VB中的涂色

VB provides an easy RGB function to convert three colours into a RGB colour code. However, it provides no way of converting it back to the three colours. It also provides no support for HTML colour codes used on web pages. We decided to write some functions to convert HTML colour codes to and from RGB codes, and also functions to break them back down into their constituent colours.

Public Const RedPart = 0

Public Const GreenPart = 1

Public Const BluePart = 2

Public Function HTML(Red As Integer, Green As Integer, Blue As Integer) As String

HTML = ""

If Len(Hex$(Red)) = 1 Then

HTML = HTML & "0" & Hex$(Red)

Else

HTML = HTML & Hex$(Red)

End If

If Len(Hex$(Green)) = 1 Then

HTML = HTML & "0" & Hex$(Green)

Else

HTML = HTML & Hex$(Green)

End If

If Len(Hex$(Blue)) = 1 Then

HTML = HTML & "0" & Hex$(Blue)

Else

HTML = HTML & Hex$(Blue)

End If

End Function

Public Function UnRGB(RGBCol As Long, Part As Integer) As Integer

注释：Part: 0=Red, 1=Green, 2=Blue

Select Case Part

Case 0

UnRGB = RGBCol And &HFF

注释：mask 000000000000000011111111 and shift bits right

Case 1

UnRGB = (RGBCol And &HFF00) / &HFF

注释：mask 000000001111111100000000 and shift bits right

Case 2

UnRGB = (RGBCol And &HFF0000) / &HFFFF

注释：mask 111111110000000000000000 and shift bits right

End Select

End Function

Public Function UnHTML(HTMLCol As String, Part As Integer) As Integer

注释：Part: 0=Red, 1=Green, 2=Blue

Select Case Part

Case 0

UnHTML = (CLng("&H" & HTMLCol) And &HFF0000) / &HFFFF

注释：mask 111111110000000000000000 and shift bits right

Case 1

UnHTML = (CLng("&H" & HTMLCol) And &HFF00) / &HFF

注释：mask 000000001111111100000000 and shift bits right

Case 2

UnHTML = CLng("&H" & HTMLCol) And &HFF

注释：mask 000000000000000011111111 and shift bits right

End Select

End Function

Public Function RGB2HTML(RGBCol As Long) As String

RGB2HTML = HTML(UnRGB(RGBCol, RedPart),

UnRGB(RGBCol, GreenPart), UnRGB(RGBCol, BluePart))

End Function

Public Function HTML2RGB(HTMLCol As String) As Long

HTML2RGB = RGB(UnHTML(HTMLCol, RedPart), UnHTML(HTMLCol, _

GreenPart), UnHTML(HTMLCol, BluePart))

End Function