/*
 * Demo of a bug with panels and updating
 *
 * cc broke2.c -lpanel -lncurses -o broke2
 *
 * address@hidden
 */

#include <ncurses.h>
#include <panel.h>

/*
 * blank a rectangluar screen region
 */
void
wblankrect(WINDOW *win, int miny, int minx, int maxy, int maxx, int saveattr)
{
	int	x, y;
	chtype	ch;

	for (y = miny; y <= maxy; ++y)
		for (x = minx; x <= maxx; ++x)
		{
			if (saveattr)
			{
				ch = mvwinch(win, y, x);
				ch &= ~0xff;
				ch |= ' ';
				mvwaddch(win, y, x, ch);
			}
			else
				mvwaddch(win, y, x, ' ');
		}
}

/*
 * Scroll a rectangular screen region
 */
void
wvscrollrect(WINDOW *win, int miny, int minx, int maxy, int maxx, int lines)
{
	int	x, y;
	chtype	ch;

	while (lines > 0)
	{
		for (y = miny; y < maxy; ++y)
			for (x = minx; x <= maxx; ++x)
			{
				ch = mvwinch(win, y+1, x);
				mvwaddch(win, y, x, ch);
			}
		wblankrect(win, maxy, minx, maxy, maxx, 1);
		--lines;
	}
	while (lines < 0)
	{
		for (y = maxy; y > miny; --y)
			for (x = minx; x <= maxx; ++x)
			{
				ch = mvwinch(win, y-1, x);
				mvwaddch(win, y, x, ch);
			}
		wblankrect(win, miny, minx, miny, maxx, 1);
		++lines;
	}
}

main()
{
	WINDOW	*win;
	WINDOW	*sub;
	PANEL	*panel;
	char	sym[16];
	int	n;

	initscr();

	win = newwin(10, 24, 0, 0);
	box(win, 0, 0);
	mvwprintw(win, 0, (24-strlen("Popup"))/2, "Popup");
	sub = derwin(win, 8, 22, 1, 1);
	panel = new_panel(win);

	mvwprintw(sub, 4, 0, "Why arent't these lines updated?");
	
	for (n = 0;; ++n)
	{
		/* Scroll the *entire* contents of the popup up 1 line */
		wvscrollrect(sub, 0, 0,
			getmaxy(sub)-1, getmaxx(sub)-1, 1);

		/* Add new line at bottom */
		mvwprintw(sub, getmaxy(sub)-1, 0,
				"%7.2f %5d %02d:%02d:%02d",
				n * 1.23,
				n,
				n, n, n
				);

		/* BUG  ?!?
		 *
		 * Only the lines in the panel which *overlay
		 * stdscr lines that have themselves been changed*
		 * will get updated!
		 *
		 * The next code shows how 2 lines in the popup
		 * will get updated, while the rest won't!
		 */
		if (1)
		{
			mvprintw(2, 0, "This is a test");
			mvprintw(8, 0, "This is a test");
		}

		update_panels();
		// refresh();
		doupdate();

		usleep(100*1000);
	}
}