TextureResourceCanvas

Parent TextureResource
Library graphics.*
Revision Current Public Release (2017.3135)
Keywords textures, performance optimization, texture memory, images
See also graphics.newTexture()
TextureResource
TextureResourceBitmap
texture.type

Overview

The object created by graphics.newTexture() when the specified type is "canvas". This texture resource is an in-memory texture which can be modified by rendering display objects to it. It is similar to a framebuffer object or a render target texture.

Properties

Methods

Gotchas

Example

local tex = graphics.newTexture( { type="canvas", width=128, height=128 } )

-- Create display object with texture as contents
local rect = display.newImageRect(
    tex.filename,  -- "filename" property required
    tex.baseDir,   -- "baseDir" property required
    display.contentWidth,
    display.contentHeight
)
rect.x = display.contentCenterX
rect.y = display.contentCenterY

-- Set background color to be applied if texture is cleared
tex:setBackground( 0, 0, 1 )

-- Create a circle and draw/render it to the texture
local circ = display.newCircle( 0, 0, 64 )
circ:setFillColor( { type="gradient", color1={0,0.2,1}, color2={0.8,0.8,0.8}, direction="down" } )
tex:draw( circ )

-- Create a polygon and draw/render it to the texture
local poly = display.newPolygon( 0, 0, {0,-55,14,-18,52,-18,22,8,32,45,0,22,-32,45,-22,8,-52,-18,-14,-18} )
poly:setFillColor( 0.2, 1, 0.2 )
tex:draw( poly )

-- Schedule texture objects to be rendered to texture before next frame
tex:invalidate()

-- Function to restore texture on resume
local function onSystemEvent( event )
    if ( event.type == "applicationResume" ) then
        tex:invalidate( "cache" )
    end
end

-- Set up a system event listener
Runtime:addEventListener( "system", onSystemEvent )