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Commit 13e3573

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bdicetimhoffm
bdice
and
timhoffm
authored
Add getters and _repr_html_ for over/under/bad values of Colormap objects. (#17900)
* Add get_bad, get_under, get_over. * Add missing docstring to is_gray. * Add under/over/bad colors to Colormap _repr_html_. Co-authored-by: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
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‎doc/users/next_whats_new/colormap_get_under_over_bad.rst

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+7Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,7 @@
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Get under/over/bad colors of Colormap objects
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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`matplotlib.colors.Colormap` now has methods
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`~.colors.Colormap.get_under`, `~.colors.Colormap.get_over`,
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`~.colors.Colormap.get_bad` for the colors used for out-of-range and masked
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values.

‎lib/matplotlib/colors.py

Copy file name to clipboardExpand all lines: lib/matplotlib/colors.py
+55-14Lines changed: 55 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -110,6 +110,8 @@ def __delitem__(self, key):
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_colors_full_map.update(BASE_COLORS)
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_colors_full_map = _ColorMapping(_colors_full_map)
112112

113+
_REPR_PNG_SIZE = (512, 64)
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def get_named_colors_mapping():
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"""Return the global mapping of names to named colors."""
@@ -607,26 +609,40 @@ def __copy__(self):
607609
cmapobject._global = False
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return cmapobject
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def get_bad(self):
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"""Get the color for masked values."""
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if not self._isinit:
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self._init()
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return self._lut[self._i_bad]
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610618
def set_bad(self, color='k', alpha=None):
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"""Set the color for masked values."""
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_warn_if_global_cmap_modified(self)
613621
self._rgba_bad = to_rgba(color, alpha)
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if self._isinit:
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self._set_extremes()
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def get_under(self):
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"""Get the color for low out-of-range values."""
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if not self._isinit:
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self._init()
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return self._lut[self._i_under]
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def set_under(self, color='k', alpha=None):
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"""
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Set the color for low out-of-range values when ``norm.clip = False``.
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"""
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"""Set the color for low out-of-range values."""
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_warn_if_global_cmap_modified(self)
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self._rgba_under = to_rgba(color, alpha)
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if self._isinit:
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self._set_extremes()
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def get_over(self):
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"""Get the color for high out-of-range values."""
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if not self._isinit:
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self._init()
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return self._lut[self._i_over]
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def set_over(self, color='k', alpha=None):
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"""
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Set the color for high out-of-range values when ``norm.clip = False``.
629-
"""
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"""Set the color for high out-of-range values."""
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_warn_if_global_cmap_modified(self)
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self._rgba_over = to_rgba(color, alpha)
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if self._isinit:
@@ -648,6 +664,7 @@ def _init(self):
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raise NotImplementedError("Abstract class only")
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def is_gray(self):
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"""Return whether the color map is grayscale."""
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if not self._isinit:
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self._init()
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return (np.all(self._lut[:, 0] == self._lut[:, 1]) and
@@ -678,8 +695,8 @@ def reversed(self, name=None):
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def _repr_png_(self):
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"""Generate a PNG representation of the Colormap."""
681-
IMAGE_SIZE = (400, 50)
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X = np.tile(np.linspace(0, 1, IMAGE_SIZE[0]), (IMAGE_SIZE[1], 1))
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X = np.tile(np.linspace(0, 1, _REPR_PNG_SIZE[0]),
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(_REPR_PNG_SIZE[1], 1))
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pixels = self(X, bytes=True)
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png_bytes = io.BytesIO()
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title = self.name + ' color map'
@@ -696,12 +713,36 @@ def _repr_html_(self):
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"""Generate an HTML representation of the Colormap."""
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png_bytes = self._repr_png_()
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png_base64 = base64.b64encode(png_bytes).decode('ascii')
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return ('<strong>' + self.name + '</strong>' +
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'<img ' +
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'alt="' + self.name + ' color map" ' +
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'title="' + self.name + '"' +
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'style="border: 1px solid #555;" ' +
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'src="data:image/png;base64,' + png_base64 + '">')
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def color_block(color):
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hex_color = to_hex(color, keep_alpha=True)
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return (f'<div title="{hex_color}" '
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'style="display: inline-block; '
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'width: 1em; height: 1em; '
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'margin: 0; '
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'vertical-align: middle; '
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'border: 1px solid #555; '
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f'background-color: {hex_color};"></div>')
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return ('<div style="vertical-align: middle;">'
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f'<strong>{self.name}</strong> '
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'</div>'
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'<div class="cmap"><img '
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f'alt="{self.name} color map" '
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f'title="{self.name}" '
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'style="border: 1px solid #555;" '
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f'src="data:image/png;base64,{png_base64}"></div>'
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'<div style="vertical-align: middle; '
735+
f'max-width: {_REPR_PNG_SIZE[0]+2}px; '
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'display: flex; justify-content: space-between;">'
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'<div style="float: left;">'
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f'{color_block(self.get_under())} under'
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'</div>'
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'<div style="margin: 0 auto; display: inline-block;">'
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f'bad {color_block(self.get_bad())}'
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'</div>'
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'<div style="float: right;">'
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f'over {color_block(self.get_over())}'
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'</div>')
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707748
class LinearSegmentedColormap(Colormap):

