René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Add from_file colormap generator and random color cycle generator","articleBody":"I want to add a few new color usage features at some point:\r\n\r\n* Consider adding some of the [NASA colormaps](https://www.giss.nasa.gov/tools/panoply/colorbars/) listed here, and ~~consider adding back [Fabio Crameri's colormaps](http://www.fabiocrameri.ch/colourmaps.php)~~ (version 0.5.0).\r\n* Add the image reader tool from [climate_science_colormapping](bradyrx/climate_science_colormapping) for loading colormaps. In #50 I added `LinearSegmentedColormap.from_file` and `ListedColormap.from_file` methods that load lists of hex strings, etc. I can let these methods read JPG and PNG files too. For colormaps, we try to read colors along the *long-axis* of the image (possibly with smoothing?), and for color cycles, we try to get *distinct* colors in the image. The latter would let us easily load cycles from tools like [Color Hunt](https://colorhunt.co/palette/163683).\r\n* ProPlot can already be used to make new colormaps, but it should also be capable of making new color cycles. I can write an algorithm that selects random colors that are \"sufficiently distinct\" in perceptually uniform colorspace by (1) picking a random HCL coordinate, then (2) stepping in random directions in HCL space such that `delta_min \u003c= square_root(delta_chroma^2 + delta_luminance^2 + min(delta_hue, 360 - delta_hue)^2) \u003c= delta_max`. The `random_cycle` function should accept an initial color and the `delta_min` and `delta_max` bounds as optional arguments, and the value of `delta` can be randomly selected between those bounds, then randomly divided into hue, chroma, and luminance steps. \r\n\r\nThese are not a release priority but would be cool.","author":{"url":"https://github.com/lukelbd","@type":"Person","name":"lukelbd"},"datePublished":"2019-11-19T19:20:51.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/66/proplot/issues/66"}