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mapnik/src/placement_finder.cpp
artemp 1e6be7abc3 + add accessor methods
2012-07-13 10:25:12 +01:00

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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2011 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 <mapnik/placement_finder.hpp>
#include <mapnik/geometry.hpp>
#include <mapnik/text_path.hpp>
#include <mapnik/fastmath.hpp>
#include <mapnik/text_placements/base.hpp>
// agg
#include "agg_path_length.h"
// boost
#include <boost/shared_ptr.hpp>
#include <boost/utility.hpp>
#include <boost/ptr_container/ptr_vector.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/foreach.hpp>
//stl
#include <string>
#include <vector>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
namespace mapnik
{
template<typename T>
std::pair<double, double> get_position_at_distance(double target_distance, T & shape_path)
{
double x1 = 0.0;
double y1 = 0.0;
double x2 = 0.0;
double y2 = 0.0;
double distance = 0.0;
bool first = true;
unsigned cmd;
double x = 0.0;
double y = 0.0;
shape_path.rewind(0);
while (!agg::is_stop(cmd = shape_path.vertex(&x2,&y2)))
{
if (first || agg::is_move_to(cmd))
{
first = false;
}
else
{
double dx = x2-x1;
double dy = y2-y1;
double segment_length = std::sqrt(dx*dx + dy*dy);
distance +=segment_length;
if (distance > target_distance)
{
x = x2 - dx * (distance - target_distance)/segment_length;
y = y2 - dy * (distance - target_distance)/segment_length;
break;
}
}
x1 = x2;
y1 = y2;
}
return std::pair<double, double>(x, y);
}
template<typename T>
double get_total_distance(T & shape_path)
{
return agg::path_length(shape_path);
}
template <typename DetectorT>
placement_finder<DetectorT>::placement_finder(Feature const& feature,
text_placement_info const& placement_info,
string_info const& info,
DetectorT & detector,
box2d<double> const& extent)
: detector_(detector),
dimensions_(extent),
info_(info),
p(placement_info.properties),
pi(placement_info),
string_width_(0),
string_height_(0),
first_line_space_(0),
valign_(V_AUTO),
halign_(H_AUTO),
line_breaks_(),
line_sizes_(),
collect_extents_(false)
{
init_string_size();
init_alignment();
}
template <typename DetectorT>
template <typename T>
void placement_finder<DetectorT>::find_point_placements(T & shape_path)
{
unsigned cmd;
double new_x = 0.0;
double new_y = 0.0;
double old_x = 0.0;
double old_y = 0.0;
bool first = true;
double total_distance = get_total_distance<T>(shape_path);
shape_path.rewind(0);
if (distance == 0) //Point data, not a line
{
double x, y;
shape_path.vertex(&x,&y);
find_point_placement(x, y);
return;
}
int num_labels = 1;
if (p.label_spacing > 0)
num_labels = static_cast<int> (floor(total_distance / pi.get_actual_label_spacing()));
if (p.force_odd_labels && num_labels % 2 == 0)
num_labels--;
if (num_labels <= 0)
num_labels = 1;
double distance = 0.0; // distance from last label
double spacing = total_distance / num_labels;
double target_distance = spacing / 2; // first label should be placed at half the spacing
while (!agg::is_stop(cmd = shape_path.vertex(&new_x,&new_y))) //For each node in the shape
{
if (first || agg::is_move_to(cmd)) //Don't do any processing if it is the first node
{
first = false;
}
else
{
//Add the length of this segment to the total we have saved up
double segment_length = std::sqrt(std::pow(old_x-new_x,2) + std::pow(old_y-new_y,2)); //Pythagoras
distance += segment_length;
//While we have enough distance to place text in
while (distance > target_distance)
{
//Try place at the specified place
double new_weight = (segment_length - (distance - target_distance))/segment_length;
find_point_placement(old_x + (new_x-old_x)*new_weight, old_y + (new_y-old_y)*new_weight);
distance -= target_distance; //Consume the spacing gap we have used up
target_distance = spacing; //Need to reset the target_distance as it is spacing/2 for the first label.
