What would be the fastest way to map (and filter) one CRGB to another

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1

What would be the fastest way to map (and filter) one CRGB to another one? Create a weighted averaging of the involved pixels based on leds[i].nscale8 and then add the results?

2

Check out the “blend” (and “nblend”) functions in colorutils.h:

// blend - computes a new color
// blended some fraction of the way
// between two other colors.
CRGB blend(
const CRGB& p1,
const CRGB& p2,
fract8 amountOfP2 );

Is this the sort of thing you were thinking?

3

CRGB also provides getAverageLight and getLuma if those are relevant.

Maybe I’m confused about what you would ideally like to use. What hypothetical API would you want to have?

4

Thanks Mark! If I understand it right, the functions are meant to blend between 2 pixels. Is that performant for a bilinear filtering or for methods which involve even more than the 4 surrounding pixels?

Right now I love the idea to render into a matrix with a higher resolution than the actual output device has and then not just scale the result down, but interpolate between relevant pixels for a smooth high quality animation (while loosing a bit of contrast).

P.S. getAverageLight is relevant for an other side project - a ambilight that softens every frame except when it’s about fading to (nearly) black which has to happen instantly. Thanks for reminding the name of the function!

5

So you’re thinking something like: generate your animation data into a 50 x 50 data matrix, but then render it visually on a 16 x 16 LED matrix?

6

Yes, that is the idea.
Or to render a 16x16 while knowing that I need at the end just data for 32 leds arranged in a circle.