c#圖片截取DEMO

DEMO

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;using System.Drawing.Imaging;namespace 圖片{    public partial class Form1 : Form    {        bool isDrag = false;        Rectangle theRectangle = new Rectangle(new Point(0, 0), new Size(0, 0));        Point startPoint, oldPoint;        private Graphics ig;        public Form1()        {            InitializeComponent();        }        private void button1_Click(object sender, EventArgs e)        {        }        private void button2_Click(object sender, EventArgs e)        {            openFileDialog1.Filter = "*.jpg,*.jpeg,*.bmp,*.gif,*.ico,*.png,*.tif,*.wmf|*.jpg;*.jpeg;*.bmp;*.gif;*.ico;*.png;*.tif;*.wmf";            openFileDialog1.ShowDialog();            Image myImage = System.Drawing.Image.FromFile(openFileDialog1.FileName);            pictureBox1.Image = myImage;        }        private void pictureBox1_MouseDown(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left)            {                //如果開始繪製，則開始記錄滑鼠位置                if ((isDrag = !isDrag) == true)                {                    startPoint = new Point(e.X, e.Y);                    oldPoint = new Point(e.X, e.Y);                }            }        }        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)        {            isDrag = false;            ig = pictureBox1.CreateGraphics();            ig.DrawRectangle(new Pen(Color.Black, 1), startPoint.X, startPoint.Y, e.X - startPoint.X, e.Y - startPoint.Y);            theRectangle = new Rectangle(startPoint.X, startPoint.Y, e.X - startPoint.X, e.Y - startPoint.Y);        }        private void pictureBox1_MouseClick(object sender, MouseEventArgs e)        {             try            {                //Graphics graphics = this.CreateGraphics();                Bitmap bitmap = new Bitmap(pictureBox1.Image);                Bitmap cloneBitmap = bitmap.Clone(theRectangle, PixelFormat.DontCare);                pictureBox2.Image = (Image)cloneBitmap;                //graphics.DrawImage(cloneBitmap, e.X, e.Y);                Graphics g = pictureBox1.CreateGraphics();                SolidBrush myBrush = new SolidBrush(Color.Transparent);                g.FillRectangle(myBrush, theRectangle);            }            catch            { }        }    }}