Keskustelu: Ohjelmointikysymykset: VB6: Onko vaihtoehtoja Set Handle = Loadpicture()?

Const RC_PALETTE As Long = &H100
Const SIZEPALETTE As Long = 104
Const RASTERCAPS As Long = 38

Private Type PALETTEENTRY
	peRed As Byte
	peGreen As Byte
	peBlue As Byte
	peFlags As Byte
End Type

Private Type LOGPALETTE
	palVersion As Integer
	palNumEntries As Integer
	palPalEntry(255) As PALETTEENTRY ' Enough for 256 colors
End Type

Private Type GUID
	Data1 As Long
	Data2 As Integer
	Data3 As Integer
	Data4(7) As Byte
End Type

Private Type PicBmp
	Size As Long
	Type As Long
	hBmp As Long
	hPal As Long
	Reserved As Long
End Type

Private Declare Function OleCreatePictureIndirect Lib "olepro32.dll" (PicDesc As PicBmp, RefIID As GUID, ByVal fPictureOwnsHandle As Long, IPic As IPicture) As Long
Private Declare Function CreateCompatibleDC Lib "gdi32" (ByVal hdc As Long) 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 GetDeviceCaps Lib "gdi32" (ByVal hdc As Long, ByVal iCapabilitiy As Long) As Long
Private Declare Function GetSystemPaletteEntries Lib "gdi32" (ByVal hdc As Long, ByVal wStartIndex As Long, ByVal wNumEntries As Long, lpPaletteEntries As PALETTEENTRY) As Long
Private Declare Function CreatePalette Lib "gdi32" (lpLogPalette As LOGPALETTE) As Long
Private Declare Function SelectPalette Lib "gdi32" (ByVal hdc As Long, ByVal hPalette As Long, ByVal bForceBackground As Long) As Long
Private Declare Function RealizePalette 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 DeleteDC Lib "gdi32" (ByVal hdc As Long) As Long
Private Declare Function GetDC Lib "user32" (ByVal hwnd As Long) As Long

Function CreateBitmapPicture(ByVal hBmp As Long, ByVal hPal As Long) As Picture
	Dim R As Long, Pic As PicBmp, IPic As IPicture, IID_IDispatch As GUID
	'Fill GUID info
	With IID_IDispatch
		.Data1 = &H20400
		.Data4(0) = &HC0
		.Data4(7) = &H46
	End With
	'Fill picture info
	With Pic
		.Size = Len(Pic) ' Length of structure
		.Type = vbPicTypeBitmap ' Type of Picture (bitmap)
		.hBmp = hBmp ' Handle to bitmap
		.hPal = hPal ' Handle to palette (may be null)
	End With
	'Create the picture
	R = OleCreatePictureIndirect(Pic, IID_IDispatch, 1, IPic)
	'Return the new picture
	Set CreateBitmapPicture = IPic
End Function

Function hDCToPicture(ByVal hDCSrc As Long, ByVal LeftSrc As Long, ByVal TopSrc As Long, ByVal WidthSrc As Long, ByVal HeightSrc As Long) As Picture
	Dim hDCMemory As Long, hBmp As Long, hBmpPrev As Long, R As Long
	Dim hPal As Long, hPalPrev As Long, RasterCapsScrn As Long, HasPaletteScrn As Long
	Dim PaletteSizeScrn As Long, LogPal As LOGPALETTE
	'Create a compatible device context
	hDCMemory = CreateCompatibleDC(hDCSrc)
	'Create a compatible bitmap
	hBmp = CreateCompatibleBitmap(hDCSrc, WidthSrc, HeightSrc)
	'Select the compatible bitmap into our compatible device context
	hBmpPrev = SelectObject(hDCMemory, hBmp)
	'Raster capabilities?
	RasterCapsScrn = GetDeviceCaps(hDCSrc, RASTERCAPS) ' Raster
	'Does our picture use a palette?
	HasPaletteScrn = RasterCapsScrn And RC_PALETTE ' Palette
	'What's the size of that palette?
	PaletteSizeScrn = GetDeviceCaps(hDCSrc, SIZEPALETTE) ' Size of
	If HasPaletteScrn And (PaletteSizeScrn = 256) Then
		'Set the palette version
		LogPal.palVersion = &H300
		'Number of palette entries
		LogPal.palNumEntries = 256
		'Retrieve the system palette entries
		R = GetSystemPaletteEntries(hDCSrc, 0, 256, LogPal.palPalEntry(0))
		'Create the palette
		hPal = CreatePalette(LogPal)
		'Select the palette
		hPalPrev = SelectPalette(hDCMemory, hPal, 0)
		'Realize the palette
		R = RealizePalette(hDCMemory)
	End If
	'Copy the source image to our compatible device context
	R = BitBlt(hDCMemory, 0, 0, WidthSrc, HeightSrc, hDCSrc, LeftSrc, TopSrc, vbSrcCopy)
	'Restore the old bitmap
	hBmp = SelectObject(hDCMemory, hBmpPrev)
	If HasPaletteScrn And (PaletteSizeScrn = 256) Then
		'Select the palette
		hPal = SelectPalette(hDCMemory, hPalPrev, 0)
	End If
	'Delete our memory DC
	R = DeleteDC(hDCMemory)
	Set hDCToPicture = CreateBitmapPicture(hBmp, hPal)
End Function