-- An object pool for Bitmap objects.

-- Should you need a largeish number of identical bitmaps for some reason, you may encounter poor

-- performance characteristics if you are forever destroying and creating new ones (the particular

-- situation that inspired the creation of this class was that it would take 300ms to spawn the

-- bitmaps required to show resources in map previews).

-- Instead, initilise a TexturePool with the URL to the target texture, and it'll do object pooling

-- for them in the obvious way.

TexturePool = Class() {

__init = function(self, textureURL, textureParent, width, height)

local Bitmap = import('/lua/maui/bitmap.lua').Bitmap

self.textureURL = textureURL

-- The object store for this pool.

local _objects = {}

-- Get a Bitmap from the pool (creating a new one if required).

self.Get = function(self)

-- Try and recycle a Bitmap from the pool...

local bmp = table.remove(_objects)

-- ... Make a fresh one if they're all checked out.

if not bmp then

-- The caller shall return this Bitmap to us via Dispose, so it actually gets pooled...

bmp = Bitmap(textureParent, textureURL)

bmp.Width:Set(width)

bmp.Height:Set(height)

end

bmp.OnHide = nil

bmp:Show()

return bmp

end

-- Return the given bitmap to the pool.

self.Dispose = function(self, bmp)

bmp:Hide()

-- This effectively "locks" the visibility of this Bitmap so it can't be shown, even if

-- the parent is shown (stopping the pool contents from appearing if the parent Group

-- is shown).

bmp.OnHide = function(self, hidden)

return true

end

table.insert(_objects, bmp)

end

-- Dispose of the Bitmap resources held by this object.

self.Destroy = function(self)

for i = 1, table.getn(_objects) do

_objects[i]:Destroy()

end

end

end

}