Change Opactiy of GDI+ Bitmap

[Lucid]

I'm having problems getting my brain to work, and I can't find anything to help me get moving on the web - so I was hoping someone here could nudge me in the right direction.

I'm trying to be able to change the opacity of a bitmap using GDI+ (the source files are all .PNG). So at times it's fully opaque, and others it's faded out. Below is a sample bit of code. How can I get the bitmap to look semi-transparent? Thanks!

 

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#include <GUIConstantsEx.au3>
#include <GDIPlus.au3>
#include <GUIConstants.au3>
#include <ColorConstantS.au3>
#include <WinAPIGdi.au3>
#include <WindowsConstants.au3>

AutoItSetOption("MustDeclareVars", 1)

_GDIPlus_Startup()

Local $hGUI = GUICreate("test", 400, 300, -1, -1, $WS_POPUP, $WS_EX_LAYERED)
GUISetBkColor(0x000000, $hGUI)

Local $hImage = _GDIPlus_ImageLoadFromFile("AnyPNGFile.png")
Local $iWidth = _GDIPlus_ImageGetWidth($hImage)
Local $iHeight = _GDIPlus_ImageGetHeight($hImage)
Local $hBitmap = _GDIPlus_BitmapCreateHBITMAPFromBitmap($hImage)

; how can I dynamically change the opacity of the bitmap?

Local $hPicCtrl = GUICtrlCreatePic("", 0, 0, $iWidth, $iHeight)
_SetBitmapToCtrl($hPicCtrl, $hBitmap)
GUICtrlSetState ($hPicCtrl, $GUI_SHOW)
GUISetState(@SW_SHOW, $hGUI)

While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            _GDIPlus_Shutdown()
            Exit
    EndSwitch
WEnd


Func _SetBitmapToCtrl($CtrlId, $hBitmap)
    Local Const $STM_SETIMAGE = 0x0172
    Local Const $IMAGE_BITMAP = 0
    Local Const $SS_BITMAP = 0xE
    Local Const $GWL_STYLE = -16
    Local $hWnd = GUICtrlGetHandle($CtrlId)
    If $hWnd = 0 Then Return SetError(1, 0, 0)
      ; set SS_BITMAP style to control
    Local $oldStyle = DllCall("user32.dll", "long", "GetWindowLong", "hwnd", $hWnd, "int", $GWL_STYLE)
    If @error Then Return SetError(2, 0, 0)
    DllCall("user32.dll", "long", "SetWindowLong", "hwnd", $hWnd, "int", $GWL_STYLE, "long", BitOR($oldStyle[0], $SS_BITMAP))
    If @error Then Return SetError(3, 0, 0)
        Local $oldBmp = DllCall("user32.dll", "hwnd", "SendMessage", "hwnd", $hWnd, "int", $STM_SETIMAGE, "int", $IMAGE_BITMAP, "int", $hBitmap)
    If @error Then Return SetError(4, 0, 0)
    If $oldBmp[0] <> 0 Then _WinAPI_DeleteObject($oldBmp[0])
    Return 1
EndFunc

 

[1957classic]

WinSetTrans($hGUI, "", 140)

 

[UEZ]

Try this:

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

AutoItSetOption("MustDeclareVars", 1)

_GDIPlus_Startup()

Global $hImage = _GDIPlus_ImageLoadFromFile("c:\Program Files (x86)\AutoIt3\Examples\GUI\Torus.png")
Global $iWidth = _GDIPlus_ImageGetWidth($hImage)
Global $iHeight = _GDIPlus_ImageGetHeight($hImage)

Global $hGUI = GUICreate("test", $iWidth, $iHeight, -1, -1, $WS_POPUP, $WS_EX_LAYERED)
GUISetState(@SW_SHOW, $hGUI)

Global $hBitmap_Transparent = _GDIPlus_BitmapCreateFromScan0($iWidth, $iHeight)
Global $hGfx = _GDIPlus_ImageGetGraphicsContext($hBitmap_Transparent)
Global $hAttribute_Transparent = _GDIPlus_AttributeCreateTransparentBitmap($hImage)
_GDIPlus_GraphicsDrawImageRectRect($hGfx, $hImage, 0, 0, $iWidth, $iHeight, 0, 0, $iWidth, $iHeight, $hAttribute_Transparent)

Global $hHBitmap = _GDIPlus_BitmapCreateHBITMAPFromBitmap($hBitmap_Transparent)
_WinAPI_BitmapDisplayTransparentInGUI($hHBitmap, $hGUI)


While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            _GDIPlus_ImageAttributesDispose($hAttribute_Transparent)
            _GDIPlus_GraphicsDispose($hGfx)
            _GDIPlus_ImageDispose($hBitmap_Transparent)
            _GDIPlus_ImageDispose($hImage)
            _WinAPI_DeleteObject($hHBitmap)
            _GDIPlus_Shutdown()
            Exit
    EndSwitch
WEnd

