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275 lines
10 KiB
275 lines
10 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 FX_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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FX_FLOAT x, FX_FLOAT y, |
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FX_FLOAT dx1, FX_FLOAT dy1, |
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FX_FLOAT dx2, FX_FLOAT dy2, |
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FX_FLOAT width, |
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FX_FLOAT approximation_scale) |
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{ |
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typedef typename VertexConsumer::value_type coord_type; |
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FX_FLOAT a1 = FXSYS_atan2(dy1, dx1); |
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FX_FLOAT a2 = FXSYS_atan2(dy2, dx2); |
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FX_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 = FXSYS_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(coord_type(x + (width * FXSYS_cos(a1)), |
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y + (width * FXSYS_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(coord_type(x + (width * FXSYS_cos(a1)), |
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y + (width * FXSYS_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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FX_FLOAT dx1, FX_FLOAT dy1, |
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FX_FLOAT dx2, FX_FLOAT dy2, |
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FX_FLOAT width, |
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line_join_e line_join, |
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FX_FLOAT miter_limit, |
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FX_FLOAT approximation_scale) |
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{ |
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typedef typename VertexConsumer::value_type coord_type; |
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FX_FLOAT xi = v1.x; |
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FX_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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FX_FLOAT d1 = calc_distance(v1.x, v1.y, xi, yi); |
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FX_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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FX_FLOAT x2 = v1.x + dx1; |
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FX_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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FX_FLOAT len, |
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line_cap_e line_cap, |
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FX_FLOAT width, |
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FX_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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FX_FLOAT dx1 = (v1.y - v0.y) / len; |
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FX_FLOAT dy1 = (v1.x - v0.x) / len; |
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FX_FLOAT dx2 = 0; |
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FX_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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FX_FLOAT a1 = FXSYS_atan2(dy1, -dx1); |
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FX_FLOAT a2 = a1 + FX_PI; |
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FX_FLOAT da = |
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FXSYS_acos(width / (width + ((1.0f / 8) / approximation_scale))) * |
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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(coord_type(v0.x + (width * FXSYS_cos(a1)), |
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v0.y + (width * FXSYS_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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FX_FLOAT len1, |
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FX_FLOAT len2, |
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FX_FLOAT width, |
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line_join_e line_join, |
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inner_join_e inner_join, |
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FX_FLOAT miter_limit, |
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FX_FLOAT inner_miter_limit, |
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FX_FLOAT approximation_scale) |
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{ |
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typedef typename VertexConsumer::value_type coord_type; |
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FX_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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FX_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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