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dreamlusion on 08/24/08

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aspnet

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Last Edited at 08/24/08 05:12pm

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ImgX Controls / ASP.NET AJAX Demo Page with Scanning, Upload and Thumbnail generation.

/ Published in: C#

To run this demo, you need to download and install the trial verson of ImgX Controls from [here](http://www.atalasoft.com/download/ImgX64.exe). You may also want to download a scanner emulator (TWAIN data source), such as _TWAIN WG sample source_ available with the TWAIN Toolkit [here](http://www.twain.org/devfiles/twainkit.exe).

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<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected override void OnInit(EventArgs e)
	{
		base.OnInit(e);
		string id = Request.Params["id"];

if (!string.IsNullOrEmpty(id) && Session[id] as byte[] != null)
		{
			byte[] thumbnailBytes = null;

/*
			 * Microsoft Support: Bitmap and Image constructor dependencies (http://support.microsoft.com/Default.aspx?id=814675)
			 * Google: "A generic error occurred in GDI+." 2147467259 (http://www.google.gr/search?num=100&hl=en&q=%22A+generic+error+occurred+in+GDI%2B.%22+2147467259)
			 * In sort, we must keep the originating stream of an Image as long as we want to do computations with that image.
			 */

using (System.IO.MemoryStream msImage = new System.IO.MemoryStream(Session[id] as byte[]))
			{
				System.Drawing.Image image = System.Drawing.Image.FromStream(msImage);

using (System.IO.MemoryStream msThumbnail = new System.IO.MemoryStream())
				{
					System.Drawing.Image.GetThumbnailImageAbort myCallback =
						new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);

int factor = 10;
					try
					{
						factor = Int32.Parse(Request.Params["factor"]);
					}
					catch
					{
						// Ignore.
					}

System.Drawing.Image thumbnail = image.GetThumbnailImage(image.Width / factor, image.Height / factor, null, IntPtr.Zero);
					thumbnail.Save(msThumbnail, System.Drawing.Imaging.ImageFormat.Jpeg);
					thumbnailBytes = new byte[msThumbnail.Length];

msThumbnail.Seek(0, System.IO.SeekOrigin.Begin);
					msThumbnail.Read(thumbnailBytes, 0, thumbnailBytes.Length);
				}
			}

Response.ContentType = "image/jpeg";
			Response.BinaryWrite(thumbnailBytes);
		}
	}

[System.Web.Services.WebMethod]
	public static string Upload(string encodedImage)
	{
		if (string.IsNullOrEmpty(encodedImage))
			throw new ArgumentException(string.Empty, "encodedImage");

string id = (new Random()).Next().ToString();
		HttpContext.Current.Session[id] = System.Convert.FromBase64String(encodedImage);

return id;
	}
</script>

var imgx = $get('ImgX');
			imgx.Images.Current = imgx.Images(0);

UpdateView();
		}

function ButtonPrevious_Click(evt) {
			evt.preventDefault();

var imgx = $get('ImgX');
			imgx.Images.Current = imgx.Images(imgx.Images.Current.Index - 1);

UpdateView();
		}

function ButtonNext_Click(evt) {
			evt.preventDefault();

var imgx = $get('ImgX');
			imgx.Images.Current = imgx.Images(imgx.Images.Current.Index + 1);

UpdateView();
		}

function ButtonLast_Click(evt) {
			evt.preventDefault();

var imgx = $get('ImgX');
			imgx.Images.Current = imgx.Images(imgx.Images.Count - 1);

UpdateView();
		}

function pageLoad(sender, e) {
			// Attach event handlers.
			$addHandler($get('<%= ButtonScan.ClientID %>'), 'click', ButtonScan_Click);
			$addHandler($get('<%= Slider1.ClientID %>'), 'change', Slider1_Change);
			$addHandler($get('<%= ButtonUpdateThumbnail.ClientID %>'), 'click', ButtonUpdateThumbnail_Click);
			$addHandler($get('<%= ButtonFirst.ClientID %>'), 'click', ButtonFirst_Click);
			$addHandler($get('<%= ButtonPrevious.ClientID %>'), 'click', ButtonPrevious_Click);
			$addHandler($get('<%= ButtonNext.ClientID %>'), 'click', ButtonNext_Click);
			$addHandler($get('<%= ButtonLast.ClientID %>'), 'click', ButtonLast_Click);
			$get('ImgXTwain').attachEvent('ImageAcquired', ImgXTwain_ImageAcquired);

// ImgX initialization.
			var imgx = $get('ImgX');
			imgx.AutoZoomType = 1;

UpdateView();
		}
		function Slider1_Change(evt) {
			$get('ImgX').Zoom = evt.target.value / 100;
		}

function ButtonUpdateThumbnail_Click(evt) {
			evt.preventDefault();
			var imgx = $get('ImgX');

var imageType = 1; // enum value for jpeg

if (imgx.Images.Count > 1) {
				imageType = 3; // enum value for Tiffs
				imgx.ImgX.TIFCompression = 4; // Set packbits compression for 8, 24, 32 bit images.
			}

// Get a base64 string representing our encoded image.
			var tempElement = (new ActiveXObject("Microsoft.XMLDOM")).createElement("tempElement");
			tempElement.dataType = "bin.base64";
			tempElement.nodeTypedValue = imgx.Export.ToMemoryFileVariant(imageType);

// Upload
			PageMethods.Upload(tempElement.text, Upload_Success);
		}

function Upload_Success(result, context, methodName) {
			var img = $get('<%=Image1.ClientID %>');
			img.src = '?id=' + result;
		}

function ButtonScan_Click(evt) {
			evt.preventDefault();
			$get('ImgXTwain').Acquire(false, theForm.ImgX.hWnd);
		}

function ImgXTwain_ImageAcquired(image) {

var imgx = $get('ImgX');

// Set scanning options. These must be set before image acquisition.
			imgx.AutoZoom = $get('<%=CheckBoxAutoZoom.ClientID %>').checked;
			imgx.AutoCrop = $get('<%=CheckBoxAutoCrop.ClientID %>').checked;
			imgx.Images.Add(theForm.ImgX.Support.GetImageFromVariant(image), 0, false);

UpdateView();
		}

function UpdateView() {
			var imgx = $get('ImgX');

$get('<%=ButtonUpdateThumbnail.ClientID %>').disabled = imgx.Images.Count == 0;

if (imgx.Images.Count < 2) {
				$get('<%=ButtonPrevious.ClientID %>').disabled =
					$get('<%=ButtonFirst.ClientID %>').disabled =
					$get('<%=ButtonLast.ClientID %>').disabled =
					$get('<%=ButtonNext.ClientID %>').disabled = true;
			}
			else {
				$get('<%=ButtonPrevious.ClientID %>').disabled =
					$get('<%=ButtonFirst.ClientID %>').disabled = imgx.Images.Current.Index == 0;
				$get('<%=ButtonLast.ClientID %>').disabled =
					$get('<%=ButtonNext.ClientID %>').disabled = imgx.Images.Count == imgx.Images.Current.Index + 1;
			}

if (imgx.Images.Count > 0) {
				$get('SpanCurrent').innerHTML = imgx.Images.Current.Index + 1;
				$get('SpanCount').innerHTML = imgx.Images.Count;
			}
			else {
				$get('SpanCurrent').innerHTML = $get('SpanCount').innerHTML = 0;
			}

$find("<%=SliderExtender1.ClientID%>").set_Value(Math.round(imgx.Zoom * 100));
		}
	</script>

URL: http://dreamlusion.eucoding.com/doku.php?id=blog:2008:08:imgx_controls_aspnet_ajax

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