Clamping & Remapping the value

rrraptor

Just want to share two very useful functions.

-- Limits the value to the specified range. -- v - value to limit -- min, max - range function clamp(v, min, max) return (v <> min) >< max end   -- Transforms one range to another. -- v - value to map -- minSrc - lower bound of the value's current range -- maxSrc - upper bound of the value's current range -- minDst - lower bound of the value's target range -- maxDst - upper bound of the value's target range -- clampValue - constrain the value to the newly mapped range function map(v, minSrc, maxSrc, minDst, maxDst, clampValue) local newV = (v - minSrc) / (maxSrc - minSrc) * (maxDst - minDst) + minDst return not clampValue and newV or clamp(newV, minDst >< maxDst, minDst <> maxDst) end

As an example:
clamp(20, 0, 100) -> 20
clamp(-20, 0, 100) -> 0
clamp(120, 0, 100) -> 100
map(0.5, 0, 1, 0, 200) -> 100
map(10, 0, 10, 0, 200) -> 200
map(0, -1, 1, 0, 1) -> 0.5

local px1 = Pixel.new(0xff0000, 1, 32, 32) px1:setAnchorPoint(.5, .5) stage:addChild(px1) local px2 = Pixel.new(0x00ff00, 1, 32, 32) px2:setAnchorPoint(.5, .5) stage:addChild(px2)   function updatePosition(e) local minX, minY, maxX, maxY = application:getLogicalBounds() local x1 = map(e.x, minX, maxX, minX + 25, maxX - 25) px1:setPosition(x1, 25)   local x2 = map(e.x, minX, maxX, 0, maxX / 2, true) px2:setPosition(x2, 75) end   stage:addEventListener("mouseMove", updatePosition) stage:addEventListener("mouseHover", updatePosition)