// FILE: drawing.cpp
//
#include "drawing.h"

// render the list of figures onto the canvas
// by drawing them and saving C as depths are jumped
// 
void drawing::render(drawable_list& L, canvas& C) {

   L.sort(); // sort figures by depth and order

   list_iterator<drawable*> I = L.first();

   int prev_depth = 0; // last layer

   if (I.has_more_elements()) {
      // get depth of first figure
      prev_depth = (*I)->get_depth();
   }

   while(I.has_more_elements()) {
      if ((*I)->get_depth() != prev_depth) {
         // jumping layers!, save canvas
         C.save_canvas(); 
         prev_depth = (*I)->get_depth();
      }
      // draw figure
      (*I)->draw(C);
      I++;
   }
}