mapnik/include/mapnik/feature_style_processor_impl.hpp
2014-11-20 15:25:50 +01:00

642 lines
21 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2014 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
*
*****************************************************************************/
// NOTE: This is an implementation header file and is only meant to be included
// from implementation files. It therefore doesn't have an include guard. To
// create a custom feature_style_processor, include this file and instantiate
// the template with the desired template arguments.
// mapnik
#include <mapnik/map.hpp>
#include <mapnik/debug.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/feature_style_processor.hpp>
#include <mapnik/query.hpp>
#include <mapnik/datasource.hpp>
#include <mapnik/feature_type_style.hpp>
#include <mapnik/box2d.hpp>
#include <mapnik/layer.hpp>
#include <mapnik/rule.hpp>
#include <mapnik/rule_cache.hpp>
#include <mapnik/attribute_collector.hpp>
#include <mapnik/expression_evaluator.hpp>
#include <mapnik/scale_denominator.hpp>
#include <mapnik/projection.hpp>
#include <mapnik/proj_transform.hpp>
#include <mapnik/util/featureset_buffer.hpp>
#include <mapnik/util/variant.hpp>
#include <mapnik/symbolizer_dispatch.hpp>
// stl
#include <vector>
#include <stdexcept>
namespace mapnik
{
// Store material for layer rendering in a two step process
struct layer_rendering_material
{
layer const& lay_;
projection const& proj0_;
projection proj1_;
box2d<double> layer_ext2_;
std::vector<feature_type_style const*> active_styles_;
std::vector<featureset_ptr> featureset_ptr_list_;
std::vector<rule_cache> rule_caches_;
layer_rendering_material(layer const& lay, projection const& dest)
:
lay_(lay),
proj0_(dest),
proj1_(lay.srs(),true) {}
};
using layer_rendering_material_ptr = std::shared_ptr<layer_rendering_material>;
template <typename Processor>
feature_style_processor<Processor>::feature_style_processor(Map const& m, double scale_factor)
: m_(m)
{
// https://github.com/mapnik/mapnik/issues/1100
if (scale_factor <= 0)
{
throw std::runtime_error("scale_factor must be greater than 0.0");
}
}
template <typename Processor>
void feature_style_processor<Processor>::apply(double scale_denom)
{
Processor & p = static_cast<Processor&>(*this);
p.start_map_processing(m_);
projection proj(m_.srs(),true);
if (scale_denom <= 0.0)
scale_denom = mapnik::scale_denominator(m_.scale(),proj.is_geographic());
scale_denom *= p.scale_factor(); // FIXME - we might want to comment this out
// Asynchronous query supports:
// This is a two steps process,
// first we setup all queries at layer level
// in a second time, we fetch the results and
// do the actual rendering
std::vector<layer_rendering_material_ptr> mat_list;
// Define processing context map used by datasources
// implementing asynchronous queries
feature_style_context_map ctx_map;
for ( layer const& lyr : m_.layers() )
{
if (lyr.visible(scale_denom))
{
std::set<std::string> names;
layer_rendering_material_ptr mat = std::make_shared<layer_rendering_material>(lyr, proj);
prepare_layer(*mat,
ctx_map,
p,
m_.scale(),
scale_denom,
m_.width(),
m_.height(),
m_.get_current_extent(),
m_.buffer_size(),
names);
// Store active material
if (!mat->active_styles_.empty())
{
mat_list.push_back(mat);
}
}
}
for ( layer_rendering_material_ptr mat : mat_list )
{
if (!mat->active_styles_.empty())
{
render_material(*mat,p);
}
}
p.end_map_processing(m_);
}
template <typename Processor>
void feature_style_processor<Processor>::apply(mapnik::layer const& lyr,
std::set<std::string>& names,
double scale_denom)
{
Processor & p = static_cast<Processor&>(*this);
p.start_map_processing(m_);
projection proj(m_.srs(),true);
if (scale_denom <= 0.0)
scale_denom = mapnik::scale_denominator(m_.scale(),proj.is_geographic());
scale_denom *= p.scale_factor();
if (lyr.visible(scale_denom))
{
apply_to_layer(lyr,
p,
proj,
m_.scale(),
scale_denom,
m_.width(),
m_.height(),
m_.get_current_extent(),
m_.buffer_size(),
names);
}
p.end_map_processing(m_);
}
/*!
