340 lines
11 KiB
C++
Executable file
340 lines
11 KiB
C++
Executable file
//----------------------------------------------------------------------------
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// Anti-Grain Geometry - Version 2.3
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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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// Stroke math
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//
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//----------------------------------------------------------------------------
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#ifndef AGG_STROKE_MATH_INCLUDED
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#define AGG_STROKE_MATH_INCLUDED
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#include "agg_math.h"
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#include "agg_vertex_sequence.h"
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namespace agg
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{
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//-------------------------------------------------------------line_cap_e
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enum line_cap_e
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{
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butt_cap,
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square_cap,
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round_cap
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};
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//------------------------------------------------------------line_join_e
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enum line_join_e
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{
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miter_join,
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miter_join_revert,
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round_join,
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bevel_join
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};
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// Minimal angle to calculate round joins, less than 0.1 degree.
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const double stroke_theta = 0.001; //----stroke_theta
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//--------------------------------------------------------stroke_calc_arc
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template<class VertexConsumer>
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void stroke_calc_arc(VertexConsumer& out_vertices,
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double x, double y,
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double dx1, double dy1,
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double dx2, double dy2,
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double width,
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double approximation_scale)
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{
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typedef typename VertexConsumer::value_type coord_type;
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//// Check if we actually need the arc (this optimization works bad)
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////-----------------
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//double dd = calc_distance(dx1, dy1, dx2, dy2);
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//if(dd < 1.0/approximation_scale)
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//{
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// out_vertices.add(coord_type(x + dx1, y + dy1));
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// if(dd > 0.25/approximation_scale)
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// {
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// out_vertices.add(coord_type(x + dx2, y + dy2));
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// }
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// return;
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//}
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double a1 = atan2(dy1, dx1);
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double a2 = atan2(dy2, dx2);
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double da = a1 - a2;
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if(fabs(da) < stroke_theta)
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{
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out_vertices.add(coord_type((x + x + dx1 + dx2) * 0.5,
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(y + y + dy1 + dy2) * 0.5));
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return;
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}
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bool ccw = da > 0.0 && da < pi;
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if(width < 0) width = -width;
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da = fabs(1.0 / (width * approximation_scale));
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if(!ccw)
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{
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if(a1 > a2) a2 += 2 * pi;
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while(a1 < a2)
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{
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out_vertices.add(coord_type(x + cos(a1) * width, y + sin(a1) * width));
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a1 += da;
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}
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}
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else
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{
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if(a1 < a2) a2 -= 2 * pi;
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while(a1 > a2)
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{
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out_vertices.add(coord_type(x + cos(a1) * width, y + sin(a1) * width));
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a1 -= da;
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}
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}
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out_vertices.add(coord_type(x + dx2, y + dy2));
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}
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//-------------------------------------------------------stroke_calc_miter
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template<class VertexConsumer>
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void stroke_calc_miter(VertexConsumer& out_vertices,
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const vertex_dist& v0,
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const vertex_dist& v1,
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const vertex_dist& v2,
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double dx1, double dy1,
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double dx2, double dy2,
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double width,
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bool revert_flag,
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double miter_limit)
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{
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typedef typename VertexConsumer::value_type coord_type;
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double xi = v1.x;
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double yi = v1.y;
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if(!calc_intersection(v0.x + dx1, v0.y - dy1,
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v1.x + dx1, v1.y - dy1,
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v1.x + dx2, v1.y - dy2,
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v2.x + dx2, v2.y - dy2,
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&xi, &yi))
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{
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// The calculation didn't succeed, most probaly
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// the three points lie one straight line
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//----------------
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if(calc_distance(dx1, -dy1, dx2, -dy2) < width * 0.025)
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{
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// This case means that the next segment continues
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// the previous one (straight line)
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//-----------------
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out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
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}
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else
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{
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// This case means that the next segment goes back
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//-----------------
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if(revert_flag)
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{
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out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
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out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
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}
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else
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{
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// If no miter-revert, calcuate new dx1, dy1, dx2, dy2
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out_vertices.add(coord_type(v1.x + dx1 + dy1 * miter_limit,
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v1.y - dy1 + dx1 * miter_limit));
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out_vertices.add(coord_type(v1.x + dx2 - dy2 * miter_limit,
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v1.y - dy2 - dx2 * miter_limit));
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}
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}
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}
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else
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{
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double d1 = calc_distance(v1.x, v1.y, xi, yi);
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double lim = width * miter_limit;
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if(d1 > lim)
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{
