This extension creates handles on nodes that can be dragged to create edges between nodes (demo, snapping demo, compound demo, compound snapping demo)
- Cytoscape.js ^3.2.0
Download the library:
- via npm:
npm install cytoscape-edgehandles, - via bower:
bower install cytoscape-edgehandles, or - via direct download in the repository (probably from a tag).
Import the library as appropriate for your project:
ES import:
import cytoscape from 'cytoscape';
import edgehandles from 'cytoscape-edgehandles';
cytoscape.use( edgehandles );CommonJS require:
let cytoscape = require('cytoscape');
let edgehandles = require('cytoscape-edgehandles');
cytoscape.use( edgehandles ); // register extensionAMD:
require(['cytoscape', 'cytoscape-edgehandles'], function( cytoscape, edgehandles ){
edgehandles( cytoscape ); // register extension
});Plain HTML/JS has the extension registered for you automatically, because no require() is needed.
You initialise the extension on the Cytoscape instance:
let cy = cytoscape({
container: document.getElementById('#cy'),
/* ... */
});
// the default values of each option are outlined below:
let defaults = {
preview: true, // whether to show added edges preview before releasing selection
hoverDelay: 150, // time spent hovering over a target node before it is considered selected
handleNodes: 'node', // selector/filter function for whether edges can be made from a given node
snap: false, // when enabled, the edge can be drawn by just moving close to a target node
snapThreshold: 50, // the target node must be less than or equal to this many pixels away from the cursor/finger
snapFrequency: 15, // the number of times per second (Hz) that snap checks done (lower is less expensive)
noEdgeEventsInDraw: false, // set events:no to edges during draws, prevents mouseouts on compounds
disableBrowserGestures: true, // during an edge drawing gesture, disable browser gestures such as two-finger trackpad swipe and pinch-to-zoom
handlePosition: function( node ){
return 'middle top'; // sets the position of the handle in the format of "X-AXIS Y-AXIS" such as "left top", "middle top"
},
handleInDrawMode: false, // whether to show the handle in draw mode
edgeType: function( sourceNode, targetNode ){
// can return 'flat' for flat edges between nodes or 'node' for intermediate node between them
// returning null/undefined means an edge can't be added between the two nodes
return 'flat';
},
loopAllowed: function( node ){
// for the specified node, return whether edges from itself to itself are allowed
return false;
},
nodeLoopOffset: -50, // offset for edgeType: 'node' loops
nodeParams: function( sourceNode, targetNode ){
// for edges between the specified source and target
// return element object to be passed to cy.add() for intermediary node
return {};
},
edgeParams: function( sourceNode, targetNode, i ){
// for edges between the specified source and target
// return element object to be passed to cy.add() for edge
// NB: i indicates edge index in case of edgeType: 'node'
return {};
},
ghostEdgeParams: function(){
// return element object to be passed to cy.add() for the ghost edge
// (default classes are always added for you)
return {};
},
show: function( sourceNode ){
// fired when handle is shown
},
hide: function( sourceNode ){
// fired when the handle is hidden
},
start: function( sourceNode ){
// fired when edgehandles interaction starts (drag on handle)
},
complete: function( sourceNode, targetNode, addedEles ){
// fired when edgehandles is done and elements are added
},
stop: function( sourceNode ){
// fired when edgehandles interaction is stopped (either complete with added edges or incomplete)
},
cancel: function( sourceNode, cancelledTargets ){
// fired when edgehandles are cancelled (incomplete gesture)
},
hoverover: function( sourceNode, targetNode ){
// fired when a target is hovered
},
hoverout: function( sourceNode, targetNode ){
// fired when a target isn't hovered anymore
},
previewon: function( sourceNode, targetNode, previewEles ){
// fired when preview is shown
},
previewoff: function( sourceNode, targetNode, previewEles ){
// fired when preview is hidden
},
drawon: function(){
// fired when draw mode enabled
},
drawoff: function(){
// fired when draw mode disabled
}
};
let eh = cy.edgehandles( defaults );The object returned by cy.edgehandles() has several functions available on it:
start( sourceNode ): manually start the gesture (as if the handle were already held)stop(): manually completes or cancels the gesturehide(): remove the handle node from the graphdisable(): disables edgehandles behaviourenable(): enables edgehandles behaviourenableDrawMode(): turn on draw mode (the entire node body acts like the handle)disableDrawMode(): turn off draw modedestroy(): remove edgehandles behaviour
These classes can be used for styling the graph as it interacts with the extension:
eh-handle: The handle nodeeh-source: The source nodeeh-target: A target nodeeh-preview: Preview elements (used withoptions.preview: true)eh-hover: Added to nodes as they are hovered over as targetseh-ghost-node: The ghost node (target)eh-ghost-edge: The ghost handle line edgeeh-ghost: A ghost elementeh-presumptive-target: A node that, during an edge drag, may become a target when releasedeh-preview-active: Applied to the source, target, and ghost edge when the preview is active
During the course of a user's interaction with the extension, several events are generated and triggered on the core. Each event callback has a number of extra parameters, and certain events have associated positions.
ehshow: when the handle is shown(event, sourceNode)event.position: handle position
ehhide: when the handle is hidden(event, sourceNode)event.position: handle position
ehstart: when the edge creation gesture starts(event, sourceNode)event.position: handle position
ehcomplete: when the edge is created(event, sourceNode, targetNode, addedEles)event.position: cursor/finger position
ehstop: when the edge creation gesture is stopped (either successfully completed or cancelled)(event, sourceNode)event.position: cursor/finger position
ehcancel: when the edge creation gesture is cancelled(event, sourceNode, cancelledTargets)event.position: cursor/finger position
ehhoverover: when hovering over a target(event, sourceNode, targetNode)event.position: cursor/finger position
ehhoverout: when leaving a target node(event, sourceNode, targetNode)event.position: cursor/finger position
ehpreviewon: when a preview is shown(event, sourceNode, targetNode, previewEles)event.position: cursor/finger position
ehpreviewoff: when the preview is removed(event, sourceNode, targetNode, previewEles)event.position: cursor/finger position
ehdrawon: when draw mode is enabled(event)
ehdrawoff: when draw mode is disabled(event)
Example binding:
cy.on('ehcomplete', (event, sourceNode, targetNode, addedEles) => {
let { position } = event;
// ...
});npm run test: Run Mocha tests in./testnpm run build: Build./src/**intocytoscape-edgehandles.jsnpm run watch: Automatically build on changes with live reloading (N.b. you must already have an HTTP server running)npm run dev: Automatically build on changes with live reloading with webpack dev servernpm run lint: Run eslint on the source
N.b. all builds use babel, so modern ES features can be used in the src.
This project is set up to automatically be published to npm and bower. To publish:
- Build the extension :
npm run build:release - Commit the build :
git commit -am "Build for release" - Bump the version number and tag:
npm version major|minor|patch - Push to origin:
git push && git push --tags - Publish to npm:
npm publish . - If publishing to bower for the first time, you'll need to run
bower register cytoscape-edgehandles https://github.com/cytoscape/edgehandles.gita - Make a new release for Zenodo.