[SOLVED] Displaying a PNG gui at a different size

[this-is-me]

EDIT: This problem is now solved using the script found here.

I am trying to create a PNG gui from an original PNG of about 256 pixels in size and display it as ~50 pixels. I don't want to save a temporary image to disk before showing it.

I have already looked among the forums and I am a novice at GDI. I understand how to display a PNG gui as the original size, but don't know how to resize the PNG before display and keep the alpha channel. I think I need to be using _GDIPlus_GraphicsDrawImageRect, which allows me to specify the size, but I don't understand what to draw to and how to do it. Right now, I don't care about the resized image quality, just about doing the resize in memory (I don't want to run an external program).

Here is the script as-is.

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#include <GDIPlus.au3>
#include <WindowsConstants.au3>
#include <GuiConstantsEx.au3>
#include <StaticConstants.au3>
Global Const $AC_SRC_ALPHA = 1

_GDIPlus_Startup()

$pngSrc = @ScriptDir & "\Windows.png" ;243x243
$GUI = _GUICreate_Alpha("Test", $pngSrc)
GUISetState()

While 1
    $msg = GUIGetMsg()
    If $msg = $GUI_EVENT_CLOSE Then ExitLoop
WEnd

_GDIPlus_Shutdown()

Func _GUICreate_Alpha($sTitle, $sPath, $iX=-1, $iY=-1, $iOpacity=255)
    Local $hGUI, $hImage, $hScrDC, $hMemDC, $hBitmap, $hOld, $pSize, $tSize, $pSource, $tSource, $pBlend, $tBlend
    $hImage = _GDIPlus_ImageLoadFromFile($sPath)
    $width = _GDIPlus_ImageGetWidth($hImage)
    $height = _GDIPlus_ImageGetHeight($hImage)
    $hGUI = GUICreate($sTitle, $width, $height, $iX, $iY, $WS_POPUP, $WS_EX_LAYERED)
    $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", $width)
    DllStructSetData($tSize, "Y", $height)
    $tSource = DllStructCreate($tagPOINT)
    $pSource = DllStructGetPtr($tSource)
    $tBlend = DllStructCreate($tagBLENDFUNCTION)
    $pBlend = DllStructGetPtr($tBlend)
    DllStructSetData($tBlend, "Alpha", $iOpacity)
    DllStructSetData($tBlend, "Format", 1)
    _WinAPI_UpdateLayeredWindow($hGUI, $hScrDC, 0, $pSize, $hMemDC, $pSource, 0, $pBlend, 2)
    _WinAPI_ReleaseDC(0, $hScrDC)
    _WinAPI_SelectObject($hMemDC, $hOld)
    _WinAPI_DeleteObject($hBitmap)
    _WinAPI_DeleteObject($hImage)
    _WinAPI_DeleteDC($hMemDC)
EndFunc ;==>_GUICreate_Alpha

Edited March 18, 2010 by this-is-me