LogLUV32Pixel Struct Reference

#include <color.h>

Public Member Functions
	operator Color () const
LogLUV32Pixel &	operator= (const float c[3])
void	GetRGB (float rgb[3]) const
void	SetRGB (const float rgb[3])
void	GetXYZ (float xyz[3]) const
void	SetXYZ (const float xyz[3])

Static Public Member Functions
static void	XYZtoRGB (const float xyz[3], float rgb[3])
static void	RGBtoXYZ (const float rgb[3], float xyz[3])

Public Attributes
uint32_t	value
	Storage for the pixel value.

Detailed Description

See also

Class Color.

Remarks

This structure is available in release 4.0 and later only.

This structure is a 32 bit pixel format that stores 1 bit for sign, 15 bits for the log of the luminance, and 16 bits of chroma.

This class stores colors in XYZ space. XYZ color space is the space define by the CIE by the red (X), green (Y) and blue (Z) response curves of the eye. So to calculate a color in XYZ space, you take the incoming light, multiply it by each response curvey and integrate the result over the visible spectrum. There are several RGB spaces, all depending on what XYZ coordinates get assigned to the red, green and blue primaries of the space. The transformations between XYZ and RGB space are all linear and can be represented as 3 by 3 matrices.

The mapping used by XYZtoRGB and RGBtoXYZ is for CCIR-709 primaries and was taken from the code in the tiff reader for the LogLUV32 format. Both XYZ and RGB methods are supplied, so developers can supply different XYZ to RGB transforms, if desired.

This transform is important, because in the LogLUV32 format the log is taken of the Y coordinate in XYZ space. So, it is important that Y not be 0. The transform helps guarantee this. In fact, Y is zero only when r, g and b are all 0.

Member Function Documentation

operator Color()

operator Color ( ) const

inline

Remarks

This method will return the pixel format as a Color.

    {
        Color c;
        GetRGB(c);
        return c;
    }

operator=()

LogLUV32Pixel & operator= ( const float  c[3] )

inline

Remarks

Assignment operator.

Parameters:

const float c[3]
The array of color values to assign in RGB order.

    {
        SetRGB(c);
        return *this;
    }

GetRGB()

void GetRGB

(

float

rgb[3]

)

const

Remarks

Retrieves the RGB space values.

Parameters:

float rgb[3]
The results are stored here.

SetRGB()

void SetRGB

(

const float

rgb[3]

)

Remarks

Sets the RGB space values.

Parameters:

const float rgb[3]
The values to set.

GetXYZ()

void GetXYZ

(

float

xyz[3]

)

const

Remarks

Retrieves the XYZ space values.

Parameters:

const float xyz[3]
The results are stored here.

SetXYZ()

void SetXYZ

(

const float

xyz[3]

)

Remarks

Sets the XYZ space values.

Parameters:

const float xyz[3]
The values to set.

XYZtoRGB()

static void XYZtoRGB ( const float  xyz[3], float  rgb[3]  )

static

Remarks

This method converts from XYZ space to RGB space.

Parameters:

const float xyz[3]
The input values to convert.

float rgb[3]
The output values are stored here.

RGBtoXYZ()

static void RGBtoXYZ ( const float  rgb[3], float  xyz[3]  )

static

Remarks

This method converts from RGB space to XYZ space.

Parameters:

const float rgb[3]
The input values to convert.

float xyz[3]
The output values are stored here.

Member Data Documentation

value

uint32_t value

Storage for the pixel value.