83 lines
3.0 KiB
C++
83 lines
3.0 KiB
C++
//----------------------------------------------------------------------------
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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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#include <cmath>
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#include "agg_line_aa_basics.h"
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namespace agg
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{
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//-------------------------------------------------------------------------
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// The number of the octant is determined as a 3-bit value as follows:
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// bit 0 = vertical flag
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// bit 1 = sx < 0
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// bit 2 = sy < 0
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//
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// [N] shows the number of the orthogonal quadrant
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// <M> shows the number of the diagonal quadrant
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// <1>
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// [1] | [0]
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// . (3)011 | 001(1) .
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// . | .
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// . | .
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// . | .
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// (2)010 .|. 000(0)
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// <2> ----------.+.----------- <0>
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// (6)110 . | . 100(4)
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// . | .
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// . | .
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// . | .
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// (7)111 | 101(5)
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// [2] | [3]
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// <3>
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// 0,1,2,3,4,5,6,7
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const int8u line_parameters::s_orthogonal_quadrant[8] = { 0,0,1,1,3,3,2,2 };
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const int8u line_parameters::s_diagonal_quadrant[8] = { 0,1,2,1,0,3,2,3 };
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//-------------------------------------------------------------------------
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void bisectrix(const line_parameters& l1,
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const line_parameters& l2,
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int* x, int* y)
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{
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double k = double(l2.len) / double(l1.len);
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double tx = l2.x2 - (l2.x1 - l1.x1) * k;
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double ty = l2.y2 - (l2.y1 - l1.y1) * k;
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//All bisectrices must be on the right of the line
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//If the next point is on the left (l1 => l2.2)
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//then the bisectix should be rotated by 180 degrees.
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if(double(l2.x2 - l2.x1) * double(l2.y1 - l1.y1) <
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double(l2.y2 - l2.y1) * double(l2.x1 - l1.x1) + 100.0)
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{
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tx -= (tx - l2.x1) * 2.0;
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ty -= (ty - l2.y1) * 2.0;
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}
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// Check if the bisectrix is too short
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double dx = tx - l2.x1;
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double dy = ty - l2.y1;
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if((int)std::sqrt(dx * dx + dy * dy) < line_subpixel_scale)
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{
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*x = (l2.x1 + l2.x1 + (l2.y1 - l1.y1) + (l2.y2 - l2.y1)) >> 1;
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*y = (l2.y1 + l2.y1 - (l2.x1 - l1.x1) - (l2.x2 - l2.x1)) >> 1;
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return;
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}
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*x = iround(tx);
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*y = iround(ty);
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}
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}
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