agg_pixfmt_rgb.h

这是VCF框架的代码

//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software 
// is granted provided this copyright notice appears in all copies. 
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: [e-mail]
//          [e-mail]
//          http://www.antigrain.com
//----------------------------------------------------------------------------
//
// Adaptation for high precision colors has been sponsored by 
// Liberty Technology Systems, Inc., visit http://lib-sys.com
//
// Liberty Technology Systems, Inc. is the provider of
// PostScript and PDF technology for software developers.
// 
//----------------------------------------------------------------------------

#ifndef AGG_PIXFMT_RGB_INCLUDED
#define AGG_PIXFMT_RGB_INCLUDED

#include <string.h>
#include "agg_basics.h"
#include "agg_color_rgba.h"
#include "agg_rendering_buffer.h"

namespace agg
{

    //=====================================================apply_gamma_dir_rgb
    template<class ColorT, class Order, class GammaLut> class apply_gamma_dir_rgb
    {
    public:
        typedef typename ColorT::value_type value_type;

        apply_gamma_dir_rgb(const GammaLut& gamma) : m_gamma(gamma) {}

        AGG_INLINE void operator () (value_type* p)
        {
            p[Order::R] = m_gamma.dir(p[Order::R]);
            p[Order::G] = m_gamma.dir(p[Order::G]);
            p[Order::B] = m_gamma.dir(p[Order::B]);
        }

    private:
        const GammaLut& m_gamma;
    };



    //=====================================================apply_gamma_inv_rgb
    template<class ColorT, class Order, class GammaLut> class apply_gamma_inv_rgb
    {
    public:
        typedef typename ColorT::value_type value_type;

        apply_gamma_inv_rgb(const GammaLut& gamma) : m_gamma(gamma) {}

        AGG_INLINE void operator () (value_type* p)
        {
            p[Order::R] = m_gamma.inv(p[Order::R]);
            p[Order::G] = m_gamma.inv(p[Order::G]);
            p[Order::B] = m_gamma.inv(p[Order::B]);
        }

    private:
        const GammaLut& m_gamma;
    };


    //=========================================================blender_rgb
    template<class ColorT, class Order> struct blender_rgb
    {
        typedef ColorT color_type;
        typedef Order order_type;
        typedef typename color_type::value_type value_type;
        typedef typename color_type::calc_type calc_type;
        enum base_scale_e { base_shift = color_type::base_shift };

        //--------------------------------------------------------------------
        static AGG_INLINE void blend_pix(value_type* p, 
                                         unsigned cr, unsigned cg, unsigned cb, 
                                         unsigned alpha, 
                                         unsigned cover=0)
        {
            p[Order::R] += (value_type)(((cr - p[Order::R]) * alpha) >> base_shift);
            p[Order::G] += (value_type)(((cg - p[Order::G]) * alpha) >> base_shift);
            p[Order::B] += (value_type)(((cb - p[Order::B]) * alpha) >> base_shift);
        }
    };


    //======================================================blender_rgb_pre
    template<class ColorT, class Order> struct blender_rgb_pre
    {
        typedef ColorT color_type;
        typedef Order order_type;
        typedef typename color_type::value_type value_type;
        typedef typename color_type::calc_type calc_type;
        enum base_scale_e { base_shift = color_type::base_shift };

        //--------------------------------------------------------------------
        static AGG_INLINE void blend_pix(value_type* p, 
                                         unsigned cr, unsigned cg, unsigned cb,
                                         unsigned alpha,
                                         unsigned cover)
        {
            alpha = color_type::base_mask - alpha;
            cover = (cover + 1) << (base_shift - 8);
            p[Order::R] = (value_type)((p[Order::R] * alpha + cr * cover) >> base_shift);
            p[Order::G] = (value_type)((p[Order::G] * alpha + cg * cover) >> base_shift);
            p[Order::B] = (value_type)((p[Order::B] * alpha + cb * cover) >> base_shift);
        }

