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Add line multi-labelling support to pal

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manisandro committed May 7, 2014
1 parent 0575c71 commit c3d7f0d0227a2151b9e30effb9d251b0cd4765a5
Showing with 77 additions and 4 deletions.
  1. +72 −3 src/core/pal/layer.cpp
  2. +1 −1 src/core/pal/layer.h
  3. +4 −0 src/core/pal/util.h
@@ -39,6 +39,7 @@
#include <iostream>
#include <cstring>
#include <cmath>
#include <vector>


#include <pal/pal.h>
@@ -228,7 +229,7 @@ namespace pal

bool Layer::registerFeature( const char *geom_id, PalGeometry *userGeom, double label_x, double label_y, const char* labelText,
double labelPosX, double labelPosY, bool fixedPos, double angle, bool fixedAngle,
int xQuadOffset, int yQuadOffset, double xOffset, double yOffset, bool alwaysShow )
int xQuadOffset, int yQuadOffset, double xOffset, double yOffset, bool alwaysShow, double repeatDistance )
{
if ( !geom_id || label_x < 0 || label_y < 0 )
return false;
@@ -284,6 +285,74 @@ namespace pal
throw InternalException::UnknownGeometry();
}

// if multiple labels are requested for lines, split the line in pieces of desired distance
if(repeatDistance > 0) {
int nSimpleGeometries = simpleGeometries->size();
for(int i = 0; i < nSimpleGeometries; ++i) {
const GEOSGeometry* geom = simpleGeometries->pop_front();
if(GEOSGeomTypeId(geom) == GEOS_LINESTRING) {

// get number of points
int n = GEOSGeomGetNumPoints(geom);

// Read points
std::vector<Point> points(n);
for(int i = 0; i < n; ++i) {
GEOSGeometry* p = GEOSGeomGetPointN(geom, i);
GEOSGeomGetX(p, &points[i].x);
GEOSGeomGetY(p, &points[i].y);
GEOSGeom_destroy(p);
}

// Cumulative length vector
std::vector<double> len(n, 0);
for(int i = 1; i < n; ++i) {
double dx = points[i].x - points[i - 1].x;
double dy = points[i].y - points[i - 1].y;
len[i] = len[i - 1] + std::sqrt(dx * dx + dy * dy);
}

// Walk along line
int cur = 0;
double lambda = 0;
std::vector<Point> part;
while(true) {
lambda += repeatDistance;
for(; cur < n && lambda > len[cur]; ++cur) {
part.push_back(points[cur]);
}
if(cur >= n) {
break;
}
double c = (lambda - len[cur - 1]) / (len[cur] - len[cur - 1]);
Point p;
p.x = points[cur - 1].x + c * (points[cur].x - points[cur - 1].x);
p.y = points[cur - 1].y + c * (points[cur].y - points[cur - 1].y);
part.push_back(p);
GEOSCoordSequence* cooSeq = GEOSCoordSeq_create(part.size(), 2);
for(std::size_t i = 0; i < part.size(); ++i) {
GEOSCoordSeq_setX(cooSeq, i, part[i].x);
GEOSCoordSeq_setY(cooSeq, i, part[i].y);
}

simpleGeometries->push_back(GEOSGeom_createLineString(cooSeq));
part.clear();
part.push_back(p);
}
// Create final part
part.push_back(points[n - 1]);
GEOSCoordSequence* cooSeq = GEOSCoordSeq_create(part.size(), 2);
for(std::size_t i = 0; i < part.size(); ++i) {
GEOSCoordSeq_setX(cooSeq, i, part[i].x);
GEOSCoordSeq_setY(cooSeq, i, part[i].y);
}
simpleGeometries->push_back(GEOSGeom_createLineString(cooSeq));
}else{
simpleGeometries->push_back( geom );
}
}
}

while ( simpleGeometries->size() > 0 )
{
const GEOSGeometry* geom = simpleGeometries->pop_front();
@@ -320,7 +389,7 @@ namespace pal
continue;
}

if ( mode == LabelPerFeature && ( type == GEOS_POLYGON || type == GEOS_LINESTRING ) )
if ( mode == LabelPerFeature && repeatDistance == 0.0 && ( type == GEOS_POLYGON || type == GEOS_LINESTRING ) )
{
if ( type == GEOS_LINESTRING )
GEOSLength( geom, &geom_size );
@@ -349,7 +418,7 @@ namespace pal
modMutex->unlock();

// if using only biggest parts...
if (( mode == LabelPerFeature || f->fixedPosition() ) && biggest_part != NULL )
if (( (mode == LabelPerFeature && repeatDistance == 0.0) || f->fixedPosition() ) && biggest_part != NULL )
{
addFeaturePart( biggest_part, labelText );
first_feat = false;
@@ -317,7 +317,7 @@ namespace pal
const char* labelText = NULL, double labelPosX = 0.0, double labelPosY = 0.0,
bool fixedPos = false, double angle = 0.0, bool fixedAngle = false,
int xQuadOffset = 0, int yQuadOffset = 0, double xOffset = 0.0, double yOffset = 0.0,
bool alwaysShow = false );
bool alwaysShow = false, double repeatDistance = 0.0 );

/** return pointer to feature or NULL if doesn't exist */
Feature* getFeature( const char* geom_id );
@@ -74,6 +74,10 @@ namespace pal
int new_label;
} ElemTrans;

struct Point {
double x, y;
};



#define EPSILON 1e-9

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