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ayshihayshih
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Remove the forced disabling of antialiasing in contourf/pcolormesh/pcolor
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4 files changed

Lines changed: 32 additions & 32 deletions

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‎doc/api/next_api_changes/behavior/32256-AYS.rst‎

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@@ -0,0 +1,7 @@
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Better antialiasing default for a few methods
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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The plotting methods :meth:`Axes.contourf`, :meth:`Axes.pcolor`, and
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:meth:`Axes.pcolormesh` would previously default to no antialiasing when no
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edgecolor was specified due to a rendering artifact for faint lines between
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patches. That rendering artifact has now been fixed. These methods now use the
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value of rcParams ``patch.antialiased`` as the default for antialiasing.

‎lib/matplotlib/axes/_axes.py‎

Lines changed: 3 additions & 21 deletions
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@@ -6693,15 +6693,6 @@ def pcolor(self, *args, shading=None, alpha=None, norm=None, cmap=None,
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Other Parameters
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----------------
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antialiaseds : bool, default: False
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The default *antialiaseds* is False if the default
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*edgecolors*\ ="none" is used. This eliminates artificial lines
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at patch boundaries, and works regardless of the value of alpha.
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If *edgecolors* is not "none", then the default *antialiaseds*
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is taken from :rc:`patch.antialiased`.
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Stroking the edges may be preferred if *alpha* is 1, but will
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cause artifacts otherwise.
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data : indexable object, optional
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DATA_PARAMETER_PLACEHOLDER
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@@ -6761,15 +6752,6 @@ def pcolor(self, *args, shading=None, alpha=None, norm=None, cmap=None,
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kwargs['edgecolors'] = kwargs.pop('edgecolor')
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ec = kwargs.setdefault('edgecolors', 'none')
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# aa setting will default via collections to patch.antialiased
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# unless the boundary is not stroked, in which case the
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# default will be False; with unstroked boundaries, aa
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# makes artifacts that are often disturbing.
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if 'antialiaseds' in kwargs:
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kwargs['antialiased'] = kwargs.pop('antialiaseds')
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if 'antialiased' not in kwargs and cbook._str_lower_equal(ec, "none"):
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kwargs['antialiased'] = False
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kwargs.setdefault('snap', False)
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if np.ma.isMaskedArray(X) or np.ma.isMaskedArray(Y):
@@ -6796,7 +6778,7 @@ def pcolor(self, *args, shading=None, alpha=None, norm=None, cmap=None,
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@_preprocess_data()
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@_docstring.interpd
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def pcolormesh(self, *args, alpha=None, norm=None, cmap=None, vmin=None,
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vmax=None, colorizer=None, shading=None, antialiased=False,
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vmax=None, colorizer=None, shading=None,
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**kwargs):
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"""
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Create a pseudocolor plot with a non-regular rectangular grid.
@@ -7007,7 +6989,7 @@ def pcolormesh(self, *args, alpha=None, norm=None, cmap=None, vmin=None,
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kwargs.setdefault('snap', mpl.rcParams['pcolormesh.snap'])
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collection = mcoll.QuadMesh(
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coords, antialiased=antialiased, shading=shading,
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coords, shading=shading,
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array=C, colorizer=colorizer, alpha=alpha, **kwargs)
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collection._scale_norm(norm, vmin, vmax)
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@@ -7206,7 +7188,7 @@ def pcolorfast(self, *args, alpha=None, norm=None, cmap=None, vmin=None,
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collection = mcoll.QuadMesh(
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coords, array=C,
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alpha=alpha, cmap=cmap, norm=norm, colorizer=colorizer,
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antialiased=False, edgecolors="none")
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edgecolors="none")
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self.add_collection(collection, autolim=False)
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xl, xr, yb, yt = x.min(), x.max(), y.min(), y.max()
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ret = collection

