C # cropping a picture

Specific what, I do not understand, I know this is OK. You can study it when you are free.

The function is: crop the picture, but keep the original size of the picture, the cropped area is filled with the specified color (white), and then saved to another new folder, the name does not change.

usingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Data;usingSystem.Drawing;usingSystem.Drawing.Imaging;usingSystem.IO;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;usingSystem.Windows.Forms;namespacewfimg{ Public Partial classForm1:form { PublicForm1 () {InitializeComponent (); }        Private voidButton1_Click (Objectsender, EventArgs e) {FolderBrowserDialog Dialog=NewFolderBrowserDialog (); Dialog. Description="Please select a file path"; if(dialog. ShowDialog () = =DialogResult.OK) {stringFoldpath =dialog.                SelectedPath;  This. TextBox1.Text =Foldpath; }        }        /// <summary>        ///Trim/// </summary>        /// <param name= "B" >Original Bitmap</param>        /// <param name= "StartX" >Start coordinate x</param>        /// <param name= "Starty" >Start coordinate y</param>        /// <param name= "iwidth" >width</param>        /// <param name= "iheight" >Height</param>        /// <returns>the bitmap after clipping</returns>         Public StaticBitmap Kicut (Bitmap B,intStartX,intStarty,intIwidth,intiheight) {            if(b = =NULL)            {                return NULL; }            intW =B.width; inth =B.height; if(StartX >= W | | Starty >=h) {return NULL; }            if(StartX + iwidth >W) {iwidth= W-StartX; }            if(Starty + iheight >h) {iheight= h-Starty; }            Try            {                //Bitmap bmpout = new Bitmap (iwidth, iheight, Pixelformat.format24bpprgb);//a picture that is cropped to a smaller sizeBitmap bmpout=NewBitmap (W, H, Pixelformat.format24bpprgb);//keep the original size, the cropping section fills with the specified colorGraphics graphics =graphics.fromimage (bmpout); Graphics. Clear (color.white);//The cropping section fills with the specified colorGraphics. DrawImage (b,NewRectangle (StartX, Starty, iwidth, iheight),NewRectangle (StartX, Starty, iwidth, iheight), GraphicsUnit.Pixel); Graphics.                Dispose (); returnbmpout; }            Catch            {                return NULL; }        }        Private voidButton2_Click (Objectsender, EventArgs e) {            intLeftsize =Convert.ToInt32 (Txtleft.text); intTopsize =Convert.ToInt32 (Txttop.text); intBottomsize =Convert.ToInt32 (Txtbottom.text); intRightsize =Convert.ToInt32 (Txtright.text); stringFoldpath =TextBox1.Text; stringNewPath = Foldpath +"_new"; if(!directory.exists (NewPath))            {directory.createdirectory (NewPath); }            //loop files in this directoryDirectoryInfo dir =NewDirectoryInfo (Foldpath); fileinfo[] Files=dir.            GetFiles (); intFcount =files.            Count (); if(Fcount >0)            {                 for(inti =0; i < Fcount; i++) {FileInfo file=Files[i]; Bitmap Map=NewBitmap (file.                    FullName); intwidth =map.                    Width; intHeight =map.                    Height; Map= Kicut (map, Leftsize, Topsize, Width-rightsize-leftsize, Height-bottomsize-topsize); Map. Save (NewPath+"\\"+file.                    Name); Label6. Text="Execution Result: Success"+ (i +1) +"a"; }            }        }    }}

The interface is what this bird looks like:

The upper and lower left and right are pixel values.

C # cropping a picture