/// <summary>
/// Works out the actual X/Y points for the each value within the
/// data and draws the line graph.
/// </summary>
private void UpdateLineGraph()
{
// Only proceed if there are some actual values and there are enough values
if (this.DataValues == null || this.DataValues.Count < 2 || container.ActualHeight == 0 || this.MaxValue <= this.MinValue)
{
GraphLine.Visibility = Visibility.Hidden;
LastPointMarkerEllipse.Visibility = Visibility.Hidden;
ScaleCurrentValue.Content = string.Empty;
return;
}
int count = this.DataValues.Count;
double max = Math.Max(this.Threshold, this.DataValues.Max());
this.MaxValue = Math.Max(DEFAULT_MAX, max);
double scale = this.MaxValue - this.MinValue;
double valuePerPoint = container.ActualHeight / scale;
double constantOffset = container.ActualWidth / Math.Min(MAX_POINTS, count);
double xOffSet = 0;
// For each item work out what the actual X/Y should be
_graphPoints.Clear();
int start = count > MAX_POINTS ? count - MAX_POINTS : 0;
for (int i = start; i < count; i++)
{
double trueDiff = this.DataValues[i] - this.MinValue;
double heightPx = trueDiff * valuePerPoint;
double yValue = container.ActualHeight - heightPx;
_graphPoints.Add(new Point(xOffSet, yValue));
xOffSet += constantOffset;
}
// Add Polygon Points
GraphLine.Points = _graphPoints;
// set LastPointMarkerEllipse
Point lastPoint = _graphPoints.Last();
LastPointMarkerEllipse.SetValue(Canvas.LeftProperty, lastPoint.X - (LastPointMarkerEllipse.Width / 2.0));
LastPointMarkerEllipse.SetValue(Canvas.TopProperty, lastPoint.Y - (LastPointMarkerEllipse.Height / 2.0));
LastPointMarkerEllipse.Visibility = Visibility.Visible;
// Set label
ScaleCurrentValue.Content = this.DataValues.Last().ToString("N0");
ScaleCurrentValue.SetValue(Canvas.LeftProperty, lastPoint.X - (LastPointMarkerEllipse.Width * 2.0));
if (lastPoint.Y < (GraphLine.ActualHeight / 2.0))
{
ScaleCurrentValue.SetValue(Canvas.TopProperty, lastPoint.Y + LastPointMarkerEllipse.Height);
}
else
{
ScaleCurrentValue.SetValue(Canvas.TopProperty, lastPoint.Y - (LastPointMarkerEllipse.Height * 3.0));
}
// Got points now so show graph
GraphLine.Visibility = Visibility.Visible;
}
/// <summary>
/// Works out the actual X/Y points for the each value within the
/// ObservableCollection<GraphDataItem> property.
/// </summary>
private void ObtainPointsForValues()
{
//Only proceed if there are some actual values and there are enough values
if (DataValues == null || container.ActualHeight == 0 || DataValues.Count < MIN_ITEMS_TO_PLOT)
{
GraphLine.Visibility = Visibility.Hidden;
LastPointMarkerEllipse.Visibility = Visibility.Hidden;
ScaleCurrentValue.Content = string.Empty;
return;
}
else
{
#region Workout Points
double scale = MaxValue - MinValue;
double valuePerPoint = container.ActualHeight / scale;
double constantOffset = container.ActualWidth / DataValues.Count;
double xOffSet = 0;
///for each item seen work out what the actual X/Y should be
///based on a bit of Maths
_graphPoints.Clear();
for (int i = 0; i < DataValues.Count; i++)
{
double trueDiff = DataValues[i] - MinValue;
double heightPx = trueDiff * valuePerPoint;
double yValue = container.ActualHeight - heightPx;
_graphPoints.Add(new Point(xOffSet, yValue));
xOffSet += constantOffset;
}
Point lastPoint = _graphPoints.Last();
//set LastPointMarkerEllipse
LastPointMarkerEllipse.SetValue(Canvas.LeftProperty, lastPoint.X - (LastPointMarkerEllipse.Width / 2));
LastPointMarkerEllipse.SetValue(Canvas.TopProperty, lastPoint.Y - (LastPointMarkerEllipse.Height / 2));
LastPointMarkerEllipse.Visibility = Visibility.Visible;
#endregion
#region Label Current Data Point
ScaleCurrentValue.Content = this.DataValues.Last().ToString("N0");
ScaleCurrentValue.SetValue(Canvas.LeftProperty, lastPoint.X - (LastPointMarkerEllipse.Width * 2));
ScaleCurrentValue.SetValue(Canvas.TopProperty, lastPoint.Y - (LastPointMarkerEllipse.Height * 2));
#endregion
//Add Polygon Points
GraphLine.Points = _graphPoints;
//Got points now so show graph
GraphLine.Visibility = Visibility.Visible;
}
}
