diff --git a/examples/pylab_examples/tripcolor_demo.py b/examples/pylab_examples/tripcolor_demo.py
index 0817c63c53b1..f97910af7d89 100644
--- a/examples/pylab_examples/tripcolor_demo.py
+++ b/examples/pylab_examples/tripcolor_demo.py
@@ -32,19 +32,19 @@
mask = np.where(xmid*xmid + ymid*ymid < min_radius*min_radius, 1, 0)
triang.set_mask(mask)
-# pcolor plot.
+# tripcolor plot.
plt.figure()
plt.gca().set_aspect('equal')
plt.tripcolor(triang, z, shading='flat', cmap=plt.cm.rainbow)
plt.colorbar()
-plt.title('tripcolor of Delaunay triangulation: flat')
+plt.title('tripcolor of Delaunay triangulation, flat shading')
# Illustrate Gouraud shading.
plt.figure()
plt.gca().set_aspect('equal')
plt.tripcolor(triang, z, shading='gouraud', cmap=plt.cm.rainbow)
plt.colorbar()
-plt.title('tripcolor with Gouraud shading')
+plt.title('tripcolor of Delaunay triangulation, gouraud shading')
# You can specify your own triangulation rather than perform a Delaunay
@@ -70,9 +70,6 @@
[-0.057,0.916],[-0.025,0.933],[-0.077,0.990],[-0.059,0.993] ])
x = xy[:,0]*180/3.14159
y = xy[:,1]*180/3.14159
-x0 = -5
-y0 = 52
-z = np.exp(-0.01*( (x-x0)*(x-x0) + (y-y0)*(y-y0) ))
triangles = np.asarray([
[67,66, 1],[65, 2,66],[ 1,66, 2],[64, 2,65],[63, 3,64],[60,59,57],
@@ -90,14 +87,21 @@
[32,31,33],[39,38,72],[33,72,38],[33,38,34],[37,35,38],[34,38,35],
[35,37,36] ])
+xmid = x[triangles].mean(axis=1)
+ymid = y[triangles].mean(axis=1)
+x0 = -5
+y0 = 52
+zfaces = np.exp(-0.01*( (xmid-x0)*(xmid-x0) + (ymid-y0)*(ymid-y0) ))
+
# Rather than create a Triangulation object, can simply pass x, y and triangles
# arrays to tripcolor directly. It would be better to use a Triangulation object
# if the same triangulation was to be used more than once to save duplicated
# calculations.
+# Can specify one color value per face rather than one per point by using the
+# facecolors kwarg.
plt.figure()
plt.gca().set_aspect('equal')
-plt.tripcolor(x, y, triangles, z, shading='flat', edgecolors='k',
- cmap='summer')
+plt.tripcolor(x, y, triangles, facecolors=zfaces, edgecolors='k')
plt.colorbar()
plt.title('tripcolor of user-specified triangulation')
plt.xlabel('Longitude (degrees)')
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 3860b031e319..312d30a76f43 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -1021,6 +1021,7 @@ def tk_window_focus():
'matplotlib.tests.test_legend',
'matplotlib.tests.test_colorbar',
'matplotlib.tests.test_patches',
+ 'matplotlib.tests.test_triangulation'
]
def test(verbosity=1):
diff --git a/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.pdf b/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.pdf
new file mode 100644
index 000000000000..ac2c3873949c
Binary files /dev/null and b/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.pdf differ
diff --git a/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.png b/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.png
new file mode 100644
index 000000000000..1e5e83701ffb
Binary files /dev/null and b/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.png differ
diff --git a/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.svg b/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.svg
new file mode 100644
index 000000000000..f9196f76c987
--- /dev/null
+++ b/lib/matplotlib/tests/baseline_images/test_triangulation/tripcolor1.svg
@@ -0,0 +1,1229 @@
+
+
+
+
diff --git a/lib/matplotlib/tests/test_triangulation.py b/lib/matplotlib/tests/test_triangulation.py
index 52279758e074..81f922a0b225 100644
--- a/lib/matplotlib/tests/test_triangulation.py
+++ b/lib/matplotlib/tests/test_triangulation.py
@@ -1,8 +1,10 @@
import numpy as np
+import matplotlib.pyplot as plt
import matplotlib.tri as mtri
import matplotlib.delaunay as mdel
from nose.tools import assert_equal
from numpy.testing import assert_array_equal, assert_array_almost_equal
+from matplotlib.testing.decorators import image_comparison
def test_delaunay():
# No duplicate points.
@@ -94,3 +96,29 @@ def test_delaunay_duplicate_points():
mpl_triang.edges)
assert_array_equal(del_triang.edge_db, converted_indices)
+@image_comparison(baseline_images=['tripcolor1'])
+def test_tripcolor():
+ x = np.asarray([0, 0.5, 1, 0, 0.5, 1, 0, 0.5, 1, 0.75])
+ y = np.asarray([0, 0, 0, 0.5, 0.5, 0.5, 1, 1, 1, 0.75])
+ triangles = np.asarray([
+ [0, 1, 3], [1, 4, 3],
+ [1, 2, 4], [2, 5, 4],
+ [3, 4, 6], [4, 7, 6],
+ [4, 5, 9], [7, 4, 9], [8, 7, 9], [5, 8, 9] ])
+
+ # Triangulation with same number of points and triangles.
