Added rcount/ccount to plot_surface(), providing an alternative to rs…

…tride/cstride

doc/users/whats_new/plot_surface.rst

@@ -0,0 +1,15 @@
+`rcount` and `ccount` for `plot_surface()`
+------------------------------------------
+
+As of v2.0, mplot3d's :func:`~mpl_toolkits.mplot3d.axes3d.plot_surface` now
+accepts `rcount` and `ccount` arguments for controlling the sampling of the
+input data for plotting. These arguments specify the maximum number of
+evenly spaced samples to take from the input data. These arguments are
+also the new default sampling method for the function, and is
+considered a style change.
+
+The old `rstride` and `cstride` arguments, which specified the size of the
+evenly spaced samples, become the default when 'classic' mode is invoked,
+and are still available for use. There are no plans for deprecating these
+arguments.
+

examples/mplot3d/surface3d_demo.py

@@ -28,7 +28,7 @@
 Z = np.sin(R)
 
 # Plot the surface.
-surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=cm.coolwarm,
+surf = ax.plot_surface(X, Y, Z, cmap=cm.coolwarm,
                        linewidth=0, antialiased=False)
 
 # Customize the z axis.

examples/mplot3d/surface3d_demo2.py

@@ -22,6 +22,6 @@
 z = 10 * np.outer(np.ones(np.size(u)), np.cos(v))
 
 # Plot the surface
-ax.plot_surface(x, y, z, rstride=4, cstride=4, color='b')
+ax.plot_surface(x, y, z, color='b')
 
 plt.show()

examples/mplot3d/surface3d_demo3.py

@@ -34,8 +34,7 @@
         colors[x, y] = colortuple[(x + y) % len(colortuple)]
 
 # Plot the surface with face colors taken from the array we made.
-surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, facecolors=colors,
-                       linewidth=0)
+surf = ax.plot_surface(X, Y, Z, facecolors=colors, linewidth=0)
 
 # Customize the z axis.
 ax.set_zlim(-1, 1)

examples/mplot3d/surface3d_radial_demo.py

@@ -28,7 +28,7 @@
 X, Y = R*np.cos(P), R*np.sin(P)
 
 # Plot the surface.
-ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=plt.cm.YlGnBu_r)
+ax.plot_surface(X, Y, Z, cmap=plt.cm.YlGnBu_r)
 
 # Tweak the limits and add latex math labels.
 ax.set_zlim(0, 1)

lib/mpl_toolkits/mplot3d/axes3d.py

@@ -1553,15 +1553,28 @@ def plot_surface(self, X, Y, Z, *args, **kwargs):
 
         The `rstride` and `cstride` kwargs set the stride used to
         sample the input data to generate the graph.  If 1k by 1k
-        arrays are passed in the default values for the strides will
-        result in a 100x100 grid being plotted.
+        arrays are passed in, the default values for the strides will
+        result in a 100x100 grid being plotted. Defaults to 10.
+        Raises a ValueError if both stride and count kwargs
+        (see next section) are provided.
+
+        The `rcount` and `ccount` kwargs supersedes `rstride` and
+        `cstride` for default sampling method for surface plotting.
+        These arguments will determine at most how many evenly spaced
+        samples will be taken from the input data to generate the graph.
+        This is the default sampling method unless using the 'classic'
+        style. Will raise ValueError if both stride and count are
+        specified.
+        Added in v2.0.0.
 
