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How to crop image using ASP.Net/C# OR Cropping image in C# before upload

May 22, 2012 40 comments

DOWNLOAD SOURCE CODE FOR CROP IMAGE IN ASP.NET

Crop images before upload to the server in C#/ASP.Net

In our previous post we demonstrate how we can re size image using C# or Create thumbnail image using ASP.Net. Here we are demonstrating how we can crop images using ASP.Net application using Jquery and C#. In some applications we need to upload images and we need only some portion of the images to get clear picture on the photo. In this case we need to give an option to users to crop image before they are uploading the image.

Include Jquery file/CSS files to the application. 

First of all we need to include following jquery/CSS files to the application.

1.       jquery.min.js     –    You can download from here

2.       jquery.Jcrop.js   –    You can download from here

3.       jquery.Jcrop.css   –    You can download from here 

Simple steps to crop image using ASP.Net,C#,Jquery

In this application we are having a browse option for selecting an image. Once we selected a image it will display int the screen.

Crop image using ASP.net C#

Select an image to crop using ASP.Net C# Jquery

In the next step we will have the option to select an area to crop the image. Once we selected an area we can click crop button on the screen.

Crop image using ASP.Net C#

Select image area to crop

Then the selected area will be cropped and displayed in the screen.

Crop image using ASP.Net C#

Cropped area of the image

ASPX Page for crop images using Jquery 

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CropImage.aspx.cs" 
Inherits="ExperimentLab.CropImage" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
 <title>Crop Image</title>
 <link href="Styles/jquery.Jcrop.css" rel="stylesheet" type="text/css" />
 <script type="text/javascript" 
 src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script>
 <script type="text/javascript" src="Scripts/jquery.Jcrop.js"></script>
 <script type="text/javascript">
 jQuery(document).ready(function () {
 jQuery('#imgCrop').Jcrop({
 onSelect: storeCoords
 });
 });
function storeCoords(c) {
 jQuery('#X').val(c.x);
 jQuery('#Y').val(c.y);
 jQuery('#W').val(c.w);
 jQuery('#H').val(c.h);
 };
</script>
</head>
<body>
 <form id="form1" runat="server">
 <div>
 <asp:Panel ID="pnlUpload" runat="server">
 <asp:FileUpload ID="Upload" runat="server" />
 <br />
 <asp:Button ID="btnUpload" runat="server" 
 OnClick="btnUpload_Click" Text="Upload" />
 <asp:Label ID="lblError" runat="server" Visible="false" />
 </asp:Panel>
 <asp:Panel ID="pnlCrop" runat="server" Visible="false">
 <asp:Image ID="imgCrop" runat="server" />
 <br />
 <asp:HiddenField ID="X" runat="server" />
 <asp:HiddenField ID="Y" runat="server" />
 <asp:HiddenField ID="W" runat="server" />
 <asp:HiddenField ID="H" runat="server" />
 <asp:Button ID="btnCrop" runat="server" Text="Crop" 
 OnClick="btnCrop_Click" />
 </asp:Panel>
 <asp:Panel ID="pnlCropped" runat="server" Visible="false">
 <asp:Image ID="imgCropped" runat="server" />
 </asp:Panel>
 </div>
 </form>
</body>
</html>

Code Behind of the ASPX page for Crop image using ASP.Net/C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using SD = System.Drawing;
using System.Drawing.Drawing2D;
namespace ExperimentLab
{
public partial class CropImage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
String path = HttpContext.Current.Request.PhysicalApplicationPath + "images\\";
protected void btnUpload_Click(object sender, EventArgs e)
{
Boolean FileOK = false;
Boolean FileSaved = false; 
if (Upload.HasFile)
{
Session["WorkingImage"] = Upload.FileName;
String FileExtension =
Path.GetExtension(Session["WorkingImage"].ToString()).ToLower();
String[] allowedExtensions = { ".png", ".jpeg", ".jpg", ".gif" };
for (int i = 0; i < allowedExtensions.Length; i++)
{
if (FileExtension == allowedExtensions[i])
{
 FileOK = true;
}
}
}
if (FileOK)
{
try
{
Upload.PostedFile.SaveAs(path + Session["WorkingImage"]);
FileSaved = true;
}
catch (Exception ex)
{
lblError.Text = "File could not be uploaded." + ex.Message.ToString();
lblError.Visible = true;
FileSaved = false;
}
}
else
{
lblError.Text = "Cannot accept files of this type.";
lblError.Visible = true;
}
if (FileSaved)
{
pnlUpload.Visible = false;
pnlCrop.Visible = true;
imgCrop.ImageUrl = "images/" + Session["WorkingImage"].ToString();
}
}
protected void btnCrop_Click(object sender, EventArgs e)
{
string ImageName = Session["WorkingImage"].ToString();
int w = Convert.ToInt32(W.Value);
int h = Convert.ToInt32(H.Value);
int x = Convert.ToInt32(X.Value);
int y = Convert.ToInt32(Y.Value);
byte[] CropImage = Crop(path + ImageName, w, h, x, y);
using (MemoryStream ms = new MemoryStream(CropImage, 0, CropImage.Length))
{
ms.Write(CropImage, 0, CropImage.Length);
using (SD.Image CroppedImage = SD.Image.FromStream(ms, true))
{
string SaveTo = path + "crop" + ImageName;
CroppedImage.Save(SaveTo, CroppedImage.RawFormat);
pnlCrop.Visible = false;
pnlCropped.Visible = true;
imgCropped.ImageUrl = "images/crop" + ImageName;
}
}
}
static byte[] Crop(string Img, int Width, int Height, int X, int Y)
{
try
{
using (SD.Image OriginalImage = SD.Image.FromFile(Img))
{
using (SD.Bitmap bmp = new SD.Bitmap(Width, Height))
{
 bmp.SetResolution(OriginalImage.HorizontalResolution, 
 OriginalImage.VerticalResolution);
 using (SD.Graphics Graphic = SD.Graphics.FromImage(bmp))
 {
 Graphic.SmoothingMode = SmoothingMode.AntiAlias;
 Graphic.InterpolationMode = InterpolationMode.HighQualityBicubic;
 Graphic.PixelOffsetMode = PixelOffsetMode.HighQuality;
 Graphic.DrawImage(OriginalImage, new SD.Rectangle(0, 0, Width, Height),
 X, Y, Width, Height, SD.GraphicsUnit.Pixel);
 MemoryStream ms = new MemoryStream();
 bmp.Save(ms, OriginalImage.RawFormat);
 return ms.GetBuffer();
 }
}
}
}
catch (Exception Ex)
{
throw (Ex);
}
}
}
}


DOWNLOAD SOURCE CODE FOR CROP IMAGE IN ASP.NET

How to maintain scrollposition after post back?

January 6, 2012 Leave a comment

How to maintain scroll position in ASP.Net Pages

When web pages are posted back to the server, by default user is returned to the top of the page. On a large web page, you might have a requirement to scroll down the user automatically to the last position on the page.

MaintainScrollPositionOnPostBack page property can be used to achieve this  in one of the following ways.

  1. Application level:To set the property by default for all pages in the website, open web.config and add the attribute to the pages node.<pages maintainScrollPositionOnPostBack=”true”>
  2. Page Level:for a particular page, open the aspx and set the property<%@ Page MaintainScrollPositionOnPostback=”true” …
  3. Code level: to set the property programmaticallyPage.MaintainScrollPositionOnPostBack = true;
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