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render a debug image of a vector tile
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Dane Springmeyer committed Dec 7, 2013
1 parent 3d26f20 commit 80f2d13
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Showing 2 changed files with 207 additions and 0 deletions.
206 changes: 206 additions & 0 deletions src/mapnik_vector_tile.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,8 @@
#include "vector_tile.pb.h"

#include <mapnik/map.hpp>
#include <mapnik/graphics.hpp>
#include <mapnik/image_util.hpp>
#include <mapnik/layer.hpp>
#include <mapnik/geom_util.hpp>
#include <mapnik/version.hpp>
Expand Down Expand Up @@ -142,6 +144,7 @@ void VectorTile::Initialize(Handle<Object> target) {
NODE_SET_PROTOTYPE_METHOD(constructor, "names", names);
NODE_SET_PROTOTYPE_METHOD(constructor, "toJSON", toJSON);
NODE_SET_PROTOTYPE_METHOD(constructor, "toGeoJSON", toGeoJSON);
NODE_SET_PROTOTYPE_METHOD(constructor, "toDebugImage", toDebugImage);
#ifdef PROTOBUF_FULL
NODE_SET_PROTOTYPE_METHOD(constructor, "toString", toString);
#endif
Expand Down Expand Up @@ -622,6 +625,209 @@ static void layer_to_geojson(mapnik::vector::tile_layer const& layer,
}
}

void draw_box(mapnik::CoordTransform const& t_,
mapnik::box2d<double> const& extent,
mapnik::image_32 & buf,
unsigned rgba)
{
mapnik::box2d<double> box = t_.forward(extent);
double x0 = box.minx();
double x1 = box.maxx();
double y0 = box.miny();
double y1 = box.maxy();
for (double x=x0; x<x1; x++)
{
buf.setPixel(x, y0, rgba);
buf.setPixel(x, y1, rgba);
}
for (double y=y0; y<y1; y++)
{
buf.setPixel(x0, y, rgba);
buf.setPixel(x1, y, rgba);
}
}

void apply_px(int x0, int y0, unsigned c, int size, mapnik::image_32 & buf) {
bool x_in = (x0 >= 0 && x0 < static_cast<int>(buf.width()));
bool y_in = (y0 >= 0 && y0 < static_cast<int>(buf.height()));
bool in_bounds = (x_in && y_in);
if (!in_bounds)
{
if (!x_in) {
if (x0 < 0) x0 = 0;
if (x0 > static_cast<int>(buf.width())) x0 = buf.width();
}
if (!y_in) {
if (y0 < 0) y0 = 0;
if (y0 > static_cast<int>(buf.width())) y0 = buf.height();
}
c = 0;
}
mapnik::image_data_32 & data = buf.data();
unsigned current = data(x0,y0);
if (current != 0) size--;
for (int x=x0-size; x<x0+size; x++)
{
for (int y=y0-size; y<y0+size; y++)
{
buf.setPixel(x, y, c);
}
}
}

class colors {
std::vector<unsigned> colors_;
std::size_t size_;
std::size_t pos_;
public:
colors() :
colors_() {
colors_.push_back(mapnik::color("red").rgba());
colors_.push_back(mapnik::color("darkorange").rgba());
colors_.push_back(mapnik::color("yellow").rgba());
colors_.push_back(mapnik::color("green").rgba());
colors_.push_back(mapnik::color("blue").rgba());
colors_.push_back(mapnik::color("purple").rgba());
size_ = colors_.size();
}

unsigned next()
{
if (pos_ >= size_) pos_ = 0;
return colors_.at(pos_++);
}

};

