mapnik/src/placement_finder.cpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 Artem Pavlenko
 * Copyright (C) 2006 10East Corp.
 *
 * 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
 *
 *****************************************************************************/

//$Id$

//stl
#include <string>
#include <vector>

// boost
#include <boost/shared_ptr.hpp>
#include <boost/utility.hpp>
#include <boost/ptr_container/ptr_vector.hpp>
#include <boost/thread/mutex.hpp>

//mapnik
#include <mapnik/geometry.hpp>
#include <mapnik/placement_finder.hpp>
#include <mapnik/text_path.hpp>

namespace mapnik
{
    placement::placement(string_info *info_, CoordTransform *ctrans_, const proj_transform *proj_trans_, geometry_ptr geom_, std::pair<double, double> dimensions_)
        : info(info_), ctrans(ctrans_), proj_trans(proj_trans_), geom(geom_), label_placement(point_placement), dimensions(dimensions_), has_dimensions(true), shape_path(*ctrans_, *geom_, *proj_trans_), total_distance_(-1.0), wrap_width(0), text_ratio(0)
    {
    }
  
    //For text
    placement::placement(string_info *info_, CoordTransform *ctrans_, const proj_transform *proj_trans_, geometry_ptr geom_, label_placement_e placement_)
        : info(info_), ctrans(ctrans_), proj_trans(proj_trans_), geom(geom_), label_placement(placement_), has_dimensions(false), shape_path(*ctrans_, *geom_, *proj_trans_), total_distance_(-1.0), wrap_width(0), text_ratio(0)
    {
    }
  
    placement::~placement()
    {
    }

    std::pair<double, double> placement::get_position_at_distance(double target_distance)
    {
        double old_x, old_y, new_x, new_y;
        double x, y;
        x = y = 0.0;
    
        double distance = 0.0;
    
        shape_path.rewind(0);
        shape_path.vertex(&new_x,&new_y);
        for (unsigned i = 0; i < geom->num_points() - 1; i++)
        {
            double dx, dy;

            old_x = new_x;
            old_y = new_y;

            shape_path.vertex(&new_x,&new_y);
      
            dx = new_x - old_x;
            dy = new_y - old_y;
      
            double segment_length = sqrt(dx*dx + dy*dy);
      
            distance += segment_length;
            if (distance > target_distance)
            {
                x = new_x - dx*(distance - target_distance)/segment_length;
                y = new_y - dy*(distance - target_distance)/segment_length;

                break;
            }
        }
    
        return std::pair<double, double>(x, y);
    }
  
    double placement::get_total_distance()
    {
        if (total_distance_ < 0.0)
        {
            double old_x, old_y, new_x, new_y;
      
            shape_path.rewind(0);
     
            shape_path.vertex(&old_x,&old_y);

            total_distance_ = 0.0;
      
            for (unsigned i = 0; i < geom->num_points() - 1; i++)
            {
                double dx, dy;
          
                shape_path.vertex(&new_x,&new_y);
          
                dx = new_x - old_x;
                dy = new_y - old_y;
          
                total_distance_ += sqrt(dx*dx + dy*dy);
          
                old_x = new_x;
                old_y = new_y;
            }
        }
    
        return total_distance_;
    }
  
    void placement::clear_envelopes()
    {
        while (!envelopes.empty())
            envelopes.pop();
    }
  
  
  
    placement_finder::placement_finder(Envelope<double> e)
        : detector_(e)
    {
    }

    bool placement_finder::find_placement(placement *p)
    {
        if (p->label_placement == point_placement)
        {
            return find_placement_horizontal(p);
        }
        else if (p->label_placement == line_placement)
        {
            return find_placement_follow(p);
        }
    
        return false;
    }

    bool placement_finder::find_placement_follow(placement *p)
    {
        std::pair<double, double> string_dimensions = p->info->get_dimensions();
        double string_width = string_dimensions.first;
        //    double string_height = string_dimensions.second;
    
        double distance = p->get_total_distance();
    