         ============= ================================================
         Argument      Description
         ============= ================================================
         *X*, *Y*, *Z* Data values as 2D arrays
-        *rstride*     Array row stride (step size), defaults to 10
-        *cstride*     Array column stride (step size), defaults to 10
+        *rstride*     Array row stride (step size)
+        *cstride*     Array column stride (step size)
+        *rcount*      Use at most this many rows, defaults to 50
+        *ccount*      Use at most this many columns, defaults to 50
         *color*       Color of the surface patches
         *cmap*        A colormap for the surface patches.
         *facecolors*  Face colors for the individual patches
@@ -1582,8 +1595,30 @@ def plot_surface(self, X, Y, Z, *args, **kwargs):
         X, Y, Z = np.broadcast_arrays(X, Y, Z)
         rows, cols = Z.shape
 
+        has_stride = 'rstride' in kwargs or 'cstride' in kwargs
+        has_count = 'rcount' in kwargs or 'ccount' in kwargs
+
+        if has_stride and has_count:
+            raise ValueError("Cannot specify both stride and count arguments")
+
         rstride = kwargs.pop('rstride', 10)
         cstride = kwargs.pop('cstride', 10)
+        rcount = kwargs.pop('rcount', 50)
+        ccount = kwargs.pop('ccount', 50)
+
+        if rcParams['_internal.classic_mode']:
+            # Strides have priority over counts in classic mode.
+            # So, only compute strides from counts
+            # if counts were explicitly given
+            if has_count:
+                rstride = int(np.ceil(rows / rcount))
+                cstride = int(np.ceil(cols / ccount))
+        else:
+            # If the strides are provided then it has priority.
+            # Otherwise, compute the strides from the counts.
+            if not has_stride:
+                rstride = int(np.ceil(rows / rcount))
+                cstride = int(np.ceil(cols / ccount))
 
         if 'facecolors' in kwargs:
             fcolors = kwargs.pop('facecolors')
@@ -1733,7 +1768,21 @@ def plot_wireframe(self, X, Y, Z, *args, **kwargs):
         The `rstride` and `cstride` kwargs set the stride used to
         sample the input data to generate the graph. If either is 0
         the input data in not sampled along this direction producing a
-        3D line plot rather than a wireframe plot.
+        3D line plot rather than a wireframe plot. The stride arguments
+        are only used by default if in the 'classic' mode. They are
+        now superseded by `rcount` and `ccount`. Will raise ValueError
+        if both stride and count are used.
+
+`       The `rcount` and `ccount` kwargs supersedes `rstride` and
+        `cstride` for default sampling method for wireframe plotting.
+        These arguments will determine at most how many evenly spaced
+        samples will be taken from the input data to generate the graph.
+        This is the default sampling method unless using the 'classic'
+        style. Will raise ValueError if both stride and count are
+        specified. If either is zero, then the input data is not sampled
+        along this direction, producing a 3D line plot rather than a
+        wireframe plot.
+        Added in v2.0.0.
 
         ==========  ================================================
         Argument    Description
@@ -1742,6 +1791,8 @@ def plot_wireframe(self, X, Y, Z, *args, **kwargs):
         *Z*
         *rstride*   Array row stride (step size), defaults to 1
         *cstride*   Array column stride (step size), defaults to 1
+        *rcount*    Use at most this many rows, defaults to 50
+        *ccount*    Use at most this many columns, defaults to 50
         ==========  ================================================
 
         Keyword arguments are passed on to
@@ -1750,15 +1801,37 @@ def plot_wireframe(self, X, Y, Z, *args, **kwargs):
         Returns a :class:`~mpl_toolkits.mplot3d.art3d.Line3DCollection`
         '''
 
-        rstride = kwargs.pop("rstride", 1)
-        cstride = kwargs.pop("cstride", 1)
-
         had_data = self.has_data()
         Z = np.atleast_2d(Z)
         # FIXME: Support masked arrays
         X, Y, Z = np.broadcast_arrays(X, Y, Z)
         rows, cols = Z.shape
 
