NETTutorial13

From Steema Software Reference Wiki
Revision as of 12:15, 22 April 2016 by Clive (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Net.png

Contents page
Previous | Next

Tutorial13 - Custom Drawing on the Chart Panel


TeeChart offers extensive custom drawing facilities via the Canvas object. With Canvas you may add shapes, lines and text anywhere on the Chart Panel and define their colours, pen and brush styles.

TeeChart Canvas

Drawing order

When using TeeChart's Canvas methods remember that drawing order is important. Drawing a Line on the Chart then adding Series data points will cause the Line to be overdrawn.  
There are four principle Chart draw events, which are, in order:

  • BeforeDraw event
  • BeforeDrawAxes event
  • BeforeDrawSeries event
  • AfterDraw event
[C#] 
private bool afterDraw;
private bool beforeDraw;
private bool beforeDrawAxis;
private bool beforeDrawSeries;

private void Form1_Load(object sender, System.EventArgs e) {  
     SetFlags(ref beforeDraw);
     Bar bar1 = new Bar(tChart1.Chart);
     bar1.FillSampleValues(20);
     radioButton1.Checked = true;
}
private void SetFlags(ref bool Flag) {
     beforeDraw = false;
     afterDraw = false;
     beforeDrawAxis = false;
     beforeDrawSeries = false;
     Flag = true;
}
private void DrawShape(Steema.TeeChart.Drawing.Graphics3D gg) {
     gg.Brush.Color = Color.Yellow;
     gg.Pen.Visible = true;
     gg.Pen.Style = System.Drawing.Drawing2D.DashStyle.Dash;
     gg.Brush.Visible = true;
     gg.Ellipse(1,1,gg.Chart.Width - 1,gg.Chart.Height - 1);
}
private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
     if(afterDraw) {
     DrawShape(g);
    }
}
private void tChart1_BeforeDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
     if(beforeDraw) {
     DrawShape(g);
    }
}
private void tChart1_BeforeDrawAxes(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
     if(beforeDrawAxis) {
     DrawShape(g);
    }
}
private void tChart1_BeforeDrawSeries(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
     if(beforeDrawSeries) {
     DrawShape(g);
    }
}
private void radioButton4_Click(object sender, System.EventArgs e) {
     SetFlags(ref afterDraw);
     tChart1.Refresh();
}
private void radioButton3_Click(object sender, System.EventArgs e) {
     SetFlags(ref beforeDrawSeries);
     tChart1.Refresh();
}
private void radioButton2_Click(object sender, System.EventArgs e) {
     SetFlags(ref beforeDrawAxis);
     tChart1.Refresh();
}
private void radioButton1_Click(object sender, System.EventArgs e) {
     SetFlags(ref beforeDraw);
     tChart1.Refresh();
}

[VB.Net]    
Private BeforeDraw As Boolean
Private BeforeDrawAxis As Boolean
Private BeforeDrawSeries As Boolean
Private AfterDraw As Boolean

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    SetFlags(BeforeDraw)
    Dim Bar1 As New Steema.TeeChart.Styles.Bar(TChart1.Chart)
    Bar1.FillSampleValues(20)
    RadioButton1.Checked = True
End Sub
Private Sub SetFlags(ByRef Flag As Boolean)
    BeforeDraw = False
    BeforeDrawAxis = False
    BeforeDrawSeries = False
    AfterDraw = False
    Flag = True
End Sub
Private Sub DrawShape(ByVal gg As Steema.TeeChart.Drawing.Graphics3D)
    gg.Brush.Color = Color.Yellow
    gg.Pen.Visible = True
    gg.Pen.Style = Drawing.Drawing2D.DashStyle.Dash
    gg.Brush.Visible = True
    gg.Ellipse(1, 1, gg.Chart.Width - 1, gg.Chart.Height - 1)
End Sub
Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
    If AfterDraw = True Then
     DrawShape(g)
    End If
End Sub
Private Sub TChart1_BeforeDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDraw
    If BeforeDraw = True Then
     DrawShape(g)
    End If
End Sub
Private Sub TChart1_BeforeDrawAxes(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDrawAxes
    If BeforeDrawAxis = True Then
     DrawShape(g)
    End If
End Sub
Private Sub TChart1_BeforeDrawSeries(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDrawSeries
    If BeforeDrawSeries = True Then
     DrawShape(g)
    End If
End Sub
Private Sub RadioButton4_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton4.Click
    SetFlags(AfterDraw)
    TChart1.Refresh()
End Sub
Private Sub RadioButton3_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton3.Click
    SetFlags(BeforeDrawSeries)
    TChart1.Refresh()
End Sub
Private Sub RadioButton2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton2.Click
    SetFlags(BeforeDrawAxis)
    TChart1.Refresh()
End Sub
Private Sub RadioButton1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton1.Click
    SetFlags(BeforeDraw)
    TChart1.Refresh()
End Sub

Ensuring that custom drawn items are saved to the Canvas

If you do not place calls to Canvas draw code in one of the Chart events, custom drawing will not be saved to the Canvas permanently thus causing any addition to be lost when an application is minimised or another Window placed over it. Your code does not need to reside directly in the Chart events; user drawn items can be saved for the life of the Chart window if you place code in BeforeDrawSeries/AfterDraw and check for flags set by your runtime Draw methods thus running your draw code when activity is flagged as true, as in the example above.

