On Tue, Jan 6, 2015 at 2:37 AM, Maximilian Albert <maximilian.alb...@gmail.com> wrote: > Happy new year everyone! > > Apologies for the long silence. I was snowed in with work before Christmas > and then mostly cut off from the internet for the past two weeks. > Fortunately, I had a chance over the holidays to flesh out the GUI which I > mentioned in my previous email. You can find it here: > > https://github.com/maxalbert/colormap-selector > > Basically, it allows you to pick the start/end color of a colormap from two > cross sections in CIELab space and interpolates those colors linearly (see > the README file for more details).
There's a downside to this approach for the kinds of colormaps we've been talking about in this thread, where we want both a large lightness range plus a colorful result. The problem is that the way color space is shaped, you can't simultaneously have both high saturation (colorfulness) *and* high/low lightness. So if you pick your extreme points to be near black and white, then they can only have a slight tinting of color, and then if you linearly interpolate between these, then you end up with slightly tinted greyscale. Colormaps like YlGnBu or cubehelix or parula are designed to start out with low saturation, then as they move into the middle of the lightness scale they arc outwards, then arc back in again. This is a lot easier to visualize (e.g. by playing with the script I posted upthread) than it is to explain in text :-). Like, if you do viscm(YlGnBu_r) and look at the plot in the lower-right then it's clear that it's not a simple straight line in (J'/K, a', b') space (which is a higher-tech analogue to L* a* b* space). -- Nathaniel J. Smith Postdoctoral researcher - Informatics - University of Edinburgh http://vorpus.org ------------------------------------------------------------------------------ Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
