Merge pull request #19401 from anntzer/clip_line_to_rect

jklymak · web-flow · commit df667ba4973b · 2021-05-10T12:36:26.000-07:00
Simplify axisartist line clipping.
diff --git a/doc/api/next_api_changes/deprecations/19401-AL.rst b/doc/api/next_api_changes/deprecations/19401-AL.rst
@@ -0,0 +1,3 @@
+``mpl_toolkits.axisartist.clip_path`` is deprecated
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+... with no replacement.
diff --git a/lib/mpl_toolkits/axisartist/clip_path.py b/lib/mpl_toolkits/axisartist/clip_path.py
@@ -4,6 +4,9 @@
 import math
 
 
+_api.warn_deprecated("3.5", name=__name__, obj_type="module")
+
+
 def atan2(dy, dx):
     if dx == 0 and dy == 0:
         _api.warn_external("dx and dy are 0")
diff --git a/lib/mpl_toolkits/axisartist/grid_finder.py b/lib/mpl_toolkits/axisartist/grid_finder.py
@@ -2,7 +2,48 @@
 
 from matplotlib import ticker as mticker
 from matplotlib.transforms import Bbox, Transform
-from .clip_path import clip_line_to_rect
+
+
+def _find_line_box_crossings(xys, bbox):
+    """
+    Find the points where a polyline crosses a bbox, and the crossing angles.
+
+    Parameters
+    ----------
+    xys : (N, 2) array
+        The polyline coordinates.
+    bbox : `.Bbox`
+        The bounding box.
+
+    Returns
+    -------
+    list of ((float, float), float)
+        Four separate lists of crossings, for the left, right, bottom, and top
+        sides of the bbox, respectively.  For each list, the entries are the
+        ``((x, y), ccw_angle_in_degrees)`` of the crossing, where an angle of 0
+        means that the polyline is moving to the right at the crossing point.
+
+        The entries are computed by linearly interpolating at each crossing
+        between the nearest points on either side of the bbox edges.
+    """
+    crossings = []
+    dxys = xys[1:] - xys[:-1]
+    for sl in [slice(None), slice(None, None, -1)]:
+        us, vs = xys.T[sl]  # "this" coord, "other" coord
+        dus, dvs = dxys.T[sl]
+        umin, vmin = bbox.min[sl]
+        umax, vmax = bbox.max[sl]
+        for u0, inside in [(umin, us > umin), (umax, us < umax)]:
+            crossings.append([])
+            idxs, = (inside[:-1] ^ inside[1:]).nonzero()
+            for idx in idxs:
+                v = vs[idx] + (u0 - us[idx]) * dvs[idx] / dus[idx]
+                if not vmin <= v <= vmax:
+                    continue
+                crossing = (u0, v)[sl]
+                theta = np.degrees(np.arctan2(*dxys[idx][::-1]))
+                crossings[-1].append((crossing, theta))
+    return crossings
 
 
 class ExtremeFinderSimple:
@@ -161,14 +202,12 @@ def _clip_grid_lines_and_find_ticks(self, lines, values, levs, bb):
         tck_levels = gi["tick_levels"]
         tck_locs = gi["tick_locs"]
         for (lx, ly), v, lev in zip(lines, values, levs):
-            xy, tcks = clip_line_to_rect(lx, ly, bb)
-            if not xy:
-                continue
+            tcks = _find_line_box_crossings(np.column_stack([lx, ly]), bb)
             gi["levels"].append(v)
-            gi["lines"].append(xy)
+            gi["lines"].append([(lx, ly)])
 
             for tck, direction in zip(tcks,
-                                      ["left", "bottom", "right", "top"]):
+                                      ["left", "right", "bottom", "top"]):
                 for t in tck:
                     tck_levels[direction].append(lev)
                     tck_locs[direction].append(t)
diff --git a/lib/mpl_toolkits/tests/test_axisartist_clip_path.py b/lib/mpl_toolkits/tests/test_axisartist_clip_path.py
@@ -1,9 +1,12 @@
 import numpy as np
+
+from matplotlib import _api
 import matplotlib.pyplot as plt
 from matplotlib.testing.decorators import image_comparison
 from matplotlib.transforms import Bbox
 
