CreateCompatibleBitmap-Funktion Diese Funktion erstellt ein Bitmap, das zu einem angegeben Device kompatibel ist.
Betriebssystem:  Win95, Win98, WinNT 3.1, Win2000, WinME	Views:  10.169

Deklaration:

Declare Function CreateCompatibleBitmap Lib "gdi32" ( _
  ByVal hdc As Long, _
   ByVal nWidth As Long, _
  ByVal nHeight As Long) As Long

Beschreibung:
Diese Funktion erstellt ein Bitmap, das zu einem angegeben Device kompatibel ist.

Parameter:

hdc	Erwartet den Devicekontext, zu dem das Bitmapkompatibel sein soll.
nWidth	Erwartet die Breite, die das Bitmap besitzen soll.
nHeight	Erwartet die Höhe, die das Bitmap besitzen soll.

Rückgabewert:
Ist die Funktion erfolgreich, so liefert sie das Handle zu dem kompatiblen Bitmap, andernfallswird "0" zurückgegeben. Unter Windows NT, 2000 und XP können Sie die GetLastError-Funktion für erweiterte Fehlerinformationenaufrufen.

Beispiel:

Private Declare Function CreateCompatibleDC Lib "gdi32" ( _
  ByVal hdc As Long)  As Long
Private Declare Function CreateBitmap Lib "gdi32" ( _
  ByVal nWidth As Long, _
   ByVal nHeight As Long, _
  ByVal nPlanes As Long, _
  ByVal nBitCount As Long, _
   lpBits As Any) As Long
Private Declare Function CreateCompatibleBitmap Lib "gdi32" ( _
  ByVal hdc As Long, _
  ByVal nWidth As Long, _
  ByVal nHeight As Long) As Long
Private Declare Function SelectObject Lib "gdi32" ( _
  ByVal hdc As Long, _
  ByVal hObject As Long) As Long
Private Declare Function SetMapMode Lib "gdi32" ( _
  ByVal hdc As Long, _
  ByVal nMapMode As Long) As Long
Private Declare Function GetMapMode Lib "gdi32" (ByVal hdc As Long) As Long
Private Declare Function BitBlt Lib "gdi32" ( _
  ByVal hDestDC As Long, _
  ByVal X  As Long, _
  ByVal Y As Long, _
  ByVal nWidth As Long, _
  ByVal nHeight As Long, _
   ByVal hSrcDC As Long, _
  ByVal xSrc As Long, _
  ByVal ySrc As Long, _
  ByVal dwRop  As Long) As Long
Private Declare Function SetBkColor Lib "gdi32" ( _
  ByVal hdc As Long, _
  ByVal crColor As Long) As Long
Private Declare Function GetBkColor Lib "gdi32" (ByVal hdc As Long) As Long
Private Declare Function DeleteDC Lib "gdi32" (ByVal hdc As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" ( _
  ByVal hObject As Long)  As Long
 
' BitBlt dwRop-Konstantem
Private Const SRCCOPY = &HCC0020
Private Const NOTSRCCOPY = &H330008
Private Const SRCAND = &H8800C6
Private Const SRCPAINT = &HEE0086

' Transparente Farbe wählen
Private Sub Command2_Click()
  On Error GoTo Err_Dlg
  With Common1
    .CancelError = True
    .ShowColor
 
    SetBkColor Picture3.hdc, .Color
  End With
End Sub

' Transparente Farbe anhand der Koordinate ermitteln
Private Sub Picture1_MouseUp(Button As Integer, Shift As Integer, X As _
Single, Y As Single)
  Picture3.BackColor = Picture1.Point(X, Y)
End Sub

' Startet das Kopieren der Maske oder des Bitmaps mit einer transparenten Farbe 
Private Sub Command1_Click()
  DrawTransparent Picture1, Picture2, GetBkColor(Picture3.hdc), Option1.Value 
End Sub

' Transparente Bitmaps kopieren (CopyBitmap = False um nur die Maske zu kopieren) 
Private Function DrawTransparent(ByVal Src As PictureBox, ByVal Dest As _
PictureBox, ByVal TransColor As Long, ByVal CopyBitmap As Boolean)
  Dim hdcBack As Long, hdcObject As Long, hdcMem As Long, hdcSave As Long
  Dim bmAndBack As Long, bmAndObject As Long, bmAndMem As Long, bmSave  _
  As Long
  Dim bmBackOld As Long, bmObjectOld As Long, bmMemOld As Long,  _
  bmSaveOld As Long
  Dim OldColor As Long
 
  ' Zielbitmap löschen
  Dest.Cls
 
  ' Einige temporäre Devicekontexte erstellen
  hdcBack = CreateCompatibleDC(Dest.hdc)
  hdcObject = CreateCompatibleDC(Dest.hdc)
  hdcMem = CreateCompatibleDC(Dest.hdc)
  hdcSave = CreateCompatibleDC(Dest.hdc)
 
