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Title: Support blitting in webagg backend by ianhi · Pull Request #19059 · matplotlib/matplotlib · GitHub

Open Graph Title: Support blitting in webagg backend by ianhi · Pull Request #19059 · matplotlib/matplotlib

X Title: Support blitting in webagg backend by ianhi · Pull Request #19059 · matplotlib/matplotlib

Description: PR Summary Closes: #4288 Closes: matplotlib/ipympl#228 Supersedes: #9240 I replaced the second Agg renderer by storing the previous buffer in a private attribute. Removing the second renderer as suggested by @tacaswell eliminates the the flickering issues noted in #9240 (comment) I also tried out a modified version of the test case by @mbewley in #9240 (comment) and found that performance was improved considerably when blitting was enabled. from imp import reload import matplotlib reload(matplotlib) matplotlib.use('nbagg') import matplotlib.backends.backend_nbagg reload(matplotlib.backends.backend_nbagg) import matplotlib.backends.backend_webagg_core reload(matplotlib.backends.backend_webagg_core) import numpy as np import matplotlib.pyplot as plt import matplotlib.patches as mpatches IMSIZE = 7000 RED = (1,0,0,1) GREEN = (0,1,0,1) plt.ion() class ExampleToggle: def __init__(self): self.fig = plt.figure() self.ax = self.fig.add_subplot(111) self.canvas = self.ax.figure.canvas self.im = np.random.randint(0, 255, [IMSIZE,IMSIZE, 3]).astype('uint8') self.tmp_colour = RED self.rect = mpatches.Rectangle([0, 0], 200, 200, edgecolor='yellow', facecolor=self.tmp_colour, linewidth=0.5, animated=True) self.ax.add_patch(self.rect) self.canvas.mpl_connect('button_press_event', self.clicked) self.ax.imshow(self.im) self.canvas.draw() self._been_clicked = False def clicked(self, event): if not self._been_clicked: self.background = self.canvas.copy_from_bbox(self.ax.bbox) self._been_clicked = True if self.tmp_colour == RED: self.tmp_colour = GREEN elif self.tmp_colour == GREEN: self.tmp_colour = RED self.rect.set_facecolor(self.tmp_colour) self.canvas.restore_region(self.background) self.ax.draw_artist(self.rect) self.canvas.blit(self.ax.bbox) et = ExampleToggle() (the modification was to use the self._been_clicked as I was finding that otherwise the figure was resizing and the bbox was incorrect) Unlike the previous PR this does not need to implement copy_from_bbox as that is inherited from backend_agg.FigureCanvasAgg. I didn't add any new tests but I did try the UAT notebook and found that the flickering mentioned is is resolved by this approach. Should we consider adding the above blit test for perforamance to the UAT notebook? One issue is that at times the animation can get tripped up and fail to properly blit. Though I believe that this is an issue that was revealed by, rather than caused by, this PR. My theory is that maybe new messages reach the frontend before it finishes a redraw and then the frontend trips over itself? This is something I've noticed on occasion with ipympl as well, even without blitting. The result looks like this, though if I increase the interval of the animation then this pathology goes away: with interval=32 with interval=100 PR Checklist [UAT] Has pytest style unit tests (and pytest passes). Is Flake 8 compliant (run flake8 on changed files to check). [N/A (i think?)] New features are documented, with examples if plot related. [N/A] Documentation is sphinx and numpydoc compliant (the docs should build without error). Conforms to Matplotlib style conventions (install flake8-docstrings and run flake8 --docstring-convention=all). New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there). API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there). would this get an API note or a new feature? or neither?

Open Graph Description: PR Summary Closes: #4288 Closes: matplotlib/ipympl#228 Supersedes: #9240 I replaced the second Agg renderer by storing the previous buffer in a private attribute. Removing the second renderer as su...

X Description: PR Summary Closes: #4288 Closes: matplotlib/ipympl#228 Supersedes: #9240 I replaced the second Agg renderer by storing the previous buffer in a private attribute. Removing the second renderer as su...

Opengraph URL: https://github.com/matplotlib/matplotlib/pull/19059

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