GDI+ Transparency

[dantay9]

I don't have a script or anything, but I was wondering if you could make a gdi picture on a window and then set a transparent color for that object.

[monoceres]

http://www.autoitscript.com/forum/index.ph...c=81686&hl=

[dantay9]

That script changes the transparency level of the picture. I want to set a specific color to be transparent. Is there any way to do this?

[Malkey]

I don't have a script or anything, but I was wondering if you could make a gdi picture on a window and then set a transparent color for that object.

Two examples.

First is the second example from GUICreate in help file slightly modified.

The child window is able to be dragged with the title bar.

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

Opt('MustDeclareVars', 1)

Example2()

; example 2
Func Example2()
    Local $gui, $background, $pic, $basti_stay, $msg
    Local $sFile = RegRead("HKEY_LOCAL_MACHINE\SOFTWARE\AutoIt v3\AutoIt", "InstallDir") & "\Examples\GUI\logo4.gif"
    
    $gui = GUICreate("Background", 400, 100)
; background picture
    $background = GUICtrlCreatePic(@SystemDir & "\oobe\images\mslogo.jpg", 0, 0, 400, 100)
    GUISetState(@SW_SHOW)

; transparent MDI child window
    $pic = GUICreate("", 175, 93, 0, 0, 0, BitOR($WS_EX_LAYERED, $WS_EX_MDICHILD), $gui)
; transparent pic
    $basti_stay = GUICtrlCreatePic($sFile, 0, 0, 169, 68)
    GUISetState(@SW_SHOW)

    Do
        $msg = GUIGetMsg()

    Until $msg = $GUI_EVENT_CLOSE
EndFunc  ;==>Example2

The second example uses the ImageColorToTransparent() function declared within the script. To change the colour you want to be transparent, change the last parameter of the ImageColorToTransparent() function at about line #33.

The colour is in Hex colour format 0xRRGGBB (Red,Green,Blue).

This example saves an image with the newly created transparent background to a file.

expandcollapse popup

#include <GDIPlus.au3>
#include <WinAPI.au3>
#include <GuiConstants.au3>
#include <WindowsConstants.au3>

$fname = FileOpenDialog("First image", "", "All images (*.jpg;*.png;*.gif;*.bmp;)")
If $fname = "" Then Exit

_GDIPlus_Startup()

$hImage = _GDIPlus_ImageLoadFromFile($fname)
Global $GuiSizeX = _GDIPlus_ImageGetWidth($hImage)
Global $GuiSizeY = _GDIPlus_ImageGetHeight($hImage)

$hGui = GUICreate("Paths", $GuiSizeX, $GuiSizeY)
GUISetState()

; Create Double Buffer, so the doesn't need to be repainted on PAINT-Event
$hGraphicGUI = _GDIPlus_GraphicsCreateFromHWND($hGui)
$hBMPBuff = _GDIPlus_BitmapCreateFromGraphics($GuiSizeX, $GuiSizeY, $hGraphicGUI)
$hGraphic = _GDIPlus_ImageGetGraphicsContext($hBMPBuff)
;End Double Buffer add-in 1 of 3

_GDIPlus_GraphicsDrawImageRect($hGraphic, $hImage, 0, 0, $GuiSizeX, $GuiSizeY)

; Create Double Buffer
GUIRegisterMsg(0xF, "MY_PAINT"); Register PAINT-Event 0x000F = $WM_PAINT (WindowsConstants.au3)
GUIRegisterMsg(0x85, "MY_PAINT"); $WM_NCPAINT = 0x0085 (WindowsConstants.au3)Restore after Minimize.
_GDIPlus_GraphicsDrawImage($hGraphicGUI, $hBMPBuff, 0, 0)
;End Double Buffer add-in 2 of 3

;Local $hBitmap = OtherColorsToWhite($hBMPBuff, 0, 0, $GuiSizeX, $GuiSizeY,0xFB0f0C,0x000000)
Local $hBitmap = ImageColorToTransparent($hBMPBuff, 0, 0, $GuiSizeX, $GuiSizeY, 0x000000); 0x000000 - Black

_GDIPlus_ImageSaveToFile($hBitmap, @DesktopDir & "\TestWrite1.png")
ShellExecute(@DesktopDir & "\TestWrite1.png")

While 1
    $msg = GUIGetMsg()
    Switch $msg
        Case $GUI_EVENT_CLOSE
            close()
    EndSwitch
WEnd

;Func to redraw on PAINT MSG
Func MY_PAINT($hWnd, $msg, $wParam, $lParam)
; Check, if the GUI with the Graphic should be repainted
; The sequencial order of these two commands is important.
    _GDIPlus_GraphicsDrawImage($hGraphicGUI, $hBMPBuff, 0, 0)
    _WinAPI_RedrawWindow($hGui, "", "", BitOR($RDW_INVALIDATE, $RDW_UPDATENOW, $RDW_FRAME)); , $RDW_ALLCHILDREN
    Return $GUI_RUNDEFMSG
EndFunc  ;==>MY_PAINT

Func close()
    _GDIPlus_GraphicsDispose($hGraphic)
    _GDIPlus_Shutdown()
    Exit
EndFunc  ;==>close

Func OtherColorsToWhite($hImage2, $iStartPosX = 0, $iStartPosY = 0, $GuiSizeX = Default, $GuiSizeY = Default, $iColor1 = Default, $iColor2 = Default)
    Local $hBitmap1, $Reslt, $width, $height, $stride, $format, $Scan0, $v_Buffer, $v_Value, $iIW, $iIH
    $iIW = _GDIPlus_ImageGetWidth($hImage2)
    $iIH = _GDIPlus_ImageGetHeight($hImage2)
    If $GuiSizeX = Default Or $GuiSizeX > $iIW - $iStartPosX Then $GuiSizeX = $iIW - $iStartPosX
    If $GuiSizeY = Default Or $GuiSizeY > $iIH - $iStartPosY Then $GuiSizeY = $iIH - $iStartPosY
    $hBitmap1 = _GDIPlus_BitmapCloneArea($hImage2, $iStartPosX, $iStartPosY, $GuiSizeX, $GuiSizeY, $GDIP_PXF32ARGB)