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// Miter limit exceeded
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//------------------------
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if(revert_flag)
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{
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// For the compatibility with SVG, PDF, etc,
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// we use a simple bevel join instead of
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// "smart" bevel
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//-------------------
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out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
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out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
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}
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else
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{
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// Smart bevel that cuts the miter at the limit point
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//-------------------
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d1 = lim / d1;
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double x1 = v1.x + dx1;
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double y1 = v1.y - dy1;
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double x2 = v1.x + dx2;
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double y2 = v1.y - dy2;
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x1 += (xi - x1) * d1;
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y1 += (yi - y1) * d1;
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x2 += (xi - x2) * d1;
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y2 += (yi - y2) * d1;
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out_vertices.add(coord_type(x1, y1));
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out_vertices.add(coord_type(x2, y2));
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}
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}
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else
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{
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// Inside the miter limit
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//---------------------
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out_vertices.add(coord_type(xi, yi));
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}
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}
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}
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//--------------------------------------------------------stroke_calc_cap
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template<class VertexConsumer>
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void stroke_calc_cap(VertexConsumer& out_vertices,
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const vertex_dist& v0,
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const vertex_dist& v1,
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double len,
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line_cap_e line_cap,
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double width,
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double approximation_scale)
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{
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typedef typename VertexConsumer::value_type coord_type;
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out_vertices.remove_all();
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double dx1 = width * (v1.y - v0.y) / len;
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double dy1 = width * (v1.x - v0.x) / len;
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double dx2 = 0;
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double dy2 = 0;
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if(line_cap == square_cap)
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{
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dx2 = dy1;
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dy2 = dx1;
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}
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if(line_cap == round_cap)
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{
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double a1 = atan2(dy1, -dx1);
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double a2 = a1 + pi;
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double da = fabs(1.0 / (width * approximation_scale));
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while(a1 < a2)
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{
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out_vertices.add(coord_type(v0.x + cos(a1) * width,
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v0.y + sin(a1) * width));
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a1 += da;
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}
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out_vertices.add(coord_type(v0.x + dx1, v0.y - dy1));
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}
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else
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{
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out_vertices.add(coord_type(v0.x - dx1 - dx2, v0.y + dy1 - dy2));
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out_vertices.add(coord_type(v0.x + dx1 - dx2, v0.y - dy1 - dy2));
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}
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}
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//-------------------------------------------------------stroke_calc_join
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template<class VertexConsumer>
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void stroke_calc_join(VertexConsumer& out_vertices,
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const vertex_dist& v0,
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const vertex_dist& v1,
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const vertex_dist& v2,
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double len1,
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double len2,
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double width,
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line_join_e line_join,
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line_join_e inner_line_join,
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double miter_limit,
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double inner_miter_limit,
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double approximation_scale)
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{
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typedef typename VertexConsumer::value_type coord_type;
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double dx1, dy1, dx2, dy2;
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dx1 = width * (v1.y - v0.y) / len1;
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dy1 = width * (v1.x - v0.x) / len1;
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dx2 = width * (v2.y - v1.y) / len2;
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dy2 = width * (v2.x - v1.x) / len2;
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out_vertices.remove_all();
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if(calc_point_location(v0.x, v0.y, v1.x, v1.y, v2.x, v2.y) > 0.0)
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{
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// Inner join
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//---------------
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stroke_calc_miter(out_vertices,
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v0, v1, v2, dx1, dy1, dx2, dy2,
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width,
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inner_line_join == miter_join_revert,
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inner_miter_limit);
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}
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else
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{
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// Outer join
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//---------------
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switch(line_join)
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{
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case miter_join:
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stroke_calc_miter(out_vertices,
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v0, v1, v2, dx1, dy1, dx2, dy2,
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width,
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false,
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miter_limit);
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break;
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case miter_join_revert:
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stroke_calc_miter(out_vertices,
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v0, v1, v2, dx1, dy1, dx2, dy2,
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width,
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true,
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miter_limit);
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break;
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case round_join:
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stroke_calc_arc(out_vertices,
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v1.x, v1.y, dx1, -dy1, dx2, -dy2,
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width, approximation_scale);
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break;
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default: // Bevel join
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out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
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if(calc_distance(dx1, dy1, dx2, dy2) > approximation_scale * 0.25)
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{
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out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
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}
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break;
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}
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}
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}
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}
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#endif
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