‎lib/matplotlib/collections.py‎

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Original file line numberDiff line numberDiff line change
@@ -2581,6 +2581,12 @@ def draw(self, renderer):
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renderer.draw_gouraud_triangles(
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gc, triangles, colors, transform.frozen())
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else:
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# If supported by the renderer, we draw antialiased patches without strokes
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# in an isolated blend group using the "plus" blend mode so that the
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# fractional alphas at edges are added to make the intended total alpha.
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# If the alphas were instead blended as if they were unrelated opacities,
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# the resulting alpha would be smaller (i.e., more transparent), which would
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# manifest as slightly transparent line artifacts along patch edges.
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isolate = (renderer._use_blend_group_for_pcolor and self._antialiased
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and (self._edgecolors.size == 0 or self._edgecolors[0][3] == 0))
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if isolate:
@@ -2701,6 +2707,12 @@ def get_edgecolor(self):
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@artist.allow_rasterization
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def draw(self, renderer):
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# If supported by the renderer, we draw antialiased patches without strokes
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# in an isolated blend group using the "plus" blend mode so that the
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# fractional alphas at edges are added to make the intended total alpha.
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# If the alphas were instead blended as if they were unrelated opacities,
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# the resulting alpha would be smaller (i.e., more transparent), which would
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# manifest as slightly transparent line artifacts along patch edges.
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isolate = (renderer._use_blend_group_for_pcolor and np.all(self._antialiaseds)
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and (self._edgecolors.size == 0 or self._edgecolors[0][3] == 0))
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if isolate:

‎lib/matplotlib/contour.py‎

Lines changed: 10 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -673,11 +673,6 @@ def __init__(self, ax, *args,
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Keyword arguments are as described in the docstring of
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`~.Axes.contour`.
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"""
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if antialiased is None and filled:
677-
# Eliminate artifacts; we are not stroking the boundaries.
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antialiased = False
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# The default for line contours will be taken from the
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# LineCollection default, which uses :rc:`lines.antialiased`.
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super().__init__(
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antialiaseds=antialiased,
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alpha=alpha,
@@ -1287,6 +1282,12 @@ def draw(self, renderer):
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n_paths = len(paths)
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edgecolors = self.get_edgecolors()
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if not self.filled or all(hatch is None for hatch in self.hatches):
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# If supported by the renderer, we draw antialiased patches without strokes
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# in an isolated blend group using the "plus" blend mode so that the
1287+
# fractional alphas at edges are added to make the intended total alpha.
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# If the alphas were instead blended as if they were unrelated opacities,
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# the resulting alpha would be smaller (i.e., more transparent), which would
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# manifest as slightly transparent line artifacts along patch edges.
12901291
isolate = (renderer._use_blend_group_for_contourf and
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self.filled and self.get_antialiased() and
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(edgecolors.size == 0 or edgecolors[0][3] == 0))
@@ -1660,18 +1661,16 @@ def _initialize_x_y(self, z):
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:class:`matplotlib.units.ConversionInterface`.
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antialiased : bool, optional
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Enable antialiasing, overriding the defaults. For
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filled contours, the default is *False*. For line contours,
1665-
it is taken from :rc:`lines.antialiased`.
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Enable or disable antialiasing, overriding the defaults.
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For filled contours, the default value is :rc:`patch.antialiased.`
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For line contours, the default value is :rc:`lines.antialiased`.
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nchunk : int >= 0, optional
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If 0, no subdivision of the domain. Specify a positive integer to
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divide the domain into subdomains of *nchunk* by *nchunk* quads.
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Chunking reduces the maximum length of polygons generated by the
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contouring algorithm which reduces the rendering workload passed
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on to the backend and also requires slightly less RAM. It can
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however introduce rendering artifacts at chunk boundaries depending
1674-
on the backend, the *antialiased* flag and value of *alpha*.
1673+
on to the backend and also requires slightly less RAM.
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linewidths : float or array-like, default: :rc:`contour.linewidth`
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*Only applies to* `.contour`.

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