GChart

Properties

dataSource

type: GDataSource
required: true

The data source for the chart. This is where the chart gets its data from.

Note

Although you can update the data in the dataSource after chart being created, this property does not have a setter. If you want to change to another instance, you need to recreate the chart object.

panels

type: List<GPanel>
required: true

The list of panels in the chart. each panel has its own graphs and axes.

pointViewPort

type: GPointViewPort
required: false
default: GPointViewPort(autoScaleStrategy: const GPointViewPortAutoScaleStrategyLatest())

The viewport which controls the visible points range along the x axis on the chart.
The visible range of all panels, x axes and graphs are synchronized so there is only one instance.
Set to your own instance to customize its behavior.

background

type: GBackground
required: false
default: GBackground()

The background component which draws the background of the chart.
The default will draw a colored rectangle. extend the GBackground class to customize the background drawing.

splitter

type: GSplitter
required: false
default: GSplitter()

The splitter component which being used to resize panels. all panels share the same splitter instance.
Set to your own instance to customize.

crosshair

type: GCrosshair
required: false
default: GCrosshair()

The crosshair component which draws crosshair lines on the chart when mouse is hovered over the chart area.
Set to your own instance to customize.

pointerScrollMode

type: GPointerScrollMode
required: false
default: GPointerScrollMode.zoom

Defines the behavior of the chart when mouse wheel is scrolled over the chart area.
See the enum values for more details.

hitTestEnable

type: bool
required: false
default: true

This is for disable hit test on all components in the chart globally.
When it is set to true, whether a component can be hit by mouse events is determined by the component’s own hitTestMode property.
When it is set to false, the hitTestMode property of all components will be ignored.

area

type: Rect
required: false
default: const Rect.fromLTWH(0, 0, 500, 500)

This is for read only. the size of the chart area will be always calculated from size of parent GChartWidget widget.

minSize

type: Size
required: false
default: const Size(200, 200)

The minimum size of the chart area.

Note

The chart may draws outside of the widget area when parent GChartWidget size is smaller than the minimum size. use constraints to limit the size of the parent widget or clip the widget.

preRender

type: void Function(GChart chart, Canvas canvas, Rect area)
required: false
default: null

The pre-render callback which is called right before rendering.

Note

Do not apply any update that would cause the chart to re-paint in this callback.

postRender

type: void Function(GChart chart, Canvas canvas, Rect area)
required: false
default: null

The post-render callback which is called right after rendering.

Note

Do not apply any update that would cause the chart to re-paint in this callback.

Enums

GPointerScrollMode

values:

• none: No action when mouse wheel is scrolled over the chart area.
• zoom: Zoom in or out the chart over x axis by changing the pointViewPort’.
• move: Scroll the chart over x axis by changing the pointViewPort’.

Methods

addPanel

void addPanel(GPanel panel)

Add a panel to the chart.

Note

Do not call chart.panels.add() directly, use this method instead.

removePanel

void removePanel(GPanel panel)

Remove a panel from the chart.

Note

Do not call chart.panels.remove() directly, use this method instead.

saveAsImage

Future<Image> saveAsImage()

Export the chart as an image.

autoScaleViewports

void autoScaleViewports({
    bool resetPointViewPort = true,
    bool resetValueViewPort = true,
    bool animation = true,
})

Reset the scale of the viewports use their own auto scale strategy.

hitTestPanelGraphs

(GPanel, GGraph, GOverlayMarker?)? hitTestPanelGraphs({
    required Offset position,
})

Get hit test result of the panel graphs at the given position.
When it hits a graph, it will return the panel, graph with a null marker.
When it hits a marker, it will return the panel, graph and the marker.

repaint

void repaint({bool layout = true})

Redraw the chart. call this method when you updated the chart data or properties that requires a re-paint.