From c92e7ab497687b249d498dbed02b11e5f74beff8 Mon Sep 17 00:00:00 2001 From: Dane Springmeyer Date: Fri, 21 Oct 2011 17:39:20 -0700 Subject: [PATCH] add a new, experimental coord_transform impl to support offsetting line verticies - closes #180 - next task of exposing functionality refs #927 --- include/mapnik/ctrans.hpp | 230 +++++++++++++++++++++++++++++++++++++- 1 file changed, 228 insertions(+), 2 deletions(-) diff --git a/include/mapnik/ctrans.hpp b/include/mapnik/ctrans.hpp index 1bfac5b8c..c0996f2b8 100644 --- a/include/mapnik/ctrans.hpp +++ b/include/mapnik/ctrans.hpp @@ -24,13 +24,21 @@ #ifndef CTRANS_HPP #define CTRANS_HPP -#include - +// mapnik #include #include #include #include +// boost +#include + +// stl +#include + +const double pi = boost::math::constants::pi(); +const double pi_by_2 = pi/2.0; + namespace mapnik { @@ -150,6 +158,224 @@ private: }; +// TODO - expose this and make chainable +template +struct MAPNIK_DECL coord_transform_parallel +{ + typedef std::size_t size_type; + typedef typename Geometry::value_type value_type; + + coord_transform_parallel(Transform const& t, + Geometry const& geom, + proj_transform const& prj_trans ) + : t_(t), + geom_(geom), + prj_trans_(prj_trans), + offset_(0.0), + threshold_(10), + m_status(initial) {} + + enum status + { + initial, + start, + first, + process, + last_vertex, + angle_joint, + end + }; + + double get_offset() const + { + return offset_; + } + + void set_offset(double offset) + { + offset_ = offset; + } + + unsigned int get_threshold() const + { + return threshold_; + } + + void set_threshold(unsigned int t) + { + threshold_ = t; + } + + unsigned vertex(double * x , double * y) + { + double z=0; + + if (offset_==0.0) + { + unsigned command = geom_.vertex(x,y); + prj_trans_.backward(*x,*y,z); + t_.forward(x,y); + return command; + } + else + { + while(true){ + switch(m_status) + { + case end: + return SEG_END; + break; + case initial: + m_pre_cmd = geom_.vertex(x,y); + prj_trans_.backward(*x,*y,z); + t_.forward(x,y); + m_pre_x = *x; + m_pre_y = *y; + //m_status = (m_pre_cmd!=SEG_END)?start:end; // + case start: + m_cur_cmd = geom_.vertex(&m_cur_x, &m_cur_y); + prj_trans_.backward(m_cur_x,m_cur_y,z); + t_.forward(&m_cur_x,&m_cur_y); + case first: + angle_a = atan2((m_pre_y-m_cur_y),(m_pre_x-m_cur_x)); + dx_pre = cos(angle_a + pi_by_2); + dy_pre = sin(angle_a + pi_by_2); + #ifdef MAPNIK_DEBUG + std::clog << "offsetting line by: " << offset_ << "\n"; + std::clog << "initial dx=" << (dx_pre * offset_) << " dy=" << (dy_pre * offset_) << "\n"; + #endif + *x = m_pre_x + (dx_pre * offset_); + *y = m_pre_y + (dy_pre * offset_); + m_status = process; + return SEG_MOVETO; + case process: + switch(m_cur_cmd) + { + case SEG_LINETO: + m_next_cmd = geom_.vertex(&m_next_x, &m_next_y); + prj_trans_.backward(m_next_x,m_next_y,z); + t_.forward(&m_next_x,&m_next_y); + switch(m_next_cmd) + { + case SEG_LINETO: + m_status = angle_joint; + break; + default: + m_status = last_vertex; + break; + } + break; + case SEG_END: + m_status = end; + return SEG_END; + } + break; + case last_vertex: + dx_curr = cos(angle_a + pi_by_2); + dy_curr = sin(angle_a + pi_by_2); + *x = m_cur_x + (dx_curr * offset_); + *y = m_cur_y + (dy_curr * offset_); + m_status = end; + return m_cur_cmd; + case angle_joint: + angle_b = atan2((m_cur_y-m_next_y),(m_cur_x-m_next_x)); + h = tan((angle_b - angle_a)/2.0); + + if (fabs(h) < threshold_) + { + dx_curr = cos(angle_a + pi_by_2); + dy_curr = sin(angle_a + pi_by_2); + *x = m_cur_x + (dx_curr * offset_) - h * (dy_curr * offset_); + *y = m_cur_y + (dy_curr * offset_) + h * (dx_curr * offset_); + } + else // skip sharp spikes + { + + #ifdef MAPNIK_DEBUG + dx_curr = cos(angle_a + pi_by_2); + dy_curr = sin(angle_a + pi_by_2); + sin_curve = dx_curr*dy_pre-dy_curr*dx_pre; + std::clog << "angle a: " << angle_a << "\n"; + std::clog << "angle b: " << angle_b << "\n"; + std::clog << "h: " << h << "\n"; + std::clog << "sin_curve: " << sin_curve << "\n"; + #endif + m_status = process; + break; + } + + // alternate sharp spike fix, but suboptimal... + + /* + sin_curve = dx_curr*dy_pre-dy_curr*dx_pre; + cos_curve = -dx_pre*dx_curr-dy_pre*dy_curr; + + #ifdef MAPNIK_DEBUG + std::clog << "sin_curve value: " << sin_curve << "\n"; + #endif + if(sin_curve > -0.3 && sin_curve < 0.3) { + angle_b = atan2((m_cur_y-m_next_y),(m_cur_x-m_next_x)); + h = tan((angle_b - angle_a)/2.0); + *x = m_cur_x + (dx_curr * offset_) - h * (dy_curr * offset_); + *y = m_cur_y + (dy_curr * offset_) + h * (dx_curr * offset_); + } else { + if (angle_b - angle_a > 0) + h = -1.0*(1.0+cos_curve)/sin_curve; + else + h = (1.0+cos_curve)/sin_curve; + *x = m_cur_x + (dx_curr + base_shift*dy_curr)*offset_; + *y = m_cur_y + (dy_curr - base_shift*dx_curr)*offset_; + } + */ + + m_pre_x = *x; + m_pre_x = *y; + m_cur_x = m_next_x; + m_cur_y = m_next_y; + angle_a = angle_b; + m_pre_cmd = m_cur_cmd; + m_cur_cmd = m_next_cmd; + m_status = process; + return m_pre_cmd; + } + } + } + } + + void rewind (unsigned pos) + { + geom_.rewind(pos); + m_status = initial; + } + +private: + Transform const& t_; + Geometry const& geom_; + proj_transform const& prj_trans_; + int offset_; + unsigned int threshold_; + status m_status; + double dx_pre; + double dy_pre; + double dx_curr; + double dy_curr; + double sin_curve; + double cos_curve; + double angle_a; + double angle_b; + double h; + unsigned m_pre_cmd; + double m_pre_x; + double m_pre_y; + unsigned m_cur_cmd; + double m_cur_x; + double m_cur_y; + unsigned m_next_cmd; + double m_next_x; + double m_next_y; +}; + + class CoordTransform { private: