From 182628e3abcc149cb5ae494904ce5c96e12b6b19 Mon Sep 17 00:00:00 2001
From: Dane Springmeyer <dane@dbsgeo.com>
Date: Sun, 20 Jun 2010 04:01:59 +0000
Subject: [PATCH] + add filter_factor on mapnik::query and allow setting of
 factor for image scaling modes which demand high quality resampling -
 bilinear requires 2x, others in future like lanzcos may require 3-4x -
 addresses #563

---
 include/mapnik/feature_style_processor.hpp | 34 +++++++++++++++++++++-
 include/mapnik/query.hpp                   | 18 ++++++++++--
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/include/mapnik/feature_style_processor.hpp b/include/mapnik/feature_style_processor.hpp
index 553a263c4..7b9e03c82 100644
--- a/include/mapnik/feature_style_processor.hpp
+++ b/include/mapnik/feature_style_processor.hpp
@@ -180,7 +180,11 @@ private:
                     {
                         active_rules=true;
                         // collect unique attribute names
-                        collector(*ruleIter);
+                        // TODO - in the future rasters should be able to be filtered...
+                        if (ds->type() == datasource::Vector)
+                        {
+                            collector(*ruleIter);
+                        }
                         if (ruleIter->has_else_filter())
                         {
                             else_rules.push_back(const_cast<rule_type*>(&(*ruleIter)));
@@ -189,6 +193,34 @@ private:
                         {
                             if_rules.push_back(const_cast<rule_type*>(&(*ruleIter)));               
                         }
+                        if (ds->type() == datasource::Raster)
+                        {
+                            if (ds->params().get<double>("filter_factor",0.0) == 0.0)
+                            {
+                                const rule_type::symbolizers& symbols = ruleIter->get_symbolizers();
+                                rule_type::symbolizers::const_iterator symIter = symbols.begin();
+                                rule_type::symbolizers::const_iterator symEnd = symbols.end();
+                                for (;symIter != symEnd;++symIter)
+                                {   
+                                    try
+                                    {
+                                        raster_symbolizer sym = boost::get<raster_symbolizer>(*symIter);
+                                        std::string scaling = sym.get_scaling();
+                                        if (scaling == "bilinear" || scaling == "bilinear8" )
+                                        {
+                                            // todo - allow setting custom value in symbolizer property?
+                                            q.filter_factor(2.0);
+                                        }
+                                    }
+                                    catch (const boost::bad_get &v)
+                                    {
+                                        // case where useless symbolizer is attached to raster layer
+                                        //throw config_error("Invalid Symbolizer type supplied, only RasterSymbolizer is supported");
+                                    }
+                                }
+                            }
+                            
+                        }
                     }
                 }
                 std::set<std::string>::const_iterator namesIter=names.begin();
diff --git a/include/mapnik/query.hpp b/include/mapnik/query.hpp
index 45872ac3c..3a0777ead 100644
--- a/include/mapnik/query.hpp
+++ b/include/mapnik/query.hpp
@@ -46,19 +46,22 @@ private:
     box2d<double> bbox_;
     resolution_type resolution_;
     double scale_denominator_;
+    double filter_factor_;
     std::set<std::string> names_;
 public:
          
     query(box2d<double> const& bbox, resolution_type const& resolution, double scale_denominator = 1.0)
         : bbox_(bbox),
           resolution_(resolution),
-          scale_denominator_(scale_denominator)
+          scale_denominator_(scale_denominator),
+          filter_factor_(1.0)
     {}
     
     query(query const& other)
         : bbox_(other.bbox_),
           resolution_(other.resolution_),
           scale_denominator_(other.scale_denominator_),
+          filter_factor_(other.filter_factor_),
           names_(other.names_)
     {}
          
@@ -68,6 +71,7 @@ public:
         bbox_=other.bbox_;
         resolution_=other.resolution_;
         scale_denominator_=other.scale_denominator_;
+        filter_factor_=other.filter_factor_;
         names_=other.names_;
         return *this;
     }
@@ -86,7 +90,17 @@ public:
     {
         return bbox_;
     }
-         
+
+    double get_filter_factor() const
+    {
+        return filter_factor_;
+    }
+    
+    void filter_factor(double factor)
+    {
+        filter_factor_ = factor;
+    }
+             
     void add_property_name(std::string const& name)
     {
         names_.insert(name);