}
}
old_x = new_x;
old_y = new_y;
}
}
template <typename DetectorT>
void placement_finder<DetectorT>::init_string_size()
{
// Get total string size
if (!info_.num_characters()) return; //At least one character is required
for (unsigned i = 0; i < info_.num_characters(); i++)
{
char_info const& ci = info_.at(i);
if (!ci.width || !ci.line_height) continue; //Skip empty chars (add no character_spacing for them)
string_width_ += ci.width + ci.format->character_spacing;
string_height_ = std::max(string_height_, ci.line_height+ci.format->line_spacing);
first_line_space_ = std::max(first_line_space_, ci.line_height-ci.avg_height);
}
string_width_ -= info_.at(info_.num_characters()-1).format->character_spacing; //Remove last space
string_height_ -= first_line_space_; //First line is a bit smaller
}
template <typename DetectorT>
void placement_finder<DetectorT>::find_line_breaks()
{
if (!line_sizes_.empty()) return;
bool first_line = true;
// check if we need to wrap the string
double wrap_at = string_width_ + 1.0;
if (p.wrap_width && string_width_ > p.wrap_width)
{
if (p.text_ratio)
{
for (double i = 1.0; ((wrap_at = string_width_/i)/(string_height_*i)) > p.text_ratio && (string_width_/i) > p.wrap_width; i += 1.0) ;
}
else
{
wrap_at = p.wrap_width;
}
}
// work out where our line breaks need to be and the resultant width to the 'wrapped' string
if ((wrap_at < string_width_) || info_.has_line_breaks())
{
first_line_space_ = 0.0;
int last_wrap_char_pos = 0; //Position of last char where wrapping is possible
double last_char_spacing = 0.0;
double last_wrap_char_width = 0.0; //Include char_spacing before and after
string_width_ = 0.0;
string_height_ = 0.0;
double line_width = 0.0;
double line_height = 0.0; //Height of tallest char in line
double word_width = 0.0; //Current unfinished word width
double word_height = 0.0;
//line_width and word_width include char width + spacing, but not the spacing after the last char
for (unsigned int ii = 0; ii < info_.num_characters(); ii++)
{
char_info const& ci = info_.at(ii);
unsigned c = ci.c;
if ((c == ci.format->wrap_char) || (c == '\n'))
{
last_wrap_char_pos = ii;
//No wrap at previous position
line_width += word_width + last_wrap_char_width;
line_height = std::max(line_height, word_height);
last_wrap_char_width = last_char_spacing + ci.width + ci.format->character_spacing;
last_char_spacing = 0.0; //Current one is included in last_wrap_char_width
word_width = 0.0;
word_height = 0.0;
} else {
//No wrap char
word_width += last_char_spacing + ci.width;
last_char_spacing = ci.format->character_spacing;
word_height = std::max(word_height, ci.line_height + ci.format->line_spacing);
//TODO: I think this calculation could be wrong if height changes for the first word in the second line
if (first_line) first_line_space_ = std::max(first_line_space_, ci.line_height-ci.avg_height);
}
// wrap text at first wrap_char after (default) the wrap width or immediately before the current word
if ((c == '\n') ||
(line_width > 0 &&
((line_width > wrap_at && !ci.format->wrap_before) ||
((line_width + last_wrap_char_width + word_width) > wrap_at && ci.format->wrap_before)) )
)
{
add_line(line_width, line_height, first_line);
line_breaks_.push_back(last_wrap_char_pos);
line_width = 0.0;
line_height = 0.0;
last_wrap_char_width = 0; //Wrap char supressed
first_line = false;
}
}
line_width += last_wrap_char_width + word_width;
line_height = std::max(line_height, word_height);
add_line(line_width, line_height, first_line);
} else {
//No linebreaks
line_sizes_.push_back(std::make_pair(string_width_, string_height_));
}
line_breaks_.push_back(info_.num_characters());
}
template <typename DetectorT>
void placement_finder<DetectorT>::add_line(double width, double height, bool first_line)
{
if (first_line) height -= first_line_space_;
string_width_ = std::max(string_width_, width); //Total width is the longest line
string_height_ += height;
line_sizes_.push_back(std::make_pair(width, height));
}
template <typename DetectorT>
void placement_finder<DetectorT>::init_alignment()
{
valign_ = p.valign;
if (valign_ == V_AUTO)
{
if (p.displacement.second > 0.0)
{
valign_ = V_BOTTOM;
} else if (p.displacement.second < 0.0)
{
valign_ = V_TOP;
} else
{
valign_ = V_MIDDLE;
}
}
halign_ = p.halign;
if (halign_ == H_AUTO)
{
if (p.displacement.first > 0.0)
{
halign_ = H_RIGHT;
} else if (p.displacement.first < 0.0)
{
halign_ = H_LEFT;
} else
{
halign_ = H_MIDDLE;
}
}
jalign_ = p.jalign;
if (jalign_ == J_AUTO)
{
if (p.displacement.first > 0.0)
{
jalign_ = J_LEFT;
} else if (p.displacement.first < 0.0)
{
jalign_ = J_RIGHT;
} else {
jalign_ = J_MIDDLE;
}
}
}
