Easily generate patterns for use in data graphics.

Color-blindness, that's why.

This library came about as part of an issue in Chart.js.

npm install patternomaly

Generate a single canvas pattern

pattern.draw('square', '#1f77b4');

Generate an array of canvas patterns

pattern.generate([
  '#1f77b4',
  '#ff7f0e',
  '#2ca02c',
  '#d62728'
]);

There are currently 21 pattern variants available. When using the generate method (above) patterns will be 'randomly' assigned.

It is however possible to provide specific patterns using the draw method.

datasets: [{
  data: [
    300, 50, 100, 210, 140
  ],
  backgroundColor: [
    pattern.draw('square', '#1f77b4'),
    pattern.draw('circle', '#ff7f0e'),
    pattern.draw('diamond', '#2ca02c'),
    pattern.draw('zigzag-horizontal', '#17becf'),
    pattern.draw('triangle', 'rgb(255, 99, 132, 0.4)') // with opacity
  ]
}]

• plus
• cross
• dash
• cross-dash
• dot
• dot-dash
• disc
• ring
• line
• line-vertical
• weave
• zigzag
• zigzag-vertical
• diagonal
• diagonal-right-left
• square
• box
• triangle
• triangle-inverted
• diamond
• diamond-box

Thanks to obedm503 for generating the example pattern image.

In order to provide an alternative view for visually impaired viewers it's a good idea to provide a patterned alternative.

See the pattern option example page for a simple implementation of a pattern toggle switch for Chart.js.

A typings file is included in this package. Just insert import {draw, generate} from 'patternomaly' in the header of your .ts file. Still you have to add the javascript file to your build e.g. in the scripts array in angular.cli.json e.g. "scripts": ["node_modules/patternomaly/dist/patternomaly.js"].