* \brief render a layer given a projection and scale.
*/
template <typename Processor>
void feature_style_processor<Processor>::apply_to_layer(layer const& lay,
Processor & p,
projection const& proj0,
double scale,
double scale_denom,
unsigned width,
unsigned height,
box2d<double> const& extent,
int buffer_size,
std::set<std::string>& names)
{
feature_style_context_map ctx_map;
layer_rendering_material mat(lay, proj0);
prepare_layer(mat,
ctx_map,
p,
scale,
scale_denom,
width,
height,
extent,
buffer_size,
names);
if (!mat.active_styles_.empty())
{
render_material(mat,p);
}
}
template <typename Processor>
void feature_style_processor<Processor>::prepare_layer(layer_rendering_material & mat,
feature_style_context_map & ctx_map,
Processor & p,
double scale,
double scale_denom,
unsigned width,
unsigned height,
box2d<double> const& extent,
int buffer_size,
std::set<std::string>& names)
{
layer const& lay = mat.lay_;
std::vector<std::string> const& style_names = lay.styles();
unsigned int num_styles = style_names.size();
if (num_styles == 0)
{
MAPNIK_LOG_DEBUG(feature_style_processor)
<< "feature_style_processor: No style for layer=" << lay.name();
return;
}
mapnik::datasource_ptr ds = lay.datasource();
if (!ds)
{
MAPNIK_LOG_DEBUG(feature_style_processor)
<< "feature_style_processor: No datasource for layer=" << lay.name();
return;
}
processor_context_ptr current_ctx = ds->get_context(ctx_map);
proj_transform prj_trans(mat.proj0_,mat.proj1_);
box2d<double> query_ext = extent; // unbuffered
box2d<double> buffered_query_ext(query_ext); // buffered
double buffer_padding = 2.0 * scale;
boost::optional<int> layer_buffer_size = lay.buffer_size();
if (layer_buffer_size) // if layer overrides buffer size, use this value to compute buffered extent
{
buffer_padding *= *layer_buffer_size;
}
else
{
buffer_padding *= buffer_size;
}
buffered_query_ext.width(query_ext.width() + buffer_padding);
buffered_query_ext.height(query_ext.height() + buffer_padding);
// clip buffered extent by maximum extent, if supplied
boost::optional<box2d<double> > const& maximum_extent = m_.maximum_extent();
if (maximum_extent)
{
buffered_query_ext.clip(*maximum_extent);
}
box2d<double> layer_ext = lay.envelope();
bool fw_success = false;
bool early_return = false;
// first, try intersection of map extent forward projected into layer srs
if (prj_trans.forward(buffered_query_ext, PROJ_ENVELOPE_POINTS) && buffered_query_ext.intersects(layer_ext))
{
fw_success = true;
layer_ext.clip(buffered_query_ext);
}
// if no intersection and projections are also equal, early return
else if (prj_trans.equal())
{
early_return = true;
}
// next try intersection of layer extent back projected into map srs
else if (prj_trans.backward(layer_ext, PROJ_ENVELOPE_POINTS) && buffered_query_ext.intersects(layer_ext))
{
layer_ext.clip(buffered_query_ext);
// forward project layer extent back into native projection
if (! prj_trans.forward(layer_ext, PROJ_ENVELOPE_POINTS))
{
MAPNIK_LOG_ERROR(feature_style_processor)
<< "feature_style_processor: Layer=" << lay.name()
<< " extent=" << layer_ext << " in map projection "
<< " did not reproject properly back to layer projection";
}
}
else
{
// if no intersection then nothing to do for layer
early_return = true;
}
std::vector<feature_type_style const*> & active_styles = mat.active_styles_;
if (early_return)
{
// check for styles needing compositing operations applied
// https://github.com/mapnik/mapnik/issues/1477
for (std::string const& style_name : style_names)
{
boost::optional<feature_type_style const&> style=m_.find_style(style_name);
if (!style)
{
continue;
}
if (style->comp_op() || style->image_filters().size() > 0)