+        has_stride = 'rstride' in kwargs or 'cstride' in kwargs
+        has_count = 'rcount' in kwargs or 'ccount' in kwargs
+
+        if has_stride and has_count:
+            raise ValueError("Cannot specify both stride and count arguments")
+
+        rstride = kwargs.pop('rstride', 1)
+        cstride = kwargs.pop('cstride', 1)
+        rcount = kwargs.pop('rcount', 50)
+        ccount = kwargs.pop('ccount', 50)
+
+        if rcParams['_internal.classic_mode']:
+            # Strides have priority over counts in classic mode.
+            # So, only compute strides from counts
+            # if counts were explicitly given
+            if has_count:
+                rstride = int(np.ceil(rows / rcount)) if rcount else 0
+                cstride = int(np.ceil(cols / ccount)) if ccount else 0
+        else:
+            # If the strides are provided then it has priority.
+            # Otherwise, compute the strides from the counts.
+            if not has_stride:
+                rstride = int(np.ceil(rows / rcount)) if rcount else 0
+                cstride = int(np.ceil(cols / ccount)) if ccount else 0
+
         # We want two sets of lines, one running along the "rows" of
         # Z and another set of lines running along the "columns" of Z.
         # This transpose will make it easy to obtain the columns.

lib/mpl_toolkits/tests/test_mplot3d.py

@@ -105,7 +105,7 @@ def f(t):
     R = np.sqrt(X ** 2 + Y ** 2)
     Z = np.sin(R)
 
-    surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1,
+    surf = ax.plot_surface(X, Y, Z, rcount=40, ccount=40,
                            linewidth=0, antialiased=False)
 
     ax.set_zlim3d(-1, 1)
@@ -141,7 +141,7 @@ def test_surface3d():
     X, Y = np.meshgrid(X, Y)
     R = np.sqrt(X ** 2 + Y ** 2)
     Z = np.sin(R)
-    surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=cm.coolwarm,
+    surf = ax.plot_surface(X, Y, Z, rcount=40, ccount=40, cmap=cm.coolwarm,
                            lw=0, antialiased=False)
     ax.set_zlim(-1.01, 1.01)
     fig.colorbar(surf, shrink=0.5, aspect=5)
@@ -194,7 +194,7 @@ def test_wireframe3d():
     fig = plt.figure()
     ax = fig.add_subplot(111, projection='3d')
     X, Y, Z = axes3d.get_test_data(0.05)
-    ax.plot_wireframe(X, Y, Z, rstride=10, cstride=10)
+    ax.plot_wireframe(X, Y, Z, rcount=13, ccount=13)
 
 
 @image_comparison(baseline_images=['wireframe3dzerocstride'], remove_text=True,
@@ -203,7 +203,7 @@ def test_wireframe3dzerocstride():
     fig = plt.figure()
     ax = fig.add_subplot(111, projection='3d')
     X, Y, Z = axes3d.get_test_data(0.05)
-    ax.plot_wireframe(X, Y, Z, rstride=10, cstride=0)
+    ax.plot_wireframe(X, Y, Z, rcount=13, ccount=0)
 
 
 @image_comparison(baseline_images=['wireframe3dzerorstride'], remove_text=True,
@@ -214,6 +214,7 @@ def test_wireframe3dzerorstride():
     X, Y, Z = axes3d.get_test_data(0.05)
     ax.plot_wireframe(X, Y, Z, rstride=0, cstride=10)
 
+
 @cleanup
 def test_wireframe3dzerostrideraises():
     fig = plt.figure()
@@ -222,6 +223,18 @@ def test_wireframe3dzerostrideraises():
     with assert_raises(ValueError):
         ax.plot_wireframe(X, Y, Z, rstride=0, cstride=0)
 
+
+@cleanup
+def test_mixedsamplesraises():
+    fig = plt.figure()
+    ax = fig.add_subplot(111, projection='3d')
+    X, Y, Z = axes3d.get_test_data(0.05)
+    with assert_raises(ValueError):
+        ax.plot_wireframe(X, Y, Z, rstride=10, ccount=50)
+    with assert_raises(ValueError):
+        ax.plot_surface(X, Y, Z, cstride=50, rcount=10)
+
+
 @image_comparison(baseline_images=['quiver3d'], remove_text=True)
 def test_quiver3d():
     fig = plt.figure()