Bitmaps, APIs, PictureBoxes = Frustrating

[Destined Soul]

Hey all. I've been beating this thing over and over, and I still don't know what's occuring.

I'm trying to get my function to load up an entire bitmap image within the space of the picturebox (ie: a thumbnail.) So far, I've been able to get the image into the box, but I can't figure a way around the color appearance. When I load a 24-bit bmp, it still displays it like a 8-bit! How do I fix this?

Here's the code I'm using (at the moment):

Public Function DisplayBMP(picBox As PictureBox, fileName As String) As Boolean
    Dim hDC As Long, hBMP As Long
    Dim fileNo As Integer, counter As Integer
    Dim imgSize As POINT
            
    DisplayBMP = False
    
    fileNo = FreeFile
    Open fileName For Binary As fileNo
        Get #fileNo, 19, imgSize
    Close fileNo
        
    counter = 0
    Do
        hDC = CreateCompatibleDC(picBox.hDC)
        counter = counter + 1
    Loop While hDC < 1 Or counter < 15
    
    If hDC < 1 Then
        MsgBox "Failed on Device Context creation"
        Exit Function
    End If
    
    hBMP = LoadImage(0, fileName, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE Or LR_DEFAULTSIZE)
    If hBMP = 0 Then
        DeleteDC hDC
        MsgBox "Failed to load the image"
        Exit Function
    End If
    
    SelectObject hDC, hBMP
    DeleteObject hBMP
            
    StretchBlt picBox.hDC, 0, 0, picBox.Width, picBox.Height, hDC, 0, 0, imgSize.X * 15, imgSize.Y * 15, vbSrcCopy
    
    picBox.Refresh
 
    DeleteDC hDC
 
End Sub

Any help on how to fix my color problem, or on how to better implement this, is greatly appreciated.

Destined

[plenderj]

Why don't you just load the image straight into an IPictureDisp and then use StretchBlt straight from there ?

[Jotaf98]

If you want a simplier way, you can use an Image control, it has a property that automatically stretches the image to its own size.

As to your code, everything seems to be fine with it, I have no idea why it shows up in 256 colors.

[plenderj]

We are of course assuming you're using a resolution of greater than 256 colours in windows

[Janus]

You need to use SetStretchBltMode and pass it COLORONCOLOR, I believe - otherwise it looks 256-color. You could also just use LoadImage, that function can do resizing at load.

[plenderj]

As I said, he should just get the image into an IPictureDisp and Blit from there.
Use a generateDC() function.

[Janus]

LoadImage uses bi-linear filtering

[plenderj]

Whatever

If you use a GenerateDC() function though you end up with a reusable device context, and its very easy to use once you have a working GenerateDC()

[Destined Soul]

Thanx everyone for the help.

plenderj
I think I just want to use pure API calls to get it working. For what it's worth, that was how I originally did it, but the colors didn't seem to come out right. And, yes, I am running in more than 256 colors.

Janus
Excellent, this worked great. I just added the following code:

...
    DeleteObject hBMP
    
    SetStretchBltMode picBox.hDC, COLORONCOLOR  ' This works!
    StretchBlt picBox.hDC, 0, 0, picBox.Width, picBox.Height, hDC, 0, 0, imgSize.x * 15, imgSize.y * 15, vbSrcCopy
    
    picBox.Refresh
    ...