Intro to Physical Computing
Jeff Feddersen
Spring 2003

A very common problem faced by programmers is that of remapping an input in one range to an output in another range:

This is the code to remap the input to the output:

on shortRemap inputValue, min1, max1, min2, max2
return (float(inputValue) - min1)/(max1 - min1) * (max2 - min2) + min2
end

And here's an explanation of how it works:

on remap inputValue, min1, max1, min2, max2
-- map a value between min1 and max1 to min2 and max2

-- Step 1: calculate the total range between the two mins and maxes
totalInputRange = max1 - min1
totalOutputRange = max2 - min2

-- Step 2: "normalize" input value by sliding it to 0
normalizedInputValue = inputValue - min1

-- Step 3: calculate input value as a percentage of the total input range
percentageValue = float(normalizedInputValue) / float(totalInputRange)

-- Step 4: apply that percentage to the output range
normalizedOutputValue = percentageValue * totalOutputRange

-- Step 4: "unnormalize" the output value by sliding it from 0 to the output minimum
outputValue = normalizedOutputValue + min2

return outputValue
end