Canvas

Available since LÖVE 0.8.0

It has been renamed from Framebuffer.

A Canvas is used for off-screen rendering. Think of it as an invisible screen that you can draw to, but that will not be visible until you draw it to the actual visible screen. It is also known as "render to texture".

By drawing things that do not change position often (such as background items) to the Canvas, and then drawing the entire Canvas instead of each item, you can reduce the number of draw operations performed each frame.

In versions prior to 0.10.0, not all graphics cards that LÖVE supported could use Canvases. love.graphics.isSupported("canvas") could be used to check for support at runtime.

When drawing content to a Canvas using regular alpha blending, the alpha values of the content get multiplied with its RGB values. Therefore the Canvas' pixel colors will have premultiplied alpha once it has been drawn to, so when drawing the Canvas to the screen or to another Canvas you must use premultiplied alpha blending – love.graphics.setBlendMode("alpha", "premultiplied").

Constructors

love.graphics.newCanvas

Creates a new Canvas.

0.8.0

Functions

Canvas:clear	Clears the contents of a Canvas to a specific color.	0.8.0	0.10.0
Canvas:generateMipmaps	Generates mipmaps for the Canvas, based on the contents of the highest-resolution mipmap level.	11.0
Canvas:getFSAA	Gets the number of FSAA samples used when drawing to the Canvas.	0.9.1	0.10.0
Canvas:getFormat	Gets the texture format of the Canvas.	0.9.1	11.0
Canvas:getImageData	Generates ImageData from the contents of the Canvas.	0.8.0	0.10.0
Canvas:getMSAA	Gets the number of MSAA samples used when drawing to the Canvas.	0.9.2
Canvas:getMipmapMode	Gets the MipmapMode this Canvas was created with.	11.0
Canvas:getPixel	Gets the pixel at the specified position in a Canvas.	0.9.0	0.10.0
Canvas:newImageData	Generates ImageData from the contents of the Canvas.	0.10.0
Canvas:renderTo	Render to a Canvas using a function.	0.8.0
Object:release	Immediately destroys the object's Lua reference.	11.0
Object:type	Gets the type of the object as a string.
Object:typeOf	Checks whether an object is of a certain type.
Texture:getDPIScale	Gets the DPI scale factor of the Texture.	11.0
Texture:getDepth	Gets the depth of a Volume Texture.	11.0
Texture:getDepthSampleMode	Gets the comparison mode used when sampling from a depth texture in a shader.	11.0
Texture:getDimensions	Gets the width and height of the Texture.	0.9.0
Texture:getFilter	Gets the filter mode of the Texture.
Texture:getFormat	Gets the pixel format of the Texture.	11.0
Texture:getHeight	Gets the height of the Texture.
Texture:getLayerCount	Gets the number of layers / slices in an Array Texture.	11.0
Texture:getMipmapCount	Gets the number of mipmaps contained in the Texture.	11.0
Texture:getMipmapFilter	Gets the mipmap filter mode for a Texture.	0.9.0
Texture:getPixelDimensions	Gets the width and height in pixels of the Texture.	11.0
Texture:getPixelHeight	Gets the height in pixels of the Texture.	11.0
Texture:getPixelWidth	Gets the width in pixels of the Texture.	11.0
Texture:getTextureType	Gets the type of the Texture.	11.0
Texture:getWidth	Gets the width of the Texture.
Texture:getWrap	Gets the wrapping properties of a Texture.
Texture:isReadable	Gets whether the Texture can be drawn and sent to a Shader.	11.0
Texture:setDepthSampleMode	Sets the comparison mode used when sampling from a depth texture in a shader.	11.0
Texture:setFilter	Sets the filter mode of the Texture.
Texture:setMipmapFilter	Sets the mipmap filter mode for a Texture.	0.9.0
Texture:setWrap	Sets the wrapping properties of a Texture.

Enums

MipmapMode

Controls whether a Canvas has mipmaps, and its behaviour when it does.

11.0

Supertypes

• Texture
• Drawable
• Object

Examples

Drawing something to the Canvas and then draw the Canvas to the screen

function love.load()
    canvas = love.graphics.newCanvas(800, 600)

    -- Rectangle is drawn to the canvas with the regular/default alpha blend mode ("alphamultiply").
    love.graphics.setCanvas(canvas)
        love.graphics.clear(0, 0, 0, 0)
        love.graphics.setBlendMode("alpha")
        love.graphics.setColor(1, 0, 0, .5)
        love.graphics.rectangle("fill", 0,0, 100,100)
    love.graphics.setCanvas()
end

function love.draw()
    -- The colors for the rectangle on the canvas have already been alpha blended.
    -- Use the "premultiplied" alpha blend mode when drawing the canvas to the screen for proper color blending.
    -- (Also set the color to white so the canvas itself doesn't get tinted.)
    love.graphics.setBlendMode("alpha", "premultiplied")
    love.graphics.setColor(1, 1, 1, 1)
    love.graphics.draw(canvas, 0,0)
    -- Observe the difference if the canvas is drawn with the regular alpha blend mode instead.
    love.graphics.setBlendMode("alpha")
    love.graphics.draw(canvas, 100,0)

    -- Rectangle is drawn directly to the screen with the regular alpha blend mode.
    love.graphics.setBlendMode("alpha")
    love.graphics.setColor(1, 0, 0, .5)
    love.graphics.rectangle("fill", 200,0, 100,100)

    -- (Helper texts.)
    love.graphics.setColor(1, 1, 1, 1)
    love.graphics.printf("canvas", 0,0, 100)
    love.graphics.printf("incorrect\n(looks too dark)", 100,0, 100)
    love.graphics.printf("rectangle\n(what canvas should look like)", 200,0, 100)
end

Save canvas as picture

	canvas:newImageData():encode("png","filename.png")

Create 90 degree rotated canvas (clockwise)

function createRotatedCanvas (canvas)
	local newCanvas = love.graphics.newCanvas (canvas:getHeight(), canvas:getWidth())
	love.graphics.setCanvas(newCanvas)
		love.graphics.setColor(1,1,1)
		love.graphics.draw (canvas, canvas:getHeight(), 0, math.pi/2)
	love.graphics.setCanvas()
	return newCanvas
end

See Also

• love.graphics
• love.graphics.setCanvas
• love.graphics.setBlendMode
• love.graphics.isSupported
• love.graphics.getDimensions
• love.graphics.draw
• ImageData:encode

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