question about hard coded adjustments to rgb

[ctrager]

Why this line?
var pixelDiff = rgba[i] * 0.3 + rgba[i + 1] * 0.6 + rgba[i + 2] * 0.1;

Where did the 0.3, 0.6, 0.1 come from?

[chrisblakley]

Those values are how to calculate color luminance. You multiply them against the R, G, and B values respectively as shown in the formula for pixelDiff.

Here is some more info about that: https://stackoverflow.com/questions/596216/formula-to-determine-perceived-brightness-of-rgb-color