改變Picture亮度

Question

增加 Picture亮度是:
Dim Bright As Integer '亮度
　　Bright = 20 '設亮度增20%（若用負數則亮度變暗如-20）
　　Picture1.AutoRedraw = True
　　For Y = 1 To Picture1.ScaleHeight Step 15
　　　　For X = 1 To Picture1.ScaleWidth Step 15
　　　　　　Tmp& = Picture1.Point(X, Y)
　　　　　　If Len(Hex(Tmp&)) < 8 Then RS = Right(Hex(Tmp&), 2)
　　　　　　If Len(Hex(Tmp&)) = 6 Then
　　　　　　　　BS = Left(Hex(Tmp&), 2)
　　　　　　　　GS = Mid(Hex(Tmp&), 3, 2)
　　　　　　End If
　　　　　　If Len(Hex(Tmp&)) = 4 Then
　　　　　　　　GS = Left(Hex(Tmp&), 2)
　　　　　　End If
　　　　　　If Len(Hex(Tmp&)) > 1 Then R = Val("&H" + RS) Else R = 0
　　　　　　If Len(Hex(Tmp&)) > 3 Then G = Val("&H" + GS) Else G = 0
　　　　　　If Len(Hex(Tmp&)) > 5 Then B = Val("&H" + BS) Else B = 0
　　　　　　If Len(Hex(Tmp&)) = 8 Then R = 1: G = 1: B = 1
　　　　　　PerC = (100 + Bright) / 100
　　　　　　R = Fix(R * PerC): G = Fix(G * PerC): B = Fix(B * PerC)
　　　　　　If R > 255 Then R = 255
　　　　　　If G > 255 Then G = 255
　　　　　　If B > 255 Then B = 255
　　　　　　If R = 0 Then R = Bright
　　　　　　If G = 0 Then G = Bright
　　　　　　If B = 0 Then B = Bright
　　　　　　Picture1.PSet (X, Y), RGB(R, G, B)
　　　　Next
　　Next
　　Picture1.AutoRedraw = False
那如何變暗ㄚ?

我不要若用負數則亮度變暗如-20
可否提供別的寫法謝謝喔

Answer 1

介不介意使用API去做?

2006-11-20 00:23:48 補充：
'表單置1個HScrollBar及2個PictureBoxConst HALFTONE = 4Private Type CJ        caSize As Integer        caFlags As Integer        caIlluminantIndex As Integer        caRedGamma As Integer        caGreenGamma As Integer        caBlueGamma As Integer        caReferenceBlack As Integer        caReferenceWhite As Integer        caContrast As Integer        caBrightness As Integer        caColorfulness As Integer        caRedGreenTint As IntegerEnd TypePrivate Declare Function StretchBlt Lib "gdi32" (ByVal hdc 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 nSrcWidth As Long, ByVal nSrcHeight As Long, ByVal dwRop As Long) As LongPrivate Declare Function SetStretchBltMode Lib "gdi32" (ByVal hdc As Long, ByVal nStretchMode As Long) As LongPrivate Declare Function GetColorAdjustment Lib "gdi32" (ByVal hdc As Long, lpca As CJ) As LongPrivate Declare Function SetColorAdjustment Lib "gdi32" (ByVal hdc As Long, lpca As CJ) As LongPrivate Declare Function GetStretchBltMode Lib "gdi32" (ByVal hdc As Long) As LongDim C As CJPrivate Sub Form_Load()    Show    With HScroll1         .Max = 100         .Min = -100         .Value = 0    End With    '載入圖片    Set Picture1.Picture = "C:\Test.bmp"    Picture1.ScaleMode = vbPixels    GetColorAdjustment Picture2.hdc, C    C.caSize = Len(C)    nBHEnd SubPrivate Sub HScroll1_Change()    nBHEnd SubPrivate Sub HScroll1_Scroll()    nBHEnd SubSub nBH()    DoEvents    C.caBrightness = HScroll1    If GetStretchBltMode(Picture2.hdc) <> HALFTONE Then SetStretchBltMode Picture2.hdc, HALFTONE    SetColorAdjustment Picture2.hdc, C    StretchBlt Picture2.hdc, 0, 0, Picture1.ScaleWidth, Picture1.ScaleHeight, Picture1.hdc, 0, 0, Picture1.ScaleWidth, Picture1.ScaleHeight, vbSrcCopyEnd Sub

Answer 2

api好ㄚ?謝謝!