{
if (style->active(scale_denom))
{
// we'll have to handle compositing ops
active_styles.push_back(&(*style));
}
}
}
return;
}
// if we've got this far, now prepare the unbuffered extent
// which is used as a bbox for clipping geometries
if (maximum_extent)
{
query_ext.clip(*maximum_extent);
}
box2d<double> & layer_ext2 = mat.layer_ext2_;
layer_ext2 = lay.envelope();
if (fw_success)
{
if (prj_trans.forward(query_ext, PROJ_ENVELOPE_POINTS))
{
layer_ext2.clip(query_ext);
}
}
else
{
if (prj_trans.backward(layer_ext2, PROJ_ENVELOPE_POINTS))
{
layer_ext2.clip(query_ext);
prj_trans.forward(layer_ext2, PROJ_ENVELOPE_POINTS);
}
}
std::vector<rule_cache> & rule_caches = mat.rule_caches_;
attribute_collector collector(names);
// iterate through all named styles collecting active styles and attribute names
for (std::string const& style_name : style_names)
{
boost::optional<feature_type_style const&> style=m_.find_style(style_name);
if (!style)
{
MAPNIK_LOG_DEBUG(feature_style_processor)
<< "feature_style_processor: Style=" << style_name
<< " required for layer=" << lay.name() << " does not exist.";
continue;
}
std::vector<rule> const& rules = style->get_rules();
bool active_rules = false;
rule_cache rc;
for(rule const& r : rules)
{
if (r.active(scale_denom))
{
rc.add_rule(r);
active_rules = true;
collector(r);
}
}
if (active_rules)
{
rule_caches.push_back(std::move(rc));
active_styles.push_back(&(*style));
}
}
// Don't even try to do more work if there are no active styles.
if (active_styles.empty())
{
return;
}
double qw = query_ext.width()>0 ? query_ext.width() : 1;
double qh = query_ext.height()>0 ? query_ext.height() : 1;
query::resolution_type res(width/qw,
height/qh);
query q(layer_ext,res,scale_denom,extent);
q.set_variables(p.variables());
if (p.attribute_collection_policy() == COLLECT_ALL)
{
layer_descriptor lay_desc = ds->get_descriptor();
for (attribute_descriptor const& desc : lay_desc.get_descriptors())
{
q.add_property_name(desc.get_name());
}
}
else
{
for (std::string const& name : names)
{
q.add_property_name(name);
}
}
q.set_filter_factor(collector.get_filter_factor());
// Also query the group by attribute
std::string const& group_by = lay.group_by();
if (!group_by.empty())
{
q.add_property_name(group_by);
}
bool cache_features = lay.cache_features() && active_styles.size() > 1;
std::vector<featureset_ptr> & featureset_ptr_list = mat.featureset_ptr_list_;
if (!group_by.empty() || cache_features)
{
featureset_ptr_list.push_back(ds->features_with_context(q,current_ctx));
}
else
{
for(std::size_t i = 0; i < active_styles.size(); ++i)
{
featureset_ptr_list.push_back(ds->features_with_context(q,current_ctx));
}
}
}
template <typename Processor>
void feature_style_processor<Processor>::render_material(layer_rendering_material & mat,
Processor & p )
{
std::vector<feature_type_style const*> & active_styles = mat.active_styles_;
std::vector<featureset_ptr> & featureset_ptr_list = mat.featureset_ptr_list_;
if (featureset_ptr_list.empty())
{
// The datasource wasn't queried because of early return
// but we have to apply compositing operations on styles
for (feature_type_style const* style : active_styles)
{
p.start_style_processing(*style);
p.end_style_processing(*style);
}
return;
}
p.start_layer_processing(mat.lay_, mat.layer_ext2_);
layer const& lay = mat.lay_;
std::vector<rule_cache> & rule_caches = mat.rule_caches_;
proj_transform prj_trans(mat.proj0_,mat.proj1_);
bool cache_features = lay.cache_features() && active_styles.size() > 1;
datasource_ptr ds = lay.datasource();
std::string group_by = lay.group_by();
// Render incrementally when the column that we group by changes value.