        //--------------------------------------------------------------------
        static AGG_INLINE void blend_pix(value_type* p, 
                                         unsigned cr, unsigned cg, unsigned cb,
                                         unsigned alpha)
        {
            alpha = color_type::base_mask - alpha;
            p[Order::R] = (value_type)(((p[Order::R] * alpha) >> base_shift) + cr);
            p[Order::G] = (value_type)(((p[Order::G] * alpha) >> base_shift) + cg);
            p[Order::B] = (value_type)(((p[Order::B] * alpha) >> base_shift) + cb);
        }

    };



    //===================================================blender_rgb_gamma
    template<class ColorT, class Order, class Gamma> class blender_rgb_gamma
    {
    public:
        typedef ColorT color_type;
        typedef Order order_type;
        typedef Gamma gamma_type;
        typedef typename color_type::value_type value_type;
        typedef typename color_type::calc_type calc_type;
        enum base_scale_e { base_shift = color_type::base_shift };

        //--------------------------------------------------------------------
        blender_rgb_gamma() : m_gamma(0) {}
        void gamma(const gamma_type& g) { m_gamma = &g; }

        //--------------------------------------------------------------------
        AGG_INLINE void blend_pix(value_type* p, 
                                  unsigned cr, unsigned cg, unsigned cb,
                                  unsigned alpha, 
                                  unsigned cover=0)
        {
            calc_type r = m_gamma->dir(p[Order::R]);
            calc_type g = m_gamma->dir(p[Order::G]);
            calc_type b = m_gamma->dir(p[Order::B]);
            p[Order::R] = m_gamma->inv((((m_gamma->dir(cr) - r) * alpha) >> base_shift) + r);
            p[Order::G] = m_gamma->inv((((m_gamma->dir(cg) - g) * alpha) >> base_shift) + g);
            p[Order::B] = m_gamma->inv((((m_gamma->dir(cb) - b) * alpha) >> base_shift) + b);
        }

    private:
        const gamma_type* m_gamma;
    };



    
    //==================================================pixfmt_alpha_blend_rgb
    template<class Blender, class RenBuf> class pixfmt_alpha_blend_rgb
    {
    public:
        typedef RenBuf   rbuf_type;
        typedef typename rbuf_type::row_data row_data;
        typedef Blender  blender_type;
        typedef typename blender_type::color_type color_type;
        typedef typename blender_type::order_type order_type;
        typedef typename color_type::value_type value_type;
        typedef typename color_type::calc_type calc_type;
        enum base_scale_e 
        {
            base_shift = color_type::base_shift,
            base_scale = color_type::base_scale,
            base_mask  = color_type::base_mask,
            pix_width  = sizeof(value_type) * 3
        };

    private:
        //--------------------------------------------------------------------
        AGG_INLINE void copy_or_blend_pix(value_type* p, 
                                          const color_type& c, 
                                          unsigned cover)
        {
            if (c.a)
            {
                calc_type alpha = (calc_type(c.a) * (cover + 1)) >> 8;
                if(alpha == base_mask)
                {
                    p[order_type::R] = c.r;
                    p[order_type::G] = c.g;
                    p[order_type::B] = c.b;
                }
                else
                {
                    m_blender.blend_pix(p, c.r, c.g, c.b, alpha, cover);
                }
            }
        }

        //--------------------------------------------------------------------
        AGG_INLINE void copy_or_blend_pix(value_type* p, 
                                          const color_type& c)
        {
            if (c.a)
            {
                if(c.a == base_mask)
                {
                    p[order_type::R] = c.r;
                    p[order_type::G] = c.g;
                    p[order_type::B] = c.b;
                }
                else
                {
                    m_blender.blend_pix(p, c.r, c.g, c.b, c.a);
                }
            }
        }


    public:
        //--------------------------------------------------------------------
        pixfmt_alpha_blend_rgb(rbuf_type& rb) :
            m_rbuf(&rb)
        {}
        void attach(rbuf_type& rb) { m_rbuf = &rb; }