‎lib/matplotlib/tests/test_colors.py

Copy file name to clipboardExpand all lines: lib/matplotlib/tests/test_colors.py
+19Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5,6 +5,7 @@
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import numpy as np
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from PIL import Image
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import pytest
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import base64
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from numpy.testing import assert_array_equal, assert_array_almost_equal
1011

@@ -303,6 +304,9 @@ def test_BoundaryNorm():
303304
cmref.set_under('white')
304305
cmshould = mcolors.ListedColormap(['white', 'blue', 'red', 'black'])
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307+
assert mcolors.same_color(cmref.get_over(), 'black')
308+
assert mcolors.same_color(cmref.get_under(), 'white')
309+
306310
refnorm = mcolors.BoundaryNorm(bounds, cmref.N)
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mynorm = mcolors.BoundaryNorm(bounds, cmshould.N, extend='both')
308312
assert mynorm.vmin == refnorm.vmin
@@ -323,6 +327,8 @@ def test_BoundaryNorm():
323327
cmref.set_under('white')
324328
cmshould = mcolors.ListedColormap(['white', 'blue', 'red'])
325329

330+
assert mcolors.same_color(cmref.get_under(), 'white')
331+
326332
assert cmref.N == 2
327333
assert cmshould.N == 3
328334
refnorm = mcolors.BoundaryNorm(bounds, cmref.N)
@@ -339,6 +345,8 @@ def test_BoundaryNorm():
339345
cmref.set_over('black')
340346
cmshould = mcolors.ListedColormap(['blue', 'red', 'black'])
341347

348+
assert mcolors.same_color(cmref.get_over(), 'black')
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342350
assert cmref.N == 2
343351
assert cmshould.N == 3
344352
refnorm = mcolors.BoundaryNorm(bounds, cmref.N)
@@ -1155,4 +1163,15 @@ def test_repr_html():
11551163
cmap = plt.get_cmap('viridis')
11561164
html = cmap._repr_html_()
11571165
assert len(html) > 0
1166+
png = cmap._repr_png_()
1167+
assert base64.b64encode(png).decode('ascii') in html
11581168
assert cmap.name in html
1169+
assert html.startswith('<div')
1170+
assert html.endswith('</div>')
1171+
1172+
1173+
def test_get_under_over_bad():
1174+
cmap = plt.get_cmap('viridis')
1175+
assert_array_equal(cmap.get_under(), cmap(-np.inf))
1176+
assert_array_equal(cmap.get_over(), cmap(np.inf))
1177+
assert_array_equal(cmap.get_bad(), cmap(np.nan))

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