Drawing Rectangles

#include <stdio.h>
#include "graphapp.h"

void redraw_it(Window *w, Graphics *g)
{
  Rect r = rect(10,10,80,10);

  set_colour(g, RED);
  draw_rect(g, r);

  set_colour(g, BLUE);
  fill_rect(g, rect(10,40,80,10));
}

int main(int argc, char *argv[])
{
  App *app = new_app(argc, argv);
  Window *w = new_window(app, rect(0,0,174,100),
                         "Graphics", STANDARD_WINDOW);
  on_window_redraw(w, redraw_it);
  show_window(w);
  main_loop(app);
  return 0;
}

Notes:

• Use rect(x,y,width,height) to specify mathematical rectangles.
• Use draw_rect draws outlines of rectangles.
• Use fill_rect fills the rectangle with colour.
• Use set_colour to change the drawing colour.
• Rects are automatic (they are created on the stack) so there is no need to delete them.