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How to center an object within an object relative to the position of the second object?

I need to center an object that is inside another object on a screen and for this to be relative to the position of the second object

For example:

-------- screen --------
|                      |
|    --------          |
|    | text |          |
|    --------          |
------------------------

Code example to center text on a screen in Lua:


local x = math.floor(screenWidth / 2 - width / 2)

local y = math.floor(screenHeight / 2 - height / 2)
Solution

  • Just center the object relative to your parent, then move it to its absolute position on the screen:

    local x = parentX + math.floor((parentWidth - width) / 2)
local y = parentY + math.floor((parentHeight - height) / 2)

    since Lua 5.3, you may use floor division (//) to shorten this:

    local x = parentX + (parentWidth - width) // 2
local y = parentY + (parentHeight - height) // 2