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Diffstat (limited to 'agg/source/agg_line_aa_basics.cpp')
-rwxr-xr-x | agg/source/agg_line_aa_basics.cpp | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/agg/source/agg_line_aa_basics.cpp b/agg/source/agg_line_aa_basics.cpp new file mode 100755 index 000000000000..34103178d7b7 --- /dev/null +++ b/agg/source/agg_line_aa_basics.cpp @@ -0,0 +1,82 @@ +//---------------------------------------------------------------------------- +// Anti-Grain Geometry - Version 2.3 +// 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 +//---------------------------------------------------------------------------- + +#include <math.h> +#include "agg_line_aa_basics.h" + +namespace agg +{ + //------------------------------------------------------------------------- + // The number of the octant is determined as a 3-bit value as follows: + // bit 0 = vertical flag + // bit 1 = sx < 0 + // bit 2 = sy < 0 + // + // [N] shows the number of the orthogonal quadrant + // <M> shows the number of the diagonal quadrant + // <1> + // [1] | [0] + // . (3)011 | 001(1) . + // . | . + // . | . + // . | . + // (2)010 .|. 000(0) + // <2> ----------.+.----------- <0> + // (6)110 . | . 100(4) + // . | . + // . | . + // . | . + // (7)111 | 101(5) + // [2] | [3] + // <3> + // 0,1,2,3,4,5,6,7 + int8u line_parameters::s_orthogonal_quadrant[8] = { 0,0,1,1,3,3,2,2 }; + int8u line_parameters::s_diagonal_quadrant[8] = { 0,1,2,1,0,3,2,3 }; + + + + //------------------------------------------------------------------------- + void bisectrix(const line_parameters& l1, + const line_parameters& l2, + int* x, int* y) + { + double k = double(l2.len) / double(l1.len); + double tx = l2.x2 - (l2.x1 - l1.x1) * k; + double ty = l2.y2 - (l2.y1 - l1.y1) * k; + + //All bisectrices must be on the right of the line + //If the next point is on the left (l1 => l2.2) + //then the bisectix should be rotated by 180 degrees. + if(double(l2.x2 - l2.x1) * double(l2.y1 - l1.y1) < + double(l2.y2 - l2.y1) * double(l2.x1 - l1.x1) + 100.0) + { + tx -= (tx - l2.x1) * 2.0; + ty -= (ty - l2.y1) * 2.0; + } + + // Check if the bisectrix is too short + double dx = tx - l2.x1; + double dy = ty - l2.y1; + if((int)sqrt(dx * dx + dy * dy) < line_subpixel_size) + { + *x = (l2.x1 + l2.x1 + (l2.y1 - l1.y1) + (l2.y2 - l2.y1)) >> 1; + *y = (l2.y1 + l2.y1 - (l2.x1 - l1.x1) - (l2.x2 - l2.x1)) >> 1; + return; + } + *x = int(tx); + *y = int(ty); + } + +} |