add a grid_view class to allow subsetting of grids for metatiling

include/mapnik/grid/grid.hpp

@@ -26,7 +26,7 @@
 // mapnik
 #include <mapnik/image_data.hpp>
 #include <mapnik/box2d.hpp>
-//#include <mapnik/grid/grid_view.hpp>
+#include <mapnik/grid/grid_view.hpp>
 #include <mapnik/global.hpp>
 #include <mapnik/value.hpp>
 #include <mapnik/feature.hpp>
@@ -223,13 +223,17 @@ public:
         return data_.getData();
     }
 
-    
-/*
-    inline mapnik::grid_view<data_type> get_view(unsigned x,unsigned y, unsigned w,unsigned h)
+    inline const value_type* getRow(unsigned row) const
     {
-        return mapnik::grid_view<data_type>(x,y,w,h,data_,key_,resolution_,names_,f_keys_,features_);
+        return data_.getRow(row);
     }
-*/    
+    
+    inline mapnik::grid_view get_view(unsigned x, unsigned y, unsigned w, unsigned h)
+    {
+        return mapnik::grid_view(x,y,w,h,
+            data_,key_,resolution_,names_,f_keys_,features_);
+    }
+    
 
 private:
 

include/mapnik/grid/grid_view.hpp

@@ -0,0 +1,205 @@
+/*****************************************************************************
+ * 
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2011 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
+ *
+ *****************************************************************************/
+
+//$Id$
+
+#ifndef MAPNIK_GRID_VIEW_HPP
+#define MAPNIK_GRID_VIEW_HPP
+
+#include <mapnik/image_data.hpp>
+#include <mapnik/box2d.hpp>
+#include <mapnik/global.hpp>
+#include <mapnik/value.hpp>
+
+// stl
+#include <map>
+#include <set>
+#include <cmath>
+#include <string>
+#include <cassert>
+#include <vector>
+
+
+namespace mapnik {
+    
+template <typename T>
+class hit_grid_view
+{
+public:
+    typedef T data_type;
+    typedef typename T::pixel_type value_type;
+    typedef std::string lookup_type;
+    typedef std::map<value_type, lookup_type> feature_key_type;
+    typedef std::map<lookup_type, value_type> key_type;
+    typedef std::map<std::string, mapnik::value> feature_properties_type;
+    typedef std::map<std::string, feature_properties_type > feature_type;
+          
+    hit_grid_view(unsigned x, unsigned y, 
+              unsigned width, unsigned height,
+              T const& data,
+              std::string const& key,
+              unsigned resolution,
+              std::set<std::string> const& names,
+              feature_key_type const& f_keys,
+              feature_type const& features
+              )
+        : x_(x),
+          y_(y),
+          width_(width),
+          height_(height),
+          data_(data),
+          key_(key),
+          resolution_(resolution),
+          names_(names),
+          f_keys_(f_keys),
+          features_(features)
+          
+    {
+        std::clog << "w,h" << width_ << " " << height_ << "\n";
+        if (x_ >= data_.width())
+            x_=data_.width()-1;
+        
+        if (y_ >= data_.height())
+            x_=data_.height()-1;
+        
+        if (x_ + width_ > data_.width())
+            width_= data_.width() - x_;
+        
+        if (y_ + height_ > data_.height())
+            height_= data_.height() - y_;
+        std::clog << "w,h" << width_ << " " << height_ << "\n";
+    }
+        
+    ~hit_grid_view() {}
+        
+    hit_grid_view(hit_grid_view<T> const& rhs)
+        : x_(rhs.x_),
+          y_(rhs.y_),
+          width_(rhs.width_),
+          height_(rhs.height_),
+          data_(rhs.data_),
+          key_(rhs.key_),
+          resolution_(rhs.resolution_),
+          names_(rhs.names_),
+          f_keys_(rhs.f_keys_),
+          features_(rhs.features_)
+          {}
+        
+    hit_grid_view<T> & operator=(hit_grid_view<T> const& rhs)
+    {
+        if (&rhs==this) return *this;
+        x_ = rhs.x_;
+        y_ = rhs.y_;
+        width_ = rhs.width_;
+        height_ = rhs.height_;
+        data_ = rhs.data_;
+        key_ = rhs.key_;
+        resolution_ = rhs.resolution_;
+        names_ = rhs.names_;
+        f_keys_ = rhs.f_keys_;
+        features_ = rhs.features_;
+    }
+        
+    inline unsigned x() const
+    {
+        return x_;
+    }
+
+    inline unsigned y() const
+    {
+        return y_;
+    }
+        
+    inline unsigned width() const
+    {
+        return width_;
+    }
+
+    inline unsigned height() const
+    {
+        return height_;
+    }
+        
+    inline const value_type* getRow(unsigned row) const
+    {
+        return data_.getRow(row + y_) + x_;
+    }
+
+    inline T& data()
+    {
+        return data_;
+    }
+
+    inline T const& data() const
+    {
+        return data_;
+    }
+
+    inline const unsigned char* raw_data() const
+    {
+        return data_.getBytes();
+    }
+
+    std::set<std::string> const& property_names() const
+    {
+        return names_;
+    }
+
+    inline const feature_type& get_grid_features() const
+    {
+        return features_;
+    }
+
+    inline const feature_key_type& get_feature_keys() const
+    {
+        return f_keys_;
+    }
+
+    inline const lookup_type& get_key() const
+    {
+        return key_;
+    }
+
+    inline unsigned int get_resolution() const
+    {
+        return resolution_;
+    }
+
+private:
+    unsigned x_;
+    unsigned y_;
+    unsigned width_;
+    unsigned height_;
+    T const& data_;
+    std::string const& key_;
+    unsigned int resolution_;
+    std::set<std::string> const& names_;
+    feature_key_type const& f_keys_;
+    feature_type const& features_;
+};
+
+typedef hit_grid_view<mapnik::ImageData<uint16_t> > grid_view;
+
+}
+
+#endif // MAPNIK_GRID_VIEW_HPP
+