c# chart vertical text annotation

Question

I'm adding annotations to a c# line chart. I'd like to change the text orientation but can't see any setting to allow this.

RectangleAnnotationannotation = new RectangleAnnotation();
annotation.AnchorDataPoint = chart1.Series[0].Points[x];
annotation.Text = "look an annotation";
annotation.ForeColor = Color.Black;
annotation.Font = new Font("Arial", 12); ;
annotation.LineWidth = 2;
chart1.Annotations.Add(annotation);

The annotation is added to the graph correctly and the rectangle and text run left to right. I want to orientate it to run up and down. Any suggestions on how to achieve this?

Answer 1

You cannot rotate annotations using the annotation library. You have to use postpaint or prepaint. Here is a good example of how to use the post-paint event. Hope this helps. I'll include the code from the link below:

protected void Chart1_PostPaint(object sender, ChartPaintEventArgs e)
{
if (e.ChartElement is Chart)
{
    // create text to draw
    String TextToDraw;
    TextToDraw = "Printed: " + DateTime.Now.ToString("MMM d, yyyy @ h:mm tt");
    TextToDraw += " -- Copyright © Steve Wellens";

    // get graphics tools
    Graphics g = e.ChartGraphics.Graphics;
    Font DrawFont = System.Drawing.SystemFonts.CaptionFont;
    Brush DrawBrush = Brushes.Black;

    // see how big the text will be
    int TxtWidth = (int)g.MeasureString(TextToDraw, DrawFont).Width;
    int TxtHeight = (int)g.MeasureString(TextToDraw, DrawFont).Height;

    // where to draw
    int x = 5;  // a few pixels from the left border

    int y = (int)e.Chart.Height.Value;
    y = y - TxtHeight - 5; // a few pixels off the bottom

    // draw the string        
    g.DrawString(TextToDraw, DrawFont, DrawBrush, x, y);
}

}

EDIT: I just realized this example doesn't actually rotate the text. I know you have to use this tool so I will try to find an example using postpaint that rotates text.

EDIT 2: Aaah. Right here at SO. Basically you need to use the e.Graphics.RotateTransform(270); property (that line would rotate 270 degrees).