Canvas (Nederlands)

Available since LÖVE 0.8.0

Het is hernoemd van Framebuffer.

Een canvas wordt gebruikt voor off-screen rendering. Denk eraan als een onzichtbaar scherm waar je op kunt tekenen, maar dat pas zichtbaar wordt wanneer je het op het daadwerkelijk zichtbare scherm tekent. Het staat ook bekend als "render to texture".

Door dingen die niet vaak van positie veranderen (zoals achtergrondelementen) naar het Canvas te tekenen en vervolgens het hele Canvas in plaats van elk item te tekenen, kun je het aantal tekenoperaties verminderen dat elke frame wordt uitgevoerd.

In versies vóór 0.10.0 konden niet alle grafische kaarten die door LÖVE werden ondersteund Canvassen gebruiken. love.graphics.isSupported("canvas") kon worden gebruikt om tijdens runtime te controleren of ondersteuning aanwezig was.

Bij het tekenen van inhoud op een Canvas met reguliere alpha blending, worden de alpha-waarden van de inhoud vermenigvuldigd met de RGB-waarden ervan. Daarom zullen de pixelkleuren van het Canvas vooraf vermenigvuldigde alpha hebben zodra het is getekend, dus bij het tekenen van het Canvas op het scherm of op een ander Canvas, moet je gebruik maken van vooraf vermenigvuldigde alpha blending – love.graphics.setBlendMode("alpha", "premultiplied").

Constructors

love.graphics.newCanvas

Creates a new Canvas.

0.8.0

Functions

Canvas:clear (Nederlands)	Clears the contents of a Canvas to a specific color.	0.8.0	0.10.0
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")

See Also

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

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