Drawing Lines

Let's add a Canvas Line:
Example (drawing a line diagonally from top left to bottom right)


[C#] 
private void Form1_Load(object sender, System.EventArgs e) {
        line1.FillSampleValues(20);
        line1.VertAxis = VerticalAxis.Both;
        line1.HorizAxis = HorizontalAxis.Both;
        tChart1.Aspect.View3D = false;
}

private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        Point s = new Point(tChart1.Axes.Left.Position, tChart1.Axes.Top.Position);
        Point e = new Point(tChart1.Axes.Right.Position, tChart1.Axes.Bottom.Position);
        g.MoveTo(s);
        g.LineTo(e,0);
}

[VB.Net]
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Line1.FillSampleValues(20)
        Line1.VertAxis = Steema.TeeChart.VerticalAxis.Both
        Line1.HorizAxis = Steema.TeeChart.HorizontalAxis.Both
        TChart1.Aspect.View3D = False
End Sub

Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim S As New Point(TChart1.Axes.Left.Position, TChart1.Axes.Top.Position)
        Dim E As New Point(TChart1.Axes.Right.Position, TChart1.Axes.Bottom.Position)
        g.MoveTo(S)
        g.LineTo(E, 0)
End Sub



On a 3D Chart the Axis positions are offset from the Chart area due to 3D orthogonal displacement. We can move the Line accordingly:
Example (drawing a Line diagonally from top left to bottom right in the Chart Area of a 3D Chart)

[C#] 
private void Form1_Load(object sender, System.EventArgs e) {
        line1.FillSampleValues(20);
        line1.VertAxis = VerticalAxis.Both;
        line1.HorizAxis = HorizontalAxis.Both;
        tChart1.Aspect.Chart3DPercent = 50;
}

private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        Steema.TeeChart.Drawing.Point3D s = new Steema.TeeChart.Drawing.Point3D();
        s.X = tChart1.Axes.Left.Position;
        s.Y = tChart1.Axes.Top.Position;
        s.Z = 0;

        Steema.TeeChart.Drawing.Point3D e = new Steema.TeeChart.Drawing.Point3D();
        e.X = tChart1.Axes.Right.Position;
        e.Y = tChart1.Axes.Bottom.Position;
        e.Z = tChart1.Aspect.Width3D;
    
        g.MoveTo(s);
        g.LineTo(e);
}

[VB.Net]
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Line1.FillSampleValues(20)
        Line1.VertAxis = Steema.TeeChart.VerticalAxis.Both
        Line1.HorizAxis = Steema.TeeChart.HorizontalAxis.Both
        TChart1.Aspect.Chart3DPercent = 50
End Sub

Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim S As New Steema.TeeChart.Drawing.Point3D()
        S.X = TChart1.Axes.Left.Position
        S.Y = TChart1.Axes.Top.Position
        S.Z = 0

        Dim E As New Steema.TeeChart.Drawing.Point3D()
        E.X = TChart1.Axes.Right.Position
        E.Y = TChart1.Axes.Bottom.Position
        E.Z = TChart1.Aspect.Width3D

        g.MoveTo(S)
        g.LineTo(E)
End Sub

Canvas Pen and Brush

The Line above is drawn using the Pen and Brush defined for the last object drawn before the Line is drawn. That may or may not be the Pen you want. Change the Pen accordingly:
Example (define Pen before drawing the Line)

[C#] 
private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        Point p5 = new Point(line1.CalcXPos(5), line1.CalcYPos(5));
        Point p15 = new Point(line1.CalcXPos(15), line1.CalcYPos(15));
        g.Pen.DashCap = System.Drawing.Drawing2D.DashCap.Triangle;
        g.Pen.EndCap = System.Drawing.Drawing2D.LineCap.DiamondAnchor;
        g.Pen.Style = System.Drawing.Drawing2D.DashStyle.DashDotDot;
        g.Pen.Transparency = 70;
        g.Pen.Width = 3;
        g.Pen.Color = Color.BlueViolet;
        g.MoveTo(p5);
        g.LineTo(p15, 0);
}

