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beolvu  
#1 Posted : Tuesday, March 01, 2005 10:28:00 AM(UTC)
beolvu

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Posts: 2

hello, is it possible for me to convert cmyk information (not from a jpeg nor gif png)
(cmyk information --- 0.1233 0.1123 0.4422 0.2222 which is extracted from PDF file. )
to RGB with ICM using graphics mill component?

the reason why i'm trying to do this is obviously if i apply the formula to convert CMYK to RGB the result color is so lighter than color's in CMYK viewed by PHOTOSHOP.

I have downloaded the demo version and found out that we can load jpeg,gif and convert the color space to others.

but i couldn't find any example source code or doc about just one color to other color spaced color conversion.

so please if this is possible, please post an example code for me.
thank you.
and i'll buy pretty this product pretty soon (lots of them if this is possible.) ^^
Andrew  
#2 Posted : Tuesday, March 01, 2005 11:28:00 PM(UTC)
Andrew

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Hello,

An ActiveX version of Graphics Mill does not allow converting individual color. However it is available in the .NET version.

If you cannot use Graphics Mill for .NET, the only way to convert the color is to create a bitmap 1x1 and your color value into the single pixel.

I have wrote a simple code sample demonstrating this. I had to fight with conversion from float CMYK channel values to the 32-bit CMYK pixel value (because of poor bitwise operations support in VB6). But fortunately I have found a workaround for a lack of bitwise shift operation and overflow.

Code:
    Dim fltCyan As Single
    Dim fltMagenta As Single
    Dim fltYellow As Single
    Dim fltBlack As Single
    
    ' I assume that CMYK values can vary in range [0, 1]
    fltCyan = 0.1233
    fltMagenta = 0.1123
    fltYellow = 0.4422
    fltBlack = 0.2222
    
    Dim cmyk As Long

    ' If the high byte is more than 7F (and therefore the highest bit = 1), the overflow 
    ' may occur. That's why we need to handle it separately.
    If fltCyan <= 0.5 Then
        cmyk = CLng(CLng(fltBlack * 255) Or CLng((fltYellow * 255) * &H100 And &HFF00) Or CLng((fltMagenta * 255) * &H10000 And &HFF0000) Or CLng((fltCyan * 255) * &H1000000 And &HFF000000))
    Else
        cmyk = CLng(CLng(fltBlack * 255) Or CLng((fltYellow * 255) * &H100 And &HFF00) Or CLng((fltMagenta * 255) * &H10000 And &HFF0000) Or CLng((CByte(fltCyan * 255) And &H7F) * &H1000000 And &HFF000000)) Or &H80000000
    End If
        
    MsgBox Hex(cmyk)
        
    Dim objBitmap As New Bitmap
    
    ' This line creates 1x1 bitmap which contains the necessary CMYK value.
    objBitmap.CreateNew 1, 1, Format32bppCmyk, cmyk, Nothing
    
    ' Do not forget to set the color management up.
    objBitmap.Data.ColorManagement.Enabled = True
    objBitmap.Data.ColorManagement.DataProfile = "c:\inputCMYK.icc"
    objBitmap.Data.ColorManagement.RgbProfile = "c:\outputRGB.icc"
    
    ' Start conversion
    objBitmap.Data.ConvertTo24bppRgb
    
    Dim rgb As Long

    ' This line specifies that we want to return the value in the format which is 
    ' used in VB6.  
    objBitmap.ColorTreatment = ColorTreatmentColorref

    ' Get converted RGB value
    rgb = objBitmap.Data.Pixels(0, 0)
    
    ' Visualize the result.
    Form1.BackColor = rgb
    
    MsgBox Hex(rgb)


Hope this helps.

Edited by user Monday, December 24, 2007 4:09:42 PM(UTC)  | Reason: Not specified

beolvu  
#3 Posted : Thursday, March 03, 2005 12:07:00 AM(UTC)
beolvu

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Joined: 3/1/2005(UTC)
Posts: 2

Hello, thank you for your help on this problem.
I was able to modify it to ASP source code and tested bunch of colors..
for the code down below the RGB color should be #BFD40D ( in photoshop)
but what i'm getting is #1C8CC6 which is totally out of color range..

is this problem of graphics mill or simply the hex conversion problem?
can you please test it out and where is wrong?

this is the testing URL for this problem.. thank you.

http://www.ohteam.com/cmyk.asp


Code:
<!-- METADATA TYPE="typelib" UUID="{3CE48541-DE7A-4909-9314-9D0ED0D1CA5A}"-->
<%

    fltCyan = 0.25

    fltMagenta = 0.6

    fltYellow = 1.00

    fltBlack = 0.00

    Dim cmyk ' As Long



    ' If the high byte is more than 7F (and therefore the highest bit = 1), the overflow 

    ' may occur. That's why we need to handle it separately.

    If fltCyan <= 0.5 Then

        cmyk = CLng(CLng(fltBlack * 255) Or CLng((fltYellow * 255) * &H100 And &HFF00) Or CLng((fltMagenta * 255) * &H10000 And &HFF0000) Or CLng((fltCyan * 255) * &H1000000 And &HFF000000))

    Else

        cmyk = CLng(CLng(fltBlack * 255) Or CLng((fltYellow * 255) * &H100 And &HFF00) Or CLng((fltMagenta * 255) * &H10000 And &HFF0000) Or CLng((CByte(fltCyan * 255) And &H7F) * &H1000000 And &HFF000000)) Or &H80000000

    End If

        
	'Create Bitmap object
	Set objBitmap = Server.CreateObject("GraphicsMill.Bitmap")

    

    ' This line creates 1x1 bitmap which contains the necessary CMYK value.

    objBitmap.CreateNew 1, 1, Format32bppCmyk, cmyk, Nothing


    ' Do not forget to set the color management up.

    objBitmap.Data.ColorManagement.IsEnabled = True

    
	objBitmap.Data.ColorManagement.DataProfile = Server.MapPath("AdobeCMYK.icm")


    objBitmap.Data.ColorManagement.RgbProfile = Server.MapPath("sRGB.icm")

    ' Start conversion

    objBitmap.Data.ConvertTo24bppRgb

  
    Dim rgb



    ' This line specifies that we want to return the value in the format which is 

    ' used in VB6.  

    objBitmap.ColorTreatment = ColorTreatmentColorref



    ' Get converted RGB value

    rgb = objBitmap.Data.Pixels(0, 0)

    

    ' Visualize the result.

    response.Write Hex(rgb)

%>

Edited by user Monday, December 24, 2007 4:10:17 PM(UTC)  | Reason: Not specified

Andrew  
#4 Posted : Friday, March 04, 2005 2:33:00 PM(UTC)
Andrew

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Could you send a CMYK color profile you use (as far as I understand, the RGB profile is a standard sRGB profile)? Please submit case with these files.

Edited by user Friday, May 23, 2008 3:34:43 PM(UTC)  | Reason: Not specified

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