Func _GDIPlus_AttributeCreateTransparentBitmap($hImage, $fTransparency = 0.25)
    Local Const $hAttribute_Alpha = _GDIPlus_ImageAttributesCreate()
    $fTransparency = $fTransparency > 1 ? 1 : $fTransparency < 0 ? 0 : $fTransparency
    Local $tColorMatrix = _GDIPlus_ColorMatrixCreateTranslate(0, 0, 0, $fTransparency * -1)
    Local Const $pColorMatrix = DllStructGetPtr($tColorMatrix)
    _GDIPlus_ImageAttributesSetColorMatrix($hAttribute_Alpha, 0, True, $pColorMatrix)
    Return $hAttribute_Alpha
EndFunc

Func _WinAPI_BitmapDisplayTransparentInGUI(ByRef $hHBitmap, ByRef $hGUI, $iOpacity = 0xFF, $bReleaseGDI = True)
    If Not BitAND(GUIGetStyle($hGUI)[1], $WS_EX_LAYERED) = $WS_EX_LAYERED Then Return SetError(1, 0, 0)
    Local $tDim = DllStructCreate($tagBITMAP)
    If Not _WinAPI_GetObject($hHBitmap, DllStructGetSize($tDim), DllStructGetPtr($tDim)) Then Return SetError(2, 0, 0)
    Local $tSize = DllStructCreate($tagSIZE), $tSource = DllStructCreate($tagPOINT), $tBlend = DllStructCreate($tagBLENDFUNCTION)
    Local Const $hScrDC = _WinAPI_GetDC(0), $hMemDC = _WinAPI_CreateCompatibleDC($hScrDC), $hOld = _WinAPI_SelectObject($hMemDC, $hHBitmap)
    $tSize.X = $tDim.bmWidth
    $tSize.Y = $tDim.bmHeight
    $tBlend.Alpha = $iOpacity
    $tBlend.Format = 1
    _WinAPI_UpdateLayeredWindow($hGUI, $hScrDC, 0, DllStructGetPtr($tSize), $hMemDC, DllStructGetPtr($tSource), 0, DllStructGetPtr($tBlend), $ULW_ALPHA)
    _WinAPI_ReleaseDC(0, $hScrDC)
    _WinAPI_SelectObject($hMemDC, $hOld)
    _WinAPI_DeleteDC($hMemDC)
    If $bReleaseGDI Then _WinAPI_DeleteObject($hHBitmap)
    Return True
EndFunc

 

Edited November 29, 2015 by UEZ

[Lucid]

Sorry for not being clear. I'm looking to be able to alter the transparency of the image, but keep the background of the GUI visible.

So in UEZ's example, if I add "GUISetBkColor(0x000000, $hGUI)" I don't see the black background I'd expect to see. I've been trying to work my way through the code and understand what it's doing, but I'm coming up with a few blanks. How can I have a semi-transparent image on top of the GUI, but still be able to see the GUI background?

Thanks!

[UEZ]

Here the modfied version:

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

AutoItSetOption("MustDeclareVars", 1)

_GDIPlus_Startup()

Global $hImage = _GDIPlus_ImageLoadFromFile("c:\Program Files (x86)\AutoIt3\Examples\GUI\Torus.png")
Global $iWidth = _GDIPlus_ImageGetWidth($hImage)
Global $iHeight = _GDIPlus_ImageGetHeight($hImage)

Global $hGUI = GUICreate("test", $iWidth, $iHeight)
GUISetBkColor(0)
GUISetState(@SW_SHOW, $hGUI)

Global $hGfx = _GDIPlus_GraphicsCreateFromHWND($hGUI)
Global $hAttribute_Transparent = _GDIPlus_AttributeCreateTransparentBitmap($hImage)

_GDIPlus_GraphicsDrawImageRectRect($hGfx, $hImage, 0, 0, $iWidth, $iHeight, 0, 0, $iWidth, $iHeight, $hAttribute_Transparent)



While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            _GDIPlus_ImageAttributesDispose($hAttribute_Transparent)
            _GDIPlus_GraphicsDispose($hGfx)
            _GDIPlus_ImageDispose($hImage)
            _GDIPlus_Shutdown()
            Exit
    EndSwitch
WEnd

Func _GDIPlus_AttributeCreateTransparentBitmap($hImage, $fTransparency = 0.25)
    Local Const $hAttribute_Alpha = _GDIPlus_ImageAttributesCreate()
    $fTransparency = $fTransparency > 1 ? 1 : $fTransparency < 0 ? 0 : $fTransparency
    Local $tColorMatrix = _GDIPlus_ColorMatrixCreateTranslate(0, 0, 0, $fTransparency * -1)
    Local Const $pColorMatrix = DllStructGetPtr($tColorMatrix)
    _GDIPlus_ImageAttributesSetColorMatrix($hAttribute_Alpha, 0, True, $pColorMatrix)
    Return $hAttribute_Alpha
EndFunc

 

[Lucid]

Thanks for the speedy reply UEZ!

I guess I'm not being clear. So what I'm trying to figure out how to do is to make an image semi-transparent on top of the background of the GUI (so you can see the background through the semi-transparent image). In the included pics, you can see that the red Torus ring is 100% in the one, but in the other the ring is like 55% transparent and the blue background shows through. How can I accomplish this with GDI+ using a PNG file?

Thanks! And sorry for not being clear enough in my first post.

 

[Lucid]

Nevermind! Totally my fault - got a number in the wrong spot in my test. Thanks UEZ! I think I'm able to move forward and try understanding/adapting your code.