[VB.Net]
Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim P5 As New Point(Line1.CalcXPos(5), Line1.CalcYPos(5))
        Dim P15 As New Point(Line1.CalcXPos(15), Line1.CalcYPos(15))
        g.Pen.DashCap = System.Drawing.Drawing2D.DashCap.Triangle
        g.Pen.EndCap = System.Drawing.Drawing2D.LineCap.DiamondAnchor
        g.Pen.Style = System.Drawing.Drawing2D.DashStyle.DashDotDot
        g.Pen.Transparency = 70
        g.Pen.Width = 3
        g.Pen.Color = Color.BlueViolet
        g.MoveTo(P5)
        g.LineTo(P15, 0)
End Sub

Adding 2D Shapes

Add Canvas Shapes in a similar manner to Canvas Lines. The following example adds a Rectangle in the centre of the Chart Area:
2D Charts only support 2D shapes.
Example
2D Charts

[C#] 
private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        Size s = new Size(100,100);
        Point l = new Point(g.ChartXCenter - (s.Width / 2), g.ChartYCenter - (s.Height / 2));
        Rectangle r = new Rectangle(l,s);
        g.Pen.Color = Color.Aquamarine;
        g.Brush.Color = Color.Blue;
        g.Rectangle(r);
}

[VB.Net]
Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim S As New Size(100, 100)
        Dim L As New Point(g.ChartXCenter - (S.Width / 2), g.ChartYCenter - (S.Height / 2))
        Dim R As New Rectangle(L, S)
        g.Pen.Color = Color.Aquamarine
        g.Brush.Color = Color.Blue
        g.Rectangle(R)
End Sub


3D Charts
On a 3D Chart you can move the Rectangle in a Z plane too. See the RectangleWithZ method. This example places the Rectangle on the Left Wall but displaces it halfway towards the rear of the Chart (towards the Back Wall).

[C#] 
private void Form1_Load(object sender, System.EventArgs e) {
        point3DSeries1.LinePen.Visible = false;
        point3DSeries1.FillSampleValues(20);
        point3DSeries1.VertAxis = VerticalAxis.Both;
        point3DSeries1.HorizAxis = HorizontalAxis.Both;
        tChart1.Aspect.Chart3DPercent = 50;
        tChart1.Axes.Depth.Visible = true;
}

private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        Size s = new Size(100,100);
        Point l = new Point(tChart1.Axes.Left.Position, g.ChartYCenter - (s.Height / 2));
        Rectangle r = new Rectangle(l,s);
        g.Pen.Color = Color.Aquamarine;
        g.Brush.Color = Color.Blue;
        g.Rectangle(r, tChart1.Aspect.Width3D/2);
}

[VB.Net]
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Point3DSeries1.LinePen.Visible = False
        Point3DSeries1.FillSampleValues(20)
        Point3DSeries1.VertAxis = Steema.TeeChart.VerticalAxis.Both
        Point3DSeries1.HorizAxis = Steema.TeeChart.HorizontalAxis.Both
        TChart1.Aspect.Chart3DPercent = 50
        TChart1.Axes.Depth.Visible = True
End Sub

Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim S As New Size(100, 100)
        Dim L As New Point(TChart1.Axes.Left.Position, g.ChartYCenter - (S.Height / 2))
        Dim R As New Rectangle(L, S)
        g.Pen.Color = Color.Aquamarine
        g.Brush.Color = Color.Blue
        g.Rectangle(R, TChart1.Aspect.Width3D / 2)
End Sub

Adding 3D Shapes

You may add 3D shapes to 3D Charts. This example draws a Cube in the middle of the Chart rectangle:

[C#] 
private void Form1_Load(object sender, System.EventArgs e) {
        point3DSeries1.LinePen.Visible = false;
        point3DSeries1.FillSampleValues(20);
        tChart1.Aspect.Chart3DPercent = 50;
        tChart1.Legend.Visible = false;
        tChart1.Axes.Depth.Visible = true;
}

private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        Size s = new Size(50,50);
        Point p = new Point(g.ChartXCenter - (s.Width/2), g.ChartYCenter - (s.Height/2));
        Rectangle r = new Rectangle(p,s);
        g.Cube(r, 0, 20, true);
}

[VB.Net]
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Point3DSeries1.LinePen.Visible = False
        Point3DSeries1.FillSampleValues(20)
        TChart1.Aspect.Chart3DPercent = 50
        TChart1.Legend.Visible = False
        TChart1.Axes.Depth.Visible = True
End Sub

Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim S As New Size(50, 50)
        Dim P As New Point(g.ChartXCenter - (S.Width / 2), g.ChartYCenter - (S.Height / 2))
        Dim R As New Rectangle(P, S)
        g.Cube(R, 0, 20, True)
End Sub

Adding text

2D Text location Add Text to the last Rectangle:
Example

[C#] 
private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        string text = "My Text";
        Size s = new Size(150, 50);
        Point p = new Point(g.ChartXCenter - (s.Width/2), g.ChartYCenter - (s.Height/2));
        Rectangle r = new Rectangle(p,s);
        g.Pen.Color = Color.Blue;
        g.Rectangle(r);

        g.TextOut(Convert.ToInt32(g.ChartXCenter - (g.TextWidth(text)/2)), Convert.ToInt32(g.ChartYCenter - (g.TextHeight(text)/2)), text);
}

[VB.Net]
Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim Text As String = "My Text"
        Dim S As New Size(50, 50)
        Dim P As New Point(g.ChartXCenter - (S.Width / 2), g.ChartYCenter - (S.Height / 2))
        Dim R As New Rectangle(P, S)
        g.Pen.Color = Color.Blue
        g.Rectangle(R)

        g.TextOut(Convert.ToInt32(g.ChartXCenter - (g.TextWidth(Text) / 2)), Convert.ToInt32(g.ChartYCenter - (g.TextHeight(Text) / 2)), Text)
End Sub


3D Text location
You can place Text in a differing 3D plane by using the TextOut overload with a z coordinate. Example

[C#] 
private void Form1_Load(object sender, System.EventArgs e) {
        point3DSeries1.FillSampleValues(20);
        point3DSeries1.LinePen.Visible = false;
        tChart1.Aspect.Chart3DPercent = 50;
}

private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        string text = "My Text";
        g.TextOut(g.ChartXCenter, g.ChartYCenter, tChart1.Aspect.Width3D / 2, text);
}

[VB.Net]
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Point3DSeries1.FillSampleValues(20)
        Point3DSeries1.LinePen.Visible = False
        TChart1.Aspect.Chart3DPercent = 50
End Sub

Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        Dim Text As String = "My Text"
        g.TextOut(g.ChartXCenter, g.ChartYCenter, TChart1.Aspect.Width3D / 2, Text)
End Sub

Applied example

This example takes the 3rd and 10th values of a Series, plots a Line between them and tells us the value of the first and Last point of the new Line and the difference between them:
Example

[C#] 
private void Form1_Load(object sender, System.EventArgs e) {
        tChart1.Aspect.View3D = false;
        line1.FillSampleValues(20);
}

private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {
        if(tChart1.Series.Count > 0){
            if(tChart1.Series[0].Count > 10) {
                Series s = tChart1.Series[0];
                int h = Convert.ToInt32(g.TextHeight("H"));
                Point p1 = new Point(s.CalcXPos(3), s.CalcYPos(3));
                Point p2 = new Point(s.CalcXPos(10), s.CalcYPos(10));
                g.Pen.Color = Color.Blue;
                g.Pen.Width = 2;
                g.Pen.Style = System.Drawing.Drawing2D.DashStyle.Dash;
                g.MoveTo(p1);
                g.LineTo(p2, 0);
                g.TextOut(p1.X, p1.Y - h, "Point value: " s.YValues[3].ToString());
                g.TextOut(p2.X, p2.Y, "Point value: " s.YValues[10].ToString());
                g.TextOut(p2.X, p2.Y h, "Change is: " Convert.ToString(s.YValues[3] - s.YValues[10]));
            }
        }
}

[VB.Net]
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TChart1.Aspect.View3D = False
        Line1.FillSampleValues(20)
End Sub

Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw
        If TChart1.Series.Count > 0 Then
            If TChart1.Series(0).Count > 10 Then
                Dim S As Steema.TeeChart.Series = TChart1.Series(0)
                Dim H As Integer = Convert.ToInt32(g.TextHeight("H"))
                Dim P1 As New Point(S.CalcXPos(3), S.CalcYPos(3))
                Dim P2 As New Point(S.CalcXPos(10), S.CalcYPos(10))
                g.Pen.Color = Color.Blue
                g.Pen.Width = 2
                g.Pen.Style = System.Drawing.Drawing2D.DashStyle.Dash
                g.MoveTo(P1)
                g.LineTo(P2, 0)
                g.TextOut(P1.X, P1.Y - H, "Point value: " & S.YValues(3))
                g.TextOut(P2.X, P2.Y, "Point value: " & S.YValues(10))
                g.TextOut(P2.X, P2.Y H, "Change is: " & (S.YValues(3) - S.YValues(10)))
            End If
        End If
End Sub




PREVIOUS

NEXT


© 1998-2020 Steema Software SL. All rights reserved.