I worked with someone who used geometry and trig calculations to get the pie
charts with the proper labels (and clickable to boot). I would google and see
if anyone has done this type of work in an open source project. The asp.net
site has a report writer application for download that might have this type
of algorithm.
---
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA
***************************
Think Outside the Box!
***************************
"rkbnair" wrote:
> I created a pie chart in an aspx. However, how can I display the data in the
> piechart itself in the right location? The code is as follows:
> (Please see the definition of float x and float y)
>
>
> private void CreatePieChart_a(string pStr_SQL, string
> dataColumnName,string labelColumnName,string title, int width)
> {
> string connString = Cls_DManager.GetOleDbConnection().ToString();
> OleDbConnection myConnection = new OleDbConnection(connString);
> myConnection.Open();
>
> //string pStr_SQL = "SELECT DISTINCT [" + dataColumnName + "], [" +
> labelColumnName + "] FROM " + tableName;
> OleDbCommand myCommand = new OleDbCommand(pStr_SQL, myConnection);
>
> // 3. Create/Populate the DataSet
> DataSet ds = new DataSet();
> OleDbDataAdapter myAdapter = new OleDbDataAdapter(myCommand);
> myAdapter.Fill(ds);
>
> // close the connection
> myConnection.Close();
>
> // find the total of the numeric data
> float total = 0.0F, tmp;
> int iLoop;
> for (iLoop=0; iLoop < ds.Tables[0].Rows.Count; iLoop++)
> {
> tmp = Convert.ToSingle(ds.Tables[0].Rows[iLoop][dataColumnName]);
> total += tmp;
> }
>
>
> // we need to create fonts for our legend and title
> Font fontLegend = new Font("Arial", 10),
> fontTitle = new Font("Arial", 15, FontStyle.Bold);
>
> // We need to create a legend and title, how big do these need to be?
> // Also, we need to resize the height for the pie chart, respective to the
> // height of the legend and title
> const int bufferSpace = 15;
> int legendHeight = fontLegend.Height * (ds.Tables[0].Rows.Count+1) +
> bufferSpace;
> int titleHeight = fontTitle.Height + bufferSpace;
> int height = width + legendHeight + titleHeight + bufferSpace;
> int pieHeight = width; // maintain a one-to-one ratio
>
> // Create a rectange for drawing our pie
> Rectangle pieRect = new Rectangle(0, titleHeight, width, pieHeight);
>
> // Create our pie chart, start by creating an ArrayList of colors
> ArrayList colors = new ArrayList();
> Random rnd = new Random();
> for (iLoop = 0; iLoop < ds.Tables[0].Rows.Count; iLoop++)
> colors.Add(new SolidBrush(Color.FromArgb(rnd.Next(255), rnd.Next(255),
> rnd.Next(255))));
>
> float currentDegree = 0.0F;
>
> // Create a Bitmap instance
> Bitmap objBitmap = new Bitmap(width, height);
> Graphics objGraphics = Graphics.FromImage(objBitmap);
>
> SolidBrush blackBrush = new SolidBrush(Color.Black);
> int xxx=0;
> // Put a white backround in
> objGraphics.FillRectangle(new SolidBrush(Color.White), 0, 0, width,
> height);
> for (iLoop = 0; iLoop < ds.Tables[0].Rows.Count; iLoop++)
> {
> objGraphics.FillPie((SolidBrush) colors[iLoop], pieRect, currentDegree,
> Convert.ToSingle(ds.Tables[0].Rows[iLoop][dataColumnName]) / total *
> 360);
> // increment the currentDegree
> currentDegree +=
> Convert.ToSingle(ds.Tables[0].Rows[iLoop][dataColumnName]) / total * 360;
>
> string drawString = ds.Tables[0].Rows[iLoop][labelColumnName].ToString();
> // Create font and brush.
> Font drawFont = new Font("Arial", 9);
> SolidBrush drawBrush = new SolidBrush(Color.Black);
> // Create point for upper-left corner of drawing.
>
> //////////////////////////////////////////////////////////////////////
> float x = currentDegree;
> float y =Convert.ToSingle(ds.Tables[0].Rows[iLoop][dataColumnName]) /
> total * 360;
>
> StringFormat drawFormat = new StringFormat();
> objGraphics.DrawString(drawString, drawFont, drawBrush, x, y, drawFormat);
> //////////////////////////////////////////////////////////////////////
>
> }
>
> // Create the title, centered
> StringFormat stringFormat = new StringFormat();
> stringFormat.Alignment = StringAlignment.Center;
> stringFormat.LineAlignment = StringAlignment.Center;
>
> objGraphics.DrawString(title, fontTitle, blackBrush,
> new Rectangle(0, 0, width, titleHeight), stringFormat);
>
> // Create the legend
> objGraphics.DrawRectangle(new Pen(Color.Black, 2), 0, height -
> legendHeight, width, legendHeight);
> for (iLoop = 0; iLoop < ds.Tables[0].Rows.Count; iLoop++)
> {
> objGraphics.FillRectangle((SolidBrush) colors[iLoop], 5,
> height - legendHeight + fontLegend.Height * iLoop + 5, 10, 10);
>
> objGraphics.DrawString(((string)
> ds.Tables[0].Rows[iLoop][labelColumnName].ToString()) + " - " +
> Convert.ToString(ds.Tables[0].Rows[iLoop][dataColumnName]), fontLegend,
> blackBrush,
> 20, height - legendHeight + fontLegend.Height * iLoop + 1);
> }
>
> // display the total
> objGraphics.DrawString("Total Inspections: " + Convert.ToString(total),
> fontLegend, blackBrush,
> 5, height - fontLegend.Height - 5);
>
> // Since we are outputting a Jpeg, set the ContentType appropriately
> Response.ContentType = "image/jpeg";
>
> // Save the image to a file
> objBitmap.Save(Response.OutputStream, ImageFormat.Jpeg);
>
> // clean up...
> objGraphics.Dispose();
> objBitmap.Dispose();
> }
>
>
>
> #region Web Form Designer generated code
> override protected void OnInit(EventArgs e)
> {
> //
> // CODEGEN: This call is required by the ASP.NET Web Form Designer.
> //
> InitializeComponent();
> base.OnInit(e);
> }
>
> /// <summary>
> /// Required method for Designer support - do not modify
> /// the contents of this method with the code editor.
> /// </summary>
> private void InitializeComponent()
> {
> this.Load += new System.EventHandler(this.Page_Load);
> }
> #endregion
> }
> }
>
>
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