HistoryProxySource QML Type
A data source that provides a history of a single item of a different data source. More...
| Import Statement: | import org.kde.quickcharts |
| Inherits: |
Properties
- fillMode : enumeration
- interval : int
- item : int
- maximumHistory : int
- source : ChartDataSource
Detailed Description
This data source will monitor a single item of another data source for changes and record them, exposing historical values as
Property Documentation
fillMode : enumeration |
The fill mode.
This determines what happens when there is not enough history yet.
The default is DoNotFill.
Note: Changing this property will clear the existing history.
| Constant | Description |
|---|---|
HistoryProxySource.DoNotFill | Do not fill with any items. The source's itemCount will be equal to the number of items in the history. |
HistoryProxySource.FillFromStart | Fill with empty values, starting at 0. The source's itemCount will be equal to maximumHistory. Items that do not have a value in the history will return a default-constructed value based on the first item of the source. |
HistoryProxySource.FillFromEnd | Fill with empty values, placing partial history at the end. This means that the first recorded history item will be shown at position maximumHistory - 1, the second at maximumHistory - 2 and so on, until maximumHistory is reached, after which items will be discarded normally. |
interval : int |
The interval, in milliseconds, with which to query the data source.
If set to a value <= 0, a new item will be added whenever source changes. Otherwise, source will be sampled every interval milliseconds and a new item will be added with whatever value it has at that point, even if it did not change.
The default is 0.
item : int |
The item of the data source to read data from.
This item will be read either when the source's dataChanged has been emitted or on an interval if interval has been set.
The default is 0.
Note: Changing this property will clear the existing history.
maximumHistory : int |
The maximum amount of history to keep.
The default is 10.
source : ChartDataSource |
The data source to read data from.
This will use the item at item from the provided source and use that to fill the history of this source.
Note: Changing this property will clear the existing history.