        //~ double delta = string_width/distance;
        double delta = distance/100.0;
    
        for (double i = 0; i < (distance - string_width)/2.0; i += delta)
        {
            p->clear_envelopes();
      
            if ( build_path_follow(p, (distance - string_width)/2.0 + i) ) {
                update_detector(p);
                return true;
            }
      
            p->clear_envelopes();
      
            if ( build_path_follow(p, (distance - string_width)/2.0 - i) ) {
                update_detector(p);
                return true;
            }
        }
    
        p->starting_x = 0;
        p->starting_y = 0;
    
        return false;
    }
  
    bool placement_finder::find_placement_horizontal(placement *p)
    {
        double distance = p->get_total_distance();
        //~ double delta = string_width/distance;
        double delta = distance/100.0;
    
        for (double i = 0; i < distance/2.0; i += delta)
        {
            p->clear_envelopes();
      
            if ( build_path_horizontal(p, distance/2.0 + i) ) {
                update_detector(p);
                return true;
            }
      
            p->clear_envelopes();
      
            if ( build_path_horizontal(p, distance/2.0 - i) ) {
                update_detector(p);
                return true;
            }
        }
    
        p->starting_x = 0;
        p->starting_y = 0;
    
        return false;
    }
  
    void placement_finder::update_detector(placement *p)
    {
        while (!p->envelopes.empty())
        {
            Envelope<double> e = p->envelopes.front();

            detector_.insert(e);

            p->envelopes.pop();
        }
    }

    bool placement_finder::build_path_follow(placement *p, double target_distance)
    {
        double new_x, new_y, old_x, old_y;
        unsigned cur_node = 0;

        double angle = 0.0;
        int orientation = 0;
    
        p->path.clear();
    
        double x, y;
        x = y = 0.0;
    
        double distance = 0.0;

        std::pair<double, double> string_dimensions = p->info->get_dimensions();
        //    double string_width = string_dimensions.first;
        double string_height = string_dimensions.second;
    
        p->shape_path.rewind(0);
        p->shape_path.vertex(&new_x,&new_y);
        for (unsigned i = 0; i < p->geom->num_points() - 1; i++)
        {
            double dx, dy;

            cur_node++;
        
            old_x = new_x;
            old_y = new_y;

            p->shape_path.vertex(&new_x,&new_y);
        
            dx = new_x - old_x;
            dy = new_y - old_y;
        
            double segment_length = sqrt(dx*dx + dy*dy);
        
            distance += segment_length;
            if (distance > target_distance)
            {
                p->starting_x = new_x - dx*(distance - target_distance)/segment_length;
                p->starting_y = new_y - dy*(distance - target_distance)/segment_length;

                angle = atan2(-dy, dx);

                if (angle > M_PI/2 || angle <= -M_PI/2) {
                    orientation = -1;
                }
                else {
                    orientation = 1;
                }

                distance -= target_distance;
            
                break;
            }
        }

        for (unsigned i = 0; i < p->info->num_characters(); i++)
        {
            character_info ci;
            unsigned c;
      
            while (distance <= 0) {
                double dx, dy;

                cur_node++;
            
                if (cur_node >= p->geom->num_points()) {
                    break;
                }
            
                old_x = new_x;
                old_y = new_y;

                p->shape_path.vertex(&new_x,&new_y);

                dx = new_x - old_x;
                dy = new_y - old_y;

                angle = atan2(-dy, dx );
            
                distance += sqrt(dx*dx+dy*dy);
            }

            if (orientation == -1) {
                ci = p->info->at(p->info->num_characters() - i - 1);
            }
            else
            {
                ci = p->info->at(i);
            }
            c = ci.character;

            Envelope<double> e;
            if (p->has_dimensions)
            {
                e.init(x, y, x + p->dimensions.first, y + p->dimensions.second);
            }

            if (orientation == -1) {
                x = new_x - (distance - ci.width)*cos(angle);
                y = new_y + (distance - ci.width)*sin(angle);