template <typename DetectorT>
void placement_finder<DetectorT>::adjust_position(text_path *current_placement)
{
// if needed, adjust for desired vertical alignment
if (valign_ == V_TOP)
{
current_placement->center.y -= 0.5 * string_height_; // move center up by 1/2 the total height
} else if (valign_ == V_BOTTOM)
{
current_placement->center.y += 0.5 * string_height_; // move center down by the 1/2 the total height
}
// set horizontal position to middle of text
if (halign_ == H_LEFT)
{
current_placement->center.x -= 0.5 * string_width_; // move center left by 1/2 the string width
} else if (halign_ == H_RIGHT)
{
current_placement->center.x += 0.5 * string_width_; // move center right by 1/2 the string width
}
// adjust text envelope position by user's x-y displacement (dx, dy)
current_placement->center.x += pi.get_scale_factor() * p.displacement.first;
current_placement->center.y += pi.get_scale_factor() * p.displacement.second;
}
template <typename DetectorT>
void placement_finder<DetectorT>::find_point_placement(double label_x,
double label_y,
double angle)
{
find_line_breaks();
double rad = M_PI * angle/180.0;
double cosa = std::cos(rad);
double sina = std::sin(rad);
double x, y;
std::auto_ptr<text_path> current_placement(new text_path(label_x, label_y));
adjust_position(current_placement.get());
// presets for first line
unsigned int line_number = 0;
unsigned int index_to_wrap_at = line_breaks_[0];
double line_width = line_sizes_[0].first;
double line_height = line_sizes_[0].second;
/* IMPORTANT NOTE:
x and y are relative to the center of the text
coordinate system:
x: grows from left to right
y: grows from bottom to top (opposite of normal computer graphics)
*/
// set for upper left corner of text envelope for the first line, bottom left of first character
y = string_height_ / 2.0 - line_height;
// RTL text is converted to a mirrored representation in get_string_info()
// so we have to fix line break order here
if (info_.get_rtl()) y = -y;
// adjust for desired justification
if (jalign_ == J_LEFT)
x = -(string_width_ / 2.0);
else if (jalign_ == J_RIGHT)
x = (string_width_ / 2.0) - line_width;
else /* J_MIDDLE */
x = -(line_width / 2.0);
// save each character rendering position and build envelope as go thru loop
std::queue< box2d<double> > c_envelopes;
for (unsigned i = 0; i < info_.num_characters(); i++)
{
char_info const& ci = info_.at(i);
double cwidth = ci.width + ci.format->character_spacing;
if (i == index_to_wrap_at)
{
index_to_wrap_at = line_breaks_[++line_number];
line_width = line_sizes_[line_number].first;
line_height= line_sizes_[line_number].second;
if (info_.get_rtl())
{
y += line_height;
} else
{
y -= line_height; // move position down to line start
}
// reset to begining of line position
if (jalign_ == J_LEFT)
x = -(string_width_ / 2.0);
else if (jalign_ == J_RIGHT)
x = (string_width_ / 2.0) - line_width;
else
x = -(line_width / 2.0);
continue;
}
else
{
// place the character relative to the center of the string envelope
double dx = x * cosa - y*sina;
double dy = x * sina + y*cosa;
current_placement->add_node(&ci, dx, dy, rad);
// compute the Bounding Box for each character and test for:
// overlap, minimum distance or edge avoidance - exit if condition occurs
box2d<double> e;
/*x axis: left to right, y axis: top to bottom (negative values higher)*/
e.init(current_placement->center.x + dx, // Bottom Left
current_placement->center.y - dy - ci.ymin, // ymin usually <0
current_placement->center.x + dx + ci.width, // Top Right
current_placement->center.y - dy - ci.ymax);
// if there is an overlap with existing envelopes, then exit - no placement
if (!detector_.extent().intersects(e) ||
(!p.allow_overlap &&
!detector_.has_point_placement(e, pi.get_actual_minimum_distance())))
{
return;
}
// if avoid_edges test dimensions contains e
if (p.avoid_edges && !dimensions_.contains(e))
{
return;
}
if (p.minimum_padding > 0)
{
double min_pad = pi.get_actual_minimum_padding();
box2d<double> epad(e.minx()-min_pad,
e.miny()-min_pad,
e.maxx()+min_pad,
e.maxy()+min_pad);
if (!dimensions_.contains(epad))
{
return;
}
}
c_envelopes.push(e); // add character's envelope to temp storage
}
x += cwidth; // move position to next character
}
// check the placement of any additional envelopes
if (!p.allow_overlap && !additional_boxes_.empty())
{
BOOST_FOREACH(box2d<double> const& box, additional_boxes_)
{
box2d<double> pt(box.minx() + current_placement->center.x,
box.miny() + current_placement->center.y,
box.maxx() + current_placement->center.x,
box.maxy() + current_placement->center.y);
// abort the whole placement if the additional envelopes can't be placed.
