ImageGear v26.5 - Updated
ImageGear.Core Assembly / ImageGear.Processing Namespace / ImGearRasterProcessing Class / ConvertColorSpace Method / ConvertColorSpace(ImGearRasterPage,ImGearColorSpace,ImGearPixel) Method
Image to change color space.
New color space.
Background to composite the image over when removing alpha channel.




In This Topic
    ConvertColorSpace(ImGearRasterPage,ImGearColorSpace,ImGearPixel) Method
    In This Topic
    Converts page to a new color space, using the specified background color for images that contain Alpha channel.
    Syntax
    'Declaration
     
    Public Overloads Shared Sub ConvertColorSpace( _
       ByVal page As ImGearRasterPage, _
       ByVal newColorSpace As ImGearColorSpace, _
       ByVal backgroundColor As ImGearPixel _
    ) 
    'Usage
     
    Dim page As ImGearRasterPage
    Dim newColorSpace As ImGearColorSpace
    Dim backgroundColor As ImGearPixel
     
    ImGearRasterProcessing.ConvertColorSpace(page, newColorSpace, backgroundColor)
    public static void ConvertColorSpace( 
       ImGearRasterPage page,
       ImGearColorSpace newColorSpace,
       ImGearPixel backgroundColor
    )
    public: static void ConvertColorSpace( 
       ImGearRasterPage* page,
       ImGearColorSpace newColorSpace,
       ImGearPixel* backgroundColor
    ) 
    public:
    static void ConvertColorSpace( 
       ImGearRasterPage^ page,
       ImGearColorSpace newColorSpace,
       ImGearPixel^ backgroundColor
    ) 

    Parameters

    page
    Image to change color space.
    newColorSpace
    New color space.
    backgroundColor
    Background to composite the image over when removing alpha channel.
    Remarks

    If conversion removes the alpha channel from the image, the image is composited over a solid background specified by BackColor. Background should be in the same color space as the original image, but without the Alpha channel. For example, if the original image is in RGBA color space and newColorSpace is CMYK, background should have an RGB color space. The method will first transform the image into RGB and then to CMYK.

    The following formula is used to burn alpha (i.e., to convert from RGBA/P to RGB):

    If Page is not pre-multiplied:

    I = I * A + B (1-A)

    If Page is pre-multiplied:

    I = I + B (1-A)

    If the image contains extra channels, and newColorSpace contains extra channels, the method does not change them.

    Note: Conversion to Grayscale colorspace takes into account human eye's sensitivity to different parts of the light spectrum. ImageGear uses the following formula when converting from RGB to Grayscale: Gray = Red * 77 / 255 + Green * 151 / 255 + Blue * 28 / 255. If you need to convert an image to Grayscale using equal weights for Red, Green and Blue, or any other weights, use ConvertColorSpace(ImGearRasterPage,ImGearColorSpace,Double[,])

    See Also