代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Windows.Forms;
using System.Reflection;
/*
* 实现图片剪切
*
*/
namespace CutImage
{
public partial class frmMain : Form
{
public frmMain()
{
InitializeComponent();
}
/// <summary>
/// 打开图片
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnOpen_Click(object sender, EventArgs e)
{
string strFilename = "";
OpenFileDialog dlgOpen = null;
try
{
dlgOpen = new OpenFileDialog();
dlgOpen.Filter = "All Image Files(*.*)|*.*";
if (dlgOpen.ShowDialog() == DialogResult.OK)
{
if (dlgOpen.FileName == "") return;
strFilename = dlgOpen.FileName;
pbxOriImage.Image = Image.FromFile(strFilename);
this.SetImageSizeMode(pbxOriImage);
}
}
catch (Exception ex)
{
MessageBox.Show("无法识别的图片格式(" + strFilename + ")\r\n" + ex.Message , "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
if (dlgOpen != null)
dlgOpen.Dispose();
dlgOpen = null;
}
}
/// <summary>
/// 设置图片显示模式
/// </summary>
/// <param name="pImage"></param>
private void SetImageSizeMode(PictureBox pImage)
{
if (pImage == null) return;
Image imgResult = pImage.Image;
if (imgResult != null)
{
//控制图片显示方式
if (imgResult.Width > pImage.Width || imgResult.Height > pImage.Height)
{
pImage.SizeMode = PictureBoxSizeMode.Zoom;
}
else
{
pImage.SizeMode = PictureBoxSizeMode.CenterImage;
}
}
}
#region 绘制及剪切
Point fPtStart; //开始位置矩形的位置
bool fHaveImage = false; //是否有图片
Point fPtFirst; //鼠标按下去的位置
Point fPtSecond; //鼠标当前位置
/// <summary>
/// 记录鼠标按下去的位置
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void pbxOriImage_MouseDown(object sender, MouseEventArgs e)
{
this.Cursor = Cursors.Cross;
fPtFirst = new Point(e.X, e.Y);
fPtStart = new Point(e.X, e.Y);
if ((sender as PictureBox).Image != null)
{
this.fHaveImage = true;
}
else
{
this.fHaveImage = false;
}
}
private void pbxOriImage_MouseMove(object sender, MouseEventArgs e)
{
if (this.Cursor == Cursors.Cross)
{
fPtSecond = new Point(e.X, e.Y);
if ((fPtSecond.X - fPtFirst.X) > 0 && (fPtSecond.Y - fPtFirst.Y) > 0)
{
//鼠标当前位置在，按下去位置的右下角
fPtStart = new Point(fPtFirst.X, fPtFirst.Y);
}
else if ((fPtSecond.X - fPtFirst.X) > 0 && (fPtSecond.Y - fPtFirst.Y) < 0)
{
//鼠标当前位置在，按下去位置的右上角
fPtStart = new Point(fPtFirst.X, fPtSecond.Y);
}
else if ((fPtSecond.X - fPtFirst.X) < 0 && (fPtSecond.Y - fPtFirst.Y) > 0)
{
//鼠标当前位置在，按下去位置的左下角
fPtStart = new Point(fPtSecond.X, fPtFirst.Y);
}
else
{
//鼠标当前位置在，按下去位置的左上角
fPtStart = new Point(fPtSecond.X, fPtSecond.Y);
}
pbxOriImage.Invalidate(); //移动时绘制矩形选择框
}
}
/// <summary>
/// 剪切图片
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void pbxOriImage_MouseUp(object sender, MouseEventArgs e)
{
if (this.fHaveImage == false) return;
try
{
fPtSecond = new Point(e.X, e.Y);
if ((fPtSecond.X - fPtFirst.X) > 0 && (fPtSecond.Y - fPtFirst.Y) > 0)
{
//鼠标当前位置在，按下去位置的右下角
fPtStart = new Point(fPtFirst.X, fPtFirst.Y);
}
