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113 lines
2.8 KiB
113 lines
2.8 KiB
//---------------------------------------------------------------------------- |
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// Anti-Grain Geometry - Version 2.4 |
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com) |
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// |
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// Permission to copy, use, modify, sell and distribute this software |
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// is granted provided this copyright notice appears in all copies. |
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// This software is provided "as is" without express or implied |
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// warranty, and with no claim as to its suitability for any purpose. |
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// |
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//---------------------------------------------------------------------------- |
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// Contact: mcseem@antigrain.com |
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// mcseemagg@yahoo.com |
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// http://www.antigrain.com |
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//---------------------------------------------------------------------------- |
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// |
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// Simple Bresenham interpolator for ellipsees |
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// |
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//---------------------------------------------------------------------------- |
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#ifndef AGG_ELLIPSE_BRESENHAM_INCLUDED |
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#define AGG_ELLIPSE_BRESENHAM_INCLUDED |
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#include "agg_basics.h" |
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namespace agg |
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{ |
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//------------------------------------------ellipse_bresenham_interpolator |
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class ellipse_bresenham_interpolator |
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{ |
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public: |
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ellipse_bresenham_interpolator(int rx, int ry) : |
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m_rx2(rx * rx), |
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m_ry2(ry * ry), |
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m_two_rx2(m_rx2 << 1), |
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m_two_ry2(m_ry2 << 1), |
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m_dx(0), |
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m_dy(0), |
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m_inc_x(0), |
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m_inc_y(-ry * m_two_rx2), |
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m_cur_f(0) |
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{} |
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int dx() const { return m_dx; } |
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int dy() const { return m_dy; } |
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void operator++ () |
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{ |
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int mx, my, mxy, min_m; |
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int fx, fy, fxy; |
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mx = fx = m_cur_f + m_inc_x + m_ry2; |
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if(mx < 0) mx = -mx; |
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my = fy = m_cur_f + m_inc_y + m_rx2; |
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if(my < 0) my = -my; |
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mxy = fxy = m_cur_f + m_inc_x + m_ry2 + m_inc_y + m_rx2; |
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if(mxy < 0) mxy = -mxy; |
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min_m = mx; |
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bool flag = true; |
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if(min_m > my) |
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{ |
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min_m = my; |
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flag = false; |
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} |
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m_dx = m_dy = 0; |
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if(min_m > mxy) |
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{ |
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m_inc_x += m_two_ry2; |
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m_inc_y += m_two_rx2; |
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m_cur_f = fxy; |
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m_dx = 1; |
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m_dy = 1; |
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return; |
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} |
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if(flag) |
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{ |
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m_inc_x += m_two_ry2; |
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m_cur_f = fx; |
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m_dx = 1; |
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return; |
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} |
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m_inc_y += m_two_rx2; |
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m_cur_f = fy; |
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m_dy = 1; |
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} |
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private: |
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int m_rx2; |
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int m_ry2; |
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int m_two_rx2; |
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int m_two_ry2; |
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int m_dx; |
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int m_dy; |
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int m_inc_x; |
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int m_inc_y; |
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int m_cur_f; |
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}; |
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} |
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#endif |
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