//---------------------------------------------------------------------------- // 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: mcseem@antigrain.com // mcseemagg@yahoo.com // http://www.antigrain.com //---------------------------------------------------------------------------- #ifndef AGG_GAMMA_LUT_INCLUDED #define AGG_GAMMA_LUT_INCLUDED #include <cmath> #include "agg_basics.h" namespace agg { template<class LoResT=int8u, class HiResT=int8u, unsigned GammaShift=8, unsigned HiResShift=8> class gamma_lut { public: typedef gamma_lut<LoResT, HiResT, GammaShift, HiResShift> self_type; enum gamma_scale_e { gamma_shift = GammaShift, gamma_size = 1 << gamma_shift, gamma_mask = gamma_size - 1 }; enum hi_res_scale_e { hi_res_shift = HiResShift, hi_res_size = 1 << hi_res_shift, hi_res_mask = hi_res_size - 1 }; ~gamma_lut() { pod_allocator<LoResT>::deallocate(m_inv_gamma, hi_res_size); pod_allocator<HiResT>::deallocate(m_dir_gamma, gamma_size); } gamma_lut() : m_gamma(1.0), m_dir_gamma(pod_allocator<HiResT>::allocate(gamma_size)), m_inv_gamma(pod_allocator<LoResT>::allocate(hi_res_size)) { unsigned i; for(i = 0; i < gamma_size; i++) { m_dir_gamma[i] = HiResT(i << (hi_res_shift - gamma_shift)); } for(i = 0; i < hi_res_size; i++) { m_inv_gamma[i] = LoResT(i >> (hi_res_shift - gamma_shift)); } } gamma_lut(double g) : m_gamma(1.0), m_dir_gamma(pod_allocator<HiResT>::allocate(gamma_size)), m_inv_gamma(pod_allocator<LoResT>::allocate(hi_res_size)) { gamma(g); } void gamma(double g) { m_gamma = g; unsigned i; for(i = 0; i < gamma_size; i++) { m_dir_gamma[i] = (HiResT) uround(pow(i / double(gamma_mask), m_gamma) * double(hi_res_mask)); } double inv_g = 1.0 / g; for(i = 0; i < hi_res_size; i++) { m_inv_gamma[i] = (LoResT) uround(pow(i / double(hi_res_mask), inv_g) * double(gamma_mask)); } } double gamma() const { return m_gamma; } HiResT dir(LoResT v) const { return m_dir_gamma[unsigned(v)]; } LoResT inv(HiResT v) const { return m_inv_gamma[unsigned(v)]; } private: gamma_lut(const self_type&); const self_type& operator = (const self_type&); double m_gamma; HiResT* m_dir_gamma; LoResT* m_inv_gamma; }; } #endif