Animate

local bEnableAnimations = true

function enable()
    bEnableAnimations = true
end

function disable()
    bEnableAnimations = false
end

local function getTableSize (tTable)
    local nSize = 0

    for _, __ in pairs (tTable) do
        nSize = nSize + 1
    end

    return nSize
end

local function getShrunkBuffer (tBuffer, nWidthScale, nHeightScale)
    nHeightScale = math.floor (nHeightScale)
    nWidthScale  = math.floor (nWidthScale)

    -- Gotta set up new width and height dimensions so getChunks doesn't freak out!
    local tShrunkBuffer = {
        tText       = {},
        tTextColors = {},
        tBackColors = {},

        tTerm        = tBuffer.tTerm,
        bCursorBlink = false
    }

    local nShrunkLineNumber = 1
    local nLeftConstraint   = tBuffer.nWidth / 2 - nWidthScale
    local nRightConstraint  = tBuffer.nWidth / 2 + nWidthScale

    for nLineNumber = math.floor (tBuffer.nHeight / 2 - nHeightScale), math.floor (tBuffer.nHeight / 2 + nHeightScale) do
        if nLineNumber >= 1 and nLineNumber <= tBuffer.nHeight then
            tShrunkBuffer.tText[nShrunkLineNumber]       = tBuffer.tText[nLineNumber]:sub (nLeftConstraint, nRightConstraint)
            tShrunkBuffer.tTextColors[nShrunkLineNumber] = tBuffer.tTextColors[nLineNumber]:sub (nLeftConstraint, nRightConstraint)
            tShrunkBuffer.tBackColors[nShrunkLineNumber] = tBuffer.tBackColors[nLineNumber]:sub (nLeftConstraint, nRightConstraint)
        end

        nShrunkLineNumber = nShrunkLineNumber + 1
    end

    tShrunkBuffer.nHeight = getTableSize (tShrunkBuffer.tText)
    return tShrunkBuffer
end

function openCenter (tBuffer, nRunTime, nModifier)
    if bEnableAnimations then
        local nModifier = nModifier or 1

        local nRequiredIterations = math.min (tBuffer.nWidth, tBuffer.nHeight)
        local nSleepTime          = nRunTime / nRequiredIterations

        -- Step needs to be the amount of growth per sleep time to make it under the run time!
        local nWidthStep  = tBuffer.nWidth / nRequiredIterations
        local nHeightStep = tBuffer.nHeight / nRequiredIterations

        local nWidthScale  = nWidthStep
        local nHeightScale = nHeightStep

        for nTime = 0, nRunTime, nSleepTime * nModifier do
            local tShrunkBuffer = setmetatable (getShrunkBuffer (tBuffer, nWidthScale, nHeightScale), { __index = tBuffer })

            if #tShrunkBuffer.tText > 0 then
                tShrunkBuffer.x = tBuffer.nWidth / 2 - tShrunkBuffer.tText[1]:len() / 2
                tShrunkBuffer.y = math.max (tBuffer.nHeight / 2 - tShrunkBuffer.nHeight / 2, tBuffer.y)

                tBuffer.render (tShrunkBuffer)
            else
                break
            end

            sleep (nSleepTime)

            nWidthScale  = nWidthScale + nWidthStep * nModifier
            nHeightScale = nHeightScale + nHeightStep * nModifier
        end
    end

    return tBuffer:render()
end

function openCenterColoredRectangle (nColor, nWidth, nHeight, nRunTime, nModifier)
    openCenter (
        Buffer.new (nWidth, nHeight, 1, 1, term.current()):setBackgroundColor (nColor):clear(),
        nRunTime,
        nModifier
    )
end