哪位能提供把图像色彩模式从RGB模式转为CMYK模式的代码？

很多地方有
但就是与PhotoShop计算的结果不一样

[名称]           颜色RGB/HSB/CMYK/Lab[数据来源]       enmity/csdn[内容简介]       空[源代码内容]Private R As Byte
Private G As Byte
Private B As Byte
Public Property Get cmyC() As Byte
    cmyC = 255 - R
End PropertyPublic Property Get cmyM() As Byte
    cmyM = 255 - G
End Property
Public Property Get cmykK() As Integer
    cmykK = Minimum(255 - R, 255 - G, 255 - B) / 2.55
End PropertyPublic Property Get cmykC() As Integer
    Dim MyR As Integer, Div As Integer
    MyR = R / 2.55    Div = (100 - cmykK)
    If Div = 0 Then Div = 1    cmykC = ((100 - MyR - cmykK) / Div) * 100
End PropertyPublic Property Get cmykM() As Integer
    Dim MyG As Integer, Div As Integer
    MyG = G / 2.55    Div = (100 - cmykK)
    If Div = 0 Then Div = 1    cmykM = ((100 - MyG - cmykK) / Div) * 100
End PropertyPublic Property Get cmykY() As Integer
    Dim MyB As Integer, Div As Integer
    MyB = B / 2.55    Div = (100 - cmykK)
    If Div = 0 Then Div = 1    cmykY = ((100 - MyB - cmykK) / Div) * 100
End PropertyPublic Property Get cmyY() As Byte
    cmyY = 255 - B
End PropertyPublic Property Get hlsH() As Integer
    Dim MyR As Single, MyG As Single, MyB As Single
    Dim Max As Single, Min As Single
    Dim Delta As Single, MyVal As Single    MyR = R / 255: MyG = G / 255: MyB = B / 255    Max = Maximum(MyR, MyG, MyB)
    Min = Minimum(MyR, MyG, MyB)    If Max <> Min Then
    Delta = Max - Min
    Select Case Max
    Case MyR
        MyVal = (MyG - MyB) / Delta
    Case MyG
        MyVal = 2 + (MyB - MyR) / Delta
    Case MyB
        MyVal = 4 + (MyR - MyG) / Delta
    End Select
    End If    MyVal = (MyVal + 1) * 60
    If MyVal < 0 Then MyVal = MyVal + 360    hlsH = MyVal
    Debug.Print hlsH
End Property
Public Property Get hlsL() As Integer
    hlsL = ((Maximum(R, G, B) + Minimum(R, G, B)) / 2) / 2.55
End Property
Public Property Get hlsS() As Integer
    Dim MyR As Single, MyG As Single, MyB As Single
    Dim Max As Single, Min As Single, MyS As Single    MyR = R / 255: MyG = G / 255: MyB = B / 255    Max = Maximum(MyR, MyG, MyB)
    Min = Minimum(MyR, MyG, MyB)    If Max <> Min Then
    If hlsL <= 50 Then
    MyS = (Max - Min) / (Max + Min)
    Else
    MyS = (Max - Min) / (2 - Max - Min)
    End If
    hlsS = MyS * 100
    End If
End PropertyPrivate Function Minimum(ParamArray Vals())
    Dim n As Integer, MinVal    MinVal = Vals(0)    For n = 0 To UBound(Vals)
    If Vals(n) < MinVal Then MinVal = Vals(n)
    Next n    Minimum = MinVal
End Function
Private Function Maximum(ParamArray Vals())
    Dim n As Integer, MaxVal    For n = 0 To UBound(Vals)
    If Vals(n) > MaxVal Then MaxVal = Vals(n)
    Next n    Maximum = MaxVal
End FunctionPublic Property Let rgbR(NewVal As Byte)
    R = NewVal
End Property
Public Property Get rgbR() As Byte
    rgbR = R
End PropertyPublic Property Get rgbG() As Byte
    rgbG = G
End PropertyPublic Property Get rgbB() As Byte
    rgbB = B
End Property
Public Property Get ycbcrY() As Byte
    ycbcrY = R * 0.2989 + G * 0.5866 + B * 0.1145
End Property
Public Property Get ycbcrCb() As Byte
    Dim MyCb As Integer
    MyCb = -0.1687 * R - 0.3313 * G + 0.5 * B + 128    ycbcrCb = IIf(MyCb <= 255, MyCb, 255)
End Property
Public Property Get ycbcrCr() As Byte
    Dim MyCr As Integer
    MyCr = 0.5 * R - 0.4187 * G - 0.0813 * B + 128    ycbcrCr = IIf(MyCr <= 255, MyCr, 255)
End PropertyPublic Property Let rgbG(NewVal As Byte)
    G = NewVal
End Property
Public Property Let rgbB(NewVal As Byte)
    B = NewVal
End Property
Public Sub SetCMY(C As Integer, M As Integer, Y As Integer)
    R = 255 - C
    G = 255 - M
    B = 255 - Y
End Sub
Public Sub SetHLS(H As Integer, L As Integer, S As Integer)
    Dim MyR As Single, MyG As Single, MyB As Single
    Dim MyH As Single, MyL As Single, MyS As Single
    Dim Min As Single, Max As Single, Delta As Single    MyH = (H / 60) - 1: MyL = L / 100: MyS = S / 100
    If MyS = 0 Then
    MyR = MyL: MyG = MyL: MyB = MyL
    Else
    If MyL <= 0.5 Then
    Min = MyL * (1 - MyS)
    Else
    Min = MyL - MyS * (1 - MyL)
    End If
    Max = 2 * MyL - Min
    Delta = Max - Min

    Select Case MyH
    Case Is < 1
        MyR = Max
        If MyH < 0 Then
        MyG = Min
        MyB = MyG - MyH * Delta
        Else
        MyB = Min
        MyG = MyH * Delta + MyB
        End If
    Case Is < 3
        MyG = Max
        If MyH < 2 Then
        MyB = Min
        MyR = MyB - (MyH - 2) * Delta
        Else
        MyR = Min
        MyB = (MyH - 2) * Delta + MyR
        End If
    Case Else
        MyB = Max
        If MyH < 4 Then
        MyR = Min
        MyG = MyR - (MyH - 4) * Delta
        Else
        MyG = Min
        MyR = (MyH - 4) * Delta + MyG
        End If
    End Select
    End If    R = MyR * 255: G = MyG * 255: B = MyB * 255
End Sub
Public Sub SetCMYK(C As Integer, M As Integer, Y As Integer, K As Integer)
    Dim MyC As Single, MyM As Single, MyY As Single, MyK As Single    MyC = C / 100: MyM = M / 100: MyY = Y / 100: MyK = K / 100    R = (1 - (MyC * (1 - MyK) + MyK)) * 255
    G = (1 - (MyM * (1 - MyK) + MyK)) * 255
    B = (1 - (MyY * (1 - MyK) + MyK)) * 255
End SubPublic Sub SetYCbCr(Y As Integer, Cb As Integer, Cr As Integer)
   Dim MyR As Integer, MyG As Integer, MyB As Integer    MyR = Y + 1.402 * (Cr - 128)
    MyG = Y - 0.34414 * (Cb - 128) - 0.71414 * (Cr - 128)
    MyB = Y + 1.772 * (Cb - 128)    If MyR > 255 Then MyR = 255
    If MyG > 255 Then MyG = 255
    If MyB > 255 Then MyB = 255    If MyR < 0 Then MyR = 0
    If MyG < 0 Then MyG = 0
    If MyB < 0 Then MyB = 0    R = MyR
    G = MyG
    B = MyB
End Sub
          |       HSB        |       CMYK
PhotoShop | H=300,S=75,B=100 |C=38,M=62,Y=0,K=1
你的程序 |  H=0,S=100,B=63  | C=0,M=75,Y=0,K=0
     以上代码保存于： SourceCode Explorer(源代码数据库)
           复制时间： 2003-02-06 23:04:22
           软件版本： 1.0.819
           软件作者： Shawls
           个人主页： Http://Shawls.Yeah.Net
             E-Mail： [email protected]
                 QQ： 9181729

