Class: OffscreenLayer2D

(abstract) Rendering.2D.OffscreenLayer2D(ctx)

Storage for a bitmap data that can be manipulated or presented on the screen.It corresponds to an OffscreenCanvas used as drawing surface.It defines the ration between actual pixels and the abstract layer dimensions.Not constructable. InkCanvas creates such layers.

Constructor

(abstract) new OffscreenLayer2D(ctx)

Parameters:

Name	Type	Description
ctx	CanvasRenderingContext2D

Properties:

Name	Type	Description
width	int	Layer width
height	int	Layer height
bounds	int	The bounds of the layer. Equals to (0, 0, width, height).
surface	HTMLCanvasElement|OffscreenCanvas	Drawing surface
ctx	CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D	Drawing surface context

Since:

• version 3.0

See:

• HTMLCanvasElement
• OffscreenCanvas
• CanvasRenderingContext2D

Extends

• Rendering.Layer

Methods

blend(source, options)

Draws the content of the 'source'. The 'source' must use a texture storage.

Parameters:

Name	Type	Description
source	Rendering.2D.OffscreenLayer2D	Layer to be drawn
options	Rendering.BlendOptions	Blending configuration

clear(rectopt, coloropt)

Clears layer area with a color

Parameters:

Name	Type	Attributes	Default	Description
rect	Common.Rect|Common.Color	<optional>	bounds	Area to clear
color	Common.Color	<optional>	Color.TRANSPERENT

createImageData(pixels, rect) → {ImageData}

Creates image data object

Parameters:

Name	Type	Description
pixels	Uint8ClampedArray	Image data pixel values
rect	Common.Rect

Returns:

Pixels image data

Type

ImageData

draw(stroke) → Common.Rect

Draws points with a brush over the layer

Parameters:

Name	Type	Description
stroke	Stroke	Stroke model instance

Returns:

Affected area

Type

Common.Rect

drawStroke(brush, path, color, matrixopt) → Common.Rect

Draws points with a brush over the layer

Parameters:

Name	Type	Attributes	Description
brush	Rendering.2D.Brush2D		Rendering brush
path	PathBuilding.InkPath2D		Contours list, where contour is points list
color	Common.Color		Stroke color
matrix	Common.Matrix	<optional>	Transforms drawing context

Returns:

Affected area

Type

Common.Rect

fill(shape, color) → Common.Rect

Fills shape with color

Parameters:

Name	Type	Description
shape	PathBuilding.PolygonArray|PathBuilding.Polygon|Polygon|Rect	Control points to work with it
color	Common.Color	Fill color

Returns:

Affected area

Type

Common.Rect

(async, abstract) getExportCanvas()

Overrides:

• Rendering.Layer#getExportCanvas

getImageData(rectopt) → {ImageData}

Read pixels data

Parameters:

Name	Type	Attributes	Default	Description
rect	Common.Rect	<optional>	bounds	Area to read

Returns:

Pixels image data

Type

ImageData

putImageData(imageData, xopt, yopt)

Write pixels data

Parameters:

Name	Type	Attributes	Default	Description
imageData	ImageData			An ImageData object containing the array of pixel values
x	int	<optional>	0	Horizontal position (x coordinate) at which to place the image data in the destination layer
y	int	<optional>	0	Vertical position (y coordinate) at which to place the image data in the destination layer

readPixels(rectopt) → {Uint8ClampedArray}

Read pixels data

Parameters:

Name	Type	Attributes	Default	Description
rect	Common.Rect	<optional>	bounds	Area to read

Returns:

Array of pixel values

Type

Uint8ClampedArray

resize(width, height)

Resize layer

Parameters:

Name	Type	Description
width	int	New width
height	int	New height

setTransform(matrix)

Configures ink transformation over underlying layer

Parameters:

Name	Type	Description
matrix	Common.Matrix

Overrides:

• Rendering.Layer#setTransform

(async) toBlob(rectopt, mimeTypeopt, qualityopt) → {Blob}

Exports layer content. Compatible in web environment.

Parameters:

Name	Type	Attributes	Default	Description
rect	Common.Rect	<optional>	bounds	Area to read
mimeType	string	<optional>	image/png	Supported values are image/png, image/jpeg and image/webp.
quality	float	<optional>	0.92	A Number between 0 and 1 indicating image quality if the requested type is image/jpeg or image/webp.If this argument is anything else, the default values 0.92 and 0.80 are used for image/jpeg and image/webp respectively.

Overrides:

• Rendering.Layer#toBlob

Returns:

Layer content

Type

Blob

(async) toBuffer(rectopt, mimeTypeopt, options) → {Buffer}

Exports layer content. Compatible in nodejs environment.

Parameters:

Name	Type	Attributes	Default	Description
rect	Common.Rect	<optional>	bounds	Area to read
mimeType	string	<optional>	image/png	Supported values are image/png and image/jpeg.
options	Rendering.Layer.PNGOptions|Rendering.Layer.JPEGOptions

Overrides:

• Rendering.Layer#toBuffer

Returns:

Layer content

Type

Buffer

writePixels(data, rectopt)

Write pixels data

Parameters:

Name	Type	Attributes	Default	Description
data	Uint8ClampedArray|Uint8Array			Array of pixel values
rect	Common.Rect	<optional>	bounds	Area to write

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