//---------------------------------------------------------------------------- // 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 //---------------------------------------------------------------------------- // // classes dda_line_interpolator, dda2_line_interpolator // //---------------------------------------------------------------------------- #ifndef AGG_DDA_LINE_INCLUDED #define AGG_DDA_LINE_INCLUDED #include <cstdlib> #include "agg_basics.h" namespace agg { //===================================================dda_line_interpolator template<int FractionShift, int YShift=0> class dda_line_interpolator { public: //-------------------------------------------------------------------- dda_line_interpolator() {} //-------------------------------------------------------------------- dda_line_interpolator(int y1, int y2, unsigned count) : m_y(y1), m_inc(((y2 - y1) << FractionShift) / int(count)), m_dy(0) { } //-------------------------------------------------------------------- void operator ++ () { m_dy += m_inc; } //-------------------------------------------------------------------- void operator -- () { m_dy -= m_inc; } //-------------------------------------------------------------------- void operator += (unsigned n) { m_dy += m_inc * n; } //-------------------------------------------------------------------- void operator -= (unsigned n) { m_dy -= m_inc * n; } //-------------------------------------------------------------------- int y() const { return m_y + (m_dy >> (FractionShift-YShift)); } int dy() const { return m_dy; } private: int m_y; int m_inc; int m_dy; }; //=================================================dda2_line_interpolator class dda2_line_interpolator { public: typedef int save_data_type; enum save_size_e { save_size = 2 }; //-------------------------------------------------------------------- dda2_line_interpolator() {} //-------------------------------------------- Forward-adjusted line dda2_line_interpolator(int y1, int y2, int count) : m_cnt(count <= 0 ? 1 : count), m_lft((y2 - y1) / m_cnt), m_rem((y2 - y1) % m_cnt), m_mod(m_rem), m_y(y1) { if(m_mod <= 0) { m_mod += count; m_rem += count; m_lft--; } m_mod -= count; } //-------------------------------------------- Backward-adjusted line dda2_line_interpolator(int y1, int y2, int count, int) : m_cnt(count <= 0 ? 1 : count), m_lft((y2 - y1) / m_cnt), m_rem((y2 - y1) % m_cnt), m_mod(m_rem), m_y(y1) { if(m_mod <= 0) { m_mod += count; m_rem += count; m_lft--; } } //-------------------------------------------- Backward-adjusted line dda2_line_interpolator(int y, int count) : m_cnt(count <= 0 ? 1 : count), m_lft(y / m_cnt), m_rem(y % m_cnt), m_mod(m_rem), m_y(0) { if(m_mod <= 0) { m_mod += count; m_rem += count; m_lft--; } } //-------------------------------------------------------------------- void save(save_data_type* data) const { data[0] = m_mod; data[1] = m_y; } //-------------------------------------------------------------------- void load(const save_data_type* data) { m_mod = data[0]; m_y = data[1]; } //-------------------------------------------------------------------- void operator++() { m_mod += m_rem; m_y += m_lft; if(m_mod > 0) { m_mod -= m_cnt; m_y++; } } //-------------------------------------------------------------------- void operator--() { if(m_mod <= m_rem) { m_mod += m_cnt; m_y--; } m_mod -= m_rem; m_y -= m_lft; } //-------------------------------------------------------------------- void adjust_forward() { m_mod -= m_cnt; } //-------------------------------------------------------------------- void adjust_backward() { m_mod += m_cnt; } //-------------------------------------------------------------------- int mod() const { return m_mod; } int rem() const { return m_rem; } int lft() const { return m_lft; } //-------------------------------------------------------------------- int y() const { return m_y; } private: int m_cnt; int m_lft; int m_rem; int m_mod; int m_y; }; //---------------------------------------------line_bresenham_interpolator class line_bresenham_interpolator { public: enum subpixel_scale_e { subpixel_shift = 8, subpixel_scale = 1 << subpixel_shift, subpixel_mask = subpixel_scale - 1 }; //-------------------------------------------------------------------- static int line_lr(int v) { return v >> subpixel_shift; } //-------------------------------------------------------------------- line_bresenham_interpolator(int x1, int y1, int x2, int y2) : m_x1_lr(line_lr(x1)), m_y1_lr(line_lr(y1)), m_x2_lr(line_lr(x2)), m_y2_lr(line_lr(y2)), m_ver(std::abs(m_x2_lr - m_x1_lr) < std::abs(m_y2_lr - m_y1_lr)), m_len(m_ver ? std::abs(m_y2_lr - m_y1_lr) : std::abs(m_x2_lr - m_x1_lr)), m_inc(m_ver ? ((y2 > y1) ? 1 : -1) : ((x2 > x1) ? 1 : -1)), m_interpolator(m_ver ? x1 : y1, m_ver ? x2 : y2, m_len) { } //-------------------------------------------------------------------- bool is_ver() const { return m_ver; } unsigned len() const { return m_len; } int inc() const { return m_inc; } //-------------------------------------------------------------------- void hstep() { ++m_interpolator; m_x1_lr += m_inc; } //-------------------------------------------------------------------- void vstep() { ++m_interpolator; m_y1_lr += m_inc; } //-------------------------------------------------------------------- int x1() const { return m_x1_lr; } int y1() const { return m_y1_lr; } int x2() const { return line_lr(m_interpolator.y()); } int y2() const { return line_lr(m_interpolator.y()); } int x2_hr() const { return m_interpolator.y(); } int y2_hr() const { return m_interpolator.y(); } private: int m_x1_lr; int m_y1_lr; int m_x2_lr; int m_y2_lr; bool m_ver; unsigned m_len; int m_inc; dda2_line_interpolator m_interpolator; }; } #endif