I am trying to listen to chart selection event; however, it didn't seem to work. Maybe my approach was not correct.
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@Listen("onPlotSelect = #chart")
public void showPoint(ChartsSelectionEvent event) {
Number pointx = event.getXAxisMax();
Number pointy = event.getYAxisMax();
Long y = pointx.longValue();
String formattedDate = TimeUtil.getFormattedTime((Long)y, "MM/dd/yyyy HH:00");
String myDateStr = new SimpleDateFormat("MM-dd-yyyy HH:00").format(pointx);
System.out.println("OnPlotSelect - Selected Date Time: " + myDateStr + " Value: " + pointx);
}
}
Maybe "click to add a point" can help you, please see https://www.zkoss.org/zkchartsdemo/dynamicclickto_add
what's the purpose of changing a data points by dragging? to create a different series on-the-fly for presentation or comparison?
I have created a feature https://tracker.zkoss.org/browse/ZKCHARTS-127
Please update use case description there, so the future implementation can fulfill your requirement.
Yes, the purpose of dragging on the particular series is to rapidly create a new different dataset for the same series on the fly for comparison. Maybe when you implement this new feature, please include ways to get arbitrary x y values in the plot area. Please see above gif.
bztom35 ( 2021-09-17 16:22:23 +0800 )editYou can call Point.getY() to get a Point's Y value.
But, currently, dragging point is just a client-side effect, zkcharts doesn't send back the changed Y value back to the server side.
After you drag a point, click the point, you call Event.getPoint().getY() still returns the point's original value, not the changed value.
However, dragging points to change its value in a series could be a feature. But considering a dragging move is usually not precise and a chart is usually a reporting tool instead of an input UI.
Could you please provide more details about use cases or related context/application background for us to evaluate this new feature?
That would be a great feature to include in the new version. I am trying to modernize some of our web start Java applications. One of the key features is to allow user to use graphical UI for data analytical interpolation. The values interpolated are rounded to the nearest hundred.
bztom35 ( 2021-09-16 00:41:20 +0800 )editAccording to your video, it seems like you want to move points by dragging, there is a similar example at zkcharts essentail examples.
I can't seem to capture the data point while dragging. I looked at the Chart 7.2.x API and can't seem to find a appropriate way to get the data. for(Point point: chart.getSelectedPoints()) { point.update(event.getXAxis(), event.getYAxis(), point.getValue());point.setSelected(false);}
bztom35 ( 2021-09-11 17:08:53 +0800 )edit
This is what I wanted to do with zkoss charts. I am using point annotation with Jfreechart.
background info:
To enable the dragging, I am listening for a combination of control + shift keys and noticed how the cursor is changing from cursor to hand pointer when enabled dragging.
I notice another problem: you should declare a ChartsEvent on your event listener according to the doc.
According to Handling Chart Events:
The zkcharts doesn't send this event before you enable "point select" by Charts.getPlotOptions().getSeries().setAllowPointSelect(true); Reference: http://api.highcharts.com/highcharts#plotOptions.series.point.events
Do you enable it?
Asked: 2021-09-02 15:36:11 +0800
Seen: 20 times
Last updated: Sep 18 '21
