx - fig_minx )
847+ fig_height_pt = abs (fig_maxy - fig_miny )
848+
849+ # Space to the left of the text converted from pixels
850+ margin_left = 8 * (fig_width_pt / fig_width_px )
851+ # Space to the top and bottom of the text converted from pixels
852+ margin_vertical = 2 * (fig_height_pt / fig_height_px )
853+
854+ text_fontsize = 10
855+ # Height of the text converted from pixels
856+ text_height = text_fontsize * (fig_height_pt / fig_height_px )
857+
858+ # Height of each bucket
859+ bucket_height = text_height + 2 * margin_vertical
860+ # Total number of buckets
861+ buckets_total = 1 + int ((fig_maxy - fig_miny - text_height ) /
862+ bucket_height )
863+ # Bit array to track which buckets are used
864+ buckets_map = 0
865+
866+ def get_bucket_index (y ):
867+ return int ((y - fig_miny ) / bucket_height )
868+
869+ # How many text SHOULD be in this bucket
870+ bucket_densities = [0 ] * buckets_total
871+ for xy in xys :
872+ data_x , data_y = xy
873+ ideal_bucket = get_bucket_index (data_y )
874+ if ideal_bucket >= 0 and ideal_bucket < buckets_total :
875+ bucket_densities [ideal_bucket ] += 1
876+
877+ def in_viewport (args ):
878+ xy = args [2 ]
879+ x , y = xy
880+ return fig_minx < x < fig_maxx and fig_miny < y < fig_maxy
881+
882+ def by_y (args ):
883+ xy = args [2 ]
884+ x , y = xy
885+ return y
886+
887+ bucket_offset = None
888+ prev_ideal_bucket = - 1
889+ # Iterate over all the handles, labels, and xy data sorted by y asc
890+ for handle , label , xy in sorted (filter (in_viewport ,
891+ zip (handles , labels , xys )),
892+ key = by_y ):
893+ data_x , data_y = xy
894+
895+ ideal_bucket = get_bucket_index (data_y )
896+ if ideal_bucket != prev_ideal_bucket :
897+ # If a bucket is dense, then we want to center the text around
898+ # the bucket. SSo, find out how many empty buckets there are
899+ # below the current bucket
900+ bucket_density = bucket_densities [ideal_bucket ]
901+ ideal_offset = bucket_density // 2
902+ empty_buckets_below = 0
903+ for i in range (ideal_bucket + 1 ,
904+ ideal_bucket - ideal_offset + 1 ,
905+ - 1 ):
906+ # If reached bottom or bucket is not empty
907+ if i == 0 or buckets_map & (1 << i ) == 1 :
908+ break
909+ empty_buckets_below += 1
910+ bucket_offset = - min (ideal_offset , empty_buckets_below )
911+ prev_ideal_bucket = ideal_bucket
912+
913+ bucket = ideal_bucket + bucket_offset
914+ text_x , text_y = None , None
915+
916+ # Find the nearest empty bucket
917+ for index in range (buckets_total ):
918+ # 0 <= bucket_index <= buckets_total
919+ bucket_index = max (0 , min (bucket + index , buckets_total ))
920+ bucket_mask = 1 << bucket_index
921+ # If this bucket is empty
922+ if buckets_map & bucket_mask == 0 :
923+ # Mark this bucket as used
924+ buckets_map |= bucket_mask
925+ text_x = data_maxx + margin_left
926+ text_y = bucket_index * bucket_height + fig_miny
927+ break
928+
929+ # If a bucket was found for the text
930+ if text_x is not None and text_y is not None :
931+ text_color = handle .get_color ()
932+ line_label = self .annotate (label , (data_maxx , data_y ),
933+ xytext = (text_x , text_y ),
934+ fontsize = text_fontsize ,
935+ color = text_color ,
936+ annotation_clip = True )
937+ self ._line_labels .append (line_label )
938+
939+ # A bucket is not necessarily aligned with the data point
940+ # If space allows, center the text around the data point
941+ # TODO(omarchehab98): group fuzzing
942+ # for line_label in self._line_labels:
943+ # datax, datay = line_label.xy
944+ # targety = datay - text_height / 2
945+ # textx, texty = line_label.get_position()
946+ # direction = 1 if targety > texty else -1
947+ # target_bucket = get_bucket_index(targety) + direction
948+ # if (get_bucket_index(targety) == get_bucket_index(texty) and
949+ # (target_bucket == -1 or
950+ # buckets_map & (1 << target_bucket) == 0)):
951+ # line_label.set_position((textx, targety))
952+
953+ def has_label_lines (self ):
954+ return self ._line_labels is not None
955+
956+ def refresh_label_lines (self , * args , ** kwargs ):
957+ for label in self ._line_labels :
958+ label .remove ()
959+ self ._line_labels = None
960+ self .label_lines (* args , ** kwargs )
961+
756962 @cbook ._rename_parameter ("3.3" , "s" , "text" )
757963 @docstring .dedent_interpd
758964 def annotate (self , text , xy , * args , ** kwargs ):
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