WoW:USERAPI ColorGradient: Difference between revisions

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(Add performance note for the common case.)
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Converts a percent value into a gradient from 2 or more RGB percent values (0.0-1.0).  If more than 2 colors are passed, the gradient will be between the two colors which perc lies in an evenly divided range.
Converts a percent value into a gradient from 2 or more RGB percent values (0.0-1.0).  If more than 2 colors are passed, the gradient will be between the two colors which perc lies in an evenly divided range.
(Note that if you will always be generating a gradient between the same number of colors, you will see *significantly* greater performance if you customize this function to take a fixed number of arguments.)


  local function ColorGradient(perc, ...)
  local function ColorGradient(perc, ...)

Revision as of 22:56, 16 April 2007

This page documents a user-defined function that you can copy and paste into your addon. Replace PREFIX with your addon or lib prefix to avoid conflicts between different versions of these functions.

User defined functions


Converts a percent value into a gradient from 2 or more RGB percent values (0.0-1.0). If more than 2 colors are passed, the gradient will be between the two colors which perc lies in an evenly divided range.

(Note that if you will always be generating a gradient between the same number of colors, you will see *significantly* greater performance if you customize this function to take a fixed number of arguments.)

local function ColorGradient(perc, ...)
	if perc >= 1 then
		local r, g, b = select(select('#', ...) - 2, ...)
		return r, g, b
	elseif perc <= 0 then
		local r, g, b = ...
		return r, g, b
	end
	
	local num = select('#', ...) / 3

	local segment, relperc = math.modf(perc*(num-1))
	local r1, g1, b1, r2, g2, b2 = select((segment*3)+1, ...)

	return r1 + (r2-r1)*relperc, g1 + (g2-g1)*relperc, b1 + (b2-b1)*relperc
end

Example

For this example we'll use 3 colors: red, yellow and green. For a percent value of 0.75 we'd expect to get back a color that's halfway between yellow and green. 0.5 would yield pure yellow, 0.25 would yield an orange.

local r,g,b = ColorGradient(0.75, 1,0,0, 1,1,0, 0,1,0)
-- r = 0.5, g = 1.0, b = 0.0