Origional Question:
-----------------------------------------
I need to resize image which was just uploaded to the server. Image can
be
any format and I need to save it as JPG. I have been using ASPImage
before.
Is it possible to do this using .NET.
Please Help
ScottGu Answer:
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Hi Tom,
Its actually really easy to do this with .NET -- both the file upload
part as well as the image resizing and save as JPG part. The below
sample I've put together demonstrates how to do this (just copy/save it
into a file called "ImageResizer.aspx" and hit it with a browser. It
allows you to select an image on the client, upload it to the server,
load it into an image object (without having to save it to disk), resize
it, and then persist it to disk as a JPG.
The file upload part of the solution is accomplished simply using the
new file upload support within ASP.NET. The Image manipulation is done
using the System.Drawing namespace -- which provides all of our graphic
manipulation APIs.
Hope this helps,
Scott
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<%@ Import Namespace=3D"System.Drawing" %>
<%@ Import Namespace=3D"System.Drawing.Imaging" %>
<html>
<script language=3D"VB" runat=3Dserver>
Sub UploadBtn_Click(Sender as Object, E as EventArgs)
' Obtain Image Object Reference from Uploaded Filestream
Dim uploadImage as System.Drawing.Image
uploadImage =3D
System.Drawing.Image.FromStream(ImageUpload.PostedFile.InputStream)
' Calculate new Image Dimensions
Dim width as Integer
Dim height as Integer
width =3D Integer.Parse(WidthTxt.Value)
height =3D Integer.Parse(HeightTxt.Value)
' Obtain Resized Image Object From Uploaded Image
Dim resizedImage as System.Drawing.Image
resizedImage =3D uploadImage.GetThumbnailImage(width, height,
Nothing, 0)
' Save Image to disk as a JPG
resizedImage.Save(Server.MapPath("test.jpg"),
ImageFormat.JPEG)
' Redirect browser to Image
Response.Redirect("test.jpg")
End Sub
</script>
<body>
<form enctype=3D"multipart/form-data" runat=3Dserver>
<h1>Welcome to ScottGu's Image Resizer</h1>
Image to Upload: <input id=3D"ImageUpload" type=3D"file"
runat=3Dserver>
<br><br>
New Horizontal Size: <input id=3D"WidthTxt" type=3D"text"
value=3D"200" runat=3Dserver> <br>
New Veritical Size: <input id=3D"HeightTxt" type=3D"text"
value=3D"400" runat=3Dserver>
<input text=3D"Upload and Resize" type=3D"submit"
OnServerClick=3D"UploadBtn_Click" runat=3Dserver>
</form>
</body>
</html>
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