Mailman 3 August 2019 - Matplotlib-devel

What is draw_path's transform's destination?
by Rob McDonald Sept. 24, 2019

Sept. 24, 2019

I'm implementing a custom path effect by inheriting from AbstractPathEffect and implementing draw_path as instructed here <https://matplotlib.org/api/patheffects_api.html#matplotlib.patheffects.Abst…>. That link references RenderBase.draw_path <https://matplotlib.org/api/backend_bases_api.html#matplotlib.backend_bases.…> to define the required interface. Unfortunately, I can't find anywhere in the associated documentation that tells me what the transform argument really entails. I've also read the transforms tutorial <https://matplotlib.org/tutorials/advanced/transforms_tutorial.html>, and while that explains the pipeline and all the intermediate transformations, it doesn't really settle what I have available to me in draw_path. It is clear that I can use it to transform coordinates from data to something -- but I don't know what to. For the big picture -- I am implementing a path effect to allow drawing hatched lines similar to this <https://www.mathworks.com/matlabcentral/fileexchange/29121-hatched-lines-an…>, which I did years ago in Matlab. Years before that, I've also done this in Java Graphics2D by implementing a custom stroke. (The Java approach is more applicable to the path effect approach, but I can't point to that code online anywhere.) Anyway, I have things mostly working -- and I am using the transform to go from data coordinates to something that looks orthogonal and reasonable on-screen. So, for minimum functionality, it works. However, I want to give the user the ability to control the length and spacing of the hatches -- which is in a coordinate system after the transformation is applied. So, in order to document this thing, I need to know what it is. Or, if there is a way to get intermediate stages of the transformation pipeline, that would work too. As for the user interface -- it seems to make the most sense to specify the hatch length and spacing in terms of something similar to a line width (typically points) or a marker size. I'm new to Python and matplotlib -- what is the Pythonic unit a user would expect to specify this in (and how do I achieve that with what is available in draw_path)? Thanks, Rob

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Reschedule weekly call
by Thomas Caswell Sept. 2, 2019

Sept. 2, 2019

Folks, Can we re-schedule the weekly call to Tuesdays 15:00 Eastern US time (UTC -05:00). This is the name time, but shifted forward a day. This would go into effect next week (2019-09-03). Tom -- Thomas Caswell tcaswell(a)gmail.com

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presentations repository history re-write
by Thomas Caswell Aug. 27, 2019

Aug. 27, 2019

Folks, I just did some history re-writing and force pushed to https://github.com/matplotlib/presentations/ to purge some files that were violating the GitHub TOS (plain-text dumps of information about the the committers to matplotlib/matplotlib) following [1] The new master branch is at: 2b00326841d21780f2ff5a7b1d638c5147091faf If you have a checkout of this repository please reset you local master to the current upstream git reset --hard 2b00326841d21780f2ff5a7b1d638c5147091faf ------ As a follow up, can people please list any recent talks they have given in the table in the readme and, if possible, add their slides to the repo? Tom [1] https://help.github.com/en/articles/removing-sensitive-data-from-a-reposito… -- Thomas Caswell tcaswell(a)gmail.com

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Turbo, An Improved Rainbow Colormap for Visualization
by Nicolas Rougier Aug. 23, 2019

Aug. 23, 2019

An interesting effort to sanitize the rainbow colormap (with a lot of comparisons with the inferno and viridis colormaps): https://ai.googleblog.com/2019/08/turbo-improved-rainbow-colormap-for.html Nicolas

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New feature for stackplot
by Jakob Rohrhirsch Aug. 9, 2019

Aug. 9, 2019

Hi, I developed a new feature for the stackplot file that I needed and want to contribute this back to matplotlib. You can see the changes here: https://github.com/JakobRohrhirsch/matplotlib/tree/stackplot_custom I tried to follow the contribution guide but I'm not sure if I'm missing something (first time I'm contributing some code). Please let me know if I should send a pull request or if I should add some testing/anything else. Best, Jakob

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3D experiments
by Nicolas Rougier Aug. 7, 2019

Aug. 7, 2019

I’m playing a bit with 3D rendering in matplotlib using the regular API (LineCollection and PolyCollection) to see how far we can go. Here are some results. I’m using a regulat axis, homogenous coordinates (that simplify everything), a model/view/projection transform, z-depth sorting, lightning and backface culling (removal of hidden triangles). I’m quite happy with the results so I share them with you. The code is not yet online because it’s still a bit messy but it is reasonably fast (but slower than the regular 3D axis projection I would say). I’m not familiar enough with the regular 3D axis projection to know if these experiments are useful or not but I’ll be happy to explain details if you want. Nicolas

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table and blume
by swfiua＠gmail.com Aug. 6, 2019

Aug. 6, 2019

Following yesterday's call, I've put a version of blume on pypi: https://pypi.org/project/blume/ The improved table is in the table.py module. There are a couple of examples in the example folder. If you are feeling brave, eggshow.py will randomly run python code in an examples sub-folder, hoping it is something like the matplotlib examples folder. eggshow and magic are changing all the time at the moment as I try to figure out what belongs where. Johnny

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Matplotlib 3.2 release schedule
by Thomas Caswell Aug. 5, 2019

Aug. 5, 2019

Folks, We discussed on the weekly call 2 weeks ago [1] the target dates for 3.2: - Create 3.2.x branch first week of August (aka, this week) - RC1 Third week of August (lets aim for Aug 18) - 3.2.0 on Sept 4 - 3.1.2 concurrently with 3.2.0 (there are a few critical bug fixes) This may be aggressive/ambitious, but lets give it a go! We currently have 276 issues/prs tagged for 3.2 can people please start re-milestoning to 3.3.0 or marking as release critical. Paul Ivanov has agreed to be the release manager for 3.2! Tom [1] https://paper.dropbox.com/doc/In-Matplotlib-2019-meeting-agenda--AiR~YoaVt3… -- Thomas Caswell tcaswell(a)gmail.com

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