Problem with zooming on a picture

[javad2000]

Hello

I have a very small black&white picture (4*4 pixels). Here's a magnified view of the picture:


I want to show this picture in a PictureBox whose "SizeMode" property is set to "Stretched". Normally, I expect the image to be larger than the source image and show something like this:


But it shows this:


How can I solve this problem?

Thank u

[.paul.]

save 1 of the larger pictures from this page + use that instead.
a larger picture made larger will probably display properly.

[javad2000]

save 1 of the larger pictures from this page + use that instead.
a larger picture made larger will probably display properly.

Thank u Paul
Let me ask my Q another way:

I need to magnify B&W pictures in B&W mode, not in color mode. I want to make all the pictures in that picturebox 'Black & white". How is it possible?

Thanks

[Fromethius]

I have an idea how to do this. I'll try writing up a function for you. Hold on.

[Fromethius]

First of all, when using the small image in the PictureBox.Image property, and setting the SizeMode to StretchImage, the image shows up exactly how you wanted it.

Secondly, your original JPEG image has speckles on it. This is probably due to the fact that it lost formatting when you saved it as a JPEG. Perhaps you should try saving the original, perfectly formatted image in Photoshop to avoid formatting loss.

If the SizeMode property isn't working for you, which it should, I wrote up this function anyways to resize an image. Maybe it will work better for you.

Public Shared Function ResizeImage(ByVal sourcePath As String, ByRef newSize As Size)
    Dim img As Image = Image.FromFile(sourcePath)
    Dim imgNew As New Bitmap(newSize.Width, newSize.Height, Imaging.PixelFormat.Format1bppIndexed)
    Dim graphics As Graphics = graphics.FromImage(imgNew)
 
    graphics.DrawImage(img, 0, 0, imgNew.Width, imgNew.Height)
 
    Return imgNew
End Function

PictureBox1.Image = ResizeImage("C:\Documents and Settings\Fromethius\Desktop\image.gif", New Size(104, 107))

If you cannot create a properly formatted image, you can always make an image black and white and then apply resizing, as that should work.

You can make an image black and white using a properly coded ColorMatrix which should look something like this:

Dim cm As New ColorMatrix(New Single()() {New Single() {0.5F, 0.5F, 0.5F, 0, 0}, New Single() {0.5F, 0.5F, 0.5F, 0, 0}, New Single() {0.5F, 0.5F, 0.5F, 0, 0}, New Single() {0, 0, 0, 1, 0, 0}, New Single() {0, 0, 0, 0, 1, 0}, New Single() {0, 0, 0, 0, 0, 1}})

Then you can use the ImageAttributes class to create a Bitmap like this.

Also, you can try looking into the Graphics.InterpolationMode for proper resizing.

[.paul.]

fromethius, did you try that with a 4*4 image as the original?

i'm not sure what you mean with the colormatrix thing. how are you making the image b+w?

[Fromethius]

No, I didn't yet because she didn't post it. I only tried this one:

http://aycu23.webshots.com/image/400...2488927_rs.jpg

About the ColorMatrix: You can make an image monochrome by using a ColorMatrix and ImageAttributes.

[.paul.]

can you give an example?

[Fromethius]

Yea, sure. Here you go. I just wrote this up:

Imports System.Drawing.Imaging
 
Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        PictureBox1.Image = GetGreyscaledImage(New Bitmap("C:\Documents and Settings\Fromethius\My Documents\My Pictures\image.png"))
    End Sub
 
    Public Shared Function GetGreyscaledImage(ByRef setImage As Image) As Image
        Dim greyscaleBitmap As Bitmap = New Bitmap(setImage.Width, setImage.Height)
        Dim greyscaleGraphics As Graphics = Graphics.FromImage(greyscaleBitmap)
 
        Dim greyscaleColorMatrix As New ColorMatrix(New Single()() { _
            New Single() {0.5F, 0.5F, 0.5F, 0, 0}, _
            New Single() {0.5F, 0.5F, 0.5F, 0, 0}, _
            New Single() {0.5F, 0.5F, 0.5F, 0, 0}, _
            New Single() {0, 0, 0, 1, 0, 0}, _
            New Single() {0, 0, 0, 0, 1, 0}, _
            New Single() {0, 0, 0, 0, 0, 1}})
 
        Dim greyscaleImageAttributes As New ImageAttributes()
        greyscaleImageAttributes.SetColorMatrix(greyscaleColorMatrix)
 
        greyscaleGraphics.DrawImage(setImage, New Rectangle(0, 0, setImage.Width, setImage.Height), 0, 0, setImage.Width, setImage.Height, GraphicsUnit.Pixel, greyscaleImageAttributes)
 
        Return greyscaleBitmap
    End Function
End Class

[.paul.]

ok thanks that works.
i'd rate you but i haven't rated 10 people since last time....