if (!detector_.has_point_placement(pt, p.minimum_distance)) return;
c_envelopes.push(pt);
}
}
// since there was no early exit, add the character envelopes to the placements' envelopes
while (!c_envelopes.empty())
{
envelopes_.push(c_envelopes.front());
c_envelopes.pop();
}
placements_.push_back(current_placement.release());
}
template <typename DetectorT>
template <typename PathT>
void placement_finder<DetectorT>::find_line_placements(PathT & shape_path)
{
#ifdef MAPNIK_LOG
if (! line_sizes_.empty())
{
MAPNIK_LOG_WARN(placement_finder) << "Internal error. Text contains line breaks, but line placement is used. Please file a bug report!";
}
#endif
unsigned cmd;
double new_x = 0.0;
double new_y = 0.0;
double old_x = 0.0;
double old_y = 0.0;
bool first = true;
//Pre-Cache all the path_positions and path_distances
//This stops the PathT from having to do multiple re-projections if we need to reposition ourself
// and lets us know how many points are in the shape.
std::vector<vertex2d> path_positions;
std::vector<double> path_distances; // distance from node x-1 to node x
double total_distance = 0;
shape_path.rewind(0);
while (!agg::is_stop(cmd = shape_path.vertex(&new_x,&new_y))) //For each node in the shape
{
if (!first && agg::is_line_to(cmd))
{
double dx = old_x - new_x;
double dy = old_y - new_y;
double distance = std::sqrt(dx*dx + dy*dy);
total_distance += distance;
path_distances.push_back(distance);
}
else
{
path_distances.push_back(0);
}
first = false;
path_positions.push_back(vertex2d(new_x, new_y, cmd));
old_x = new_x;
old_y = new_y;
}
//Now path_positions is full and total_distance is correct
//shape_path shouldn't be used from here
// Ensure lines have a minimum length.
if (total_distance < p.minimum_path_length)
return;
double distance = 0.0;
double displacement = p.displacement.second; // displace by dy
//Calculate a target_distance that will place the labels centered evenly rather than offset from the start of the linestring
if (total_distance < string_width_) //Can't place any strings
return;
//If there is no spacing then just do one label, otherwise calculate how many there should be
int num_labels = 1;
if (p.label_spacing > 0)
num_labels = static_cast<int>(floor(total_distance / (pi.get_actual_label_spacing() + string_width_)));
if (p.force_odd_labels && (num_labels % 2 == 0))
num_labels--;
if (num_labels <= 0)
num_labels = 1;
//Now we know how many labels we are going to place, calculate the spacing so that they will get placed evenly
double spacing = total_distance / num_labels;
double target_distance = (spacing - string_width_) / 2; // first label should be placed at half the spacing
//Calculate or read out the tolerance
double tolerance_delta, tolerance;
if (p.label_position_tolerance > 0)
{
tolerance = p.label_position_tolerance;
tolerance_delta = std::max ( 1.0, p.label_position_tolerance/100.0 );
}
else
{
tolerance = spacing/2.0;
tolerance_delta = std::max ( 1.0, spacing/100.0 );
}
first = true;
for (unsigned index = 0; index < path_positions.size(); index++) //For each node in the shape
{
cmd = path_positions[index].cmd;
new_x = path_positions[index].x;
new_y = path_positions[index].y;
if (first || agg::is_move_to(cmd)) //Don't do any processing if it is the first node
{
first = false;
}
else
{
//Add the length of this segment to the total we have saved up
double segment_length = path_distances[index];
distance += segment_length;
//While we have enough distance to place text in
while (distance > target_distance)
{
for (double diff = 0; diff < tolerance; diff += tolerance_delta)
{
for(int dir = -1; dir < 2; dir+=2) //-1, +1
{
