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274 lines
9.9 KiB
274 lines
9.9 KiB
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//----------------------------------------------------------------------------
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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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enum line_cap_e {
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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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enum line_join_e {
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miter_join = 0,
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miter_join_revert = 1,
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miter_join_round = 4,
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round_join = 2,
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bevel_join = 3
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};
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enum inner_join_e {
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inner_bevel,
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inner_miter,
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inner_jag,
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inner_round
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};
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const float stroke_theta = 1.0f / 1000.0f;
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template<class VertexConsumer>
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void stroke_calc_arc(VertexConsumer& out_vertices,
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float x, float y,
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float dx1, float dy1,
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float dx2, float dy2,
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float width,
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float approximation_scale)
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{
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typedef typename VertexConsumer::value_type coord_type;
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float a1 = atan2(dy1, dx1);
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float a2 = atan2(dy2, dx2);
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float da = a1 - a2;
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bool ccw = da > 0 && da < FX_PI;
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if(width < 0) {
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width = -width;
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}
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da = acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2;
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out_vertices.add(coord_type(x + dx1, y + dy1));
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if (da > 0) {
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if (!ccw) {
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if (a1 > a2) {
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a2 += 2 * FX_PI;
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}
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a2 -= da / 4;
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a1 += da;
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while (a1 < a2) {
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out_vertices.add(
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coord_type(x + (width * cos(a1)), y + (width * sin(a1))));
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a1 += da;
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}
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} else {
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if (a1 < a2) {
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a2 -= 2 * FX_PI;
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}
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a2 += da / 4;
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a1 -= da;
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while (a1 > a2) {
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out_vertices.add(
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coord_type(x + (width * cos(a1)), y + (width * sin(a1))));
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a1 -= da;
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}
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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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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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float dx1, float dy1,
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float dx2, float dy2,
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float width,
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line_join_e line_join,
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float miter_limit,
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float approximation_scale)
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{
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typedef typename VertexConsumer::value_type coord_type;
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float xi = v1.x;
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float yi = v1.y;
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bool miter_limit_exceeded = true;
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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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float d1 = calc_distance(v1.x, v1.y, xi, yi);
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float lim = width * miter_limit;
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if(d1 <= lim) {
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out_vertices.add(coord_type(xi, yi));
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miter_limit_exceeded = false;
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}
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} else {
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float x2 = v1.x + dx1;
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float y2 = v1.y - dy1;
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if ((((x2 - v0.x) * dy1) - ((v0.y - y2) * dx1) < 0) !=
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(((x2 - v2.x) * dy1) - ((v2.y - y2) * dx1) < 0)) {
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out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
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miter_limit_exceeded = false;
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}
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}
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if(miter_limit_exceeded) {
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switch(line_join) {
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case miter_join_revert:
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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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break;
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case miter_join_round:
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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:
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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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break;
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}
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}
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}
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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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float len,
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line_cap_e line_cap,
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float width,
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float 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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float dx1 = (v1.y - v0.y) / len;
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float dy1 = (v1.x - v0.x) / len;
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float dx2 = 0;
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float dy2 = 0;
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dx1 = dx1 * width;
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dy1 = dy1 * width;
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if(line_cap != round_cap) {
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if(line_cap == square_cap) {
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dx2 = dy1;
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dy2 = dx1;
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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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} else {
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float a1 = atan2(dy1, -dx1);
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float a2 = a1 + FX_PI;
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float da = acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2;
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out_vertices.add(coord_type(v0.x - dx1, v0.y + dy1));
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a1 += da;
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a2 -= da / 4;
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while (a1 < a2) {
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out_vertices.add(
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coord_type(v0.x + (width * cos(a1)), v0.y + (width * sin(a1))));
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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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}
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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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float len1,
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float len2,
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float width,
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line_join_e line_join,
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inner_join_e inner_join,
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float miter_limit,
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float inner_miter_limit,
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float approximation_scale)
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{
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typedef typename VertexConsumer::value_type coord_type;
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float 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) {
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switch(inner_join) {
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default:
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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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break;
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case inner_miter:
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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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miter_join_revert,
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inner_miter_limit,
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1.0f);
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break;
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case inner_jag:
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case inner_round: {
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float d = (dx1 - dx2) * (dx1 - dx2) + (dy1 - dy2) * (dy1 - dy2);
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if(d < len1 * len1 && d < len2 * len2) {
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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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miter_join_revert,
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inner_miter_limit,
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1.0f);
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} else {
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if(inner_join == inner_jag) {
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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, v1.y ));
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out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
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} else {
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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, v1.y ));
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stroke_calc_arc(out_vertices,
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v1.x, v1.y, dx2, -dy2, dx1, -dy1,
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width, approximation_scale);
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out_vertices.add(coord_type(v1.x, v1.y ));
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out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
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}
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}
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}
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break;
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}
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} else {
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switch(line_join) {
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case miter_join:
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case miter_join_revert:
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case miter_join_round:
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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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line_join,
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miter_limit,
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approximation_scale);
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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:
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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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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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