                //Center the text on the line.
                x += (((double)string_height/2.0) - 1.0)*cos(angle+M_PI/2);
                y -= (((double)string_height/2.0) - 1.0)*sin(angle+M_PI/2);
          
                if (!p->has_dimensions)
                {
                    e.init(x, y, x + ci.width*cos(angle+M_PI), y - ci.width*sin(angle+M_PI));
                    e.expand_to_include(x - ci.height*sin(angle+M_PI), y - ci.height*cos(angle+M_PI));
                    e.expand_to_include(x + (ci.width*cos(angle+M_PI) - ci.height*sin(angle+M_PI)), y - (ci.width*sin(angle+M_PI) + ci.height*cos(angle+M_PI)));
                }
            }
            else
            {
                x = new_x - distance*cos(angle);
                y = new_y + distance*sin(angle);

                //Center the text on the line.
                x += (((double)string_height/2.0) - 1.0)*cos(angle-M_PI/2);
                y -= (((double)string_height/2.0) - 1.0)*sin(angle-M_PI/2);

                if (!p->has_dimensions)
                {
                    e.init(x, y, x + ci.width*cos(angle), y - ci.width*sin(angle));
                    e.expand_to_include(x - ci.height*sin(angle), y - ci.height*cos(angle));
                    e.expand_to_include(x + (ci.width*cos(angle) - ci.height*sin(angle)), y - (ci.width*sin(angle) + ci.height*cos(angle)));
                }
            }
        
            if (!detector_.has_placement(e))
            {
                return false;
            }
        
            p->envelopes.push(e);
        
            p->path.add_node(c, x - p->starting_x, -y + p->starting_y, (orientation == -1 ? angle + M_PI : angle));
        
            distance -= ci.width;
        }
    
        return true;
    }

    /*
   bool placement_finder::build_path_horizontal(placement *p, double target_distance)
  {
    double x, y;
  
    p->path.clear();
    
    std::pair<double, double> string_dimensions = p->info->get_dimensions();
    double string_width = string_dimensions.first;
    double string_height = string_dimensions.second;
    
    x = -string_width/2.0;
    y = -string_height/2.0 + 1.0;
    
    if (p->geom->type() == LineString)
    {
      std::pair<double, double> starting_pos = p->get_position_at_distance(target_distance);
      
      p->starting_x = starting_pos.first;
      p->starting_y = starting_pos.second;
    }
    else
    {
      p->geom->label_position(&p->starting_x, &p->starting_y);
      //  TODO: 
      //  We would only want label position in final 'paper' coords.
      //  Move view and proj transforms to e.g. label_position(x,y,proj_trans,ctrans)?
      double z=0;  
      p->proj_trans->backward(p->starting_x, p->starting_y, z);
      p->ctrans->forward(&p->starting_x, &p->starting_y);
    }
    
    for (unsigned i = 0; i < p->info->num_characters(); i++)
    {
        character_info ci;;
        ci = p->info->at(i);
        
        unsigned c = ci.character;
      
        p->path.add_node(c, x, y, 0.0);

        Envelope<double> e;
        if (p->has_dimensions)
        {
            e.init(p->starting_x - (p->dimensions.first/2.0), p->starting_y - (p->dimensions.second/2.0), p->starting_x + (p->dimensions.first/2.0), p->starting_y + (p->dimensions.second/2.0));
        }
        else
        {
          e.init(p->starting_x + x, p->starting_y - y, p->starting_x + x + ci.width, p->starting_y - y - ci.height);
        }
        
        if (!detector_.has_placement(e))
        {
          return false;
        }
        
        p->envelopes.push(e);
      
        x += ci.width;
    }
    return true;
  }
    */
    
    bool placement_finder::build_path_horizontal(placement *p, double target_distance)
    {
    
        p->path.clear();
    
        std::pair<double, double> string_dimensions = p->info->get_dimensions();
        double string_width = string_dimensions.first;
        double string_height = string_dimensions.second;
    
        // check if we need to wrap the string
        double wrap_at = string_width + 1;
        if (p->wrap_width && string_width > p->wrap_width)
        {
            if (p->text_ratio)
                for (int i = 1; ((wrap_at = string_width/i)/(string_height*i)) > p->text_ratio && (string_width/i) > p->wrap_width; ++i);
            else
                wrap_at = p->wrap_width;
            //std::clog << "Wrapping string at" << wrap_at << std::endl;
        }

