OpenLIME

Class: FocusContext

FocusContext

FocusContext manages the focus+context visualization technique for lens-based interaction. It handles the distribution of user interactions between lens movement (focus) and camera movement (context) to maintain optimal viewing conditions.

Key responsibilities:

  • Maintains proper spacing between lens and viewport boundaries
  • Distributes pan and zoom operations between lens and camera
  • Ensures lens stays within valid viewport bounds
  • Adapts camera transform to accommodate lens position
  • Manages lens radius constraints

new FocusContext()

Source:

Methods

<static> adaptContext(viewport, focus, context, desiredScale)

Adjusts the camera transform to ensure focus+context conditions are met for a given lens

Parameters:
Name Type Description
viewport Viewport

The current viewport
focus Focus

The lens object
context Transform

The camera transform to be updated
desiredScale number

Target scale for the camera transform
Source:

<static> pan(viewport, focus, context, delta, imageSize)

Distributes a pan operation between lens movement and camera transform to maintain focus+context

Parameters:
Name Type Description
viewport Viewport

The current viewport
focus Focus

The lens object to be updated
context Transform

The camera transform to be updated
delta Object

Pan amount in dataset pixels

Properties
Name Type Description
x number

Horizontal pan amount
y number

Vertical pan amount
imageSize Object

Dataset dimensions

Properties
Name Type Description
w number

Dataset width
h number

Dataset height
Source:

<static> scale(camera, focus, context, dz)

Distributes a scale operation between lens radius and camera zoom to maintain focus+context

Parameters:
Name Type Description
camera Camera

The camera object containing viewport and zoom constraints
focus Focus

The lens object to be updated
context Transform

The camera transform to be updated
dz number

Scale factor to be applied (multiplier)
Source: