resize image in vb.net

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what should i add to this code to resize the images that i am saving to be of width 100px

VB

Dim extension1 As String = Path.GetExtension(Fileupload1.PostedFile.FileName)
           If extension1.ToString = ".png" Or extension1.ToString = ".jpg" Or extension1.ToString = ".bmp" Or extension1.ToString = ".gif" Then
               Dim strdir1 As String = Server.MapPath("uploads/pics/")
               Fileupload1.PostedFile.SaveAs(strdir1 & cmd_id & extension1)
               textbox2.Text = cmd_id & extension1

Thanks

Posted 15-Aug-13 1:31am

Hidhoud1991

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ZurdoDev 15-Aug-13 7:40am

I have used a 3rd party control in the past to do it, http://www.websupergoo.com/products.htm#ig I am not sure it is a simple thing to do in .Net.

Now, do you actually need to resize them? Or, when you display on page can you just set the width to 100 and let the browser size it?

Sergey Alexandrovich Kryukov 15-Aug-13 7:47am

Why? This is a simply thing. Please see my answer.
As to the browser resize, this is a good point.
—SA

ZurdoDev 15-Aug-13 7:57am

Why use a control where someone has already done this? Why not use your solution? Your solution has 5 separate links none of which are ready to use. Getting a control where someone has already done it seems a whole lot easier.

Sergey Alexandrovich Kryukov 15-Aug-13 8:09am

You underestimate the hassles of using 3rd-party. "My" solutions is extremely easy (what, do you want to protect OP from some work and practicing? :-) and uses only .NET FCL which is already there...
—SA

ZurdoDev 15-Aug-13 8:37am

I recommended that one because I have used it and it is very easy. There certainly is value in writing the code yourself so I am not at all discounting your solution. I am just pointing out that there is no issue with my suggestion.

Sergey Alexandrovich Kryukov 15-Aug-13 8:42am

Understood.
—SA

Sergey Alexandrovich Kryukov 15-Aug-13 7:50am

It really depends on the purpose. If much less sizes are always needed, and the image is shown much more often than viewed, resampling of the image on the server side is the right decision, it would greatly save the traffic.
—SA

[no name] 15-Aug-13 7:54am

in the browser it is good but i need that for exporting them to word the pic is viewed in its original size and dont know how to resize

Sergey Alexandrovich Kryukov 15-Aug-13 8:09am

I answered. As I say, yes, it makes perfect sense to do it on server side.
—SA

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Sergey Alexandrovich Kryukov · Answer 1 · 2013-08-15T01:46:00

This is called resampling.

Read the image using the class System.Drawing.Bitmap and create a brand new image of required size:
http://msdn.microsoft.com/en-us/library/0cbhe98f.aspx[^],
http://msdn.microsoft.com/en-us/library/7we6s1x3.aspx[^].

For this new image, obtain the instance of System.Drawing.Graphics; it can be used to draw on the image:
http://msdn.microsoft.com/en-us/library/system.drawing.graphics.fromimage.aspx[^].

Draw original image on the second one, with appropriate resize, using the Graphic instance obtained on the previous step. First of all, choose the quality of interpolation for resampling:
http://msdn.microsoft.com/en-us/library/system.drawing.graphics.interpolationmode.aspx[^].

And draw: http://msdn.microsoft.com/en-us/library/yws82c40.aspx[^].

You should remember that resampling bitmaps can only be good if you reduce the size, in worst case, enlarge, but only slightly. Any considerable enlargement will give bad quality, pixellation.

—SA

OriginalGriff · Answer 2 · 2013-08-15T01:49:00

Firstly, stop calling ToString on items which are already String - it isn't needed, it wastes time and resources, and it looks like you don't know what you are doing! :laugh:

In order to resize an image, you have to first load it as an image, and then re-draw it to a different size. Assuming you already know how to convert your data to an image of some form, the Image class has a method Image.GetThumbnailImage which does all the work for you - it proportionally resizes the image into the rectangle you want, maintaining the aspect ratio: MSDN[^]
The link includes an example.

pdoxtader · Answer 3 · 2013-08-21T05:42:00

Solution 3

Check out my answer to this similar question:

Graphics, Image Manipulation in VB.NET

I provide a class you can use to do what you need.

Hope this helps,

- Pete

Posted 21-Aug-13 5:42am

pdoxtader

resize image in vb.net

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