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//----------------------------------------------------------------------------
// 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
//----------------------------------------------------------------------------
//
// Stroke math
//
//----------------------------------------------------------------------------
#ifndef AGG_STROKE_MATH_INCLUDED
#define AGG_STROKE_MATH_INCLUDED
#include "agg_math.h"
#include "agg_vertex_sequence.h"
namespace agg
{
enum line_cap_e {
butt_cap,
square_cap,
round_cap
};
enum line_join_e {
miter_join = 0,
miter_join_revert = 1,
miter_join_round = 4,
round_join = 2,
bevel_join = 3
};
enum inner_join_e {
inner_bevel,
inner_miter,
inner_jag,
inner_round
};
const float stroke_theta = 1.0f / 1000.0f;
template<class VertexConsumer>
void stroke_calc_arc(VertexConsumer& out_vertices,
float x, float y,
float dx1, float dy1,
float dx2, float dy2,
float width,
float approximation_scale)
{
typedef typename VertexConsumer::value_type coord_type;
float a1 = atan2(dy1, dx1);
float a2 = atan2(dy2, dx2);
float da = a1 - a2;
bool ccw = da > 0 && da < FX_PI;
if(width < 0) {
width = -width;
}
da = acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2;
out_vertices.add(coord_type(x + dx1, y + dy1));
if (da > 0) {
if (!ccw) {
if (a1 > a2) {
a2 += 2 * FX_PI;
}
a2 -= da / 4;
a1 += da;
while (a1 < a2) {
out_vertices.add(
coord_type(x + (width * cos(a1)), y + (width * sin(a1))));
a1 += da;
}
} else {
if (a1 < a2) {
a2 -= 2 * FX_PI;
}
a2 += da / 4;
a1 -= da;
while (a1 > a2) {
out_vertices.add(
coord_type(x + (width * cos(a1)), y + (width * sin(a1))));
a1 -= da;
}
}
}
out_vertices.add(coord_type(x + dx2, y + dy2));
}
template<class VertexConsumer>
void stroke_calc_miter(VertexConsumer& out_vertices,
const vertex_dist& v0,
const vertex_dist& v1,
const vertex_dist& v2,
float dx1, float dy1,
float dx2, float dy2,
float width,
line_join_e line_join,
float miter_limit,
float approximation_scale)
{
typedef typename VertexConsumer::value_type coord_type;
float xi = v1.x;
float yi = v1.y;
bool miter_limit_exceeded = true;
if(calc_intersection(v0.x + dx1, v0.y - dy1,
v1.x + dx1, v1.y - dy1,
v1.x + dx2, v1.y - dy2,
v2.x + dx2, v2.y - dy2,
&xi, &yi)) {
float d1 = calc_distance(v1.x, v1.y, xi, yi);
float lim = width * miter_limit;
if(d1 <= lim) {
out_vertices.add(coord_type(xi, yi));
miter_limit_exceeded = false;
}
} else {
float x2 = v1.x + dx1;
float y2 = v1.y - dy1;
if ((((x2 - v0.x) * dy1) - ((v0.y - y2) * dx1) < 0) !=
(((x2 - v2.x) * dy1) - ((v2.y - y2) * dx1) < 0)) {
out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
miter_limit_exceeded = false;
}
}
if(miter_limit_exceeded) {
switch(line_join) {
case miter_join_revert:
out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
break;
case miter_join_round:
stroke_calc_arc(out_vertices,
v1.x, v1.y, dx1, -dy1, dx2, -dy2,
width, approximation_scale);
break;
default:
out_vertices.add(coord_type(v1.x + dx1 + (dy1 * miter_limit),
v1.y - dy1 + (dx1 * miter_limit)));
out_vertices.add(coord_type(v1.x + dx2 - (dy2 * miter_limit),
v1.y - dy2 - (dx2 * miter_limit)));
break;
}
}
}
template<class VertexConsumer>
