Visual-Heatmap Js

Visual Heatmap, an open-source JavaScript module, emerges as a powerful tool designed to render large-scale heatmaps with exceptional performance. This framework is based on advanced graphical rendering - WebGL/Shaders. It can render 500,000+ data points with a good framerate.

Examples:

Installing

npm

npm i visual-heatmap --save

Or Download source code from below links

• visualHeatmap.min.js
• visualHeatmap.js
• visualHeatmap.esm.js

Usage

Importing

Visual-Heatmap offers both ES6 and UMD modules, making it possible to integrate the module into applications as needed.

import Heatmap from 'visual-heatmap'

Instance Creation API

visualHeatmap provides a API to create heatmap instance. API accepts container/containerId and config as an input. A context element will be created under the provided Div #containerId.

let instance = Heatmap('#containerId', {
        size: 30.0,  //Radius of the data point, in pixels. Default: 20
        max: 100,  // if not set, will be derived from data
        min: 0,  // if not set, will be derived from data
        intensity: 1.0, 
        background: {
            url: "urlPath",
            width: 100, // if not set, viewport width of the image will be considered
            height: 100, // if not set, viewport height of the image will be considered
            x: 0,
            y: 0
        },
        gradient: [{
            color: [0, 0, 255, 1.0],
            offset: 0
        }, {
            color: [0, 0, 255, 1.0],
            offset: 0.2
        }, {
            color: [0, 255, 0, 1.0],
            offset: 0.45
        }, {
            color: [255, 255, 0, 1.0],
            offset: 0.85
        }, {
            color: [255, 0, 0, 1.0],
            offset: 1.0
        }]
    });

Container/ContainerId : The container div element or a string CSS Query selector which identifies the container.

Config Object :

{
     size : Radius of the data point, in pixels. Default: 20
     max : Max data Value for relative gradient computation. if not set, will be derived from data.
     min : Min data Value for relative gradient computation. if not set, will be derived from data.
     intensity : intensity factor. Default: 1.0
     opacity : Opacity factor. Default: 1.0
     rotationAngle : Rotation angle. Default: 0
     translate : translate vector [x, y]. Default: [0,0]
     zoom : Zoom Factor. Default: 1.0
     gradient : Color Gradient, array of objects with color value and offset.
     background: To set background of the heatMap. Value : { url: , x: , y: , height: , width: }
}

Adding Data API

instance.renderData([])

Accepts an array of data points with 'x', 'y' and 'value'. Demo

instance.renderData([{x: , y: , value: }])

instance.addData([], transformationIntactflag);

Accepts an array of data points with 'x', 'y' and 'value' and a boolean flag to specify to apply existing heatmap transformations on the newly added data points. After adding data points, need to invoke .render() method to update the heatmap. Try Example

instance.addData([{x: , y: , value: }],transformationIntactflag)

Render API

Method to re-render the heatmap. This method needs to be invoked as and when configurations get changed. Example

instance.render()

Configuration Setting API

instance.setMax(number)

To set max data value, for relative gradient calculations.

instance.setMin(number)

To set min data value, for relative gradient calculations.

instance.setTranslate([number, number])

Api to perform translate transformation on the canvas. Accepts array[x, y] as an input. Try Example

instance.setZoom(number)

Api to perform zoom transformation on the canvas. Accepts float value as an input. Try Example

instance.setRotationAngle(number)

Api to perform rotation transformation on the canvas. Accepts angle in radians. Try Example

instance.setSize(number)

Api to set point radius. Accepts float value as an input. Try Example

instance.setGradient(gradient)

Api to set color gradient. Accepts array of objects with color value and offset.

instance.setIntensity(number)

Api to set Intensity factor. Accepts float value as an input. Try Example

instance.setOpacity(number)

Api to set Opacity factor. Accepts float value as an input. Try Example

instance.setBackgroundImage({ url: , x: , y: , height: , width: })

Api to set Background image. Accepts Object with { Url, height, width, x, and y} properties as input Try Example

instance.projection({x: , y: })

Api to get projected co-ordinates relative to the heatmap layer. Try Example

instance.resize()

Api to rerender heatmep on parent container resizes.

instance.clear()

Api to clear canvas.