http://expert.csdn.net/Expert/topic/608/608813.xml?temp=.8782465
主　　题：  例子代码：颜色转换函数(RGB、HSB、CMYK、Lab)
作　　者：  enmity (灵感之源)
等　　级：
信誉值：  100
所属论坛：  VB 基础类
问题点数：  50
回复次数：  15
发表时间：  2002-3-29 13:47:37 回复人： zyl910(910：分儿，我来了！) (  ) 信誉：166  2002-3-29 22:05:26  得分:14


与PhotoShop算的不一样！
比如：R=255,G=64,B=255          |       HSB        |       CMYK
PhotoShop | H=300,S=75,B=100 |C=38,M=62,Y=0,K=1
你的程序 |  H=0,S=100,B=63  | C=0,M=75,Y=0,K=0

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回复人： zyl910(910：分儿，我来了！) (  ) 信誉：166  2002-3-29 22:07:26  得分:0


我见过许多这样的算法，算得结果跟你的差不多，就是与颜色对话框、PhotoShop 算的不一样

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这个算法有点问题：
较准确的公式为：
（1）RGB -> CMYK
K=Min(1-R,1-G,1-B) //取最小值
C=(1-R-K)/(1-K)
M=(1-G-K)/(1-K)
Y=(1-B-K)/(1-K)（2）CMYK->RGB
R=(1-K)*(1-C)
G=(1-K)*(1-M)
B=(1-K)*(1-Y)说明：
（1）RGB,CMYK范围：0.0-1.0,不再此范围内时需转化。
如RGB范围：0-255，则除以255.0,
如：红Red 255,则R=255/255.0,如某色为Red 128,Green 100,Blue 50,则R=128/255.0,G=100/255.0,B=50/255.0
CMYK范围：0-100，则除以100.0)（2）经过上面公式计算出来的结果仍与Photoshop有差异（事实上，不同版本的Photoshop的RGB与CMYK之间的转换也有差异），这是由于Photoshop是根据印刷环境（油墨、印刷纸张、印刷工厂的环境等）的不同而作了ICC文件修正的。更多细节（参看：http://www.neuro.sfc.keio.ac.jp/~aly/polygon/info/color-space-faq.html）
这个网址我可是找了近20小时！缘由：
我本想在C#环境下开发印刷格式的300DPI CMYK TIF图像转化为RGB 72DPI 的JPG格式图像，虽然找到了公式，但仍无法得到满意的答案（主要原因是：CMYK图像读入后转RGB时严重变色，主要是变暗）。不知各位有否更好的解决方案？（强烈建议研究成果共享！）

其实没有RGB<->CMYK映射公式虽然光波被纸张和油墨吸收算减色效应，但CMYK与RGB之间并不是简单的“255 - ?”的关系。CMYK的颜色是由纸张和油墨的物理性质决定的，所以CMYK的色彩空间是一个四维非线性的空间，无法与三维的平滑的RGB空间对应，自然没有映射公式。至于PhotoShop，我记得它有一个好几十MB的映射文件

David啊,你的div怎么样了?
CMYK是普遍的彩印用色,包括品红,亮蓝,黑,黄四种.有时间给你研究一下.

zyl910：
我所说的所谓“公式”是指的目前计算机程序处理时的较常用的转换公式（包括UNIX、Linux、Windows下）均用它们。
正如你所说，由于CMYK是基于减色效应原理，所以较为专业的软件如Photoshop均是采用ICC的映射文件而非简单的计算公式。
对于我们编程而言，上述的简单公式基本已经够用。谁有办法在C#读取中读取CMYK图像某像素的CMYK值啊？

调试易

哪位能提供把图像色彩模式从RGB模式转为CMYK模式的代码？

解决方案 »