[2016.8] RenderTarget:save()

hgy29 · August 2016

Gideros now comes with the ability to save the content of a render target to a file, either in .png or .jpg format.

First thing that comes to my mind with this new feature (beside the specific case for which I actually needed it), is that it allows to save a screen shot of your app, just a part of it, or even a not displayed compisition of sprites, to a temporary file for later upload to some website or facebook.

It can also be used for dynamic texture creation, for exemple to generate different versions of a base texture at run time, possibly through shaders. The app package will then be smaller and textures can be generated on first launch.

Exemple: to make a screenshot, you could do:

local rt=RenderTarget.new(application:getContentWidth(),application:getContentHeight())
rt:draw(stage)
rt:save("|T|screenshot.png")

I hope you'll find it useful!

n1cke · August 2016

Paint app:

rnd @ |math.random(0, 0xFFFFFF)|
app @ application
size @ 0.01
 
app:setLogicalDimensions(app:getDeviceWidth(), app:getDeviceHeight())
 
local w, h = app:getContentWidth(), app:getContentHeight()
local pixel = Pixel.new(0, 1, size * w, size * h)
local texture = RenderTarget.new(w, h)
local canvas = Bitmap.new(texture)
stage:addChild(canvas)
 
local function draw(e)
	pixel:setColor(rnd)
	pixel:setPosition(e.x or e.touch.x, e.y or e.touch.y)
	texture:draw(pixel)
end
 
stage:addEventListener(Event.MOUSE_DOWN, draw)
stage:addEventListener(Event.MOUSE_MOVE, draw)
stage:addEventListener(Event.TOUCHES_BEGIN, draw)
stage:addEventListener(Event.TOUCHES_MOVE, draw)
 
stage:addEventListener(Event.KEY_DOWN, function()
	texture:save("|T|screenshot"..os.time()..".png")
	print "YOUR AWESOME PIC IS SAVED!"
	texture:clear(0, 0)
end)

You draw with "rainbow" brush and you can save your pics if you press any key.

antix · August 2016

This is a very nice feature to have, thank you.

Xman · August 2016

pretty good feature.

I notice a tiny drawback of the draw api of RenderTarget.
when draw a sprite, it always starts from the position(0,0),it's not possible to draw the whole device screen if the Logical Translate is not 0 on some devices.

It would be useful to add extra parameters x, y to the draw api.

antix · August 2016

Err nevermind

hgy29 · August 2016

@Xman, yes I see what you mean, good idea!

totebo · August 2016

I agree @Xman. I'd also like to use RenderTarget on negative coordinates. If it's a sprite, it first has to be moved, then drawn, then moved back to its original position. I use this method quite a bit, and I suspect it could cause an overhead if the target sprite has hundreds of nested sprites inside of it (like mine does).

hgy29 · August 2016

I'll add extra x,y parameters then, and a second form with a transform matrix as parameter for more complex transformations (scale/rotate/shear/...)

hgy29 · August 2016

Although not yet in the docs yet, 2016.8.1 includes a few more RenderTarget improvements.

Now you can create a repeatable rendertarget by setting the fourth argument to true:

 -- Create a 128x128, filtered and repeatable render target
 rt=RenderTarget.new(128,128,true,true)

And you can supply translation or transform when drawing on sprite on it:

 -- Draw sprite at -10,30 instead of 0,0
 rt:draw(sprite,-10,30)
-- Draw rotated sprite
m=Matrix.new()
m:setRotationZ(15)
rt:draw(sprite,m)

totebo · August 2016

AWESOME.

Howdy, Stranger!

Categories

In this Discussion

Top Posters

[2016.8] RenderTarget:save()

Comments

Howdy, Stranger!

Quick Links

Categories

In this Discussion

Top Posters

[2016.8] RenderTarget:save()

Comments