Transparent Forms

[kal2004]

I want to add a picture to the actual form and then make a certain color from the picture transparent. I have got code to make this work but it will only work with .bmp added to form, but obviously makes the final program huge in size

Please see attached picture.
Example

It makes color "0, 0, 255" transparent, but i need it to do the same thing with a .jpg image..

Please help.

Kal


The code i have is:

"Form code"

Dim g_nTransparency As Integer
    Dim color As Long
    Dim flag As Byte

Private Sub Form_load()
    On Error GoTo ErrorRtn
    color = RGB(0, 0, 255)
    flag = 0
    If chkcolor.Value = 1 Then flag = flag Or LWA_COLORKEY
    If chkAlpha.Value = 1 Then flag = flag Or LWA_ALPHA
                
    'value between 0 and 255
    g_nTransparency = txtTransparency.Text
    If g_nTransparency < 0 Then g_nTransparency = 0
    If g_nTransparency > 255 Then g_nTransparency = 255
    Me.Show
    SetTranslucent2 Me.hWnd, color, g_nTransparency, flag
    
    Exit Sub
ErrorRtn:
    MsgBox Err.Description & " Source : " & Err.Source
    
    
'initialize
    txtTransparency.Text = 150
    g_nTransparency = 150
    Me.Show
    
End Sub

"API Module"

Option Explicit
Public Const LWA_COLORKEY = 1
Public Const LWA_ALPHA = 2
Public Const LWA_BOTH = 3
Public Const WS_EX_LAYERED = &H80000
Public Const GWL_EXSTYLE = -20
Public Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hwnd As Long, ByVal color As Long, ByVal X As Byte, ByVal alpha As Long) As Boolean
Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Public Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long

"Misc Module"

Option Explicit

Sub SetTranslucent(ThehWnd As Long, nTrans As Integer)
    On Error GoTo ErrorRtn

    'SetWindowLong and SetLayeredWindowAttributes are API functions, see MSDN for details
    Dim attrib As Long
    attrib = GetWindowLong(ThehWnd, GWL_EXSTYLE)
    SetWindowLong ThehWnd, GWL_EXSTYLE, attrib Or WS_EX_LAYERED
    SetLayeredWindowAttributes ThehWnd, RGB(255, 255, 0), nTrans, LWA_ALPHA
    Exit Sub
ErrorRtn:
    MsgBox Err.Description & " Source : " & Err.Source
    
End Sub


Sub SetTranslucent2(ThehWnd As Long, color As Long, nTrans As Integer, flag As Byte)
    On Error GoTo ErrorRtn

    'SetWindowLong and SetLayeredWindowAttributes are API functions, see MSDN for details
    Dim attrib As Long
    attrib = GetWindowLong(ThehWnd, GWL_EXSTYLE)
    SetWindowLong ThehWnd, GWL_EXSTYLE, attrib Or WS_EX_LAYERED
    'anything with color value color will completely disappear if flag = 1 or flag = 3
    SetLayeredWindowAttributes ThehWnd, color, nTrans, flag
    Exit Sub
ErrorRtn:
    MsgBox Err.Description & " Source : " & Err.Source
    
End Sub

I am sure this code could be simplified also, this code requires 2 checkboxes and a textbox with the transparency value, in order to work.