void stroke_calc_cap(VertexConsumer& out_vertices,
const vertex_dist& v0,
const vertex_dist& v1,
float len,
line_cap_e line_cap,
float width,
float approximation_scale)
{
typedef typename VertexConsumer::value_type coord_type;
out_vertices.remove_all();
float dx1 = (v1.y - v0.y) / len;
float dy1 = (v1.x - v0.x) / len;
float dx2 = 0;
float dy2 = 0;
dx1 = dx1 * width;
dy1 = dy1 * width;
if(line_cap != round_cap) {
if(line_cap == square_cap) {
dx2 = dy1;
dy2 = dx1;
}
out_vertices.add(coord_type(v0.x - dx1 - dx2, v0.y + dy1 - dy2));
out_vertices.add(coord_type(v0.x + dx1 - dx2, v0.y - dy1 - dy2));
} else {
float a1 = atan2(dy1, -dx1);
float a2 = a1 + FX_PI;
float da = acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2;
out_vertices.add(coord_type(v0.x - dx1, v0.y + dy1));
a1 += da;
a2 -= da / 4;
while (a1 < a2) {
out_vertices.add(
coord_type(v0.x + (width * cos(a1)), v0.y + (width * sin(a1))));
a1 += da;
}
out_vertices.add(coord_type(v0.x + dx1, v0.y - dy1));
}
}
template<class VertexConsumer>
void stroke_calc_join(VertexConsumer& out_vertices,
const vertex_dist& v0,
const vertex_dist& v1,
const vertex_dist& v2,
float len1,
float len2,
float width,
line_join_e line_join,
inner_join_e inner_join,
float miter_limit,
float inner_miter_limit,
float approximation_scale)
{
typedef typename VertexConsumer::value_type coord_type;
float dx1, dy1, dx2, dy2;
dx1 = width * (v1.y - v0.y) / len1;
dy1 = width * (v1.x - v0.x) / len1;
dx2 = width * (v2.y - v1.y) / len2;
dy2 = width * (v2.x - v1.x) / len2;
out_vertices.remove_all();
if(calc_point_location(v0.x, v0.y, v1.x, v1.y, v2.x, v2.y) > 0) {
switch(inner_join) {
default:
out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
break;
case inner_miter:
stroke_calc_miter(out_vertices,
v0, v1, v2, dx1, dy1, dx2, dy2,
width,
miter_join_revert,
inner_miter_limit,
1.0f);
break;
case inner_jag:
case inner_round: {
float d = (dx1 - dx2) * (dx1 - dx2) + (dy1 - dy2) * (dy1 - dy2);
if(d < len1 * len1 && d < len2 * len2) {
stroke_calc_miter(out_vertices,
v0, v1, v2, dx1, dy1, dx2, dy2,
width,
miter_join_revert,
inner_miter_limit,
1.0f);
} else {
if(inner_join == inner_jag) {
out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
out_vertices.add(coord_type(v1.x, v1.y ));
out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
} else {
out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
out_vertices.add(coord_type(v1.x, v1.y ));
stroke_calc_arc(out_vertices,
v1.x, v1.y, dx2, -dy2, dx1, -dy1,
width, approximation_scale);
out_vertices.add(coord_type(v1.x, v1.y ));
out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
}
}
}
break;
}
} else {
switch(line_join) {
case miter_join:
case miter_join_revert:
case miter_join_round:
stroke_calc_miter(out_vertices,
v0, v1, v2, dx1, dy1, dx2, dy2,
width,
line_join,
miter_limit,
approximation_scale);
break;
case round_join:
stroke_calc_arc(out_vertices,
v1.x, v1.y, dx1, -dy1, dx2, -dy2,
width, approximation_scale);
break;
default:
out_vertices.add(coord_type(v1.x + dx1, v1.y - dy1));
out_vertices.add(coord_type(v1.x + dx2, v1.y - dy2));
break;
}
}
}
}
#endif
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