else if ((fPtSecond.X - fPtFirst.X) > 0 && (fPtSecond.Y - fPtFirst.Y) < 0)
{
//鼠标当前位置在，按下去位置的右上角
fPtStart = new Point(fPtFirst.X, fPtSecond.Y);
}
else if ((fPtSecond.X - fPtFirst.X) < 0 && (fPtSecond.Y - fPtFirst.Y) > 0)
{
//鼠标当前位置在，按下去位置的左下角
fPtStart = new Point(fPtSecond.X, fPtFirst.Y);
}
else
{
//鼠标当前位置在，按下去位置的左上角
fPtStart = new Point(fPtSecond.X, fPtSecond.Y);
}
Rectangle rectDisplay = this.GetPictureDisplaySize(pbxOriImage); //图片实际显示的大小
int Width = Math.Abs((fPtSecond.X - fPtFirst.X));
int Height = Math.Abs((fPtSecond.Y - fPtFirst.Y));
double dWRate = pbxOriImage.Image.Width / (double)rectDisplay.Width; //缩放比例：宽
double dHRate = pbxOriImage.Image.Height / (double)rectDisplay.Height; //缩放比例：高
int intRealWidth = (int)(dWRate * Width); //实际需要截取的图片宽度
int intRealHeight = (int)(dHRate * Height); //实际需要截取的图片高度
int intRealX = (int)((fPtStart.X - rectDisplay.X) * dWRate); //实际的X坐标
int intRealY = (int)((fPtStart.Y - rectDisplay.Y) * dHRate); //实际的Y坐标
Bitmap bmpDest = new Bitmap(intRealWidth, intRealHeight, PixelFormat.Format32bppRgb); //目标图片大小
Graphics g = Graphics.FromImage(bmpDest); //创建GDI
Rectangle rectDest = new Rectangle(0, 0, intRealWidth, intRealHeight);
Rectangle rectSource = new Rectangle(intRealX,intRealY, intRealWidth, intRealHeight);
g.DrawImage(pbxOriImage.Image, rectDest, rectSource, GraphicsUnit.Pixel); //绘图
pbxCutImage.Image = (Image)bmpDest;
g.Dispose();
SetImageSizeMode(pbxCutImage);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{ this.Cursor = Cursors.Default; }
}
/// <summary>
/// 获取图片实际显示的大小
/// </summary>
/// <param name="pbxImage"></param>
/// <returns></returns>
public Rectangle GetPictureDisplaySize(PictureBox pbxImage)
{
if (pbxImage != null)
{
PropertyInfo ppiImageRect = pbxImage.GetType().GetProperty("ImageRectangle", BindingFlags.Instance | BindingFlags.NonPublic);
return (Rectangle)ppiImageRect.GetValue(pbxImage, null);
}
return new Rectangle(0, 0, 1, 1);
}
/// <summary>
/// 绘制矩形选择框
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void pbxOriImage_Paint(object sender, PaintEventArgs e)
{
int intWidth = 0;
int intHeight = 0;
if (this.fHaveImage == true)
{
Pen p = new Pen(Color.Black, 1);
p.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
intWidth = Math.Abs(fPtFirst.X - fPtSecond.X);
intHeight = Math.Abs(fPtFirst.Y - fPtSecond.Y);
Rectangle rectDraw = new Rectangle(fPtStart, new Size(intWidth, intHeight));
e.Graphics.DrawRectangle(p, rectDraw);
}
}
#endregion
/// <summary>
/// 保存剪切后的图片
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnSave_Click(object sender, EventArgs e)
{
SaveFileDialog dlgSave = new SaveFileDialog();
if (dlgSave.ShowDialog() == DialogResult.OK)
{
pbxCutImage.Image.Save(dlgSave.FileName);
}
}
}
}
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2014/7/11 9:25:00
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C# 图片截取