淺談C#使用GDI+

C#使用GDI+

當我們的軟體需要各種餅狀圖和柱狀圖來表示資料時，我們或許會想到用Offices中的圖形控制項或是第三方控制項，但現在的第三方控制項大都需要註冊，有些免費的控制項會有開發商的標記等。而對於使用Offices的圖形控制項來說，並不能在程式中得於很好控制，其使用的簡易程度也較低，所以在這我給出在C#使用GDI+實現餅狀圖和柱狀圖跟資料庫聯結顯示資料的方法。

using System;  using System.IO;//用於檔案存取  using System.Data;//用於資料訪問  using System.Drawing;//提供畫GDI+圖形的準系統  using System.Drawing.Text;//提供畫GDI+圖形的進階功能  using System.Drawing.Drawing2D;//提供畫進階二維，向量圖形功能  using System.Drawing.Imaging;//提供畫GDI+圖形的進階功能  namespace BaseLayer  {  public class PieChart  {  public PieChart()  {  }  //Render是圖形大標題，圖開小標題，圖形寬度，圖形長度，餅圖的資料集和餅圖的資料集要表示出來的資料  public Image Render(string title, string subTitle, int width,int height, DataSet chartData,int DataLine)  {  const int SIDE_LENGTH = 400;  const int PIE_DIAMETER = 200;  DataTable dt = chartData.Tables[0];   //通過輸入參數，取得餅圖中的總基數  float sumData = 0;  foreach(DataRow dr in dt.Rows)  {  sumData += Convert.ToSingle(dr[DataLine]);  }  //產生一個image對象，並由此產生一個Graphics對象  Bitmap bm = new Bitmap(width,height);  Graphics g = Graphics.FromImage(bm);  //設定對象g的屬性  g.ScaleTransform((Convert.ToSingle(width))/SIDE_LENGTH,(Convert.ToSingle(height))/SIDE_LENGTH);  g.SmoothingMode = SmoothingMode.Default;  g.TextRenderingHint = TextRenderingHint.AntiAlias;   //畫布和邊的設定  g.Clear(Color.White);  g.DrawRectangle(Pens.Black,0,0,SIDE_LENGTH-1,SIDE_LENGTH-1);  //畫餅表徵圖題  g.DrawString(title,new Font("Tahoma",14),Brushes.Black,new PointF(5,5));  //畫餅圖的圖例  g.DrawString(subTitle,new Font("Tahoma",12),Brushes.Black,new PointF(7,35));  //畫餅圖  float curAngle = 0;  float totalAngle = 0;  for(int i=0;i<dt.Rows.Count;i++)  {  curAngle = Convert.ToSingle(dt.Rows[i][DataLine]) / sumData * 360;   g.FillPie(new SolidBrush(ChartUtil.GetChartItemColor(i)),100,65,PIE_DIAMETER,PIE_DIAMETER,totalAngle,curAngle);  g.DrawPie(Pens.Black,100,65,PIE_DIAMETER,PIE_DIAMETER,totalAngle,curAngle);  totalAngle += curAngle;  }  //畫圖例框及其文字  g.DrawRectangle(Pens.Black,200,300,199,99);  g.DrawString("圖表說明",new Font("Tahoma",12,FontStyle.Bold),Brushes.Black,new PointF(200,300));   //畫圖例各項  PointF boxOrigin = new PointF(210,330);  PointF textOrigin = new PointF(235,326);  float percent = 0;  for(int i=0;i<dt.Rows.Count;i++)  {  g.FillRectangle(new SolidBrush(ChartUtil.GetChartItemColor(i)),boxOrigin.X,boxOrigin.Y,20,10);  g.DrawRectangle(Pens.Black,boxOrigin.X,boxOrigin.Y,20,10);  percent = Convert.ToSingle(dt.Rows[i][DataLine]) / sumData * 100;  g.DrawString(dt.Rows[i][1].ToString() + " - " + dt.Rows[i][0].ToString() + " (" + percent.ToString("0") + "%)",new Font("Tahoma",10),Brushes.Black,textOrigin);  boxOrigin.Y += 15;  textOrigin.Y += 15;  }  //回收資源  g.Dispose();  return (Image) bm;   }  }   //畫橫條圖  public class BarChart  {  public BarChart()  {  }  //Render是圖形大標題，圖開小標題，圖形寬度，圖形長度，餅圖的資料集和餅圖的資料集  public Image Render(string title, string subTitle, int width, int height, DataSet chartData)  {  const