mapnik/include/mapnik/image_view.hpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 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 IMAGE_VIEW_HPP
#define IMAGE_VIEW_HPP


namespace mapnik {
    
   template <typename T> 
   class image_view  
   {
      public:
         typedef typename T::pixel_type pixel_type;
          
         image_view(unsigned x, unsigned y, unsigned width, unsigned height, T const& data)
            : x_(x),
              y_(y),
              width_(width),
              height_(height),
              data_(data) 
         {
            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_;
         }
        
         ~image_view() {}
        
         image_view(image_view<T> const& rhs)
            : x_(rhs.x_),
              y_(rhs.y_),
              width_(rhs.width_),
              height_(rhs.height_),
              data_(rhs.data_) {}
        
         image_view<T> & operator=(image_view<T> const& rhs)
         {
            if (&rhs==this) return *this;
            x_ = rhs.x_;
            y_ = rhs.y_;
            width_ = rhs.width_;
            height_ = rhs.height_;
            data_ = rhs.data_;
         }
        
         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 pixel_type* getRow(unsigned row) const
         {
            return data_.getRow(row + y_) + x_;
         }
         inline T& data()
         {
            return data_;
         }
         inline T const& data() const
         {
            return data_;
         }
          
      private:
         unsigned x_;
         unsigned y_;
         unsigned width_;
         unsigned height_;
         T const& data_;
   };
}

#endif // IMAGE_VIEW_HPP