//Record details for the start of the string placement
int orientation = 0;
std::auto_ptr<text_path> current_placement = get_placement_offset(path_positions, path_distances, orientation, index, segment_length - (distance - target_distance) + (diff*dir));
//We were unable to place here
if (current_placement.get() == NULL)
continue;
//Apply displacement
//NOTE: The text is centered on the line in get_placement_offset, so we are offsetting from there
if (displacement != 0)
{
//Average the angle of all characters and then offset them all by that angle
double anglesum = 0;
for (unsigned i = 0; i < current_placement->nodes_.size(); i++)
{
double angle = current_placement->nodes_[i].angle;
//Normalize angle in range -PI ... PI
while (angle > M_PI) {
angle -= 2*M_PI;
}
anglesum += angle;
}
anglesum /= current_placement->nodes_.size(); //Now it is angle average
double cosa = orientation * cos(anglesum);
double sina = orientation * sin(anglesum);
//Offset all the characters by this angle
for (unsigned i = 0; i < current_placement->nodes_.size(); i++)
{
current_placement->nodes_[i].pos.x -=
pi.get_scale_factor() * displacement * sina;
current_placement->nodes_[i].pos.y +=
pi.get_scale_factor() * displacement * cosa;
}
}
bool status = test_placement(current_placement, orientation);
if (status) //We have successfully placed one
{
placements_.push_back(current_placement.release());
update_detector();
//Totally break out of the loops
diff = tolerance;
break;
}
else
{
//If we've failed to place, remove all the envelopes we've added up
while (!envelopes_.empty())
envelopes_.pop();
}
//Don't need to loop twice when diff = 0
if (diff == 0)
break;
}
}
distance -= target_distance; //Consume the spacing gap we have used up
target_distance = spacing; //Need to reset the target_distance as it is spacing/2 for the first label.
}
}
old_x = new_x;
old_y = new_y;
}
}
template <typename DetectorT>
std::auto_ptr<text_path> placement_finder<DetectorT>::get_placement_offset(std::vector<vertex2d> const& path_positions,
std::vector<double> const& path_distances,
int & orientation,
unsigned index,
double distance)
{
//Check that the given distance is on the given index and find the correct index and distance if not
while (distance < 0 && index > 1)
{
index--;
distance += path_distances[index];
}
if (index <= 1 && distance < 0) //We've gone off the start, fail out
return std::auto_ptr<text_path>(NULL);
//Same thing, checking if we go off the end
while (index < path_distances.size() && distance > path_distances[index])
{
distance -= path_distances[index];
index++;
}
if (index >= path_distances.size())
return std::auto_ptr<text_path>(NULL);
//Keep track of the initial index,distance incase we need to re-call get_placement_offset
const unsigned initial_index = index;
const double initial_distance = distance;
double old_x = path_positions[index-1].x;
double old_y = path_positions[index-1].y;
double new_x = path_positions[index].x;
double new_y = path_positions[index].y;
double dx = new_x - old_x;
double dy = new_y - old_y;
double segment_length = path_distances[index];
if (segment_length == 0) {
// Not allowed to place across on 0 length segments or discontinuities
return std::auto_ptr<text_path>(NULL);
}
std::auto_ptr<text_path> current_placement(
new text_path((old_x + dx*distance/segment_length),
(old_y + dy*distance/segment_length)
)
);
double angle = atan2(-dy, dx);
bool orientation_forced = (orientation != 0); // Whether the orientation was set by the caller
if (!orientation_forced)
orientation = (angle > 0.55*M_PI || angle < -0.45*M_PI) ? -1 : 1;
unsigned upside_down_char_count = 0; //Count of characters that are placed upside down.
