OpenLIME

Class: LayerMaskedImage

LayerMaskedImage

LayerMaskedImage provides specialized handling for masked scalar images with bilinear interpolation. It implements custom texture sampling and masking operations through WebGL shaders.

Features:

  • Custom scalar image handling
  • Bilinear interpolation with masking
  • WebGL shader-based processing
  • Support for both WebGL 1 and 2
  • Nearest-neighbor texture filtering
  • Masked value visualization

Technical Details:

  • Uses LUMINANCE format for single-channel data
  • Implements custom bilinear sampling in shader
  • Handles mask values through alpha channel
  • Supports value rescaling (255.0/254.0 scale with -1.0/254.0 bias)
  • Uses custom texture parameters for proper sampling

Shader Implementation:

  • Performs bilinear interpolation in shader
  • Handles masked values (0 = masked)
  • Implements value rescaling
  • Provides visualization of masked areas (in red)
  • Uses texelFetch for precise sampling

new LayerMaskedImage(options)

Creates a new LayerMaskedImage instance

Parameters:
Name Type Description
options LayerMaskedImageOptions

Configuration options
Source:
Throws:

  • If rasters options is not empty

    Type
    Error

  • If url is not provided and layout has no URLs

    Type
    Error
Example
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```javascript
// Create masked image layer
const maskedLayer = new OpenLIME.Layer({
  type: 'maskedimage',
  url: 'masked-data.png',
  format: 'vec4'
});

// Add to viewer
viewer.addLayer('masked', maskedLayer);
```

Extends

Methods

addControl(name, value)

Adds a shader parameter control

Parameters:
Name Type Description
name string

Control identifier
value *

Initial value
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Overrides:
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Throws:

If control already exists

Type
Error

addShaderFilter(filter)

Adds a filter to the current shader

Parameters:
Name Type Description
filter Object

Filter specification
Inherited From:
Overrides:
Source:
Throws:

If no shader is set

Type
Error

boundingBox()

Gets layer bounding box in scene coordinates

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Returns:

Bounding box

Type
BoundingBox

clearShaderFilters(name)

Removes all filters from the current shader

Parameters:
Name Type Description
name Object

Filter name
Inherited From:
Overrides:
Source:
Throws:

If no shader is set

Type
Error

getControl(name)

Gets the shader parameter control corresponding to name

Parameters:
Name Type Description
name *

The name of the control. return {*} The control
Inherited From:
Overrides:
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getMode()

Gets the current shader visualization mode

Inherited From:
Overrides:
Source:
Returns:

Current mode or null if no shader

Type
string | null

getModes()

Gets available shader modes

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Returns:

Array of available modes

Type
Array.<string>

getState( [stateMask])

Gets the current layer state

Parameters:
Name Type Argument Default Description
stateMask Object <optional>
 null

Optional mask to filter returned state properties
Inherited From:
Overrides:
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Returns:

Current state object

Type
Object

interpolateControls()

Updates control interpolation

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Returns:

Whether all interpolations are complete

Type
boolean

<async> loadTile(tile, callback)

Loads and processes a single image tile with optimized resource management. Implements request batching, concurrent loading, and proper error handling.

Parameters:
Name Type Description
tile Object

Tile specification object

Properties
Name Type Argument Description
index string

Unique tile identifier
url string

Base URL for tile resource
start number <optional>

Start byte for partial content (for tarzoom)
end number <optional>

End byte for partial content (for tarzoom)
offsets Array.<Object> <optional>

Byte offsets for interleaved formats
callback function

Completion callback(error, size)
Inherited From:
Overrides:
Source:
Throws:

If tile is already in processing queue

Type
Error
Returns:
Type
Promise.<void>

pixelSizePerMM()

Gets pixel size in millimeters

Inherited From:
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Returns:

Size of one pixel in mm

Type
number

removeShaderFilter(name)

Removes a filter from the current shader

Parameters:
Name Type Description
name Object

Filter name
Inherited From:
Overrides:
Source:
Throws:

If no shader is set

Type
Error

scale()

Gets layer scale

Inherited From:
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Returns:

Current scale value

Type
number

setControl(name, value [, dt] [, easing])

Sets a shader control value with optional animation

Parameters:
Name Type Argument Default Description
name string

Control identifier
value *

New value
dt number <optional>

Animation duration in ms
easing string <optional>
 'linear'

Easing function
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setMode(mode)

Sets shader visualization mode

Parameters:
Name Type Description
mode string

Mode to set
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setShader(id)

Sets the active shader

Parameters:
Name Type Description
id string

Shader identifier from registered shaders
Inherited From:
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Fires:
Throws:

If shader ID is not found

Type
Error

setState(state [, dt] [, easing])

Sets the layer state with optional animation

Parameters:
Name Type Argument Default Description
state Object

State object with controls and mode
dt number <optional>

Animation duration in ms
easing string <optional>
 'linear'

Easing function ('linear'|'ease-out'|'ease-in-out')
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setTransform(tx)

Sets the layer's transform

Parameters:
Name Type Description
tx Transform

New transform
Inherited From:
Overrides:
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Fires:
  • Layer#event:updateSize

setViewport(view)

Sets the layer's viewport

Parameters:
Name Type Description
view Object

Viewport specification

Properties
Name Type Description
x number

X position
y number

Y position
dx number

Width
dy number

Height
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setVisible(visible)

Sets layer visibility

Parameters:
Name Type Description
visible boolean

Whether layer should be visible
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setZindex(zindex)

Sets layer rendering order

Parameters:
Name Type Description
zindex number

Stack order value
Inherited From:
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Fires:

Events

ready

The event is fired when a layer is initialized.

Inherited From:
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update

The event is fired if a redraw is needed.

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