技术资料 > .Net专区 > 控件开发和使用 : 图象显示和翻转控件（用户自定义控件）

图象显示和翻转控件（用户自定义控件）

March 25,2004

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;

namespace ImageZoomer
{
/// <summary>
///
/// </summary>

//枚举类型定义，定义图象的四种翻转方式
public enum FlipModeStyle
{
      NoFlip=0,//不翻转
      FlipX=1,//水平翻转
      FlipY=2,//垂直翻转
      FlipXY=3//水平垂直翻转
}

//事件数据类定义，报告图象的显示尺寸
public class DisplaySizeChangedEventArgs:System.EventArgs
{
      public int Width;
      public int Height;
      public DisplaySizeChangedEventArgs()
      {
      }
}

//事件代表的声明
public delegate void DisplaySizeChangedEventHandler(object sender,DisplaySizeChangedEventArgs e);

//用户自定义控件类
public class ImageZoomerControl : System.Windows.Forms.Control
{
      private int width;//控件宽度
      private int height;//控件高度
      private System.Drawing.Bitmap bitmap;//控件上的图象
      private FlipModeStyle flip;//图象的翻转方式
      private event DisplaySizeChangedEventHandler eventHandler;//事件

      //构造方法，初始化数据成员
      public ImageZoomerControl()
      {
         width=this.width;
         height=this.height;
         bitmap=null;
         eventHandler=null;
      }

      //宽度属性
      [
      Category("ImageZoomer"),
      Description("The displayed image width.")
      ]
      public int DisplayWidth
      {
         get
         {
            return width;
         }
         set
         {
            if(value>=0)
            {
                  width=value;
                  Invalidate(this.ClientRectangle);
            }
         }
      }

      //高度属性
      [
      Category("ImageZoomer"),
      Description("The displayed image height.")
      ]
      public int DisplayHeight
      {
         get
         {
            return height;
         }
         set
         {
            if(value>=0)
            {
                  height=value;
                  this.Invalidate(this.ClientRectangle);
            }
         }
      }

      //图象属性
      [
      Category("ImageZoomer"),
      Description("The image displayed by this control."),
      DefaultValue(null)
      ]
      public Bitmap DisplayImage
      {
         get
         {
            return bitmap;
         }
         set
         {
            bitmap=value;
            if(bitmap!=null)
            {
                  width=bitmap.Width;
                  height=bitmap.Height;
            }
            else
            {
                  width=this.width;
                  height=this.height;
            }
            this.Invalidate(this.ClientRectangle);
         }
      }

      //翻转方式属性
      [
      Category("ImageZoomer"),
      Description("Specify how the image will be flipped.")
      ]
      public FlipModeStyle FlipMode
      {
         get
         {
            return flip;
         }
         set
         {
            flip=value;
            this.Invalidate(this.ClientRectangle);
         }
      }

      //事件属性
      [
      Category("ImageZoomer"),
      Description("Occurs when the image size is changed.")
      ]
      public event DisplaySizeChangedEventHandler DisplaySizeChanged
      {
         add
         {
            eventHandler+=value;
         }
         remove
         {
            eventHandler-=value;
         }
      }

      protected override void OnPaint(PaintEventArgs pe)
      {
         if(bitmap==null)
         {
            return;
         }
         Graphics g=pe.Graphics;

         //转换距阵
         System.Drawing.Drawing2D.Matrix transform;//距阵
         if(flip.Equals(FlipModeStyle.FlipX))
         {
            transform=new System.Drawing.Drawing2D.Matrix(-1,0,0,1,width,0);
         }
         else if(flip.Equals(FlipModeStyle.FlipY))
         {
            transform=new System.Drawing.Drawing2D.Matrix(1,0,0,-1,0,height);
         }
         else if(flip.Equals(FlipModeStyle.FlipXY))
         {
            transform=new System.Drawing.Drawing2D.Matrix(-1,0,0,-1,width,height);
         }
         else
         {
            transform=new System.Drawing.Drawing2D.Matrix(1,0,0,1,0,0);
         }
         //设置转换距阵
         g.Transform=transform;
         g.DrawImage(bitmap,new System.Drawing.Rectangle(0,0,width,height),
            0,0,bitmap.Width,bitmap.Height,
            GraphicsUnit.Pixel);
         //恢复绘图平面
         g.ResetTransform();

      }

      //发出事件的方法
      protected virtual void OnDisplaySizeChanged(DisplaySizeChangedEventArgs e)
      {
         //调用事件对象指向的方法
         this.Invoke(eventHandler,new object[]
            {
                  this,e
            }
            );
      }

      //重载方法，调用OnDisplaySizeChanged()发出事件
      protected override void OnMouseDown(MouseEventArgs e)
      {
         width=e.X;
         height=e.Y;
         this.Invalidate(this.ClientRectangle);

         DisplaySizeChangedEventArgs eventData=new DisplaySizeChangedEventArgs();
         eventData.Width=width;
         eventData.Height=height;

         this.OnDisplaySizeChanged(eventData);

         base.OnMouseDown(e);
      }

}
}