for (unsigned i = 0; i < info_.num_characters(); ++i)
{
// grab the next character according to the orientation
char_info const &ci = orientation > 0 ? info_.at(i) : info_.at(info_.num_characters() - i - 1);
double cwidth = ci.width + ci.format->character_spacing;
double last_character_angle = angle;
//Coordinates this character will start at
if (segment_length == 0) {
// Not allowed to place across on 0 length segments or discontinuities
return std::auto_ptr<text_path>(NULL);
}
double start_x = old_x + dx*distance/segment_length;
double start_y = old_y + dy*distance/segment_length;
//Coordinates this character ends at, calculated below
double end_x = 0;
double end_y = 0;
if (segment_length - distance >= cwidth)
{
//if the distance remaining in this segment is enough, we just go further along the segment
distance += cwidth;
end_x = old_x + dx*distance/segment_length;
end_y = old_y + dy*distance/segment_length;
}
else
{
//If there isn't enough distance left on this segment
// then we need to search until we find the line segment that ends further than ci.width away
do
{
old_x = new_x;
old_y = new_y;
index++;
if (index >= path_positions.size()) //Bail out if we run off the end of the shape
{
//MAPNIK_LOG_ERROR(placement_finder) << "FAIL: Out of space";
return std::auto_ptr<text_path>(NULL);
}
new_x = path_positions[index].x;
new_y = path_positions[index].y;
dx = new_x - old_x;
dy = new_y - old_y;
segment_length = path_distances[index];
}
while (std::sqrt(std::pow(start_x - new_x, 2) + std::pow(start_y - new_y, 2)) < cwidth); //Distance from start_ to new_
//Calculate the position to place the end of the character on
find_line_circle_intersection(
start_x, start_y, cwidth,
old_x, old_y, new_x, new_y,
end_x, end_y); //results are stored in end_x, end_y
//Need to calculate distance on the new segment
distance = std::sqrt(std::pow(old_x - end_x, 2) + std::pow(old_y - end_y, 2));
}
//Calculate angle from the start of the character to the end based on start_/end_ position
angle = fast_atan2(start_y-end_y, end_x-start_x);
//Test last_character_angle vs angle
// since our rendering angle has changed then check against our
// max allowable angle change.
double angle_delta = last_character_angle - angle;
// normalise between -180 and 180
while (angle_delta > M_PI)
angle_delta -= 2*M_PI;
while (angle_delta < -M_PI)
angle_delta += 2*M_PI;
if (p.max_char_angle_delta > 0 &&
fabs(angle_delta) > p.max_char_angle_delta)
{
//MAPNIK_LOG_ERROR(placement_finder) << "FAIL: Too Bendy!";
return std::auto_ptr<text_path>(NULL);
}
double render_angle = angle;
double cosa = fast_cos(angle);
double sina = fast_sin(angle);
double render_x = start_x;
double render_y = start_y;
//Center the text on the line
double char_height = ci.avg_height;
render_x += char_height/2.0*sina;
render_y += char_height/2.0*cosa;
if (orientation < 0)
{
// rotate in place
render_x += cwidth*cosa - char_height*sina;
render_y -= cwidth*sina + char_height*cosa;
render_angle += M_PI;
}
current_placement->add_node(&ci,
render_x - current_placement->center.x,
-render_y + current_placement->center.y,
render_angle);
//Normalise to 0 <= angle < 2PI
while (render_angle >= 2*M_PI)
render_angle -= 2*M_PI;
while (render_angle < 0)
render_angle += 2*M_PI;
if (render_angle > M_PI/2 && render_angle < 1.5*M_PI)
upside_down_char_count++;
}
//If we placed too many characters upside down
if (upside_down_char_count >= info_.num_characters()/2.0)
{
//if we auto-detected the orientation then retry with the opposite orientation
if (!orientation_forced)
{
orientation = -orientation;
current_placement = get_placement_offset(path_positions,
path_distances,
orientation,
initial_index,
initial_distance);
}
else
{
//Otherwise we have failed to find a placement
//MAPNIK_LOG_ERROR(placement_finder) << "FAIL: Double upside-down!";
return std::auto_ptr<text_path>(NULL);
}
}
return current_placement;
}
template <typename DetectorT>
bool placement_finder<DetectorT>::test_placement(std::auto_ptr<text_path> const& current_placement,
int orientation)
{
//Create and test envelopes
bool status = true;
for (unsigned i = 0; i < info_.num_characters(); ++i)
{
//TODO: I think this can be simplified by taking the char_info from vertex() but this needs to be carefully tested!
