Readonly engineInterface for end user API of the LCJS engine. It provides some useful capabilities over the area enclosed by a single LCJS context (which can be just a single chart, or a Dashboard with several charts).
Scale for panel area in pixels.
Scale for panel area in percentages (0-100).
Add a legendbox.
Legendbox is a type of UI element, that floats inside the chart/component it is created inside. It can be freely moved around with user interactions, as well as positioned in application code.
The purpose of legendbox is to describe the series and other visual components of the chart, by displaying their names and colors. Hovering over a series' legendbox entry will highlight that series, and clicking on the entry will toggle that series' visibility.
Legendbox alignment:
Alignment of legendbox can be selected by supplying one of the available LegendBoxBuilders to addLegendBox:
// Default (vertical) LegendBox.
const legendBox = ChartXY.addLegendBox()
// Horizontal LegendBox.
const horizontalLegendBox = ChartXY.addLegendBox(LegendBoxBuilders.HorizontalLegendBox)
Custom Legendbox positioning:
By default LegendBoxes are placed on the right side, or bottom of the chart (depending on alignment).
A custom location can be configured with UIElement API:
Position coordinate system is specified when creating legendbox.
addLegendBox( LegendBoxBuilders.VerticalLegendBox )
// Position = [0, 100] as percentages.
.setPosition({ x: 50, y: 50 })
addLegendBox( LegendBoxBuilders.VerticalLegendBox, chart.pixelScale )
// Position = pixels.
.setPosition({ x: 300, y: 100 })
addLegendBox( LegendBoxBuilders.VerticalLegendBox, { x: chartXY.getDefaultAxisX(), y: chartXY.getDefaultAxisY() } )
// Position = Axis values.
.setPosition({ x: 5, y: 5 })
LegendBox
LegendBoxBuilder. If omitted, VerticalLegendBox will be selected. Use LegendBoxBuilders for selection.
Optional parameter for altering the coordinate system used for positioning the LegendBox. Defaults to whole Chart in percentages [0, 100].
Add a stand-alone UIElement using a builder.
Example usage:
addUIElement( UIElementBuilders.TextBox )
// Position = [0, 100] as percentages.
.setPosition({ x: 50, y: 50 })
addUIElement( UIElementBuilders.TextBox, chart.pixelScale )
// Position = pixels.
.setPosition({ x: 300, y: 100 })
addUIElement( UIElementBuilders.TextBox, { x: chartXY.getDefaultAxisX(), y: chartXY.getDefaultAxisY() } )
// Position = Axis values.
.setPosition({ x: 5, y: 5 })
Object that fulfills interfaces: UIElementType (typeparam) and UIElement
Type of UIElement that is specified by 'builder'-parameter.
UIElementBuilder. If omitted, TextBoxBuilder will be selected. Use UIElementBuilders for selection.
Optional parameter for altering the coordinate system used for positioning the UIElement. Defaults to whole Chart in percentages [0, 100].
Permanently destroy the component.
To fully allow Garbage-Collection to free the resources used by the component, make sure to remove any references to the component and its children in application code.
let chart = ...ChartXY()
let axisX = chart.getDefaultAxisX()
// Dispose Chart, and remove all references so that they can be garbage-collected.
chart.dispose()
chart = undefined
axisX = undefined
Object itself for fluent interface
Subscribe to mouse-click event on Chart background
Subscribe to mouse-doubleClick event on Chart background
Subscribe to mouse-down event on Chart background
Subscribe to mouse-drag event on Chart background
Subscribe to mouse-drag start event on Chart background
Subscribe to mouse-drag stop event on Chart background
Subscribe to mouse-enter event on Chart background
Subscribe to mouse-leave event on Chart background
Subscribe to mouse-move event on Chart background
Subscribe to mouse-up event on Chart background
Subscribe to mouse-wheel event on Chart background
Subscribe to touch-end event on Chart background
Subscribe to touch-move event on Chart background
Subscribe to touch-start event on Chart background
Subscribe onDispose event.
This event is triggered whenever the Control (Dashboards and all chart types) is disposed.
// Example usage
Chart.onDispose(() => {
console.log('chert was disposed')
})
Chart.dispose()
Token of subscription
Subscribe to resize event.
This event is triggered whenever the area of chart changes (due to document or dashboard resizing).
// Example usage,
ChartXY.onResize((chart, width, height, engineWidth, engineHeight) => {
console.log('Chart resized', 'width', width, 'height', height, 'engineWidth', engineWidth, 'engineHeight', engineHeight)
})
Token of subscription
Handler function for event
Capture rendered state in an image file. Prompts the browser to download the created file.
NOTE: The download might be blocked by browser/plugins as harmful. To prevent this, only call the method in events tied to user-interactions. From mouse-event handlers, for example.
Has two optional parameters which directly reference JavaScript API HTMLCanvasElement.toDataURL. For supported image formats, compression quality, Etc. refer to:
https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toDataURL
Example usage:
// Download 'screenshot.png'
Panel.saveToFile('screenshot')
// Attempt download 'maybeNotSupported.bmp'
Panel.saveToFile('maybeNotSupported', 'image/bmp')
// Attempt download jpeg.file with specified compression quality
Panel.saveToFile('fileName', 'image/jpeg', 0.50)
If 'type' is not supported by browser, an Error will be thrown.
Name of prompted download file as string. File extension shouldn't be included as it is automatically detected from 'type'-argument.
Optional type: stringA DOMString indicating the image format. The default format type is image/png.
Optional encoderOptions: numberA Number between 0 and 1 indicating the image quality to use for image formats that use lossy compression such as image/jpeg and image/webp. If this argument is anything else, the default value for image quality is used. The default value is 0.92.
Set FillStyle of chart background.
// Example usage,
ChartXY.setBackgroundFillStyle(new SolidFill({ color: ColorRGBA( 80, 0, 0 ) }))
Related API:
Transparent chart backgrounds:
LightningChart JS charts can be configured to be fully or partially transparent.
// Example, partially transparent chart
// Engine background exists under all LCJS components. In case of Dashboard, there is only 1 shared engine background.
chart.engine.setBackgroundFillStyle(emptyFill)
// Chart background covers every 1 chart. In case of Dashboard, every chart has its own chart background.
chart.setBackgroundFillStyle(new SolidFill({ color: ColorRGBA(0, 0, 0, 100) }))
// Some charts also have a separate series background.
chart.setSeriesBackgroundFillStyle(new SolidFill({ color: ColorRGBA(0, 0, 0, 100) }))
Object itself
FillStyle or function which mutates the active FillStyle.
Set LineStyle of chart background border stroke.
// Example usage,
ChartXY.setBackgroundStrokeStyle(new SolidLine({
thickness: 2,
fillStyle: new SolidFill({ color: ColorRGBA( 0, 255, 0 ) })
}))
Related API:
Object itself
LineStyle or function which mutates the active LineStyle.
Class for a panel that can have UI elements added into it.