C#切割指定区域图片操作

OpenFileDialog opdialog = new OpenFileDialog();
opdialog.InitialDirectory = @"C:\";
opdialog.FilterIndex = 1;
opdialog.Filter = "Image   Files(*.BMP;*.JPG;*.PNG)|*.BMP;*.JPG;*.PNG";
if (opdialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
this.pb_photo_original.Image = Image.FromFile(opdialog.FileName);

if (e.Button != MouseButtons.Left)
return;

if (oldCutRect.Contains(e.Location))
{
this.newCutRect.Offset(e.Location.X - this.m_LastMSPoint.X, e.Location.Y - this.m_LastMSPoint.Y);
if (newCutRect.Location.X < 0)
newCutRect.X = 0;
if (newCutRect.Location.Y < 0)
newCutRect.Y = 0;
if (newCutRect.Location.X + 128 > 300)
newCutRect.X = 300 - 128;
if (newCutRect.Location.Y + 160 > 300)
newCutRect.Y = 300 - 160;

this.panel_shade.Invalidate(oldCutRect, false);
this.panel_shade.Invalidate(newCutRect, false);
this.m_LastMSPoint = e.Location;
oldCutRect = newCutRect;
}

Bitmap bitmap = new Bitmap(128, 160);
//创建作图区域
Graphics graphic = Graphics.FromImage(bitmap);
Point p = this.pb_photo_original.PointToScreen(this.oldCutRect.Location);
//截取原图相应区域写入作图区
//graphic.DrawImage(this.pb_photo_original.Image, new Rectangle(0, 0, 128, 160), oldCutRect, GraphicsUnit.Pixel);
graphic.CopyFromScreen(p.X, p.Y, 0, 0, new Size(128, 160));

Bitmap zoomBitmap = new Bitmap(bitmap, new Size(80, 100));
this.pb_photo_cut.Image = zoomBitmap;

//保存图象
zoomBitmap.Save(@"D:\test.jpg");

bitmap.Dispose();
graphic.Dispose();