Client js cannot operate files, so you can only upload images and then cut images on the server.
1. upload images
2. js cut the image (in fact, just select the part to cut)
3. server side cut
(1) cut in the cs file on the page. You must put several hidden controls to return the coordinates selected by js.
Cut the source code of the image:
Code
Using System;
Using System. Collections. Generic;
Using System. Text;
Using System. Drawing;
Public class Cut
{
/// <Summary>
/// Crop the image
/// </Summary>
/// <Param name = "sourceImg"> original image path </param>
/// <Param name = "desImg"> crop the image path </param>
/// <Param name = "left"> X </param>
/// <Param name = "top"> Y </param>
/// <Param name = "width"> width </param>
/// <Param name = "height"> height </param>
Public static void CutImage (string sourceImg, string desImg, int left, int top, int width, int height)
{
System. Drawing. Image img = System. Drawing. Bitmap. FromFile (sourceImg );
System. Drawing. Image imgToSave = new System. Drawing. Bitmap (width, height );
System. Drawing. Graphics g = System. Drawing. Graphics. FromImage (imgToSave );
RectangleF sourceRect = new RectangleF (left, top, width, height );
RectangleF destinationRect = new RectangleF (0, 0, width, height );
G. DrawImage (img,
DestinationRect,
SourceRect,
GraphicsUnit. Pixel
);
G. Save ();
ImgToSave. Save (desImg, System. Drawing. Imaging. ImageFormat. Jpeg );
G. Dispose ();
ImgToSave. Dispose ();
Img. Dispose ();
}
}
(2) cut in ashx to return the file stream. Use parameters to pass coordinates.
Code
Using System;
Using System. Web;
Using System. Drawing;
Using System. IO;
Public class ImgCropper_WebHandler: IHttpHandler
{
Public void ProcessRequest (HttpContext context)
{
String Pic = Convert. ToString (context. Request ["p"]);
Int PointX = Convert. ToInt32 (context. Request ["x"]);
Int PointY = Convert. ToInt32 (context. Request ["y"]);
Int CutWidth = Convert. ToInt32 (context. Request ["w"]);
Int CutHeight = Convert. ToInt32 (context. Request ["h"]);
Int PicWidth = Convert. ToInt32 (context. Request ["pw"]);
Int PicHeight = Convert. ToInt32 (context. Request ["ph"]);
Context. Response. ContentType = "image/jpeg ";
ResetImg (context, System. web. httpContext. current. server. mapPath (Pic), PicWidth, PicHeight, PointX, PointY, CutWidth, CutHeight ). writeTo (context. response. outputStream );
}
Public MemoryStream ResetImg (HttpContext context, string ImgFile, int PicWidth, int PicHeight, int PointX, int PointY, int CutWidth, int CutHeight)
{
Image imgPhoto = Image. FromFile (ImgFile );
Bitmap BMP hoto = new Bitmap (CutWidth, CutHeight, System. Drawing. Imaging. PixelFormat. Format24bppRgb );
Graphics gbmPhoto = Graphics. FromImage (BMP hoto );
GbmPhoto. drawImage (imgPhoto, new Rectangle (0, 0, CutWidth, CutHeight), PointX * imgPhoto. width/PicWidth, PointY * imgPhoto. height/PicHeight, CutWidth * imgPhoto. width/PicWidth, CutHeight * imgPhoto. height/PicHeight, GraphicsUnit. pixel );
// Save the image to the server
BMP hoto. Save (context. Server. MapPath ("upload/") + Guid. NewGuid () + ". jpg", System. Drawing. Imaging. ImageFormat. Jpeg );
// Generate file stream return
MemoryStream ms2 = new MemoryStream ();
BMP hoto. Save (ms2, System. Drawing. Imaging. ImageFormat. Jpeg );
ImgPhoto. Dispose ();
GbmPhoto. Dispose ();
BMP hoto. Dispose ();
Return ms2;
}
Public bool IsReusable
{
Get
{
Return false;
}
}
}