        //--------------------------------------------------------------------
        Blender& blender() { return m_blender; }

        //--------------------------------------------------------------------
        AGG_INLINE unsigned width()  const { return m_rbuf->width();  }
        AGG_INLINE unsigned height() const { return m_rbuf->height(); }

        //--------------------------------------------------------------------
        const int8u* row_ptr(int y) const
        {
            return m_rbuf->row_ptr(y);
        }

        //--------------------------------------------------------------------
        const int8u* pix_ptr(int x, int y) const
        {
            return m_rbuf->row_ptr(y) + x * pix_width;
        }

        //--------------------------------------------------------------------
        row_data row(int x, int y) const
        {
            return m_rbuf->row(y);
        }

        //--------------------------------------------------------------------
        AGG_INLINE static void make_pix(int8u* p, const color_type& c)
        {
            ((value_type*)p)[order_type::R] = c.r;
            ((value_type*)p)[order_type::G] = c.g;
            ((value_type*)p)[order_type::B] = c.b;
        }

        //--------------------------------------------------------------------
        AGG_INLINE color_type pixel(int x, int y) const
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(y) + x + x + x;
            return color_type(p[order_type::R], 
                              p[order_type::G], 
                              p[order_type::B]);
        }

        //--------------------------------------------------------------------
        AGG_INLINE void copy_pixel(int x, int y, const color_type& c)
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(x, y, 1) + x + x + x;
            p[order_type::R] = c.r;
            p[order_type::G] = c.g;
            p[order_type::B] = c.b;
        }

        //--------------------------------------------------------------------
        AGG_INLINE void blend_pixel(int x, int y, const color_type& c, int8u cover)
        {
            copy_or_blend_pix((value_type*)m_rbuf->row_ptr(x, y, 1) + x + x + x, c, cover);
        }


        //--------------------------------------------------------------------
        AGG_INLINE void copy_hline(int x, int y, 
                                   unsigned len, 
                                   const color_type& c)
        {
            value_type* p = (value_type*)m_rbuf->row_ptr(x, y, len) + x + x + x;
            do
            {
                p[order_type::R] = c.r; 
                p[order_type::G] = c.g; 
                p[order_type::B] = c.b;
                p += 3;
            }
            while(--len);
        }


        //--------------------------------------------------------------------
        AGG_INLINE void copy_vline(int x, int y,
                                   unsigned len, 
                                   const color_type& c)
        {
            do
            {
                value_type* p = (value_type*)
                    m_rbuf->row_ptr(x, y++, 1) + x + x + x;
                p[order_type::R] = c.r; 
                p[order_type::G] = c.g; 
                p[order_type::B] = c.b;
            }
            while(--len);
        }


        //--------------------------------------------------------------------
        void blend_hline(int x, int y,
                         unsigned len, 
                         const color_type& c,
                         int8u cover)
        {
            if (c.a)
            {
                value_type* p = (value_type*)
                    m_rbuf->row_ptr(x, y, len) + x + x + x;

                calc_type alpha = (calc_type(c.a) * (calc_type(cover) + 1)) >> 8;
                if(alpha == base_mask)
                {
                    do
                    {
                        p[order_type::R] = c.r; 
                        p[order_type::G] = c.g; 
                        p[order_type::B] = c.b;
                        p += 3;
                    }
                    while(--len);
                }
                else
                {
                    do
                    {
                        m_blender.blend_pix(p, c.r, c.g, c.b, alpha, cover);
                        p += 3;
                    }
                    while(--len);
                }
            }
        }


        //--------------------------------------------------------------------
        void blend_vline(int x, int y,
                         unsigned len, 
                         const color_type& c,
                         int8u cover)
        {
            if (c.a)
            {
                value_type* p;
                calc_type alpha = (calc_type(c.a) * (cover + 1)) >> 8;
                if(alpha == base_mask)
                {
                    do
                    {