OpenLIME

Class: LayerLens

LayerLens

LayerLens implements a magnifying lens effect that can display content from one or two layers. It provides an interactive lens that can be moved and resized, showing different layer content inside and outside the lens area.

Features:

  • Interactive lens positioning and sizing
  • Support for base and overlay layers
  • Animated transitions
  • Customizable border appearance
  • Dashboard UI integration
  • Optimized viewport rendering

Technical Details:

  • Uses framebuffer composition for layer blending
  • Implements viewport optimization for performance
  • Handles coordinate transformations between systems
  • Supports animated parameter changes
  • Manages WebGL resources efficiently

new LayerLens(options)

Creates a new LayerLens instance

Parameters:
Name Type Description
options LayerLensOptions

Configuration options
Source:
Throws:

If camera is not provided

Type
Error
Example
```javascript
// Create lens with base layer
const lens = new OpenLIME.LayerLens({
  camera: viewer.camera,
  radius: 150,
  borderEnable: true,
  borderColor: [0, 0, 0, 1]
});

// Set layers
lens.setBaseLayer(baseLayer);
lens.setOverlayLayer(overlayLayer);

// Animate lens position
lens.setCenter(500, 500, 1000, 'ease-out');

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

Extends

Methods

addControl(name, value)

Adds a shader parameter control

Parameters:
Name Type Description
name string

Control identifier
value *

Initial value
Inherited From:
Overrides:
Source:
Throws:

If control already exists

Type
Error

addShader(id, shader)

Adds a shader to the layer's available shaders

Parameters:
Name Type Description
id string

Unique identifier for the shader
shader Shader

Shader instance to add
Inherited From:
Overrides:
Source:
Throws:

If shader with the same id already exists

Type
Error
Returns:

This layer instance for method chaining

Type
Layer
Example
```javascript
const customShader = new OpenLIME.Shader({...});
layer.addShader('custom', customShader);
layer.setShader('custom');
```

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

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

derive( [options])

Creates a new Layer that shares tiles with this layer but uses a different shader. This method allows efficient creation of derivative layers that share the same source textures, which is useful for applying different visual effects to the same image data without duplicating resources.

Parameters:
Name Type Argument Default Description
options Object <optional>
 {}

Options for the new layer

Properties
Name Type Argument Description
shaders Object <optional>

Map of shaders for the new layer
defaultShader string <optional>

ID of shader to set as active
label string <optional>

Label for the new layer (defaults to original label)
zindex number <optional>

Z-index for the new layer (defaults to original + 1)
visible boolean <optional>

Layer visibility (defaults to same as original)
transform Transform <optional>

Custom transform (defaults to copy of original)
mipmapBias number <optional>

Custom mipmap bias (defaults to original value)
pixelSize number <optional>

Custom pixel size (defaults to original value)
debug boolean <optional>

Debug mode flag (defaults to original value)
Inherited From:
Overrides:
Source:
Returns:

A new layer sharing textures with this one

Type
Layer
Example
```javascript
// Create a derived layer with edge detection shader
const enhancedShader = new OpenLIME.ShaderEdgeDetection();
const derivedLayer = originalLayer.derive({
    label: 'Edge Detection',
    shaders: { 'edge': enhancedShader },
    defaultShader: 'edge',
    zindex: 10
});
viewer.addLayer('edges', derivedLayer);
```
or
```javascript
const enhancedShader = new OpenLIME.ShaderEdgeDetection();
const derivedLayer = layer.derive({
    label: 'Enhanced Image'
});
derivedLayer.addShader('enhanced', enhancedShader);
derivedLayer.setShader('enhanced');
viewer.addLayer('Enhanced Image', derivedLayer);
```

getBorderColor()

Gets current border color

Source:
Returns:

RGBA color array

Type
Array.<number>

getBorderWidth()

Gets current border width

Source:
Returns:

Border width in pixels

Type
number

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:
Source:

getCurrentCenter()

Gets current lens center position

Source:
Returns:

Center position in scene coordinates

Type
Object

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

Inherited From:
Overrides:
Source:
Returns:

Array of available modes

Type
Array.<string>

getPixelValues(x, y)

Gets pixel values for a specific pixel location Works with both single images and tiled formats

Parameters:
Name Type Description
x number

X coordinate in image space (0,0 at top-left)
y number

Y coordinate in image space (0,0 at top-left)
Inherited From:
Overrides:
Source:
Returns:

Array containing RGBA values for each raster at the specified pixel

Type
Array.<Uint8Array>

getRadius()

Gets current lens radius

Source:
Returns:

Current radius in pixels

Type
number

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:
Source:
Returns:

Current state object

Type
Object

getTargetCenter()

Gets target lens position for ongoing animation

Source:
Returns:

Target position in scene coordinates

Type
Object

interpolateControls()

Updates control interpolation

Inherited From:
Overrides:
Source:
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:
Overrides:
Source:
Returns:

Size of one pixel in mm

Type
number

regenerateFrameBuffers(layer)

Sets the overlay layer (shown inside lens)

Parameters:
Name Type Description
layer Layer

Overlay layer instance
Source:

removeOverlayLayer()

Removes the overlay layer, returning to single layer mode

Source:

removeShader(id)

Removes a shader from the layer's available shaders

Parameters:
Name Type Description
id string

Identifier of the shader to remove
Inherited From:
Overrides:
Source:
Throws:

If shader with the specified id doesn't exist

Type
Error
Returns:

This layer instance for method chaining

Type
Layer
Example
```javascript
// Remove a shader that's no longer needed
layer.removeShader('oldEffect');
```

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

setBaseLayer(layer)

Sets the base layer (shown inside lens)

Parameters:
Name Type Description
layer Layer

Base layer instance
Source:
Fires:

setCenter(x, y [, delayms] [, easing])

Sets lens center position with optional animation

Parameters:
Name Type Argument Default Description
x number

X coordinate in scene space
y number

Y coordinate in scene space
delayms number <optional>
 100

Animation duration
easing string <optional>
 'linear'

Animation easing function
Source:

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
Inherited From:
Overrides:
Source:
Fires:

setMode(mode)

Sets shader visualization mode

Parameters:
Name Type Description
mode string

Mode to set
Inherited From:
Overrides:
Source:
Fires:

setOverlayLayer(layer)

Sets the overlay layer (shown outside lens)

Parameters:
Name Type Description
layer Layer

Overlay layer instance
Source:

setRadius(radius [, delayms] [, easing])

Sets lens radius with optional animation

Parameters:
Name Type Argument Default Description
radius number

New radius in pixels
delayms number <optional>
 100

Animation duration
easing string <optional>
 'linear'

Animation easing function
Source:

setShader(id)

Sets the active shader

Parameters:
Name Type Description
id string

Shader identifier from registered shaders
Inherited From:
Overrides:
Source:
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')
Inherited From:
Overrides:
Source:

setTransform(tx)

Sets the layer's transform

Parameters:
Name Type Description
tx Transform

New transform
Inherited From:
Overrides:
Source:
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
Inherited From:
Overrides:
Source:
Fires:

setVisible(visible)

Sets layer visibility and updates dashboard if present

Parameters:
Name Type Description
visible boolean

Whether layer should be visible
Inherited From:
Overrides:
Source:
Fires:

setZindex(zindex)

Sets layer rendering order

Parameters:
Name Type Description
zindex number

Stack order value
Inherited From:
Overrides:
Source:
Fires:

Events

ready

The event is fired when a layer is initialized.

Inherited From:
Overrides:
Source:

update

The event is fired if a redraw is needed.

Inherited From:
Overrides:
Source: