Feature: #76108 - Replace ExtJS category tree with D3 and SVG¶
See Issue #76108
The Backend ExtJS category tree (renderType
selectTree) has been replaced with one based on D3.js and SVG.
Tree implements a ‘virtual scroll’ pattern, meaning that it renders only as many nodes as fit in the viewport.
Additionally the tree now display icon overlay (e.g. for disabled categories).
There are three RequireJS modules:
- SvgTree.js - this is a base JS object able to render a SVG based tree. It can expand and collapse child nodes, render icons for each node, and keep track of the select nodes.
- SelectTree.js - extends the SvgTree object (prototype inheritance) with checkboxes
- SvgTreeToolbar.js - toolbar for SvgTree which allows to search, collapse all and expand all tree nodes
SvgTree renders only as many nodes as fit in the wrapping container. This requires that the wrapping container has a fixed height set. So e.g. if one node takes 20px height, and the wrapper has 200px, only 10 nodes will be rendered at the time.
Thanks to D3, each SVG node representing tree item is bound to the data object. The general idea is that all operations (like showing/hiding/selecting…) are first performed on the dataset, and then the view (SVG) is refreshed.
initialize function SvgTree loads the whole tree as json
- New tree is faster.
- A new ‘indeterminate’ state for the category has been introduced introduced. The category is in the ‘indeterminate’ state if at last one of its descendants is selected (checked).
- Tree data is not rendered inline in HTML any more but fetched via Ajax