This module provides a namespace for managing modules that make use of the z-axis, providing events, css classes and coding conventions that modules must use to interact with other modules that use the z-axis
Terminology and concepts
A Layer refers to the owned DOM, or portion of owned DOM, of any module that makes use of the z-axis.
A Layer context refers to a HTML element where every layer lying within it should only be concerned with other layers if they also lie within it. e.g. Within an interactive graphic any popups only need concern themselves with the state of other popups which also overlay the same graphic; they can safely disregard popups overlaying a different graphic.
document.body is the default layer context.
This class should be added to any element (other than
document.body) which needs to behave as a layer context. All layers must either
In general a new layer context should only be defined if you are very sure any layers it contains will never interfere (either through directly overlapping or by leaving a distracting, no longer needed UI element) with anything outside of it.
All layer contexts (with the exception of
document.body) should have the following css properties defined (
o-layers does not provide sass for this as there is considerable variation in acceptable values)
position- must not be
z-index- must be
0or higher (this mitigates problems with z-index of layers in nested layer contexts)
oLayers#getLayerContext(el) will return the given element's layer context.
The following custom events must be fired on a layer's closest ancestor with the class
o-layers__context (or on
document.body if no such element exists). The
Event.details property must define all the properties from the list below that are truthy for the given layer
- el - Reference to the layer's DOM node
This should be fired immediately before any layer is added to the DOM/displayed.
This should be fired immediately after any layer is removed from the DOM/hidden.
Any module which controls one or more layers must implement the following patterns:
Listen for the event
oLayers.newon the layer context of each of its layers and react to these events by either:
- closing the layer
- inspecting the new layer's owned DOM to determine what action should be taken.
Copyright (c) 2016 Financial Times Ltd. All rights reserved.
This software is published under the MIT licence.