+ triang = mtri.Triangulation(x, y, triangles)
+
+ Cpoints = x + 0.5*y
+
+ xmid = x[triang.triangles].mean(axis=1)
+ ymid = y[triang.triangles].mean(axis=1)
+ Cfaces = 0.5*xmid + ymid
+
+ plt.subplot(121)
+ plt.tripcolor(triang, Cpoints, edgecolors='k')
+ plt.title('point colors')
+
+ plt.subplot(122)
+ plt.tripcolor(triang, facecolors=Cfaces, edgecolors='k')
+ plt.title('facecolors')
diff --git a/lib/matplotlib/tri/tripcolor.py b/lib/matplotlib/tri/tripcolor.py
index aaf7896be39d..b65290bcaa6a 100644
--- a/lib/matplotlib/tri/tripcolor.py
+++ b/lib/matplotlib/tri/tripcolor.py
@@ -28,12 +28,20 @@ def tripcolor(ax, *args, **kwargs):
:class:`~matplotlib.tri.Triangulation` for a explanation of these
possibilities.
- The next argument must be *C*, the array of color values, one per
- point in the triangulation.
-
- *shading* may be 'flat', 'faceted' or 'gouraud'. If *shading* is
- 'flat' or 'faceted', the colors used for each triangle are from
- the mean C of the triangle's three points.
+ The next argument must be *C*, the array of color values, either
+ one per point in the triangulation if color values are defined at
+ points, or one per triangle in the triangulation if color values
+ are defined at triangles. If there are the same number of points
+ and triangles in the triangulation it is assumed that color
+ values are defined at points; to force the use of color values at
+ triangles use the kwarg *facecolors*=C instead of just *C*.
+
+ *shading* may be 'flat' (the default) or 'gouraud'. If *shading*
+ is 'flat' and C values are defined at points, the color values
+ used for each triangle are from the mean C of the triangle's
+ three points. If *shading* is 'gouraud' then color values must be
+ defined at points. *shading* of 'faceted' is deprecated;
+ please use *edgecolors* instead.
The remaining kwargs are the same as for
:meth:`~matplotlib.axes.Axes.pcolor`.
@@ -50,35 +58,78 @@ def tripcolor(ax, *args, **kwargs):
vmin = kwargs.pop('vmin', None)
vmax = kwargs.pop('vmax', None)
shading = kwargs.pop('shading', 'flat')
+ facecolors = kwargs.pop('facecolors', None)
tri, args, kwargs = Triangulation.get_from_args_and_kwargs(*args, **kwargs)
- x = tri.x
- y = tri.y
- triangles = tri.get_masked_triangles()
- C = np.asarray(args[0])
- if C.shape != x.shape:
- raise ValueError('C array must have same length as triangulation x and'
- ' y arrays')
+ # C is the colors array, defined at either points or faces (i.e. triangles).
+ # If facecolors is None, C are defined at points.
+ # If facecolors is not None, C are defined at faces.
+ if facecolors is not None:
+ C = facecolors
+ else:
+ C = np.asarray(args[0])
+
+ # If there are a different number of points and triangles in the
+ # triangulation, can omit facecolors kwarg as it is obvious from
+ # length of C whether it refers to points or faces.
+ # Do not do this for gouraud shading.
+ if (facecolors is None and len(C) == len(tri.triangles) and
+ len(C) != len(tri.x) and shading != 'gouraud'):
+ facecolors = C
+
+ # Check length of C is OK.
+ if ( (facecolors is None and len(C) != len(tri.x)) or
+ (facecolors is not None and len(C) != len(tri.triangles)) ):
+ raise ValueError('Length of color values array must be the same '
+ 'as either the number of triangulation points '
+ 'or triangles')
+
+
+ # Handling of linewidths, shading, edgecolors and antialiased as
+ # in Axes.pcolor
+ linewidths = (0.25,)
+ if 'linewidth' in kwargs:
+ kwargs['linewidths'] = kwargs.pop('linewidth')
+ kwargs.setdefault('linewidths', linewidths)
+
+ if shading == 'faceted': # Deprecated.
+ edgecolors = 'k',
+ else:
+ edgecolors = 'none'
+ if 'edgecolor' in kwargs:
+ kwargs['edgecolors'] = kwargs.pop('edgecolor')
+ ec = kwargs.setdefault('edgecolors', edgecolors)
+
+ if 'antialiased' in kwargs:
+ kwargs['antialiaseds'] = kwargs.pop('antialiased')
+ if 'antialiaseds' not in kwargs and ec.lower() == "none":
+ kwargs['antialiaseds'] = False
+
if shading == 'gouraud':
+ if facecolors is not None:
+ raise ValueError('Gouraud shading does not support the use '
+ 'of facecolors kwarg')
+ if len(C) != len(tri.x):
+ raise ValueError('For gouraud shading, the length of color '
+ 'values array must be the same as the '
+ 'number of triangulation points')
collection = TriMesh(tri, **kwargs)
else:
- if shading == 'faceted':
- edgecolors = (0,0,0,1),
- linewidths = (0.25,)
- else:
- edgecolors = 'face'
- linewidths = (1.0,)
- kwargs.setdefault('edgecolors', edgecolors)
- kwargs.setdefault('antialiaseds', (0,))
- kwargs.setdefault('linewidths', linewidths)
-
# Vertices of triangles.
- verts = np.concatenate((x[triangles][...,np.newaxis],
- y[triangles][...,np.newaxis]), axis=2)
- # Color values, one per triangle, mean of the 3 vertex color values.
- C = C[triangles].mean(axis=1)
+ maskedTris = tri.get_masked_triangles()
+ verts = np.concatenate((tri.x[maskedTris][...,np.newaxis],
+ tri.y[maskedTris][...,np.newaxis]), axis=2)
+
+ # Color values.
+ if facecolors is None:
+ # One color per triangle, the mean of the 3 vertex color values.
+ C = C[maskedTris].mean(axis=1)
+ elif tri.mask is not None:
+ # Remove color values of masked triangles.
+ C = C.compress(1-tri.mask)
+
collection = PolyCollection(verts, **kwargs)
collection.set_alpha(alpha)
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