Lines

[dataqip]

Is it possible to draw lines (horizontal and vertical) on the chart? Or better yet, color fill the gaps between Y-axes and when sweeping.

I want to draw lines to separate the Y-axes (in the gap when stacked) and the data gap on the X-axis when sweeping (this one needs to be updated to move along with the gap).

[ArctionPasi]

Probably best way to make separator lines in Y axis gaps area, is to use Annotations in Arrow style.

Thread-fed multi-channel example with separator lines

SeparatorLines.png (214.27 KiB) Viewed 13881 times

In ExampleThreadMultiChannel.xaml.cs, buttonStartStop_Click

Code: Select all

for (int iChannel = 0; iChannel < m_iChannelCount; iChannel++)
{
AxisY axisY = new AxisY(chartView);
axisY.SetRange(YMin, YMax);
axisY.Title.Font = new WPFFont(System.Drawing.FontFamily.GenericSansSerif, 8.0, System.Drawing.FontStyle.Regular);
axisY.Title.Text = string.Format("Ch {0}", iChannel + 1);
axisY.Title.Angle = 0;
axisY.Units.Visible = false;
chartView.YAxes.Add(axisY);

if (iChannel < m_iChannelCount - 1)
{

//Add a horizontal line to represent a line between axes, in the gap area. 
AnnotationXY annot = new AnnotationXY(chartView, chartView.XAxes[0], axisY);
annot.TargetCoordSystem = AnnotationTargetCoordinates.ScreenCoordinates;
annot.LocationCoordinateSystem = CoordinateSystem.ScreenCoordinates;
annot.Style = AnnotationStyle.Arrow;
annot.ArrowStyleEnd = ArrowStyle.None;
annot.ArrowStyleBegin = ArrowStyle.None;
annot.ArrowLineStyle.Pattern = LinePattern.DashDot;
annot.ArrowLineStyle.Width = 1;
annot.MouseInteraction = false;
annot.ArrowLineStyle.Color = System.Windows.Media.Colors.White;
annot.TextStyle.Visible = false;
chartView.Annotations.Add(annot);
}
}

and in BeforeRendering or SizeChanged event of the chart, run the following code to arrange the annotation lines between in the middle of the gaps:

Code: Select all

            m_chart.BeginUpdate();

            GraphSegmentInfo gsi = m_chart.ViewXY.GetGraphSegmentInfo();
            float fLeft = (float)m_chart.ViewXY.Margins.Left;
            float fRight = (float)(m_chart.ActualWidth - m_chart.ViewXY.Margins.Right); 
            float fSegmentTop = gsi.FirstSegmentTop;


            foreach (AnnotationXY annot in m_chart.ViewXY.Annotations)
            {
                float yCoord = fSegmentTop + gsi.SegmentHeight + gsi.GapHeight / 2f;
                annot.LocationScreenCoords.X = fLeft;
                annot.LocationScreenCoords.Y = yCoord; 
                annot.TargetScreenCoords.X = fRight;
                annot.TargetScreenCoords.Y = yCoord; 
                fSegmentTop += gsi.SegmentShift;
            }
            
            m_chart.EndUpdate(); 

To show a vertical line in the sweeping gap (real-time monitoring position), use a LineSeriesCursor. Update its ValueAtXAxis property to same value than your latest data X value is. Another approach is to use one Annotation in pretty much similar way than instructed above, but you may need to use XAxis.ValueToCoord method to convert the latest X value to location.X and target.X.

[dataqip]

I had the same idea with regards to Annotations, but thanks for the code; that helped.

The LineSeriesCursor works well, with one caveat. It's hard to get it close to the gap without disappearing. I tried using an Annotation for this as well, but I'm having trouble calculating the proper screen coordinate (it changes depending on the sweep page).

[ArctionPasi]

It seems the annotation gets clipped off if it's placed just in the the edge of sweeping gap. I'd recommend setting xAxis.SweepingGap = 0, and using the following code:

Code: Select all

            //Initialization
            chartView.XAxes[0].SweepingGap = 0; 

            AnnotationXY annotVertLine = new AnnotationXY(chartView, chartView.XAxes[0], chartView.YAxes[0]);
            annotVertLine.TargetCoordSystem = AnnotationTargetCoordinates.ScreenCoordinates;
            annotVertLine.LocationCoordinateSystem = CoordinateSystem.ScreenCoordinates;
            annotVertLine.Style = AnnotationStyle.Arrow;
            annotVertLine.ArrowStyleEnd = ArrowStyle.None;
            annotVertLine.ArrowStyleBegin = ArrowStyle.None;
            annotVertLine.ArrowLineStyle.Pattern = LinePattern.DashDot;
            annotVertLine.ArrowLineStyle.Width = 3;
            annotVertLine.MouseInteraction = false;
            annotVertLine.ArrowLineStyle.Color = System.Windows.Media.Colors.White;
            annotVertLine.TextStyle.Visible = false;
            chartView.Annotations.Add(annotVertLine); 

Code: Select all

            //Updating data 
            ...
            chartView.XAxes[0].ScrollPosition = m_dLatestX;

            //Update vertical sweep gap indicator
            float fXCoord;
            bool bInSecondPage = m_dLatestX >= chartView.XAxes[0].Maximum; 
            if(bInSecondPage)
                fXCoord = chartView.XAxes[0].ValueToCoord(m_dLatestX - (chartView.XAxes[0].Maximum - chartView.XAxes[0].Minimum));
            else 
                fXCoord = chartView.XAxes[0].ValueToCoord(m_dLatestX);


            chartView.Annotations[0].TargetScreenCoords.X =fXCoord;
            chartView.Annotations[0].TargetScreenCoords.Y = (float) chartView.Margins.Top; 

            chartView.Annotations[0].LocationScreenCoords.X = fXCoord;
            chartView.Annotations[0].LocationScreenCoords.Y = (float)(m_chart.ActualHeight - chartView.Margins.Bottom);

Then it produces a running line.

Annotation in sweeping gap

AnnotInSweepingGap.PNG (122.25 KiB) Viewed 13864 times

If you want to make the sweeping yet more stylish, you can use Band with black transparent color in the other edge, as we have made here:

Sweeping gap with band, EEG

SweepingGapWithBand.png (441.24 KiB) Viewed 13864 times

http://www.youtube.com/watch?feature=pl ... 1cEr0NAXS4

[dataqip]

Yes, that works much better. Thank you.