Transparency revisited

[qwert 36]

This was provided as a rule of thumb in a post a couple of years ago:

If you use the $WS_EX_LAYERED property and you add an image, every pixel within the entire GUI that is the same color as the top-left pixel of the LAST image added will be transparent.

It's been many months since I've worked with this and I'm confounded by the result I'm getting now that I'm trying to use the technique. Here's a very simple example to demonstrate what I'm seeing (bmp is attached below):

#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>
#include <Misc.au3>

$gui = GUICreate("", 800, 600, -1, -1, -1, $WS_EX_LAYERED)      ; removed $WS_POPUP for this test
GUISetBkColor(0x808080)
$img = GUICtrlCreatePic(@ScriptDir & "\sailboat2.bmp", 0, 0, 100, 200)
GUISetState(@SW_SHOW)
GUISetState()

While 1
    Sleep ( 250 )
    If _IsPressed("1B") Then
        MsgBox(0,"_IsPressed", "Esc Key Pressed")
        ExitLoop
    EndIf
WEnd
Exit

The small screen capture shows the result I'm getting. Rather than the pink color being entirely transparent, only the leading edge and the bottom edge are transparent. I'm sure it's something simple that I'm missing, but after trying a dozen variations, I can't see it.

I will appreciate any suggestion of what I have missed.

Thanks in advance.

Sailboat2.bmp

[UEZ 1,096]

Try this:

#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>
#include <Misc.au3>

$gui = GUICreate("", 84, 128, -1, -1, $WS_POPUP, $WS_EX_LAYERED)    ; removed $WS_POPUP for this test
GUISetBkColor(0x808080)
$hLabel = GUICtrlCreateLabel("", 8, 6, 66, 111, -1, $GUI_WS_EX_PARENTDRAG)
$img = GUICtrlCreatePic(@ScriptDir & "\sailboat2.bmp", 0, 0, 0, 0)
GUISetState(@SW_SHOW)

While 1
    Sleep ( 250 )
    If _IsPressed("1B") Then
        MsgBox(0,"_IsPressed", "Esc Key Pressed")
        ExitLoop
    EndIf
WEnd
Exit

Transparency will only work when you set the width and height to 0 in GUICtrlCreatePic() function!

Br,

UEZ

Edited November 9, 2010 by UEZ

[qwert 36]

Transparency will only work when you set the width and height to 0 in GUICtrlCreatePic() function!

Perfect! But how did you know that? The help file only says "if you want the picture to have the same size as the content, use 0's". It's not something I would have thought of ... yet if I had tried the example 2, it would have worked.

Anyway, thanks for the solution. I think it will help others, as well.