BeforeDraw and CalcPosValue

[newbie]

Hello,
I use TeeChart.NET 2.0.3309.32489 and want to display an rectangle at a certain position in the background. I use scrolling and zooming.

Code: Select all

Private Sub TChart1_BeforeDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDraw
    Dim x As Integer = TChart1.Axes.Bottom.CalcPosValue(0)
    Dim w As Integer = TChart1.Axes.Bottom.CalcPosValue(knownWITDH) - x
    Dim y As Integer = TChart1.Axes.Left.CalcPosValue(knownHEIGTH)
    Dim h As Integer = TChart1.Axes.Left.CalcPosValue(0) - y

    g.FillRectangle(Brushes.Tomato, 0, 0, TChart1.Width, TChart1.Height) 'Fill the entire background
    g.FillRectangle(Brushes.White, x, y, w, h) 'fill only the desired rectangle
  End Sub

I experience, that the calculation of the screen position is only correct, if the chart was already drawn.
Is the a way to force the calculation to update in the BeforeDraw event?
Or can I calculate the Screenpixel belonging to a certain position using another method?
Thanks
NEWBIE

[Sandra]

Hello Newbie,

I think you use other Event as you allow achieve as you want, so you need know if you use BeforeDraw event, the chart still isn't drawn, for this reason I think you can use BeforeDrawValues as I do in following lines:

Code: Select all

Private Sub Series1_BeforeDrawValues(sender As Object, g As Steema.TeeChart.Drawing.Graphics3D)
	Dim x As Integer = tChart1.Axes.Bottom.CalcPosValue(0)
	Dim w As Integer = tChart1.Axes.Bottom.CalcPosValue(Series1.XValues.Maximum) - x
	Dim y As Integer = tChart1.Axes.Left.CalcPosValue(Series1.YValues.Maximum)
	Dim h As Integer = tChart1.Axes.Left.CalcPosValue(0) - y
	g.FillRectangle(Brushes.Tomato, 0, 0, tChart1.Width, tChart1.Height)
	''Fill the entire background
	g.FillRectangle(Brushes.White, x, y, w, h)
	' 'fill only the desired rectangle
End Sub

Can you tell us, if previous code works as you expected?

I hope will helps.

Thanks,

[newbie]

Hi Sandra,
thanks for your answer,
I tested your proposal, but it does not do the job.
It will be drawn only if there is a point in the series, and the Rectangles are drawn in front of the chart.
I want to have it in the background, behind the axes and all chart areas. And it should be drawn also on a empty chart.
NewBIE

[newbie]

Hi there, I have a workaround, but it involves the chart to be drawn twice. I still hope for a better solution

Code: Select all

Dim TChart1_x As Integer, TChart1_y As Integer, TChart1_w As Integer, TChart1_h As Integer
Private Sub TChart1_BeforeDrawSeries(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDrawSeries
    Dim x As Integer = TChart1.Axes.Bottom.CalcPosValue(0)
    Dim w As Integer = TChart1.Axes.Bottom.CalcPosValue(knownWITDH) - x
    Dim y As Integer = TChart1.Axes.Left.CalcPosValue(knownHEIGTH)
    Dim h As Integer = TChart1.Axes.Left.CalcPosValue(0) - y
    If Not (TChart1_x = x And TChart1_y = y And TChart1_w = w And TChart1_h = h) Then
        TChart1.Invalidate() 'if something was changed between the drawing, this will force a redraw
    End If  
End Sub
Private Sub TChart1_BeforeDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDraw
    Dim x As Integer = TChart1.Axes.Bottom.CalcPosValue(0)
    Dim w As Integer = TChart1.Axes.Bottom.CalcPosValue(knownWITDH) - x
    Dim y As Integer = TChart1.Axes.Left.CalcPosValue(knownHEIGTH)
    Dim h As Integer = TChart1.Axes.Left.CalcPosValue(0) - y
    TChart1_x = x : TChart1_y = y : TChart1_w = w : TChart1_h = h
    g.FillRectangle(Brushes.Tomato, 0, 0, TChart1.Width, TChart1.Height) 'Fill the entire background
    g.FillRectangle(Brushes.White, x, y, w, h) 'fill only the desired rectangle
End Sub

[Sandra]

Hello newbie,

I am glad that you can find a solution for your problem . On the other hand, I have made a simple code to draw your rectangles in the BeferoDrawAxes and I think you can do something as next:

Code: Select all

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            tChart1.Aspect.View3D = false;
            checkBox1.Checked = false;
            tChart1.Walls.Back.Visible = false;
            tChart1.Axes.Bottom.Grid.Visible = false;
            tChart1.Axes.Left.Grid.Visible = false;
            tChart1.Axes.Left.SetMinMax(0, 700);
            tChart1.Axes.Bottom.SetMinMax(0, 10);
            tChart1.BeforeDrawAxes += new Steema.TeeChart.PaintChartEventHandler(tChart1_BeforeDrawAxes);
        }
        private Steema.TeeChart.Styles.Bar Series1;
        private void InitializeSeries()
        {
            Series1 = new Steema.TeeChart.Styles.Bar(tChart1.Chart);
           
