[RESOLVED] Dynamically sizing an ImageBox based on image size

[eyeRmonkey]

I am having trouble getting this code to work the way I want. I think it might have something to with the .Stretch property of the ImageBox being set to true. But when I set it to false it doesn't act at ALL like I want it to.

If anyone could help with this I would be very appreciative. The project is attached.

[jcis]

Im looking your code.
Do you want the image to have the same height than the PictureBox?

[eyeRmonkey]

I want the image to be scaled based on the size of the picture box (which isn't a square). So the code first needs to decide which is dimension of the image is bigger than the picture box (the width or the height). Then it needs to scale that dimension based on the dimensions of the picture box.

That should yeild a percent that we can use to scale both the percents.

In short, I want the picture to be scaled into the picture box, but keep its proportions.

[MagicT]

eyeRMonkey,
First, thanks foryour useful links...

I tried running your project. What I notice is if
1) I run image 1 first, it does not resize to the picture box
2) I restart program, run image 3, then image 1...image 1 appears to work the way you describe you want...
3) I restart program, run image 2, then image 1...image 1 is paints beyond the border of the picture box

Q: Am I right? Start Program, show Image 3, then image 1 and you get what you are looking for? I was unclear about what you were saying in your post.

-MagicT

[jcis]

Well, finally, I think I got it.

Private Sub SizePreview()
    Dim lDif     As Double
    Dim lPercent As Double
 
    With imgPreview
        .Stretch = True
        .Visible = False
        If .Picture.Height = 0 Then Exit Sub
 
        If (.Picture.Height - picHolder.Height) > (.Picture.Width - picHolder.Width) Then
            lDif = .Picture.Height - picHolder.Height
            lPercent = lDif * 100 / .Picture.Height
            .Width = .Picture.Width - (lPercent * .Picture.Width / 100)
            .Height = .Picture.Height - (lPercent * .Picture.Height / 100)
        Else
            lDif = .Picture.Width - picHolder.Width
            lPercent = lDif * 100 / .Picture.Width
            .Width = .Picture.Width - (lPercent * .Picture.Width / 100)
            .Height = .Picture.Height - (lPercent * .Picture.Height / 100)
        End If
 
        .Move 0, 0, .Width, .Height
        .Visible = True
    End With
End Sub

[eyeRmonkey]

Thanks a ton for trying, but that doesn't quite do what I need either. It doesn't maintain the aspect ratio of the original picture. If you make the PictureBox very very wide and go to picture 2 then it stretches to fit the box.

What I want it to do figure out which dimension is biggest (I think your code does that). Then I want the image to be scaled so it fits inside the picture box without losing its original aspect ratio.

It LOOKs like your code does what I want, but I think something is too dependent on the width/height of the PictureBox and that is causing it to stretch to the size of the picturebox.


PS - The .Move at the end is unecessary because setting the .Width and .Height move it anyway. .Move is only for when you want to prevent flickering by changing everything at once using numbers ot variables, not the properties that already do that.

[jcis]

Private Sub SizePreview()
    Dim lDif     As Double
    Dim lPercent As Double
    Dim lx       As Long
    Dim ly       As Long
    Dim Xscaled  As Double
    Dim Yscaled  As Double
    
    With imgPreview
        .Visible = False
        If .Picture.Height = 0 Then Exit Sub
        .Stretch = False
        
        Xscaled = .Picture.Width * 0.5712
        Yscaled = .Picture.Height * 0.5712
        
        If Yscaled > picHolder.Height Or Xscaled > picHolder.Width Then
            If (Yscaled > picHolder.Height) Then
                lDif = Yscaled - picHolder.Height
                lPercent = lDif * 100 / Yscaled
                .Width = Xscaled - (lPercent * Xscaled / 100)
                .Height = Yscaled - (lPercent * Yscaled / 100)
                Xscaled = .Width  'Update Width
                Yscaled = .Height 'Update Height
            End If
            If (Xscaled > picHolder.Width) Then
                lDif = Xscaled - picHolder.Width
                lPercent = lDif * 100 / Xscaled
                .Width = Xscaled - (lPercent * Xscaled / 100)
                .Height = Yscaled - (lPercent * Yscaled / 100)
            End If
            .Stretch = True
        End If
                        
        'this centers the image
        lx = ly = 0
        If .Width < picHolder.Width Then lx = (picHolder.Width - .Width) / 2
        If .Height < picHolder.Height Then ly = (picHolder.Height - .Height) / 2
        .Move lx, ly, .Width, .Height
        .Visible = True
    End With
End Sub

[eyeRmonkey]

I didn't mean the changing the picture boxes.stretch property. I just meant that it seems like the picture box is somethins stretching itself (getting wider) to the width of the picture box and that makese me think that the calculations are wrong.

I haven't actually tested your newest code yet, but I will when I get home later today.

Is there confusion on what I am asking for? I didn't feel that I explained it very well. Or maybe I am just getting different results on my computer than you are getting.

Thanks again and I will let you know if that worked.

[jcis]

Ok, now i think its not working fine always.
And i see picHolder.Height and ImgPreview.Picture.Height use different scales, something like picHolder.Height = ImgPreview .Picture.Width * 0.5712.

[jcis]

Well, I edited my post number #7 and pasted a new function, that one is working perfectly here, i tested chaging the picturebox size many times, im testing with 15 different jpgs, now all of them show well.

[eyeRmonkey]

Wow! Thanks so much jcis. That is perfect. I wish I could rep you again. I will try to remember once the system lets me.

Thanks a million.

[jcis]

You're welcome