Abstract Readonly coordsSelector for "client" Coordinate System.
This references the coordinate system used in HTML.
It starts at top left of the web page and is measured in pixels.
For example, { x: 100, y: 20 } corresponds to 100 pixels from left and 20 pixels from top.
JavaScript events are tracked and HTML elements are positioned in the client coordinate system.
This selector can be used for translating client coordinates to other coordinate systems and vice versa. For example, in order to:
See translateCoordinate for more detailed use case information and example usage.
Readonly coordsSelector for "relative" Coordinate System.
This coordinate system is relative to the bottom left corner of the Control (chart/dashboard/etc.), and is measured as pixels.
For example, { x: 100, y: 20 } corresponds to 100 pixels from left and 20 pixels from bottom.
This selector can be used for two purposes:
Positioning LCJS UI elements in pixels:
// Position UI element in pixels by supplying `Control.coordsRelative` as its positioning system.
const textBox = Control.addUIElement(UIElementBuilders.TextBox, Control.coordsRelative)
.setOrigin(UIOrigins.LeftBottom)
.setPosition({ x: 100, y: 20 })
Translations between coordinate systems:
Use with translateCoordinate method to translate coordinates from "relative" to another coordinate system.
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.
Deprecated since v4.2.0. Use coordsRelative instead. It works exactly the same.
Scale for panel area in percentages (0-100).
While it is not functionally equal to this, using coordsRelative coordinate system is preferred (more confidence for long term support).
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.coordsRelative )
// 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.coordsRelative )
// 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
Get Array of all legend boxes created using addLegendBox method.
This will not include any legend boxes that were destroyed with dispose method.
Array of legend boxes.
Abstract getGet size of control as pixels.
For stand-alone component, the size will be equal to the size of its containing HTML <div> (Control.engine.container)
For component inside Dashboard, the size will only include the component itself, so size can be less than the size of containing HTML <div>.
Object with x and y properties { x: number, y: number }, where both are pixel values.
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 inViewChange event.
This event is triggered when the chart transitions from being off-screen to being on-screen and vice versa.
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.
Translate a coordinate in HTML client coordinate system to relative coordinates within the component.
const locationClient = { clientX: document.body.clientWidth * 0.2, clientY: document.body.clientHeight * 0.5 }
const locationRelative = chart.translateCoordinate(locationClient, chart.coordsRelative)
// locationRelative is in pixels relative to bottom left corner of the chart
Relative coordinates can be used for positioning LightningChart JS UI components:
const textBox = chart.addUIElement(UIElementBuilders.TextBox, chart.coordsRelative)
// Left bottom of TextBox is positioned 20 pixels right and 20 pixels up from charts bottom left corner
.setOrigin(UIOrigins.LeftBottom)
.setPosition({ x: 20, y: 20 })
NOTE: Currently coordinate translations can't be guaranteed to be in sync with latest updates to charts.
For example, if you change axis interval, or add data to a series, you need to wait for 1 frame to be displayed before translateCoordinate will behave as expected.
LineSeries.add(myData)
requestAnimationFrame(() => {
// translateCoordinate should now consider data added just now.
})
Translate a coordinate from relative control coordinates to HTML client coordinate system.
// 10 pixels left and 20 pixels up from controls bottom left corner
const locationRelative = { x: 10, y: 20 }
const locationClient = chart.translateCoordinate(locationRelative, chart.coordsRelative, chart.coordsClient)
Client coordinates can be used to absolute position HTML elements using CSS, for example.
myHTMLElement.style.position = 'absolute'
myHTMLElement.style.left = locationClient.clientX
myHTMLElement.style.top = locationClient.clientY
NOTE: Currently coordinate translations can't be guaranteed to be in sync with latest updates to charts.
For example, if you change axis interval, or add data to a series, you need to wait for 1 frame to be displayed before translateCoordinate will behave as expected.
LineSeries.add(myData)
requestAnimationFrame(() => {
// translateCoordinate should now consider data added just now.
})
Abstract base class for charts and UI panels