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aspx thread: Resizing Uploaded Images
Message #1 by "Hugh McLaughlin" <hugh@k...> on Wed, 18 Sep 2002 04:39:55
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Hello Everyone and thanks for your help in advance. I am working on an
application that allows the user to upload an image to the server. It
uses the syntax that I have found in many examples, i.e.
ImageStream = PersonImage.PostedFile.InputStream
Dim ImageContent(intImageSize) As Byte
Dim intStatus As Integer
intStatus = ImageStream.Read(ImageContent, 0, intImageSize)
From there, the ImageContent is set equal to a stored procedure parameter
and add to a database. This works fine, however, I want to be able to
resize the image before inserting the image. But since the image is read
into an array, I do not know how to change the array to a
System.Drawing>image type in order to ascertain the height and width of
the image, and then perform resizing. Any help on this topic would be
greatly appreciated. Thanks.
Message #2 by "Márcio Roberto de MatosVarella" <marciovarella123@y...> on Wed, 18 Sep 2002 14:26:32
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> Hello Everyone and thanks for your help in advance. I am working on an
a> pplication that allows the user to upload an image to the server. It
u> ses the syntax that I have found in many examples, i.e.
> ImageStream = PersonImage.PostedFile.InputStream
> Dim ImageContent(intImageSize) As Byte
> Dim intStatus As Integer
> intStatus = ImageStream.Read(ImageContent, 0, intImageSize)
> From there, the ImageContent is set equal to a stored procedure
parameter
a> nd add to a database. This works fine, however, I want to be able to
r> esize the image before inserting the image. But since the image is
read
i> nto an array, I do not know how to change the array to a
S> ystem.Drawing>image type in order to ascertain the height and width of
t> he image, and then perform resizing. Any help on this topic would be
g> reatly appreciated. Thanks.
Message #3 by "Hugh McLaughlin" <hugh@k...> on Wed, 18 Sep 2002 14:30:46
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Marcio,
Your response did not post.
Hugh
> > Hello Everyone and thanks for your help in advance. I am working on
an
a> > pplication that allows the user to upload an image to the server.
It
u> > ses the syntax that I have found in many examples, i.e.
> > ImageStream = PersonImage.PostedFile.InputStream
> > Dim ImageContent(intImageSize) As Byte
> > Dim intStatus As Integer
> > intStatus = ImageStream.Read(ImageContent, 0, intImageSize)
> > From there, the ImageContent is set equal to a stored procedure
p> arameter
a> > nd add to a database. This works fine, however, I want to be able
to
r> > esize the image before inserting the image. But since the image is
r> ead
i> > nto an array, I do not know how to change the array to a
S> > ystem.Drawing>image type in order to ascertain the height and width
of
t> > he image, and then perform resizing. Any help on this topic would
be
g> > reatly appreciated. Thanks.
Message #4 by "Mingkun Goh" <mangokun@h...> on Fri, 20 Sep 2002 00:32:56
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Below is the full set of my image resizing functions:
#Region "Proportional Image Resizing Functions"
' This function returns a proportional size for thumbnail image
Public Function ScaledThumbnailSize(ByVal ImageWidth As Integer, ByVal
ImageHeight As Integer, ByVal MaxWidth As Integer, ByVal MaxHeight As
Integer) As Size
Dim NewSize As New Size()
If MaxWidth >= ImageWidth And MaxHeight >= ImageHeight Then
' no need to make thumbnail
' as current image already smaller than required size
NewSize.Width = ImageWidth
NewSize.Height = ImageHeight
Else
' Calculate the Size of the New image
Dim tempMultiplier As Double
If ImageWidth = ImageHeight Then ' square image
If MaxWidth <= MaxHeight Then
tempMultiplier = MaxWidth / ImageWidth
Else
tempMultiplier = MaxHeight / ImageWidth
End If
Else ' landscape/portrait
image
If MaxWidth = MaxHeight Then
If ImageWidth > ImageHeight Then ' landscape
tempMultiplier = MaxWidth / ImageWidth
Else ' portrait
tempMultiplier = MaxHeight / ImageHeight
End If
Else
If MaxWidth < ImageWidth And MaxHeight < ImageHeight
Then
' thumbnail area totally inside image area
' try using ImageWidth
tempMultiplier = MaxWidth / ImageWidth
If CInt(ImageHeight * tempMultiplier) > MaxHeight
Then
tempMultiplier = MaxHeight / ImageHeight
End If
ElseIf MaxWidth > ImageWidth Then
' thumbnail area longer than image area
tempMultiplier = MaxHeight / ImageHeight
Else
' thumbnail area taller than image area
tempMultiplier = MaxWidth / ImageWidth
End If
End If
End If
NewSize.Width = CInt(ImageWidth * tempMultiplier)
NewSize.Height = CInt(ImageHeight * tempMultiplier)
End If
Return NewSize
End Function
' This overloaded function takes in a different set of parameters
Public Function ScaledThumbnailSize(ByVal ImageSize As Size, ByVal
MaxSize As Size) As Size
Return ScaledThumbnailSize(ImageSize.Width, ImageSize.Height,
MaxSize.Width, MaxSize.Height)
End Function
' This function would take in an image, and returns a proportional
resized thumbnail image
' The 1st parameter OrginalImage would be the image you want to be
scaled to fit within a container
' The 2nd parameter Container can be an control such as PictureBox, or
an structure such as Rectangle
Public Function ScaledThumbnailImage(ByVal OriginalImage As Image,
ByVal Container As Object) As Image
Dim NewSize As New Size()
NewSize = ScaledThumbnailSize(OriginalImage.Size, Container.Size)
Return OriginalImage.GetThumbnailImage(NewSize.Width,
NewSize.Height, Nothing, Nothing)
End Function
' This overloaded function takes in a different set of parameters
Public Function ScaledThumbnailImage(ByVal OriginalImage As Image,
ByVal ContainerSize As Size) As Image
Dim NewSize As New Size()
NewSize = ScaledThumbnailSize(OriginalImage.Size, ContainerSize)
Return OriginalImage.GetThumbnailImage(NewSize.Width,
NewSize.Height, Nothing, Nothing)
End Function
' This overloaded function takes in a different set of parameters
Public Function ScaledThumbnailImage(ByVal OriginalImage As Image,
ByVal ContainerWidth As Integer, ByVal ContainerHeight As Integer) As Image
Dim NewSize As New Size()
NewSize = ScaledThumbnailSize(OriginalImage.Size.Width,
OriginalImage.Size.Height, ContainerWidth, ContainerHeight)
Return OriginalImage.GetThumbnailImage(NewSize.Width,
NewSize.Height, Nothing, Nothing)
End Function
#End Region
Note that you MAY HAVE to add 2 namespace to the top of your code, which
are:
Imports System.Drawing
Imports System.Drawing.Imaging
Here are some example usage:
1. Dim imgPhoto As Image = Image.FromFile(OpenFileDialog1.FileName)
PictureBox1.Image = ScaledThumbnailImage(imgPhoto, PictureBox1)
2. Dim img As Image = GetHttpImage(HttpStockChartImageUri)
img = ScaledThumbnailImage(img, 300, 200)
Return img
3. imgPhoto = Image.FromFile(OpenFileDialog1.FileName)
Dim thumbSize As New Size()
thumbSize = ScaledThumbnailSize(imgPhoto.Size, PictureBox1.Size)
PictureBox1.Image = imgPhoto.GetThumbnailImage(thumbSize.Width,
thumbSize.Height, Nothing, Nothing)
You can put my 'Proportional Image Resizing Functions' into a Module file
or a Class Library, or even build it into a reusable DLL (althrough the
later approach is typically prefered).
Similar Thread in p2p.wrox.com - aspx
Question on ASPToday Image Resizing Article
http://p2p.wrox.com/archive/aspx/2002-04/72.asp
Previous message:
Hello Everyone and thanks for your help in advance. I am working on an
application that allows the user to upload an image to the server. It
uses the syntax that I have found in many examples, i.e.
ImageStream = PersonImage.PostedFile.InputStream
Dim ImageContent(intImageSize) As Byte
Dim intStatus As Integer
intStatus = ImageStream.Read(ImageContent, 0, intImageSize)
From there, the ImageContent is set equal to a stored procedure parameter
and add to a database. This works fine, however, I want to be able to
resize the image before inserting the image. But since the image is read
into an array, I do not know how to change the array to a
System.Drawing>image type in order to ascertain the height and width of
the image, and then perform resizing. Any help on this topic would be
greatly appreciated. Thanks.
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