Dynamic Loading of Textures

OZApps · May 2013

Logically this should work, as the textures that are available in the resource directory should be available, however can images that are not added to the project but downloaded from the internet (or created dynamically as could be via render2Texture) be used to load them using the Bitmap.new?

Can put that to rest by trying it out, but if anyone has an idea, please chime in...

ar2rsawseen · May 2013

@OZApps that is one of the default examples coming with Gideros

local function onComplete(event)
	info:setText("done")
 
	local out = io.open("|D|image.png", "wb")
    out:write(event.data)
    out:close()
 
    local b = Bitmap.new(Texture.new("|D|image.png"))
	b:setAnchorPoint(0.5, 0.5)
	b:setPosition(160, 240)
    stage:addChild(b)
end
 
local loader = UrlLoader.new("<a href="http://www.giderosmobile.com/giderosmobile.png&quot" rel="nofollow">http://www.giderosmobile.com/giderosmobile.png&quot</a><img class="emoji" src="http://forum.gideros.rocks/resources/emoji/wink.png" title=";)" alt=";)" height="20" />

OZApps · May 2013

@ar2rsawseen, so If I use a 3rd party library to generate textures on the fly, they can be used.

ar2rsawseen · May 2013

If you can receive raw bytes of image in lua, then yes, they can be used. As you will be able to save them to Documents or temporary folder and then read as normal image in Gideros

OZApps · May 2013

@ar2sawseen, I plan to create a plug-in (wrap it around GD libraries) and that will save the image to the device which could then be opened from Gideros.

krisis · May 2013

I use similar code to the above to dynamically load in Facebook friend profile pics into a table view. I queue up all the relevant URLs, download and save the .png, then swap them in for the placeholder profile pic as they become available. They are then cached for the next load. Periodically I can flush the cache as needed to refresh the images.

Make sure you're passing a valid image file (in a supported format) to Texture.new or it'll barf/crash. e.g. Facebook sometimes return profile pics as .gif files which aren't supported by Texture.new(), so I check image headers and ignore gifs:

	-- first save data to disk as self.currentFilename then check
	self.TYPE_MAP = {
		["^GIF8[7,9]a"] = "gif",
	}
	local file, err = io.open(self.currentFilename, "rb")
	local header = file:read(256)
	local found = false
	for pattern, format in pairs(self.TYPE_MAP) do
		if header:find(pattern) then
			found = true
			file:close()
			if format == "gif" then
				print("GIF detected for "..self.currentFilename..". Unsupported image type.")
				os.remove(self.currentFilename)
				return false
			end
		end
	end
	if not found then
		file:close()
	end

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