Horseshoe meter API reference

• Example
• Properties
• Methods
• Events
• Effects

Example

<script>
    horseshoe = new RGraph.SVG.Horseshoe({
        id: 'chart-container',
        min: 0,
        max: 100,
        value: 63,
        options: {
            labelsCenterDecimals: 1,
            labelsCenterUnitsPost: '%'
        }
    }).grow();
    
    var d = 2500; setTimeout(f = function ()
    {
        horseshoe.value = horseshoe.value + RGraph.SVG.random({min: -7, max: 5});
        horseshoe.grow();
        
        setTimeout(f, d);
    }, d);
</script>

Properties

You can use these properties to control how the chart appears. You can set them by including them in the options section of the configuration as shown above.

• Chart configuration properties
• Margin properties
• Color properties
• Labels and text properties
• Other properties

Methods

obj.get(name)

This can be used to get properties if necessary. It's normally used after the chart is drawn if you need to get parameters (if you're doing custom coding for example).

obj.set(name, value)

This can be used to set properties if necessary. It's normally used after the chart is drawn if you need to set additional parameters or change them.

obj.on(event, handler)

This function adds an event listener (such as beforedraw or draw) to the chart object. For example:

obj.on('draw', function (obj)
{
    // Put your code here
});

obj.exec(func)

This function can be used to execute a function (immediately). It's not event-based (ie it doesn't run when something happens) - it just runs immediately - and only once. You might use it when you need to get something from the chart when it has been drawn and then call the redraw function. Because this function only runs once the RGraph.SVG.redraw function would not cause a loop - which would happen if you used the draw event.

obj.exec(function (obj)
{
    // Put your code here
});

obj.responsive(configuration)

The responsive function helps your charts respond to different browser window sizes and screen resolutions. For example, for smaller screens, you might want to have angled labels or show shorter versions of them completely.

Update: There is now the responsive configuration option available to you and this is now the preferred method of configuration.

The responsive function and configuration option are documented on their own page here.

obj.getAngle(event or value))

When you click on the chart this method can be used to get the corresponding angle. Angles are measured in radians and go from (approximately) -(Math.PI / 2) (middle top) to 1.5 * Math.PI. Example usage is:

<script>
    horseshoe = new RGraph.SVG.Horseshoe({
        id: 'chart-container',
        min: 0,
        max: 100,
        value: 63,
        options: {
            width: 60,
            labelsCenterDecimals: 1
        }
    }).draw();
    
    horseshoe.container.onclick = function (e)
    {
        var angle = horseshoe.getAngle(e);
        // var angle = horseshoe.getAngle(51); // You can also pass the function a value too
        
        alert(angle);
    };
</script>

obj.getValue(event or angle)

When you click on the chart this method can be used to get the corresponding value. The value is based on the minimum and maximum values. Example usage is:

<script>
    horseshoe = new RGraph.SVG.Horseshoe({
        id: 'chart-container',
        min: 0,
        max: 100,
        value: 63,
        options: {
            width: 60,
            labelsCenterDecimals: 1
        }
    }).draw();
    
    horseshoe.container.onclick = function (e)
    {
        var value = horseshoe.getValue(e);
        // var value = horseshoe.getValue(angle); // You can also pass the function an angle too
        
        alert(value);
    };
</script>

obj.getRadius(event)

When you click on the chart this method can be used to get the corresponding radius of the click starting from the center of the chart. Example usage is:

<script>
    horseshoe = new RGraph.SVG.Horseshoe({
        id: 'chart-container',
        min: 0,
        max: 100,
        value: 63,
        options: {
            width: 60,
            labelsCenterDecimals: 1
        }
    }).draw();
    
    horseshoe.container.onclick = function (e)
    {
        var radius = horseshoe.getRadius(e);
        
        alert(radius);
    };
</script>

Events

RGraph supports custom events that allow you to easily add interactivity to your charts if required. The following events are available:

• beforedraw This event fires at the start of the draw method before anything has been done.
• draw This event fires at the end of the draw function.
• firstdraw This event fires at the end of the draw function - but only the first time and so it fires only once after the first draw call.
• adjustbegin This event fires at the start of the adjusting process.
• adjust This event fires (repeatedly) during the adjusting process.
• adjustend This event fires at the end of the adjusting process.

For example:

new RGraph.SVG.Horseshoe({
    id: 'chart-container',
    min: 0,
    max: 100,
    value: 54,
    options: {
        adjustable: true
    }
}).draw().on('adjustbegin', function (obj)
{
    console.log('Adjusting has started');

}).on('adjust', function (obj)
{
    console.log('Adjusting is in progress...');

}).on('adjustend', function (obj)
{
    alert('Adjusting has finished. New value is: ' + obj.value);
});

Effects

These effects are available and can be used instead of the draw function.

• The grow effect (demo available in the download archive)

<script>
    //
    // Optional callback function that's called when the effect is complete
    //
    function myCallback (obj)
    {
        // ...
    }


    horseshoe RGraph.SVG.Horseshoe({
        id: 'chart-container',
        min: 0,
        max: 100,
        value: 63,
        options: {
            width: 60,
            labelsCenterDecimals: 1
        }
    }).grow({frames: 60, callback: myCallback});
</script>