PaletteKnife lets you use thousands of high-quality color palettes from "cpt-city" in your FastLED animations.
A basic understanding of FastLED color palettes is absolutely required.
To get started with FastLED color palettes, run the FastLED "ColorPalette" example, and review the included notes/comments to refresh your understanding of what FastLED color palettes are, and how to program with them. If you skip this step, nothing that follows will make sense or work. It's not too complicated, but there is no substitute for hands-on experience here.
A second palette-use example, "Fire2012WithPalette", is also included with FastLED.
CHROME or SAFARI is REQUIRED; will NOT work with FF or IE (or NCSA Mosiac).
Drag this bookmarklet into a browser toolbar: [PaletteKnife]
CRGBPalette16 myPal = purplefly_gp;
static uint8_t index = 0; index++; fill_palette( leds, NUM_LEDS, index, 6, myPal);
leds[i] = ColorFromPalette( myPal, index);
All color palettes from cpt-city are "gradient palettes", which are discussed here: Gradient color palettes. Because they are so compact, you can probably add dozens of color palettes to your FastLED animation without running out of program space.
If you want to cross-fade between one palette and another, check out this post, video, and sample code on G+: Color Palette Crossfades
cpt-city color palettes are converted to FastLED color palettes with an automatic gamma correction. You can control the gamma, by appending "?gamma=2.2" (or other values) onto the cpt-city URL and then activating PaletteKnife. Independent R, G, and B gammas can be specified with "?rgamma=2.5&ggamma=2.2&bgamma=2.7" (or other values).
The maintainer of cpt-city has graciously said that FastLED developers are welcome to use PaletteKnife; please be courteous and gracious in return. cpt-city is a fantastic resource, please treat it with respect and gratitude!