  ' 2 Schwarzweißbitmaps erstellen
  bmAndBack = CreateBitmap(Dest.ScaleWidth, Dest.ScaleHeight, 1, 1,  _
  ByVal 0&)
  bmAndObject = CreateBitmap(Dest.ScaleWidth, Dest.ScaleHeight, 1, 1,  _
  ByVal 0&)
 
  ' 2 Normale Bitmaps erstellen
  bmAndMem = CreateCompatibleBitmap(Src.hdc, Dest.ScaleWidth, Dest.ScaleHeight) 
  bmSave = CreateCompatibleBitmap(Src.hdc, Dest.ScaleWidth, Dest.ScaleHeight) 
 
  ' Die Bitmap den Devices zuweisen
  SelectObject hdcBack, bmAndBack
  SelectObject hdcObject, bmAndObject
  SelectObject hdcMem, bmAndMem
  SelectObject hdcSave, bmSave
 
  ' Mapmode des Ziels einstellen
  SetMapMode Src.hdc, GetMapMode(Dest.hdc)
 
  ' Sicherheitskopie des Originals anlegen
  BitBlt hdcSave, 0, 0, Src.ScaleWidth, Src.ScaleHeight, Src.hdc, 0, 0, SRCCOPY 
 
  ' Hintergrund des Originalbitmaps mit der transparenten Farbe füllen
  OldColor = SetBkColor(Src.hdc, TransColor)
 
  ' Schwarzweißkopie (Objektmaske) des Bitmaps erstellen
  BitBlt hdcObject, 0, 0, Src.ScaleWidth, Src.ScaleHeight, Src.hdc, 0,  _
  0, SRCCOPY
 
  ' Original Hintergrundfarbe wiederherstellen
  SetBkColor Src.hdc, OldColor
 
  ' Schwarzweißkopie (Objektmaske) invertieren
  BitBlt hdcBack, 0, 0, Src.ScaleWidth, Src.ScaleHeight, hdcObject, 0,  _
  0, NOTSRCCOPY
 
  If CopyBitmap = False Then ' nur die Maske kopieren
 
    ' Hintergrund des Quellbildes kopieren
    BitBlt hdcMem, 0, 0, Src.ScaleWidth, Src.ScaleHeight, Src.hdc, 0,  _
    0, SRCCOPY
 
    ' Maskieren des Bereiches, in dem das Bitmap platziert werden soll
    BitBlt hdcMem, 0, 0, Src.ScaleWidth, Src.ScaleHeight, hdcObject,  _
    0, 0, SRCAND
 
    ' Maskieren der transparenten Farbe des Ziels
    BitBlt Dest.hdc, 0, 0, Src.ScaleWidth, Src.ScaleHeight, hdcBack,  _
    0, 0, SRCAND
 
    ' XOR Operation mit dem Hintergrund des Ziels durchführen
    BitBlt hdcMem, 0, 0, Src.ScaleWidth, Src.ScaleHeight, Dest.hdc,  _
    0, 0, SRCPAINT
 
  Else ' Bitmap Kopieren
 
    ' Hintergrund des Ziels kopieren
    BitBlt hdcMem, 0, 0, Dest.ScaleWidth, Dest.ScaleHeight, Dest.hdc,  _
    0, 0, SRCCOPY
 
    ' Maskieren des Bereiches, in dem das Bitmap platziert werden soll
    BitBlt hdcMem, 0, 0, Src.ScaleWidth, Src.ScaleHeight, hdcObject,  _
    0, 0, SRCAND
 
    ' Maskieren der transparenten Farbe
    BitBlt Src.hdc, 0, 0, Src.ScaleWidth, Src.ScaleHeight, hdcBack,  _
    0, 0, SRCAND
 
    ' XOR Operation mit dem Hintergrund der Quelle durchführen
    BitBlt hdcMem, 0, 0, Src.ScaleWidth, Src.ScaleHeight, Src.hdc, 0,  _
    0, SRCPAINT
 
  End If
 
  ' Kopieren des Bitmaps in das Ziel
  BitBlt Dest.hdc, 0, 0, Src.ScaleWidth, Src.ScaleHeight, hdcMem, 0, 0, SRCCOPY 
 
  ' Sicherheitskopie des Originals wiederherstellen
  BitBlt Src.hdc, 0, 0, Src.ScaleWidth, Src.ScaleHeight, hdcSave, 0, 0, SRCCOPY 
 
  ' Temporäre Bitmaps zerstören
  DeleteObject SelectObject(hdcBack, bmBackOld)
  DeleteObject SelectObject(hdcObject, bmObjectOld)
  DeleteObject SelectObject(hdcMem, bmMemOld)
  DeleteObject SelectObject(hdcSave, bmSaveOld)
 
  ' Erstellte Devices zerstören
  DeleteDC hdcMem
  DeleteDC hdcBack
  DeleteDC hdcObject
  DeleteDC hdcSave
  DeleteDC hdcTemp
End Function