透明度计算函数
Public Function TMC(TMD As Single, UpC As Long, DnC As Long) As Long
'TMD:透明度。0:完全透明;1:不透明。
'UpC:上层色
'DownC:下层色
Dim UpR As Long, UpG As Long, UpB As Long
Dim DnR As Long, DnG As Long, DnB As Long
Dim OutR As Long, OutG As Long, OutB As Long
UpR = UpC And &HFF
UpG = (UpC And &HFF00&) \ &H100
UpB = (UpC And &HFF0000) \ &H10000
DnR = DnC And &HFF
DnG = (DnC And &HFF00&) \ &H100
DnB = (DnC And &HFF0000) \ &H10000
OutR = DnR + CLng((UpR - DnR) * TMD)
If OutR < 0 Then OutR = 0
If OutR > 255 Then OutR = 255
OutG = DnG + CLng((UpG - DnG) * TMD)
If OutG < 0 Then OutG = 0
If OutG > 255 Then OutG = 255
OutB = DnB + CLng((UpB - DnB) * TMD)
If OutB < 0 Then OutB = 0
If OutB > 255 Then OutB = 255
TMC = RGB(OutR, OutG, OutB) ' OutR + OutG * &H100& + OutB * &H10000