René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Define additional/custom hatches","articleBody":"\u003c!--\r\nWelcome! Thanks for thinking of a way to improve Matplotlib.\r\n\r\n\r\nBefore creating a new feature request please search the issues for relevant feature requests.\r\n--\u003e\r\n\r\n### Problem\r\n\r\nThe current set of hatching options within matplotlib is somewhat limited, being only the following, with the ability to make more dense ones.\r\n![image](https://user-images.githubusercontent.com/1148889/126292084-467b893d-994d-41ae-bd56-9f065867f2f8.png)\r\nIn geoscience (and possibly other fields, but that is my background) there are a number of other hatching patterns that have long historical use and are still common, cf the USGS templates, available as a pdf [here](https://ngmdb.usgs.gov/fgdc_gds/geolsymstd/fgdc-geolsym-patternchart.pdf). Some of these are complex enough to be difficult to generate programmatically (eg 706: contorted schist), while others are much simpler (eg 328-K, which is a grid of offset `+`).\r\n\r\nIs there a means to safely define hatches such the latter? A workaround, adding custom hatches to `_hatch_types` [can be done](https://github.com/agile-geoscience/striplog/blob/0c68f63d645c5bb7a5cc73b9bdaa197c4fb3cc33/striplog/hatches.py) but raises a deprecation warning (`MatplotlibDeprecationWarning: hatch must consist of a string of \"*+-./OX\\ox|\" or None, but found the following invalid values \"p\". Passing invalid values is deprecated since 3.4 and will become an error two minor releases later.`) since PR https://github.com/matplotlib/matplotlib/pull/17926, and is therefore not a stable long-term solution.\r\n\r\n### Proposed Solution\r\n\r\nIt would be good to have a means to define custom hatches in a safe way. In many cases I think it likely to be package maintainers adding the functionality (as `striplog` does) rather than users.\r\n\r\nA less comprehensive solution that would still cover many common use-cases would be to allow for repetitive hatching of a single (user-chosen) symbol. (That is, being able to place a regular grid of `+` or `L` in the way that the current hatches API handles cases like `.` and `o`.)\r\n\r\n### Additional context and prior art\r\n\r\n","author":{"url":"https://github.com/mtb-za","@type":"Person","name":"mtb-za"},"datePublished":"2021-07-20T09:47:44.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":25},"url":"https://github.com/20690/matplotlib/issues/20690"}