// grab the next character according to the orientation
char_info const& ci = orientation > 0 ? info_.at(i) : info_.at(info_.num_characters() - i - 1);
double cwidth = ci.width + ci.format->character_spacing;
char_info_ptr c;
double x, y, angle;
current_placement->vertex(&c, &x, &y, &angle);
x = current_placement->center.x + x;
y = current_placement->center.y - y;
double sina = fast_sin(angle);
double cosa = fast_cos(angle);
if (orientation < 0)
{
// rotate in place
x += cwidth * cosa - string_height_ * sina;
y -= cwidth * sina + string_height_ * cosa;
angle += M_PI;
//sin(x+PI) = -sin(x)
sina = -sina;
cosa = -cosa;
}
box2d<double> e(x, y, x + cwidth*cosa, y - cwidth*sina);
// put four corners of the letter into envelope
e.expand_to_include(x - ci.height()*sina,
y - ci.height()*cosa);
e.expand_to_include(x + (cwidth*cosa - ci.height()*sina),
y - (cwidth*sina + ci.height()*cosa));
if (!detector_.extent().intersects(e) ||
(!p.allow_overlap &&
!detector_.has_placement(e, info_.get_string(), pi.get_actual_minimum_distance())
)
)
{
//MAPNIK_LOG_ERROR(placement_finder) << "No Intersects:" << !dimensions_.intersects(e) << ": " << e << " @ " << dimensions_;
//MAPNIK_LOG_ERROR(placement_finder) << "No Placements:" << !detector_.has_placement(e, info.get_string(), p.minimum_distance);
status = false;
break;
}
if (p.avoid_edges && !dimensions_.contains(e))
{
//MAPNIK_LOG_ERROR(placement_finder) << "Fail avoid edges";
status = false;
break;
}
if (p.minimum_padding > 0)
{
double min_pad = pi.get_actual_minimum_padding();
box2d<double> epad(e.minx()-min_pad,
e.miny()-min_pad,
e.maxx()+min_pad,
e.maxy()+min_pad);
if (!dimensions_.contains(epad))
{
status = false;
break;
}
}
envelopes_.push(e);
}
current_placement->rewind();
return status;
}
template <typename DetectorT>
void placement_finder<DetectorT>::find_line_circle_intersection(
double cx, double cy, double radius,
double x1, double y1, double x2, double y2,
double & ix, double & iy)
{
double dx = x2 - x1;
double dy = y2 - y1;
double A = dx * dx + dy * dy;
double B = 2 * (dx * (x1 - cx) + dy * (y1 - cy));
double C = (x1 - cx) * (x1 - cx) + (y1 - cy) * (y1 - cy) - radius * radius;
double det = B * B - 4 * A * C;
if (A <= 0.0000001 || det < 0)
{
//Should never happen
//' No real solutions.
return;
}
else if (det == 0)
{
//Could potentially happen....
//One solution.
double t = -B / (2 * A);
ix = x1 + t * dx;
iy = y1 + t * dy;
return;
}
else
{
//Two solutions.
//Always use the 1st one
//We only really have one solution here, as we know the line segment will start in the circle and end outside
double t = (-B + std::sqrt(det)) / (2 * A);
ix = x1 + t * dx;
iy = y1 + t * dy;
//t = (-B - std::sqrt(det)) / (2 * A);
//ix = x1 + t * dx;
//iy = y1 + t * dy;
return;
}
}
template <typename DetectorT>
void placement_finder<DetectorT>::update_detector()
{
if (collect_extents_) extents_.init(0,0,0,0);
// add the bboxes to the detector and remove from the placement
while (!envelopes_.empty())
{
box2d<double> e = envelopes_.front();
detector_.insert(e, info_.get_string());
envelopes_.pop();
if (collect_extents_)
{
extents_.expand_to_include(e);
}
}
}
template <typename DetectorT>
void placement_finder<DetectorT>::clear_placements()
{
placements_.clear();
while (!envelopes_.empty()) envelopes_.pop();
}
template class placement_finder<DetectorType>;
template void placement_finder<DetectorType>::find_point_placements<ClippedPathType>(ClippedPathType &);
template void placement_finder<DetectorType>::find_line_placements<ClippedPathType>(ClippedPathType &);
template void placement_finder<DetectorType>::find_point_placements<PathType>(PathType &);
template void placement_finder<DetectorType>::find_line_placements<PathType>(PathType &);
} // namespace
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