//---------------------------------------------------------------------------- // Anti-Grain Geometry (AGG) - Version 2.5 // A high quality rendering engine for C++ // Copyright (C) 2002-2006 Maxim Shemanarev // Contact: mcseem@antigrain.com // mcseemagg@yahoo.com // http://antigrain.com // // AGG is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License // as published by the Free Software Foundation; either version 2 // of the License, or (at your option) any later version. // // AGG is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with AGG; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, // MA 02110-1301, USA. //---------------------------------------------------------------------------- #ifndef AGG_GRADIENT_LUT_INCLUDED #define AGG_GRADIENT_LUT_INCLUDED #include "agg_array.h" #include "agg_dda_line.h" #include "agg_color_rgba.h" #include "agg_color_gray.h" namespace agg { //======================================================color_interpolator template<class ColorT> struct color_interpolator { public: typedef ColorT color_type; color_interpolator(const color_type& c1, const color_type& c2, unsigned len) : m_c1(c1), m_c2(c2), m_len(len), m_count(0) {} void operator ++ () { ++m_count; } color_type color() const { return m_c1.gradient(m_c2, double(m_count) / m_len); } private: color_type m_c1; color_type m_c2; unsigned m_len; unsigned m_count; }; //======================================================================== // Fast specialization for rgba8 template<> struct color_interpolator<rgba8> { public: typedef rgba8 color_type; color_interpolator(const color_type& c1, const color_type& c2, unsigned len) : r(c1.r, c2.r, len), g(c1.g, c2.g, len), b(c1.b, c2.b, len), a(c1.a, c2.a, len) {} void operator ++ () { ++r; ++g; ++b; ++a; } color_type color() const { return color_type(r.y(), g.y(), b.y(), a.y()); } private: agg::dda_line_interpolator<14> r, g, b, a; }; //======================================================================== // Fast specialization for gray8 template<> struct color_interpolator<gray8> { public: typedef gray8 color_type; color_interpolator(const color_type& c1, const color_type& c2, unsigned len) : v(c1.v, c2.v, len), a(c1.a, c2.a, len) {} void operator ++ () { ++v; ++a; } color_type color() const { return color_type(v.y(), a.y()); } private: agg::dda_line_interpolator<14> v,a; }; //============================================================gradient_lut template<class ColorInterpolator, unsigned ColorLutSize=256> class gradient_lut { public: typedef ColorInterpolator interpolator_type; typedef typename interpolator_type::color_type color_type; enum { color_lut_size = ColorLutSize }; //-------------------------------------------------------------------- gradient_lut() : m_color_lut(color_lut_size) {} // Build Gradient Lut // First, call remove_all(), then add_color() at least twice, // then build_lut(). Argument "offset" in add_color must be // in range [0...1] and defines a color stop as it is described // in SVG specification, section Gradients and Patterns. // The simplest linear gradient is: // gradient_lut.add_color(0.0, start_color); // gradient_lut.add_color(1.0, end_color); //-------------------------------------------------------------------- void remove_all(); void add_color(double offset, const color_type& color); void build_lut(); // Size-index Interface. This class can be used directly as the // ColorF in span_gradient. All it needs is two access methods // size() and operator []. //-------------------------------------------------------------------- static unsigned size() { return color_lut_size; } const color_type& operator [] (unsigned i) const { return m_color_lut[i]; } private: //-------------------------------------------------------------------- struct color_point { double offset; color_type color; color_point() {} color_point(double off, const color_type& c) : offset(off), color(c) { if(offset < 0.0) offset = 0.0; if(offset > 1.0) offset = 1.0; } }; typedef agg::pod_bvector<color_point, 4> color_profile_type; typedef agg::pod_array<color_type> color_lut_type; static bool offset_less(const color_point& a, const color_point& b) { return a.offset < b.offset; } static bool offset_equal(const color_point& a, const color_point& b) { return a.offset == b.offset; } //-------------------------------------------------------------------- color_profile_type m_color_profile; color_lut_type m_color_lut; }; //------------------------------------------------------------------------ template<class T, unsigned S> void gradient_lut<T,S>::remove_all() { m_color_profile.remove_all(); } //------------------------------------------------------------------------ template<class T, unsigned S> void gradient_lut<T,S>::add_color(double offset, const color_type& color) { m_color_profile.add(color_point(offset, color)); } //------------------------------------------------------------------------ template<class T, unsigned S> void gradient_lut<T,S>::build_lut() { quick_sort(m_color_profile, offset_less); m_color_profile.cut_at(remove_duplicates(m_color_profile, offset_equal)); if(m_color_profile.size() >= 2) { unsigned i; unsigned start = uround(m_color_profile[0].offset * color_lut_size); unsigned end; color_type c = m_color_profile[0].color; for(i = 0; i < start; i++) { m_color_lut[i] = c; } for(i = 1; i < m_color_profile.size(); i++) { end = uround(m_color_profile[i].offset * color_lut_size); interpolator_type ci(m_color_profile[i-1].color, m_color_profile[i ].color, end - start + 1); while(start < end) { m_color_lut[start] = ci.color(); ++ci; ++start; } } c = m_color_profile.last().color; for(; end < m_color_lut.size(); end++) { m_color_lut[end] = c; } } } } #endif |