Patchcollection keeps original patch by hhalwan · Pull Request #22814 · matplotlib/matplotlib · GitHub

PR Summary

Fixes this issue. PatchCollection currently ignores the hatches of the provided patches, only allowing a hatch passed as a keyword into the constructor. If match_original is true, we now keep the hatch of the first patch provided in the collection, rather than using the hatch passed as a keyword into the constructor. Edited the doc strings to reflect this. Additionally, the hatchcolor is determined by the edge color, so we will only initialize the collection with the edgecolors of the patches if the edgecolor is not blank - its default color of [0, 0, 0, 0]. This ensures that the hatch will use its default of black in the case where no edgecolor of the patches is ever set.

PR Checklist

Tests and Styling

Has pytest style unit tests (and pytest passes).
Is Flake 8 compliant (install flake8-docstrings and run flake8 --docstring-convention=all).

Documentation

[n/a] New features are documented, with examples if plot related.
[n/a] New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there).
[n/a] API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there).
[n/a] Documentation is sphinx and numpydoc compliant (the docs should build without error).

…llection. PatchCollection will currently ignore hatches of the provided patches, only allowing a hatch passed as a keyword into the constructor. If match_original is true, we now keep the hatch of the first patch provided in the collection. Additionally, the hatchcolor is determined by the edge color, so we will only pass the edgecolors of the patches to the Collection if the edgecolor is not blank - its default color of [0, 0, 0, 0]. This ensures that the hatch will use its default of black in the case where no edgecolor of the patches was ever set.

…r a PatchCollection when match_original is true.

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If we are going to only pick of the hatch from the first patch, then we should warn or raise if we are going to ignore the rest of the hatches.

Why? If that's true, it would be impossible to make a collection of multiple patches w/ hatches without getting a warning.

sorry I was not clear. The check should be "are all of the hatches the same? if so carry on, if not fail!" As implemented if the user passes in

[
        mpatches.Rectangle((0, 0), 0.2, .2, hatch="/"),
        mpatches.Rectangle((0.4, 0.4), 0.2, .2, hatch="\\")
]

then the first hatch will be used for both and we will silently drop the "\\" on the second one!

This in only the default default (that is, there is a set of rcparams which will cause this to be miss. Looking at

matplotlib/lib/matplotlib/patches.py

Lines 315 to 339 in c19cd34

    
               def _set_edgecolor(self, color): 
        
                   set_hatch_color = True 
        
                   if color is None: 
        
                       if (mpl.rcParams['patch.force_edgecolor'] or 
        
                               not self._fill or self._edge_default): 
        
                           color = mpl.rcParams['patch.edgecolor'] 
        
                       else: 
        
                           color = 'none' 
        
                           set_hatch_color = False 
        
                   self._edgecolor = colors.to_rgba(color, self._alpha) 
        
                   if set_hatch_color: 
        
                       self._hatch_color = self._edgecolor 
        
                   self.stale = True 
        
               def set_edgecolor(self, color): 
        
                   """ 
        
                   Set the patch edge color. 
        
                   Parameters 
        
                   ---------- 
        
                   color : color or None 
        
                   """ 
        
                   self._original_edgecolor = color 
        
                   self._set_edgecolor(color)

we have some private state (which we are allowed to use inside of Matplotlib) to check this. In this case, I think it is better to check p._original_edgecolor and if None either re-implement the default logic or pass in None here (if we can) and let the next layer down deal with resolving the default behavior.

Thank you for working on this @hhalwan and apologies for the delay in getting this reviewed.

Do my comments make sense?

…h._original_edgecolor to see if edgecolors were set.

Should use _api.warn_external? Also should be tested.

@hhalwan do you plan to come back to this?

@timhoffm I don't have time right now, I'm happy to let someone else take it up.

Superseeded by #27937.

hhalwan added 2 commits April 9, 2022 14:48

Added a new test: The hatch of the original patches should be used fo…

b7e9588

…r a PatchCollection when match_original is true.

github-actions Bot reviewed Apr 9, 2022

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oscargus added status: needs workflow approval For PRs from new contributors, from which GitHub blocks workflows by default. topic: collections and mappables labels Apr 10, 2022

tacaswell added this to the v3.6.0 milestone Apr 10, 2022

tacaswell reviewed Apr 11, 2022

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tacaswell reviewed Apr 12, 2022

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Added warning if more than one type of hatch is detected. Checks patc…

ed48cb0

…h._original_edgecolor to see if edgecolors were set.

oscargus added status: needs review status: needs rebase and removed status: needs workflow approval For PRs from new contributors, from which GitHub blocks workflows by default. labels Aug 2, 2022

QuLogic reviewed Aug 9, 2022

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QuLogic modified the milestones: v3.6.0, v3.7.0 Aug 24, 2022

timhoffm added status: orphaned PR status: needs revision and removed status: needs review labels Sep 26, 2022

tacaswell modified the milestones: v3.7.0, future releases Dec 21, 2022

tacaswell marked this pull request as draft December 21, 2022 21:39

Impaler343 mentioned this pull request Mar 4, 2024

[Bug]: PatchCollection fails to keep hatch from Patch #22654

Open

Impaler343 mentioned this pull request Mar 16, 2024

Fixed hatching in PatchCollection class #27937

Open

4 tasks done

timhoffm closed this Sep 15, 2025

github-project-automation Bot moved this from Needs decision to Waiting for author in First Time Contributors Sep 15, 2025

melissawm moved this from Waiting for author to Done in First Time Contributors Mar 6, 2026

                           kwargs['linestyles'] = [p.get_linestyle() for p in patches]
                           kwargs['antialiaseds'] = [p.get_antialiased() for p in patches]
+                          if patches:
+                              kwargs['hatch'] = patches[0].get_hatch()

+                              hatch = patches[0].get_hatch()
+                              kwargs['hatch'] = hatch
+                              if any(p.get_hatch() != hatch for p in patches):
+                                  warnings.warn("More than one type of hatch detected in "

Patchcollection keeps original patch by hhalwan · Pull Request #22814 · matplotlib/matplotlib · GitHub

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Patchcollection keeps original patch - #22814

Patchcollection keeps original patch#22814
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                                   return patch.get_facecolor()
                               return [0, 0, 0, 0]
+                          def is_default(c):

	def _set_edgecolor(self, color):
	set_hatch_color = True
	if color is None:
	if (mpl.rcParams['patch.force_edgecolor'] or
	not self._fill or self._edge_default):
	color = mpl.rcParams['patch.edgecolor']
	else:
	color = 'none'
	set_hatch_color = False

	self._edgecolor = colors.to_rgba(color, self._alpha)
	if set_hatch_color:
	self._hatch_color = self._edgecolor
	self.stale = True

	def set_edgecolor(self, color):
	"""
	Set the patch edge color.

	Parameters
	----------
	color : color or None
	"""
	self._original_edgecolor = color
	self._set_edgecolor(color)

Patchcollection keeps original patch by hhalwan · Pull Request #22814 · matplotlib/matplotlib · GitHub

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Patchcollection keeps original patch - #22814

Patchcollection keeps original patch#22814hhalwan wants to merge 3 commits intomatplotlib:mainmatplotlib/matplotlib:mainfrom hhalwan:patchcollection-keeps-original-patchhhalwan/matplotlib:patchcollection-keeps-original-patchCopy head branch name to clipboard

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hhalwan commented Apr 9, 2022

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Patchcollection keeps original patch#22814
hhalwan wants to merge 3 commits into
matplotlib:mainfrom
hhalwan:patchcollection-keeps-original-patch

hhalwan Apr 12, 2022 •
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