;If $iColor = Default Then $iColor = GDIPlus_BitmapGetPixel($hBitmap1, 1, 1); Transparent color

    ProgressOn("Making a color Transparent", "The image is being processed.", "0 percent", -1, -1, 16)

    $Reslt = _GDIPlus_BitmapLockBits($hBitmap1, 0, 0, $GuiSizeX, $GuiSizeY, BitOR($GDIP_ILMREAD, $GDIP_ILMWRITE), $GDIP_PXF32ARGB)

;Get the returned values of _GDIPlus_BitmapLockBits ()
    $width = DllStructGetData($Reslt, "width")
    $height = DllStructGetData($Reslt, "height")
    $stride = DllStructGetData($Reslt, "stride")
    $format = DllStructGetData($Reslt, "format")
    $Scan0 = DllStructGetData($Reslt, "Scan0")
    For $i = 0 To $GuiSizeX - 1
        For $j = 0 To $GuiSizeY - 1
            $v_Buffer = DllStructCreate("dword", $Scan0 + ($j * $stride) + ($i * 4))
            $v_Value = DllStructGetData($v_Buffer, 1)
            If (Hex($v_Value, 6) = Hex($iColor1, 6)) Or (Hex($v_Value, 6) = Hex($iColor2, 6)) Then

            Else
                DllStructSetData($v_Buffer, 1, 0xFFFFFFFF); Sets to white
            EndIf
        Next
        ProgressSet(Int(100 * $i / ($GuiSizeX)), Int(100 * $i / ($GuiSizeX)) & " percent")
    Next
    _GDIPlus_BitmapUnlockBits($hBitmap1, $Reslt)
    ProgressOff()
    Return $hBitmap1
EndFunc  ;==>OtherColorsToWhite

;$iColor - Colour to be made transparent. Hex colour format 0xRRGGBB. If Default used then top left pixel colour of image
; is used as the transparent colour.
Func ImageColorToTransparent($hImage2, $iStartPosX = 0, $iStartPosY = 0, $GuiSizeX = Default, $GuiSizeY = Default, $iColor = Default)
    Local $hBitmap1, $Reslt, $width, $height, $stride, $format, $Scan0, $v_Buffer, $v_Value, $iIW, $iIH
    $iIW = _GDIPlus_ImageGetWidth($hImage2)
    $iIH = _GDIPlus_ImageGetHeight($hImage2)
    If $GuiSizeX = Default Or $GuiSizeX > $iIW - $iStartPosX Then $GuiSizeX = $iIW - $iStartPosX
    If $GuiSizeY = Default Or $GuiSizeY > $iIH - $iStartPosY Then $GuiSizeY = $iIH - $iStartPosY
    $hBitmap1 = _GDIPlus_BitmapCloneArea($hImage2, $iStartPosX, $iStartPosY, $GuiSizeX, $GuiSizeY, $GDIP_PXF32ARGB)

    If $iColor = Default Then $iColor = GDIPlus_BitmapGetPixel($hBitmap1, 1, 1); Transparent color

    ProgressOn("Making a color Transparent", "The image is being processed.", "0 percent", -1, -1, 16)

    $Reslt = _GDIPlus_BitmapLockBits($hBitmap1, 0, 0, $GuiSizeX, $GuiSizeY, BitOR($GDIP_ILMREAD, $GDIP_ILMWRITE), $GDIP_PXF32ARGB)

;Get the returned values of _GDIPlus_BitmapLockBits ()
    $width = DllStructGetData($Reslt, "width")
    $height = DllStructGetData($Reslt, "height")
    $stride = DllStructGetData($Reslt, "stride")
    $format = DllStructGetData($Reslt, "format")
    $Scan0 = DllStructGetData($Reslt, "Scan0")
    For $i = 0 To $GuiSizeX - 1
        For $j = 0 To $GuiSizeY - 1
            $v_Buffer = DllStructCreate("dword", $Scan0 + ($j * $stride) + ($i * 4))
            $v_Value = DllStructGetData($v_Buffer, 1)
            If Hex($v_Value, 6) = Hex($iColor, 6) Then
                DllStructSetData($v_Buffer, 1, Hex($iColor, 6)); Sets Transparency here. Alpha Channel = 00, not written to.
            EndIf
        Next
        ProgressSet(Int(100 * $i / ($GuiSizeX)), Int(100 * $i / ($GuiSizeX)) & " percent")
    Next
    _GDIPlus_BitmapUnlockBits($hBitmap1, $Reslt)
    ProgressOff()
    Return $hBitmap1
EndFunc  ;==>ImageColorToTransparent

;The GetPixel method gets the color of a specified pixel in this bitmap.
Func GDIPlus_BitmapGetPixel($hBitmap, $iX, $iY)
    Local $tArgb, $pArgb, $aRet
    $tArgb = DllStructCreate("dword Argb")
    $pArgb = DllStructGetPtr($tArgb)
    $aRet = DllCall($ghGDIPDll, "int", "GdipBitmapGetPixel", "hwnd", $hBitmap, "int", $iX, "int", $iY, "ptr", $pArgb)
    Return "0x" & Hex(DllStructGetData($tArgb, "Argb"))
EndFunc  ;==>GDIPlus_BitmapGetPixel

[dantay9]

Wow! Thanks a lot Malkey. That opens up a whole new realm of possibilities. Thanks!