transparency

[funkheads]

i have this code for transparency, but it seems to run a little slow. here it is:


Private Sub TransBack(ByVal xstart As Long, ByVal ystart As Long, ByVal xend As Long, ByVal yend As Long, ByVal bgcolor As Long, ByVal thdc As Long, ByVal thWnd As Long)

'declare region variables
Dim rgn2 As Long, rgn3 As Long, rgn4 As Long

'declare substitute variables for the function parameters
Dim Top As Long, Left As Long, Right As Long, Bottom As Long, temptop As Long

'create some region buffers
rgn = CreateRectRgn(0, 0, 0, 0)
rgn2 = CreateRectRgn(0, 0, 0, 0)
rgn3 = CreateRectRgn(0, 0, 0, 0)

'this loop picks out the transparent colors,
'there MUST be three loops or Windows has a hard
'time handling the complex regions

Left = xstart
Right = (xend - xstart) + 1: Bottom = (yend - ystart) + 1

Do While Left < Right 'go through and scan left to right
Top = ystart
Do While Top < Bottom 'go through and scan top to botom
If GetPixel(thdc, Left, Top) <> bgcolor Then
temptop = Top
Do While GetPixel(thdc, Left, Top + 1) <> bgcolor
Top = Top + 1
If Top = Bottom Then Exit Do
Loop
rgn4 = CreateRectRgn(Left, temptop, Left + 1, Top + 1)
CombineRgn rgn3, rgn2, rgn2, 5
CombineRgn rgn2, rgn4, rgn3, 2
DeleteObject rgn4
End If
Top = Top + 1
Loop
CombineRgn rgn3, rgn, rgn, 5
CombineRgn rgn, rgn2, rgn3, 2
DoEvents
Left = Left + 1
Loop

DeleteObject rgn2
SetWindowRgn thWnd, rgn, True

End Sub


does anyone know a better code to use for transparency? hopefully a faster, more optimized one? any help will be accepted with great appreciation.

--michael