Handle<Value> VectorTile::toDebugImage(const Arguments& args)
{
HandleScope scope;
if (args.Length() < 1)
return ThrowException(Exception::Error(
String::New("first argument must be either a layer name (string) or layer index (integer)")));
Local<Value> layer_id = args[0];
if (! (layer_id->IsString() || layer_id->IsNumber()) )
return ThrowException(Exception::TypeError(
String::New("'layer' argument must be either a layer name (string) or layer index (integer)")));
VectorTile* d = node::ObjectWrap::Unwrap<VectorTile>(args.This());
mapnik::vector::tile const& tiledata = d->get_tile();
std::size_t layer_num = tiledata.layers_size();
int layer_idx = -1;

if (layer_id->IsString()) {
std::string layer_name = TOSTR(layer_id);
bool found = false;
unsigned int idx(0);
for (unsigned i=0; i < layer_num; ++i)
{
mapnik::vector::tile_layer const& layer = tiledata.layers(i);
if (layer.name() == layer_name)
{
found = true;
layer_idx = idx;
break;
}
++idx;
}
if (!found)
{
std::ostringstream s;
s << "Layer name '" << layer_name << "' not found";
return ThrowException(Exception::TypeError(String::New(s.str().c_str())));
}
}
else if (layer_id->IsNumber())
{
layer_idx = layer_id->IntegerValue();
if (layer_idx < 0) {
std::ostringstream s;
s << "Zero-based layer index '" << layer_idx << "' not valid"
<< " must be a positive integer";
if (layer_num > 0)
{
s << "only '" << layer_num << "' layers exist in map";
}
else
{
s << "no layers found in map";
}
return ThrowException(Exception::TypeError(String::New(s.str().c_str())));
} else if (layer_idx >= static_cast<int>(layer_num)) {
std::ostringstream s;
s << "Zero-based layer index '" << layer_idx << "' not valid, ";
if (layer_num > 0)
{
s << "only '" << layer_num << "' layers exist in map";
}
else
{
s << "no layers found in map";
}
return ThrowException(Exception::TypeError(String::New(s.str().c_str())));
}
} else {
return ThrowException(Exception::TypeError(String::New("layer id must be a string or index number")));
}

try {
mapnik::image_32 im(512,512);
double minx,miny,maxx,maxy;
mapnik::vector::spherical_mercator merc(d->width());
merc.xyz(d->x_,d->y_,d->z_,minx,miny,maxx,maxy);
mapnik::box2d<double> bbox(minx,miny,maxx,maxy);
int inset = 30;
mapnik::CoordTransform tr(im.width()-inset,im.height()-inset,bbox,-(inset/2),-(inset/2));
draw_box(tr,bbox,im,4294967295);
mapnik::vector::tile_layer const& layer = tiledata.layers(layer_idx);
boost::shared_ptr<mapnik::vector::tile_datasource> ds = boost::make_shared<
mapnik::vector::tile_datasource>(
layer,
d->x_,
d->y_,
d->z_,
d->width()
);
ds->set_envelope(bbox);
mapnik::query q(bbox);
mapnik::featureset_ptr fs = ds->features(q);
if (fs)
{
mapnik::feature_ptr feature;
colors color_itr;
while ((feature = fs->next()))
{
unsigned color = color_itr.next();
BOOST_FOREACH ( mapnik::geometry_type & path, feature->paths() )
{
double x0 = 0;
double y0 = 0;
path.rewind(0);
unsigned command;
while (mapnik::SEG_END != (command = path.vertex(&x0, &y0)))
{
if (command == mapnik::SEG_CLOSE) continue;
tr.forward(&x0,&y0);
apply_px(x0,y0,color,2,im);
}
}
}
}
std::string s = save_to_string(im, "png");
#if NODE_VERSION_AT_LEAST(0, 11, 0)
return scope.Close(node::Buffer::New((char*)s.data(),s.size()));
#else
return scope.Close(node::Buffer::New((char*)s.data(),s.size())->handle_);
#endif
}
catch (std::exception const& ex)
{
return ThrowException(Exception::Error(
String::New(ex.what())));
}
return scope.Close(Undefined());

}

Handle<Value> VectorTile::toGeoJSON(const Arguments& args)
{
HandleScope scope;
Expand Down
1 change: 1 addition & 0 deletions src/mapnik_vector_tile.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ class VectorTile: public node::ObjectWrap {
static Handle<Value> toJSON(Arguments const& args);
static Handle<Value> query(Arguments const& args);
static Handle<Value> names(Arguments const& args);
static Handle<Value> toDebugImage(Arguments const& args);
static Handle<Value> toGeoJSON(Arguments const& args);
#ifdef PROTOBUF_FULL
static Handle<Value> toString(Arguments const& args);
Expand Down

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