44# See COPYING and COPYING.LESSER in the root of the repository for full
55# licensing details.
66
7-
7+ import matplotlib as mpl
88from matplotlib .contour import QuadContourSet
99import matplotlib .path as mpath
1010import numpy as np
11+ import packaging
1112
1213
1314class GeoContourSet (QuadContourSet ):
@@ -20,66 +21,91 @@ class GeoContourSet(QuadContourSet):
2021 # fiddling with instance.__class__.
2122
2223 def clabel (self , * args , ** kwargs ):
23- # nb: contour labelling does not work very well for filled
24- # contours - it is recommended to only label line contours.
25- # This is especially true when inline=True.
26-
27- # This wrapper exist because mpl does not properly transform
28- # paths. Instead it simply assumes one path represents one polygon
29- # (not necessarily the case), and it assumes that
30- # transform(path.verts) is equivalent to transform_path(path).
31- # Unfortunately there is no way to easily correct this error,
32- # so we are forced to pre-transform the ContourSet's paths from
33- # the source coordinate system to the axes' projection.
34- # The existing mpl code then has a much simpler job of handling
35- # pre-projected paths (which can now effectively be transformed
36- # naively).
37-
38- for col in self .collections :
39- # Snaffle the collection's path list. We will change the
40- # list in-place (as the contour label code does in mpl).
41- paths = col .get_paths ()
24+ if packaging .version .parse (mpl .__version__ ).release [:2 ] < (3 , 8 ):
25+ # nb: contour labelling does not work very well for filled
26+ # contours - it is recommended to only label line contours.
27+ # This is especially true when inline=True.
28+
29+ # This wrapper exist because mpl does not properly transform
30+ # paths. Instead it simply assumes one path represents one polygon
31+ # (not necessarily the case), and it assumes that
32+ # transform(path.verts) is equivalent to transform_path(path).
33+ # Unfortunately there is no way to easily correct this error,
34+ # so we are forced to pre-transform the ContourSet's paths from
35+ # the source coordinate system to the axes' projection.
36+ # The existing mpl code then has a much simpler job of handling
37+ # pre-projected paths (which can now effectively be transformed
38+ # naively).
39+
40+ for col in self .collections :
41+ # Snaffle the collection's path list. We will change the
42+ # list in-place (as the contour label code does in mpl).
43+ paths = col .get_paths ()
44+
45+ # Define the transform that will take us from collection
46+ # coordinates through to axes projection coordinates.
47+ data_t = self .axes .transData
48+ col_to_data = col .get_transform () - data_t
49+
50+ # Now that we have the transform, project all of this
51+ # collection's paths.
52+ new_paths = [col_to_data .transform_path (path )
53+ for path in paths ]
54+ new_paths = [path for path in new_paths
55+ if path .vertices .size >= 1 ]
56+
57+ # The collection will now be referenced in axes projection
58+ # coordinates.
59+ col .set_transform (data_t )
60+
61+ # Clear the now incorrectly referenced paths.
62+ del paths [:]
63+
64+ for path in new_paths :
65+ if path .vertices .size == 0 :
66+ # Don't persist empty paths. Let's get rid of them.
67+ continue
68+
69+ # Split the path if it has multiple MOVETO statements.
70+ codes = np .array (
71+ path .codes if path .codes is not None else [0 ])
72+ moveto = codes == mpath .Path .MOVETO
73+ if moveto .sum () <= 1 :
74+ # This is only one path, so add it to the collection.
75+ paths .append (path )
76+ else :
77+ # The first MOVETO doesn't need cutting-out.
78+ moveto [0 ] = False
79+ split_locs = np .flatnonzero (moveto )
80+
81+ split_verts = np .split (path .vertices , split_locs )
82+ split_codes = np .split (path .codes , split_locs )
83+
84+ for verts , codes in zip (split_verts , split_codes ):
85+ # Add this path to the collection's list of paths.
86+ paths .append (mpath .Path (verts , codes ))
87+
88+ else :
89+ # Where contour paths exist at the edge of the globe, sometimes a
90+ # complete path in data space will become multiple paths when
91+ # transformed into axes or screen space. Matplotlib's contour
92+ # labelling does not account for this so we need to give it the
93+ # pre-transformed paths to work with.
4294
4395 # Define the transform that will take us from collection
4496 # coordinates through to axes projection coordinates.
4597 data_t = self .axes .transData
46- col_to_data = col .get_transform () - data_t
98+ col_to_data = self .get_transform () - data_t
4799
48100 # Now that we have the transform, project all of this
49101 # collection's paths.
102+ paths = self .get_paths ()
50103 new_paths = [col_to_data .transform_path (path ) for path in paths ]
51- new_paths = [ path for path in new_paths if path . vertices . size >= 1 ]
104+ paths [:] = new_paths
52105
53106 # The collection will now be referenced in axes projection
54107 # coordinates.
55- col .set_transform (data_t )
56-
57- # Clear the now incorrectly referenced paths.
58- del paths [:]
59-
60- for path in new_paths :
61- if path .vertices .size == 0 :
62- # Don't persist empty paths. Let's get rid of them.
63- continue
64-
65- # Split the path if it has multiple MOVETO statements.
66- codes = np .array (
67- path .codes if path .codes is not None else [0 ])
68- moveto = codes == mpath .Path .MOVETO
69- if moveto .sum () <= 1 :
70- # This is only one path, so add it to the collection.
71- paths .append (path )
72- else :
73- # The first MOVETO doesn't need cutting-out.
74- moveto [0 ] = False
75- split_locs = np .flatnonzero (moveto )
76-
77- split_verts = np .split (path .vertices , split_locs )
78- split_codes = np .split (path .codes , split_locs )
79-
80- for verts , codes in zip (split_verts , split_codes ):
81- # Add this path to the collection's list of paths.
82- paths .append (mpath .Path (verts , codes ))
108+ self .set_transform (data_t )
83109
84110 # Now that we have prepared the collection paths, call on
85111 # through to the underlying implementation.
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