int SIDE_LENGTH = 400;  const int CHART_TOP = 75;  const int CHART_HEIGHT = 200;  const int CHART_LEFT = 50;  const int CHART_WIDTH = 300;  DataTable dt = chartData.Tables[0];   //計算最高的點  float highPoint = 0;  foreach(DataRow dr in dt.Rows)  {  if(highPoint<Convert.ToSingle(dr[0]))  {  highPoint = Convert.ToSingle(dr[0]);  }  }  //建立一個Graphics對象執行個體  Bitmap bm = new Bitmap(width,height);  try  {  Graphics g = Graphics.FromImage(bm);  //設定條圖圖形和文字屬性  g.ScaleTransform((Convert.ToSingle(width))/SIDE_LENGTH,(Convert.ToSingle(height))/SIDE_LENGTH);  g.SmoothingMode = SmoothingMode.Default;  g.TextRenderingHint = TextRenderingHint.AntiAlias;   //設定畫布和邊  g.Clear(Color.White);  g.DrawRectangle(Pens.Black,0,0,SIDE_LENGTH-1,SIDE_LENGTH-1);  //畫大標題  g.DrawString(title,new Font("Tahoma",14),Brushes.Black,new PointF(5,5));  //畫小標題  g.DrawString(subTitle,new Font("Tahoma",12),Brushes.Black,new PointF(7,35));  //畫橫條圖  float barWidth = CHART_WIDTH / (dt.Rows.Count * 2);  PointF barOrigin = new PointF(CHART_LEFT + (barWidth / 2),0);  float barHeight = dt.Rows.Count;  for(int i=0;i<dt.Rows.Count;i++)  {  barHeight = Convert.ToSingle(dt.Rows[i][0]) * 200 / highPoint * 1;  barOrigin.Y = CHART_TOP + CHART_HEIGHT - barHeight;  g.FillRectangle(new SolidBrush(ChartUtil.GetChartItemColor(i)),barOrigin.X,barOrigin.Y,barWidth,barHeight);  barOriginbarOrigin.X = barOrigin.X + (barWidth * 2);  }  //設定邊  g.DrawLine(new Pen(Color.Black,2),new Point(CHART_LEFT,CHART_TOP),new Point(CHART_LEFT,CHART_TOP + CHART_HEIGHT));  g.DrawLine(new Pen(Color.Black,2),new Point(CHART_LEFT,CHART_TOP + CHART_HEIGHT),new Point(CHART_LEFT + CHART_WIDTH,CHART_TOP + CHART_HEIGHT));  //畫圖例框和文字  g.DrawRectangle(new Pen(Color.Black,1),200,300,199,99);  g.DrawString("圖表說明",new Font("Tahoma",12,FontStyle.Bold),Brushes.Black,new PointF(200,300));   //畫圖例  PointF boxOrigin = new PointF(210,330);  PointF textOrigin = new PointF(235,326);  for(int i=0;i<dt.Rows.Count;i++)  {  g.FillRectangle(new SolidBrush(ChartUtil.GetChartItemColor(i)),boxOrigin.X,boxOrigin.Y,20,10);  g.DrawRectangle(Pens.Black,boxOrigin.X,boxOrigin.Y,20,10);  g.DrawString(dt.Rows[i][1].ToString() + " - " + dt.Rows[i][0].ToString(),new Font("Tahoma",10),Brushes.Black,textOrigin);  boxOrigin.Y += 15;  textOrigin.Y += 15;  }  //輸出圖形  g.Dispose();  return bm;  }  catch  {  return bm;  }  }  }  public class ChartUtil  {  public ChartUtil()  {  }  public static Color GetChartItemColor(int itemIndex)  {  Color selectedColor;  switch(itemIndex)  {  case 0:  selectedColor = Color.Blue;  break;  case 1:  selectedColor = Color.Red;  break;  case 2:  selectedColor = Color.Yellow;  break;  case 3:  selectedColor = Color.Purple;  break;  default:  selectedColor = Color.Green;  break;  }  return selectedColor;  }  }  }

以上是一個完整的WinForm中製作餅狀圖和柱狀圖來源程式，大家可以通過以上程式的更改，做出能滿足自己程式的需要。C#使用GDI+實現餅狀圖和柱狀圖跟資料庫聯結顯示資料的方法。