ASP.NET Method for Creating Dynamic Thumbnails
- 2021-06-29 10:49:08
- OfStack
This article provides an example of how ASP.NET creates dynamic thumbnails.Share it for your reference.Specific analysis is as follows:
Tips:
1. Import System.IO
2. Create class C lass "CreateThumbnails"
or any class and place following function inside that class
You need one function to response call back to main function
Function ImageAbortDummyCallback() As Boolean
Return False
End Function
The code is as follows:
Function CreateJPEGThumbnail(ByVal inSourceFile As String, ByVal inDestinationFile As String, ByVal ThumbWidth As Integer, ByVal ThumbHeight As Integer) As Boolean
Dim imageFile As System.Drawing.Image
Dim outputFstream As New FileStream(inSourceFile, FileMode.Open, FileAccess.Read)
'Exposes a System.IO.Stream around a file, supporting both synchronous and asynchronous read and write operations.
Dim ImageAbortCallBack As System.Drawing.Image.GetThumbnailImageAbort
'This method returns true if it decides that the System.Drawing.Image.GetThumbnailImage method should prematurely stop execution; otherwise, it returns false.
imageFile = System.Drawing.Image.FromStream(outputFstream)
ImageAbortCallBack = New System.Drawing.Image.GetThumbnailImageAbort(AddressOf ImageAbortDummyCallback)
imageFile = imageFile.GetThumbnailImage(ThumbWidth, ThumbHeight, ImageAbortCallBack, IntPtr.Zero)
'IntPtr = A platform-specific type that is used to represent a pointer or a handle.
imageFile.Save(inDestinationFile, System.Drawing.Imaging.ImageFormat.Jpeg)
outputFstream.Close()
outputFstream = Nothing
imageFile = Nothing
End Function
I hope that the description in this paper will be helpful to everyone's asp.net program design.