how to evenly space items using item height, number of items, and the middle point-CodePudding

I can't figure out the solution to a simple math problem. I have an array of 0...n items. I know the mid point of this area and the height of each item. I need to set the yAxis for each item so they're evenly spaced.

let group = [..., {id: A, height: 20, yAxis: 0}, {id: B, height: 20, yAxis: 0}, {id: C, height: 20, yAxis: 0}];
let midPoint = 100;

I've tried getting the total height of the group/group.length, but how do I set the positions relative to the establised midPoint?

CodePudding user response：

I'm assuming that in your case a value of 0 for the yAxis is the mid point.

If this assumptions are true, you could set the yAxis for each object using this logic (in pseudocode)

totalBetweenSpace = (betweenSpace * (group.size - 1))
maxYAxis = (totalHeight   totalBetweenSpace)  / 2
currentYAxis = maxYAxis
for obj in group
  currentYAxis = currentYAxis - obj.height
  if (obj is not first object in group)
    currentYAxis = currentYAxis - betweenSpace
  obj.yAxis = currentYAxis

Where

totalHeight is the sum of all the objects' heights in the group
betweenSpace is the amount of space you want in between each object