/***************************************************************************** * * This file is part of Mapnik (c++ mapping toolkit) * * Copyright (C) 2013 Artem Pavlenko * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * *****************************************************************************/ // mapnik #include #include // boost namespace mapnik { double vertex_cache::angle(double width) { /* IMPORTANT NOTE: See note about coordinate systems in placement_finder::find_point_placement() * for imformation about why the y axis is inverted! */ double tmp = width + position_in_segment_; if ((tmp <= current_segment_->length) && (tmp >= 0)) { //Only calculate angle on request as it is expensive if (!angle_valid_) { angle_ = atan2(-(current_segment_->pos.y - segment_starting_point_.y), current_segment_->pos.x - segment_starting_point_.x); } return width >= 0 ? angle_ : angle_ + M_PI; } else { scoped_state s(*this); pixel_position const& old_pos = s.get_state().position(); move(width); double angle = atan2(-(current_position_.y - old_pos.y), current_position_.x - old_pos.x); return angle; } } bool vertex_cache::next_subpath() { if (!initialized_) { current_subpath_ = subpaths_.begin(); initialized_ = true; } else { current_subpath_++; } if (current_subpath_ == subpaths_.end()) return false; rewind_subpath(); //Initialize position values return true; } void vertex_cache::rewind_subpath() { current_segment_ = current_subpath_->vector.begin(); //All subpaths contain at least one segment (i.e. the starting point) segment_starting_point_ = current_position_ = current_segment_->pos; position_in_segment_ = 0; angle_valid_ = false; position_ = 0; } void vertex_cache::reset() { initialized_ = false; } bool vertex_cache::next_segment() { segment_starting_point_ = current_segment_->pos; //Next segments starts at the end of the current one if (current_segment_ == current_subpath_->vector.end()) return false; current_segment_++; angle_valid_ = false; if (current_segment_ == current_subpath_->vector.end()) return false; return true; } bool vertex_cache::previous_segment() { if (current_segment_ == current_subpath_->vector.begin()) return false; current_segment_--; angle_valid_ = false; if (current_segment_ == current_subpath_->vector.begin()) { //First segment is special segment_starting_point_ = current_segment_->pos; return true; } segment_starting_point_ = (current_segment_-1)->pos; return true; } vertex_cache & vertex_cache::get_offseted(double offset, double region_width) { if (fabs(offset) < 0.01) { return *this; } vertex_cache_ptr offseted_line; offseted_lines_map::iterator pos = offseted_lines_.find(offset); if (pos != offseted_lines_.end()) { offseted_line = pos->second; } else { offset_converter converter(*this); converter.set_offset(offset); offseted_line = vertex_cache_ptr(new vertex_cache(converter)); } offseted_line->reset(); offseted_line->next_subpath(); //TODO: Multiple subpath support // find the point on the offset line closest to the current position, // which we'll use to make the offset line aligned to this one. double seek = offseted_line->position_closest_to(current_position_); offseted_line->move(seek); offseted_lines_[offset] = offseted_line; return *offseted_line; } inline double dist_sq(pixel_position const &d) { return d.x*d.x + d.y*d.y; } double vertex_cache::position_closest_to(pixel_position const &target_pos) { bool first = true; pixel_position old_pos, new_pos; double lin_pos = 0.0, min_pos = 0.0, min_dist_sq = std::numeric_limits::max(); // find closest approach of each individual segment to the // target position. would be good if there were some kind // of prior, or fast test to avoid calculating on each // segment, but i can't think of one. for (segment const &seg : current_subpath_->vector) { if (first) { old_pos = seg.pos; min_pos = lin_pos; min_dist_sq = dist_sq(target_pos - old_pos); first = false; } else { new_pos = seg.pos; pixel_position d = new_pos - old_pos; if ((d.x != 0.0) || (d.y != 0)) { pixel_position c = target_pos - old_pos; double t = (c.x * d.x + c.y * d.y) / dist_sq(d); if ((t >= 0.0) && (t <= 1.0)) { pixel_position pt = (d * t) + old_pos; double pt_dist_sq = dist_sq(target_pos - pt); if (pt_dist_sq < min_dist_sq) { min_dist_sq = pt_dist_sq; min_pos = lin_pos + seg.length * t; } } } old_pos = new_pos; lin_pos += seg.length; double end_dist_sq = dist_sq(target_pos - old_pos); if (end_dist_sq < min_dist_sq) { min_dist_sq = end_dist_sq; min_pos = lin_pos; } } } return min_pos; } bool vertex_cache::forward(double length) { if (length < 0) { MAPNIK_LOG_ERROR(vertex_cache) << "vertex_cache::forward() called with negative argument!\n"; return false; } return move(length); } bool vertex_cache::backward(double length) { if (length < 0) { MAPNIK_LOG_ERROR(vertex_cache) << "vertex_cache::backward() called with negative argument!\n"; return false; } return move(-length); } bool vertex_cache::move(double length) { position_ += length; length += position_in_segment_; while (length >= current_segment_->length) { length -= current_segment_->length; if (!next_segment()) return false; //Skip all complete segments } while (length < 0) { if (!previous_segment()) return false; length += current_segment_->length; } double factor = length / current_segment_->length; position_in_segment_ = length; current_position_ = segment_starting_point_ + (current_segment_->pos - segment_starting_point_) * factor; return true; } void vertex_cache::rewind(unsigned) { vertex_subpath_ = subpaths_.begin(); vertex_segment_ = vertex_subpath_->vector.begin(); } unsigned vertex_cache::vertex(double *x, double *y) { if (vertex_segment_ == vertex_subpath_->vector.end()) { vertex_subpath_++; if (vertex_subpath_ == subpaths_.end()) return agg::path_cmd_stop; vertex_segment_ = vertex_subpath_->vector.begin(); } *x = vertex_segment_->pos.x; *y = vertex_segment_->pos.y; unsigned cmd = (vertex_segment_ == vertex_subpath_->vector.begin()) ? agg::path_cmd_move_to : agg::path_cmd_line_to; vertex_segment_++; return cmd; } vertex_cache::state vertex_cache::save_state() const { state s; s.current_segment = current_segment_; s.position_in_segment = position_in_segment_; s.current_position = current_position_; s.segment_starting_point = segment_starting_point_; s.position_ = position_; return s; } void vertex_cache::restore_state(state const& s) { current_segment_ = s.current_segment; position_in_segment_ = s.position_in_segment; current_position_ = s.current_position; segment_starting_point_ = s.segment_starting_point; position_ = s.position_; angle_valid_ = false; } } //ns mapnik