i was searching google for some kind solution and i found one, i tried to implement it in my code but it doesn't work. The problem is that after resizing white images they gets gray border.
Here is the link of soloution i found:
It says: This problem is occuring because you are interpolating your image data to a new size, but along the edges there are no pixels to interpolate and .NET uses black pixels for these edges by default. To fix this you need to use an ImageAttributes class in your DrawImage call....
CODE 1: And this is my code WITH IMPLEMENTATION OF ImageAttributes:
Private Shared Function ResizeImageFile(ByVal imageFile As Byte(), ByVal targetSize As Integer) As Byte()
Using oldImage As System.Drawing.Image = System.Drawing.Image.FromStream(New MemoryStream(imageFile))
Dim newSize As Size = CalculateDimensions(oldImage.Size, targetSize)
Using newImage As New Bitmap(newSize.Width, newSize.Height, PixelFormat.Format32bppRgb)
Using canvas As Graphics = Graphics.FromImage(newImage)
Using ia As New ImageAttributes
ia.SetWrapMode(Drawing2D.WrapMode.TileFlipXY)
canvas.SmoothingMode = SmoothingMode.AntiAlias
canvas.InterpolationMode = InterpolationMode.HighQualityBicubic
canvas.PixelOffsetMode = PixelOffsetMode.HighQuality
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize), 0, 0, newImage.Width, newImage.Height, GraphicsUnit.Pixel, ia)
Dim m As New MemoryStream()
newImage.Save(m, ImageFormat.Png)
Return m.GetBuffer()
End Using
End Using
End Using
End Using
End Function
Private Shared Function CalculateDimensions(ByVal oldSize As Size, ByVal targetSize As Integer) As Size
Dim newSize As New Size()
If oldSize.Height > oldSize.Width Then
newSize.Width = CInt((oldSize.Width * (CSng(targetSize) / CSng(oldSize.Height))))
newSize.Height = targetSize
Else
newSize.Width = targetSize
newSize.Height = CInt((oldSize.Height * (CSng(targetSize) / CSng(oldSize.Width))))
End If
Return newSize
End Function
CODE 2: CODE THAT COUSES A GRAY BORDER ON WHITE IMAGE
Here is the image after resizing:
new image size in width = 400px
Private Shared Function ResizeImageFile(ByVal imageFile As Byte(), ByVal targetSize As Integer) As Byte()
Using oldImage As System.Drawing.Image = System.Drawing.Image.FromStream(New MemoryStream(imageFile))
Dim newSize As Size = CalculateDimensions(oldImage.Size, targetSize)
Using newImage As New Bitmap(newSize.Width, newSize.Height, PixelFormat.Format32bppRgb)
Using canvas As Graphics = Graphics.FromImage(newImage)
canvas.SmoothingMode = SmoothingMode.AntiAlias
canvas.InterpolationMode = InterpolationMode.HighQualityBicubic
canvas.PixelOffsetMode = PixelOffsetMode.HighQuality
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize))
Dim m As New MemoryStream()
newImage.Save(m, ImageFormat.Png)
Return m.GetBuffer()
End Using
End Using
End Using
End Function
Private Shared Function CalculateDimensions(ByVal oldSize As Size, ByVal targetSize As Integer) As Size
Dim newSize As New Size()
If oldSize.Height > oldSize.Width Then
newSize.Width = CInt((oldSize.Width * (CSng(targetSize) / CSng(oldSize.Height))))
newSize.Height = targetSize
Else
newSize.Width = targetSize
newSize.Height = CInt((oldSize.Height * (CSng(targetSize) / CSng(oldSize.Width))))
End If
Return newSize
End Function
UPDATE 30.07.2011.:
CODE 1 solved the problem with the gray borders on white images, but there is new problem. The problem is in this line of code:
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize), 0, 0, newImage.Width, newImage.Height, GraphicsUnit.Pixel, ia)
With this code I get output image with desired width and height and without gray borders but the oldImage isn't scaled.
For example:
If I want to upload, resize and save the image that is orginaly for instance 640x480px and that the targetSize is 400px. As output I get an image that is width: 400px, height: 300px, without gray borders, but oldImage isn't resized/scaled to 400px. Insted of this, oldImage is drawn with the original resolution. How to scale oldImage to be drawn correctly? Can someone point me to the right solution or modify the code?
Thanx to everyone, but I found the solution to all my problems.
The CODE 1 didn't work correctly because of the following line of code:
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize), 0, 0, newImage.Width, newImage.Height, GraphicsUnit.Pixel, ia)
SOLUTION:
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize), 0, 0, oldImage.Width, oldImage.Height, GraphicsUnit.Pixel, ia)
HERE IS THE FULL WORKING CODE (resized image without gray/black borders):
Private Shared Function ResizeImageFile(ByVal imageFile As Byte(), ByVal targetSize As Integer) As Byte()
Using oldImage As System.Drawing.Image = System.Drawing.Image.FromStream(New MemoryStream(imageFile))
Dim newSize As Size = CalculateDimensions(oldImage.Size, targetSize)
Using newImage As New Bitmap(newSize.Width, newSize.Height, PixelFormat.Format32bppRgb)
Using canvas As Graphics = Graphics.FromImage(newImage)
Using ia As New ImageAttributes
ia.SetWrapMode(Drawing2D.WrapMode.TileFlipXY)
canvas.SmoothingMode = SmoothingMode.AntiAlias
canvas.InterpolationMode = InterpolationMode.HighQualityBicubic
canvas.PixelOffsetMode = PixelOffsetMode.HighQuality
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize), 0, 0, oldImage.Width, oldImage.Height, GraphicsUnit.Pixel, ia)
Dim m As New MemoryStream()
newImage.Save(m, ImageFormat.Png)
Return m.GetBuffer()
End Using
End Using
End Using
End Using
End Function
Private Shared Function CalculateDimensions(ByVal oldSize As Size, ByVal targetSize As Integer) As Size
Dim newSize As New Size()
If oldSize.Height > oldSize.Width Then
newSize.Width = CInt((oldSize.Width * (CSng(targetSize) / CSng(oldSize.Height))))
newSize.Height = targetSize
Else
newSize.Width = targetSize
newSize.Height = CInt((oldSize.Height * (CSng(targetSize) / CSng(oldSize.Width))))
End If
Return newSize
End Function
newSizewill be so we can see what you're seeing. I tried the code you provided and I don't see an issue. (Although technically I wouldn't really call this resizing an image, you're really just drawing the old image on a larger canvas.) – Chris Haas