if (!group_by.empty())
{
featureset_ptr features = *featureset_ptr_list.begin();
if (features)
{
// Cache all features into the memory_datasource before rendering.
std::shared_ptr<featureset_buffer> cache = std::make_shared<featureset_buffer>();
feature_ptr feature, prev;
while ((feature = features->next()))
{
if (prev && prev->get(group_by) != feature->get(group_by))
{
// We're at a value boundary, so render what we have
// up to this point.
std::size_t i = 0;
for (feature_type_style const* style : active_styles)
{
cache->prepare();
render_style(p, style,
rule_caches[i],
cache,
prj_trans);
++i;
}
cache->clear();
}
cache->push(feature);
prev = feature;
}
std::size_t i = 0;
for (feature_type_style const* style : active_styles)
{
cache->prepare();
render_style(p, style, rule_caches[i], cache, prj_trans);
++i;
}
cache->clear();
}
}
else if (cache_features)
{
std::shared_ptr<featureset_buffer> cache = std::make_shared<featureset_buffer>();
featureset_ptr features = *featureset_ptr_list.begin();
if (features)
{
// Cache all features into the memory_datasource before rendering.
feature_ptr feature;
while ((feature = features->next()))
{
cache->push(feature);
}
}
std::size_t i = 0;
for (feature_type_style const* style : active_styles)
{
cache->prepare();
render_style(p, style,
rule_caches[i],
cache, prj_trans);
++i;
}
}
// We only have a single style and no grouping.
else
{
std::size_t i = 0;
std::vector<featureset_ptr>::iterator featuresets = featureset_ptr_list.begin();
for (feature_type_style const* style : active_styles)
{
featureset_ptr features = *featuresets++;
render_style(p, style,
rule_caches[i],
features,
prj_trans);
++i;
}
}
p.end_layer_processing(mat.lay_);
}
template <typename Processor>
void feature_style_processor<Processor>::render_style(
Processor & p,
feature_type_style const* style,
rule_cache const& rc,
featureset_ptr features,
proj_transform const& prj_trans)
{
p.start_style_processing(*style);
if (!features)
{
p.end_style_processing(*style);
return;
}
mapnik::attributes vars = p.variables();
feature_ptr feature;
bool was_painted = false;
while ((feature = features->next()))
{
bool do_else = true;
bool do_also = false;
for (rule const* r : rc.get_if_rules() )
{
expression_ptr const& expr = r->get_filter();
value_type result = util::apply_visitor(evaluate<feature_impl,value_type,attributes>(*feature,vars),*expr);
if (result.to_bool())
{
was_painted = true;
do_else=false;
do_also=true;
rule::symbolizers const& symbols = r->get_symbolizers();
if(!p.process(symbols,*feature,prj_trans))
{
for (symbolizer const& sym : symbols)
{
util::apply_visitor(symbolizer_dispatch<Processor>(p,*feature,prj_trans),sym);
}
}
if (style->get_filter_mode() == FILTER_FIRST)
{
// Stop iterating over rules and proceed with next feature.
do_also=false;
break;
}
}
}
if (do_else)
{
for( rule const* r : rc.get_else_rules() )
{
was_painted = true;
rule::symbolizers const& symbols = r->get_symbolizers();
if(!p.process(symbols,*feature,prj_trans))
{
for (symbolizer const& sym : symbols)
{
util::apply_visitor(symbolizer_dispatch<Processor>(p,*feature,prj_trans),sym);
}
}
}
}
if (do_also)
{
for( rule const* r : rc.get_also_rules() )
{
was_painted = true;
rule::symbolizers const& symbols = r->get_symbolizers();
if(!p.process(symbols,*feature,prj_trans))
{
for (symbolizer const& sym : symbols)
{
util::apply_visitor(symbolizer_dispatch<Processor>(p,*feature,prj_trans),sym);
}
}
}
}
}
p.painted(p.painted() | was_painted);
p.end_style_processing(*style);
}
}