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color-rgba.h

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/** \file color-rgba.h

    A class to handle a RGBA color as one unit.

    Authors:
      bulia byak <buliabyak@gmail.com>

    Copyright (C) 2004 Authors

    Released under GNU GPL, read the file 'COPYING' for more information
*/
#ifndef SEEN_COLOR_RGBA_H
#define SEEN_COLOR_RGBA_H

#include <glib.h> // g_assert()
#include <glib/gmessages.h>
#include "libnr/nr-pixops.h"
#include "decimal-round.h"

/**
    \brief  A class to contain a floating point RGBA color.
*/
00023 class ColorRGBA {
public:
    /**
        \brief  A constructor to create the color from four floating
                point values.
        \param  c0  Red
        \param  c1  Green
        \param  c2  Blue
00031         \param  c3  Alpha

        Load the values into the array of floats in this object.
    */
    ColorRGBA(float c0, float c1, float c2, float c3)
    {
        _c[0] = c0; _c[1] = c1;
        _c[2] = c2; _c[3] = c3;
    }
00040 
    /**
        \brief  Create a quick ColorRGBA with all zeros
    */
    ColorRGBA(void)
    {
        for (int i = 0; i < 4; i++)
            _c[i] = 0.0;
    }

    /**
        \brief  A constructor to create the color from an unsigned
                int, as found everywhere when dealing with colors
        \param  intcolor   rgba32 "unsigned int representation (0xRRGGBBAA)

00055         Separate the values and load them into the array of floats in this object.
        TODO : maybe get rid of the NR_RGBA32_x C-style functions and replace
            the calls with the bitshifting they do
    */
    ColorRGBA(unsigned int intcolor)
    {
         _c[0] = NR_RGBA32_R(intcolor)/255.0;
         _c[1] = NR_RGBA32_G(intcolor)/255.0;
         _c[2] = NR_RGBA32_B(intcolor)/255.0;
         _c[3] = NR_RGBA32_A(intcolor)/255.0;

    }

    /**
        \brief  Create a ColorRGBA using an array of floats
00070         \param  in_array  The values to be placed into the object

        Go through each entry in the array and put it into \c _c.
    */
    ColorRGBA(float in_array[4])
    {
        for (int i = 0; i < 4; i++)
            _c[i] = in_array[i];
    }

    /**
        \brief  Overwrite the values in this object with another \c ColorRGBA.
        \param  m  Values to use for the array
00083         \return This ColorRGBA object

        Copy all the values from \c m into \c this.
    */
    ColorRGBA &operator=(ColorRGBA const &m) {
        for (unsigned i = 0 ; i < 4 ; ++i) {
            _c[i] = m._c[i];
        }
        return *this;
    }

    /**
        \brief  Grab a particular value from the ColorRGBA object
        \param  i  Which value to grab
        \return The requested value.
00098 
        First checks to make sure that the value is within the array,
        and then return the value if it is.
    */
    float operator[](unsigned int const i) const {
        g_assert( unsigned(i) < 4 );
        return _c[i];
    }

    /**
        \brief  Check to ensure that two \c ColorRGBA's are equal
        \param  other  The guy to check against
        \return Whether or not they are equal
00111 
        Check each value to see if they are equal.  If they all are,
        return TRUE.
    */
    bool operator== (const ColorRGBA other) const {
        for (int i = 0; i < 4; i++) {
            if (_c[i] != other[i])
                return false;
        }
        return true;
    }

    bool operator!=(ColorRGBA const &o) const {
        return !(*this == o);
    }

    /**
        \brief  Average two \c ColorRGBAs to create another one.
        \param  second  The second RGBA, with this being the first
        \param  weight  How much of each should be used.  Zero is all
                        this while one is all the second.  Default is
                        half and half.
        
        This function goes through all the points in the two objects and
00135         merges them together based on the weighting.  The current objects
        value are multiplied by 1.0 - weight and the second object by weight.
        This means that they should always be balanced by the parameter.
    */
    ColorRGBA average (const ColorRGBA second, const float weight = 0.5) const {
        float returnval[4];

        for (int i = 0; i < 4; i++) {
            returnval[i] = _c[i] * (1.0 - weight) + second[i] * weight; 
        }

        return ColorRGBA(returnval[0], returnval[1], returnval[2], returnval[3]);
    }

    /**
        \brief  Give the rgba32 "unsigned int" representation of the color

00152         round each components*255 and combine them (RRGGBBAA).
        WARNING : this reduces color precision (from float to 0->255 int per component)
            but it should be expected since we request this kind of output
    */
    unsigned int getIntValue() const {

         return   (int(Inkscape::decimal_round(_c[0]*255, 0)) << 24) | 
                        (int(Inkscape::decimal_round(_c[1]*255, 0))  << 16) | 
                        (int(Inkscape::decimal_round(_c[2]*255, 0))  << 8) | 
                        (int(Inkscape::decimal_round(_c[3]*255, 0)));
00162     }

private:
    /** \brief  Array of values that are stored. */
    float _c[4];
};


#endif /* !SEEN_COLOR_RGBA_H */

/*
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*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :

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