cytoscape-canvas
v3.0.1
Published
A Cytoscape extension to enable drawing over and under a graph
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cytoscape-canvas
Description
An extension to create a canvas over or under a Cytoscape graph. Useful for customizing nodes/edges, drawing backgrounds, etc.
Demo
Dependencies
- Cytoscape.js >=3.0.0
Example
var cytoscape = require('cytoscape');
var cyCanvas = require('cytoscape-canvas');
cyCanvas(cytoscape); // Register extension
var cy = cytoscape({/* ... */});
var layer = cy.cyCanvas();
var canvas = layer.getCanvas();
var ctx = canvas.getContext('2d');
cy.on("render cyCanvas.resize", function(evt) {
layer.resetTransform(ctx);
layer.clear(ctx);
// Draw fixed elements
ctx.fillRect(0, 0, 100, 100); // Top left corner
layer.setTransform(ctx);
// Draw model elements
cy.nodes().forEach(function(node) {
var pos = node.position();
ctx.fillRect(pos.x, pos.y, 100, 100); // At node position
});
});
Usage instructions
Download the library:
- via npm:
npm install cytoscape-canvas
, - via bower:
bower install cytoscape-canvas
, or - via direct download in the repository (probably from a tag).
require()
the library as appropriate for your project:
CommonJS:
var cytoscape = require('cytoscape');
var cyCanvas = require('cytoscape-canvas');
cyCanvas(cytoscape); // Register extension
AMD:
require(['cytoscape', 'cytoscape-canvas'], function(cytoscape, cyCanvas) {
cyCanvas(cytoscape); // Register extension
});
Plain HTML/JS has the extension registered for you automatically, because no require()
is needed.
Initialisation
var cy = cytoscape({/* ... */});
var layer = cy.cyCanvas({
zIndex: 1,
pixelRatio: "auto",
});
API
layer.getCanvas()
- return: Canvas The generated canvas
layer.setTransform(ctx)
Set the context transform to match Cystoscape's zoom & pan. Further drawing will be on model position.
- param: CanvasRenderingContext2D ctx
layer.resetTransform(ctx)
Reset the context transform. Further drawing will be on rendered position.
- param: CanvasRenderingContext2D ctx
layer.clear(ctx)
Clear the entire canvas.
- param: CanvasRenderingContext2D ctx
Events
cyCanvas.resize
: When the extension's canvas is resized