            Series1.FillSampleValues(10);

            tChart1.Axes.Left.SetMinMax(0, Series1.YValues.Maximum);
            tChart1.Axes.Bottom.SetMinMax(0, Series1.XValues.Maximum);
            tChart1.Draw();
        }

        void tChart1_BeforeDrawAxes(object sender, Steema.TeeChart.Drawing.Graphics3D g)
        {

            if (Series1 != null)
            {
                int x = tChart1.Axes.Bottom.CalcPosValue(0);
                int w = tChart1.Axes.Bottom.CalcPosValue(tChart1.Axes.Bottom.Maximum) - x;
                int y = tChart1.Axes.Left.CalcPosValue(tChart1.Axes.Left.Maximum);
                int h = tChart1.Axes.Left.CalcPosValue(0) - y;
                g.FillRectangle(Brushes.Tomato, 0, 0, tChart1.Width, tChart1.Height);//'Fill the entire background
                g.FillRectangle(Brushes.White, x, y, w, h);// 'fill only the desired rect
            }
            else
            {
                
                int x = tChart1.Axes.Bottom.CalcPosValue(0);
                int w = tChart1.Axes.Bottom.CalcPosValue(tChart1.Axes.Bottom.Maximum) - x;
                int y = tChart1.Axes.Left.CalcPosValue(tChart1.Axes.Left.Maximum);
                int h = tChart1.Axes.Left.CalcPosValue(0) - y;
                g.FillRectangle(Brushes.Tomato, 0, 0, tChart1.Width, tChart1.Height);//'Fill the entire background
                g.FillRectangle(Brushes.White, x, y, w, h);// 'fill only the desired rect
            }
        }

       

        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {
            if (checkBox1.Checked)
            {
                InitializeSeries();

            }
            else
            {
                tChart1.Series.Clear();
                tChart1.Axes.Left.SetMinMax(0, 700);
                tChart1.Axes.Bottom.SetMinMax(0, 10);
            }
          
        }

Can you tell us if previous code works fine with your values? If it doesn't works as you expect, please send us a simple project so we can adapt the solution with your data and try to find a optimal solution for you.
I hope will helps.

Thanks,

[newbie]

Hello Sandra,

Thanks, BeforeDrawAxes is better. Only the limiting lines of the chart area are overpainted and the legend.

So at the end of BeforeDrawAxes I force the legend to paint again, and I also draw the lines again inside this method.

Newbie

[Sandra]

Hello Newbie,

I suggest you draw the legend, using property CustomPosition of Legend as do in next code:

Code: Select all

      public Form1()
        {
            InitializeComponent();
            tChart1.Aspect.View3D = false;
            checkBox1.Checked = false;
            tChart1.Walls.Back.Visible = false;
            tChart1.Axes.Bottom.Grid.Visible = false;
            tChart1.Axes.Left.Grid.Visible = false;
            tChart1.Axes.Left.SetMinMax(0, 700);
            tChart1.Axes.Bottom.SetMinMax(0, 10);
            tChart1.Panel.MarginRight = 15;
            tChart1.Draw();
            tChart1.Legend.CustomPosition = true;
            tChart1.Legend.Top = tChart1.Axes.Left.IStartPos;
            tChart1.Legend.Left= tChart1.Axes.Bottom.IEndPos+10;
            
            
            tChart1.BeforeDrawAxes += new Steema.TeeChart.PaintChartEventHandler(tChart1_BeforeDrawAxes);
        }
        private Steema.TeeChart.Styles.Bar Series1;
        private void InitializeSeries()
        {
            Series1 = new Steema.TeeChart.Styles.Bar(tChart1.Chart);
           
            Series1.FillSampleValues(10);

            tChart1.Axes.Left.SetMinMax(0, Series1.YValues.Maximum);
            tChart1.Axes.Bottom.SetMinMax(0, Series1.XValues.Maximum);
            tChart1.Draw();
        }

        void tChart1_BeforeDrawAxes(object sender, Steema.TeeChart.Drawing.Graphics3D g)
        {

            if (Series1 != null)
            {
                int x = tChart1.Axes.Bottom.CalcPosValue(0);
                int w = tChart1.Axes.Bottom.CalcPosValue(tChart1.Axes.Bottom.Maximum) - x;
                int y = tChart1.Axes.Left.CalcPosValue(tChart1.Axes.Left.Maximum);
                int h = tChart1.Axes.Left.CalcPosValue(0) - y;
                g.FillRectangle(Brushes.Tomato, 0, 0, tChart1.Width, tChart1.Height);//'Fill the entire background
                g.FillRectangle(Brushes.White, x, y, w, h);// 'fill only the desired rect
            }
            else
            {
                
                int x = tChart1.Axes.Bottom.CalcPosValue(0);
                int w = tChart1.Axes.Bottom.CalcPosValue(tChart1.Axes.Bottom.Maximum) - x;
                int y = tChart1.Axes.Left.CalcPosValue(tChart1.Axes.Left.Maximum);
                int h = tChart1.Axes.Left.CalcPosValue(0) - y;
                g.FillRectangle(Brushes.Tomato, 0, 0, tChart1.Width, tChart1.Height);//'Fill the entire background
                g.FillRectangle(Brushes.White, x, y, w, h);// 'fill only the desired rect
            }
        }

I hope will helps.

Thanks,