-from mpl_toolkits.axisartist.clip_path import clip_line_to_rect
+with _api.suppress_matplotlib_deprecation_warning():
+    from mpl_toolkits.axisartist.clip_path import clip_line_to_rect
 
 
 @image_comparison(['clip_path.png'], style='default')
diff --git a/lib/mpl_toolkits/tests/test_axisartist_grid_finder.py b/lib/mpl_toolkits/tests/test_axisartist_grid_finder.py
@@ -1,6 +1,27 @@
+import numpy as np
+import pytest
+
+from matplotlib.transforms import Bbox
 from mpl_toolkits.axisartist.grid_finder import (
-    FormatterPrettyPrint,
-    MaxNLocator)
+    _find_line_box_crossings, FormatterPrettyPrint, MaxNLocator)
+
+
+def test_find_line_box_crossings():
+    x = np.array([-3, -2, -1, 0., 1, 2, 3, 2, 1, 0, -1, -2, -3, 5])
+    y = np.arange(len(x))
+    bbox = Bbox.from_extents(-2, 3, 2, 12.5)
+    left, right, bottom, top = _find_line_box_crossings(
+        np.column_stack([x, y]), bbox)
+    ((lx0, ly0), la0), ((lx1, ly1), la1), = left
+    ((rx0, ry0), ra0), ((rx1, ry1), ra1), = right
+    ((bx0, by0), ba0), = bottom
+    ((tx0, ty0), ta0), = top
+    assert (lx0, ly0, la0) == (-2, 11, 135)
+    assert (lx1, ly1, la1) == pytest.approx((-2., 12.125, 7.125016))
+    assert (rx0, ry0, ra0) == (2, 5, 45)
+    assert (rx1, ry1, ra1) == (2, 7, 135)
+    assert (bx0, by0, ba0) == (0, 3, 45)
+    assert (tx0, ty0, ta0) == pytest.approx((1., 12.5, 7.125016))
 
 
 def test_pretty_print_format():
diff --git a/lib/mpl_toolkits/tests/test_axisartist_grid_helper_curvelinear.py b/lib/mpl_toolkits/tests/test_axisartist_grid_helper_curvelinear.py
@@ -1,5 +1,4 @@
 import numpy as np
-import platform
 
 import matplotlib.pyplot as plt
 from matplotlib.path import Path
@@ -16,8 +15,7 @@
     GridHelperCurveLinear
 
 
-@image_comparison(['custom_transform.png'], style='default',
-                  tol=0.03 if platform.machine() == 'x86_64' else 0.04)
+@image_comparison(['custom_transform.png'], style='default', tol=0.2)
 def test_custom_transform():
     class MyTransform(Transform):
         input_dims = output_dims = 2
@@ -79,8 +77,7 @@ def inverted(self):
     ax1.grid(True)
 
 
-@image_comparison(['polar_box.png'], style='default',
-                  tol={'aarch64': 0.04}.get(platform.machine(), 0.03))
+@image_comparison(['polar_box.png'], style='default', tol=0.04)
 def test_polar_box():
     # Remove this line when this test image is regenerated.
     plt.rcParams['text.kerning_factor'] = 6
@@ -143,7 +140,7 @@ def test_polar_box():
     ax1.grid(True)
 
 
-@image_comparison(['axis_direction.png'], style='default', tol=0.03)
+@image_comparison(['axis_direction.png'], style='default', tol=0.07)
 def test_axis_direction():
     # Remove this line when this test image is regenerated.
     plt.rcParams['text.kerning_factor'] = 6

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+``mpl_toolkits.axisartist.clip_path`` is deprecated
	`2`	`+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`
	`3`	`+... with no replacement.`