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 enginePublic, safe interface of rendering engine.
Add callback function to be triggered when specified event is fired.
// Example syntax
object.addEventListener('click', (event) => {
console.log(event)
})
Some classes also report extra information about the interacted object with the second parameter:
// Most series share information about interacted data point
series.addEventListener('click', (event, info) => {
console.log(info)
})
Optional third parameter allows registering event handlers that will automatically remove themselves after first trigger:
// Example this listener will only fire once
object.addEventListener('click', (event) => {})
Each class has its own list of supported events.
Some events are from HTML standard (click, pointerdown, etc.),
while others are own events from LightningChart JS (dispose, resize, etc.)
To find what events are available, you can try following:
TypeScript enabled, just write addEventListener and see what possible event types the IDE suggests. These APIs are strongly typed, and even the callback event will be correctly typed.K type parameter extends.Callback function that is triggered when event is fired.
Optional info: unknownOptional options: LCJSAddEventListenerOptionsOptional extra configuration options.
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
Optional builder: UILegendBoxBuilder<InternalBackground>LegendBoxBuilder. If omitted, VerticalLegendBox will be selected. Use LegendBoxBuilders for selection.
Optional scale: UserScaleDefinitionOptional 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.
Optional uiElementBuilder: UIElementBuilder<UIElementType>Optional scale: UserScaleDefinitionOptional parameter for altering the coordinate system used for positioning the UIElement. Defaults to whole component in percentages [0, 100].
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.
Get 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.
Remove event listener added using addEventListener.
The expected argument should be the exact same callback function that was supplied using addEventListener:
// Basic example syntax
const listener = () => {}
obj.addEventListener('click', listener)
obj.removeEventListener('click', listener)
// Basic boilerplate of custom interaction when user drags on an object
obj.addEventListener('pointerdown', (eventDown) => {
let prevCoord = eventDown
const handlePointerMove: LCJSInteractionEventListener<'pointermove'> = (eventMove) => {
const delta = { x: eventMove.clientX - prevCoord.clientX, y: eventMove.clientY - prevCoord.clientY }
prevCoord = eventMove
console.log(delta, eventMove.clientX, eventMove.clientY)
}
const handlePointerUp: LCJSInteractionEventListener<'pointerup'> = (eventUp) => {
window.removeEventListener('pointermove', handlePointerMove)
window.removeEventListener('pointerup', handlePointerUp)
}
window.addEventListener('pointermove', handlePointerMove)
window.addEventListener('pointerup', handlePointerUp)
})
Listener that was added using addEventListener.
Optional info: unknownCapture 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'
saveToFile('screenshot')
// Attempt download 'maybeNotSupported.bmp'
saveToFile('maybeNotSupported', 'image/bmp')
// Attempt download jpeg.file with specified compression quality
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.
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 super class for a Control. Meaning a stand-alone Charting component, which owns a rendering Engine. Eq. Panel, Dashboard, ...