        // work out where our line breaks need to be
        std::vector<int> line_breaks;
        std::vector<double> line_widths;
        if (wrap_at < string_width && p->info->num_characters() > 0)
        {
            int line_count=0; 
            int last_space = 0;
            string_width = 0;
            string_height = 0;
            double line_width = 0;
            double line_height = 0;
            double word_width = 0;
            double word_height = 0;
            for (unsigned int ii = 0; ii < p->info->num_characters(); ii++)
            {
                character_info ci;
                ci = p->info->at(ii);
            
                unsigned c = ci.character;
                word_width += ci.width;
                word_height = word_height > ci.height ? word_height : ci.height;
                ++line_count;
    
                if (c == ' ')
                {
                    last_space = ii;
                    line_width += word_width;
                    line_height = line_height > word_height ? line_height : word_height;
                    word_width = 0;
                    word_height = 0;
                }
                if (line_width > 0 && line_width > wrap_at)
                {
                    string_width = string_width > line_width ? string_width : line_width;
                    string_height += line_height;
                    line_breaks.push_back(last_space);
                    line_widths.push_back(line_width);
                    ii = last_space;
                    line_count = 0;
                    line_width = 0;
                    line_height = 0;
                    word_width = 0;
                    word_height = 0;
                }
            }
            line_width += word_width;
            string_width = string_width > line_width ? string_width : line_width;
            line_breaks.push_back(p->info->num_characters() + 1);
            line_widths.push_back(line_width);
        }
        if (line_breaks.size() == 0)
        {
            line_breaks.push_back(p->info->num_characters() + 1);
            line_widths.push_back(string_width);
        }

        p->info->set_dimensions(string_width, string_height);
    
        if (p->geom->type() == LineString)
        {
            std::pair<double, double> starting_pos = p->get_position_at_distance(target_distance);
      
            p->starting_x = starting_pos.first;
            p->starting_y = starting_pos.second;
        }
        else
        {
            p->geom->label_position(&p->starting_x, &p->starting_y);
            //  TODO: 
            //  We would only want label position in final 'paper' coords.
            //  Move view and proj transforms to e.g. label_position(x,y,proj_trans,ctrans)?
            double z=0;  
            p->proj_trans->backward(p->starting_x, p->starting_y, z);
            p->ctrans->forward(&p->starting_x, &p->starting_y);
        }
    
        double line_height = 0;
        unsigned int line_number = 0;
        unsigned int index_to_wrap_at = line_breaks[line_number];
        double line_width = line_widths[line_number];

        double x = -line_width/2.0;
        double y = -string_height/2.0 + 1.0;
    
        for (unsigned i = 0; i < p->info->num_characters(); i++)
        {
            character_info ci;
            ci = p->info->at(i);
        
            unsigned c = ci.character;
      
            if (i == index_to_wrap_at)
            {
                index_to_wrap_at = line_breaks[++line_number];
                line_width = line_widths[line_number];
                y -= line_height;
                x = -line_width/2.0;
                line_height = 0;
                continue;
            }
            else
            {
                p->path.add_node(c, x, y, 0.0);

                Envelope<double> e;
                if (p->has_dimensions)
                {
                    e.init(p->starting_x - (p->dimensions.first/2.0), 
                           p->starting_y - (p->dimensions.second/2.0), 
                           p->starting_x + (p->dimensions.first/2.0), 
                           p->starting_y + (p->dimensions.second/2.0));
                }
                else
                {
                    e.init(p->starting_x + x, 
                           p->starting_y - y, 
                           p->starting_x + x + ci.width, 
                           p->starting_y - y - ci.height);
                }
            
                if (!detector_.has_placement(e))
                {
                    return false;
                }
            
                p->envelopes.push(e);
            }
            x += ci.width;
            line_height = line_height > ci.height ? line_height : ci.height;
        }
        return true;
    }
}