mapnik::grid::value_type get_pixel(mapnik::grid const& grid, int x, int y)
{
if (x < static_cast<int>(grid.width()) && y < static_cast<int>(grid.height()))
{
mapnik::grid::data_type const & data = grid.data();
return data(x,y);
}
PyErr_SetString(PyExc_IndexError, "invalid x,y for grid dimensions");
boost::python::throw_error_already_set();
return 0;
}
int get_pixel(mapnik::grid const& grid, int x, int y)
{
if (x < static_cast<int>(grid.width()) && y < static_cast<int>(grid.height()))
{
mapnik::grid::value_type const * row = grid.getRow(y);
mapnik::grid::value_type const pixel = row[x];
return pixel;
}
PyErr_SetString(PyExc_IndexError, "invalid x,y for grid dimensions");
boost::python::throw_error_already_set();
return 0;
}
void render_layer_for_grid(mapnik::Map const& map,
mapnik::grid & grid,
unsigned layer_idx,
boost::python::list const& fields,
double scale_factor,
unsigned offset_x,
unsigned offset_y)
{
std::vector<mapnik::layer> const& layers = map.layers();
std::size_t layer_num = layers.size();
if (layer_idx >= layer_num) {
std::ostringstream s;
s << "Zero-based layer index '" << layer_idx << "' not valid, only '"
<< layer_num << "' layers are in map\n";
throw std::runtime_error(s.str());
}
// convert python list to std::set
boost::python::ssize_t num_fields = boost::python::len(fields);
for(boost::python::ssize_t i=0; i<num_fields; i++) {
boost::python::extract<std::string> name(fields[i]);
if (name.check())
{
grid.add_field(name());
}
else
{
std::stringstream s;
s << "list of field names must be strings";
throw mapnik::value_error(s.str());
}
}
// copy field names
std::set<std::string> attributes = grid.get_fields();
// todo - make this a static constant
std::string known_id_key = "__id__";
if (attributes.find(known_id_key) != attributes.end())
{
attributes.erase(known_id_key);
}
std::string join_field = grid.get_key();
if (known_id_key != join_field &&
attributes.find(join_field) == attributes.end())
{
attributes.insert(join_field);
}
mapnik::grid_renderer<mapnik::grid> ren(map,grid,scale_factor,offset_x,offset_y);
mapnik::layer const& layer = layers[layer_idx];
ren.apply(layer,attributes);
}
bool painted(mapnik::grid const& grid)
{
return grid.painted();
}