GUI, GDI+ and transparency

[MrChiliCheese]

Hi Guys,

i have a little problem here. I'm trying with GDI and transparent png backgrounds for GUIs and it works but i want to draw a semitransparent png on the background, and this don't work.

I think it has to do with the color i set as transpareny color. Maybe u can give me a tip where i made the mistake...

Here is the Script

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#NoTrayIcon
#include <GDIPlus.au3>
#include <WindowsConstants.au3>
#include <GuiConstantsEx.au3>
#include <ButtonConstants.au3>
#include <WinAPI.au3>

Global Const $AC_SRC_ALPHA = 1
If @DesktopHeight = 1080 Then
    $gPosX = (-1280 - 238) / 2
    $gPosY = (1024 - 471) / 2
Else
    $gPosX = -1
    $gPosY = -1
EndIf

_GDIPlus_Startup()
$bg = _GDIPlus_ImageLoadFromFile(@ScriptDir & "\bg.png")
$icon_a = _GDIPlus_ImageLoadFromFile(@ScriptDir & "\icon_1a.png")
$icon_b = _GDIPlus_ImageLoadFromFile(@ScriptDir & "\icon_1b.png")

GUICtrlCreateButton("TEST", 10, 10, 50, 20)
$bgGUI = GUICreate("SysControl", 325, 425, -1, -1, $WS_POPUP, $WS_EX_LAYERED)
SetBitMap($bgGUI, $bg, 0)
GUIRegisterMsg($WM_NCHITTEST, "WM_NCHITTEST")
GUISetState()
WinSetOnTop($bgGUI, "", 1)

For $i = 5 To 255 Step 10
    SetBitmap($bgGUI, $bg, $i)
    Sleep(1)
Next

$realGUI = GUICreate("CONTROL_GUI", 325, 425, -1, -1, $WS_POPUP, BitOR($WS_EX_LAYERED, $WS_EX_MDICHILD), $bgGUI)

GUICtrlCreatePic(@ScriptDir & "\trans1.gif", 0, 0, 325, 425)
GUICtrlSetState(-1, $GUI_DISABLE)

GUISetState()
$ZEROGraphic = _GDIPlus_GraphicsCreateFromHWND($realGUI)
_GDIPlus_GraphicsDrawImageRectRect($ZEROGraphic, $icon_a, 0, 0, 256, 256, 15, 10, 128, 128)
_GDIPlus_GraphicsDrawImageRectRect($ZEROGraphic, $icon_b, 0, 0, 256, 256, 143, 10, 128, 128)

While 1
    $msg = GUIGetMsg()
    Select
        Case $msg = $GUI_EVENT_CLOSE
            Exit
    EndSelect
WEnd


Func WM_NCHITTEST($hWnd, $iMsg, $iwParam, $ilParam)
    If ($hWnd = $bgGUI) And ($iMsg = $WM_NCHITTEST) Then Return $HTCAPTION
EndFunc   ;==>WM_NCHITTEST

Func SetBitmap($hGUI, $hImage, $iOpacity)
    Local $hScrDC, $hMemDC, $hBitmap, $hOld, $pSize, $tSize, $pSource, $tSource, $pBlend, $tBlend

    $hScrDC = _WinAPI_GetDC(0)
    $hMemDC = _WinAPI_CreateCompatibleDC($hScrDC)
    $hBitmap = _GDIPlus_BitmapCreateHBITMAPFromBitmap($hImage)
    $hOld = _WinAPI_SelectObject($hMemDC, $hBitmap)
    $tSize = DllStructCreate($tagSIZE)
    $pSize = DllStructGetPtr($tSize)
    DllStructSetData($tSize, "X", _GDIPlus_ImageGetWidth($hImage))
    DllStructSetData($tSize, "Y", _GDIPlus_ImageGetHeight($hImage))
    $tSource = DllStructCreate($tagPOINT)
    $pSource = DllStructGetPtr($tSource)
    $tBlend = DllStructCreate($tagBLENDFUNCTION)
    $pBlend = DllStructGetPtr($tBlend)
    DllStructSetData($tBlend, "Alpha", $iOpacity)
    DllStructSetData($tBlend, "Format", $AC_SRC_ALPHA)
    _WinAPI_UpdateLayeredWindow($hGUI, $hScrDC, 0, $pSize, $hMemDC, $pSource, 0, $pBlend, $ULW_ALPHA)
    _WinAPI_ReleaseDC(0, $hScrDC)
    _WinAPI_SelectObject($hMemDC, $hOld)
    _WinAPI_DeleteObject($hBitmap)
    _WinAPI_DeleteDC($hMemDC)
EndFunc   ;==>SetBitmap

And here is a picture of my problem. I want the firefox logo also transparent, but i won't work

Here the source code and graphics:

[martin]

The pink bits are not all the same colour so that is the first problem I think. Then when you change the opacity you are also changing the colour as far as transparency is concerned perhaps.

There was a similar requirement here which was solved using a different approach which might do what you want, but first you would have to get all those pink bits the same colour.

[MrChiliCheese]

Thanks for your reply, but i'm not really good in this graphics stuff, so i think it would be difficult for me to remove every pink bit/pixel... or is this easy?

[martin]

Thanks for your reply, but i'm not really good in this graphics stuff, so i think it would be difficult for me to remove every pink bit/pixel... or is this easy?

It's quite easy. You don't need to remove every pixel but just make them the same. It could be done with mspaint.

[MrChiliCheese]

Thank you, but i found an easier way. I integrated the firefox logo to the background image and put a label with $SS_Notify on it Works for me