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Curses Windowing Example
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demo | |
*.swp |
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#include <ncurses.h> | |
#include <unistd.h> | |
void draw_borders(WINDOW *screen) { | |
int x, y, i; | |
getmaxyx(screen, y, x); | |
// 4 corners | |
mvwprintw(screen, 0, 0, "+"); | |
mvwprintw(screen, y - 1, 0, "+"); | |
mvwprintw(screen, 0, x - 1, "+"); | |
mvwprintw(screen, y - 1, x - 1, "+"); | |
// sides | |
for (i = 1; i < (y - 1); i++) { | |
mvwprintw(screen, i, 0, "|"); | |
mvwprintw(screen, i, x - 1, "|"); | |
} | |
// top and bottom | |
for (i = 1; i < (x - 1); i++) { | |
mvwprintw(screen, 0, i, "-"); | |
mvwprintw(screen, y - 1, i, "-"); | |
} | |
} | |
int main(int argc, char *argv[]) { | |
int parent_x, parent_y, new_x, new_y; | |
int score_size = 3; | |
initscr(); | |
noecho(); | |
curs_set(FALSE); | |
// set up initial windows | |
getmaxyx(stdscr, parent_y, parent_x); | |
WINDOW *field = newwin(parent_y - score_size, parent_x, 0, 0); | |
WINDOW *score = newwin(score_size, parent_x, parent_y - score_size, 0); | |
draw_borders(field); | |
draw_borders(score); | |
while(1) { | |
getmaxyx(stdscr, new_y, new_x); | |
if (new_y != parent_y || new_x != parent_x) { | |
parent_x = new_x; | |
parent_y = new_y; | |
wresize(field, new_y - score_size, new_x); | |
wresize(score, score_size, new_x); | |
mvwin(score, new_y - score_size, 0); | |
wclear(stdscr); | |
wclear(field); | |
wclear(score); | |
draw_borders(field); | |
draw_borders(score); | |
} | |
// draw to our windows | |
mvwprintw(field, 1, 1, "Field"); | |
mvwprintw(score, 1, 1, "Score"); | |
// refresh each window | |
wrefresh(field); | |
wrefresh(score); | |
} | |
endwin(); | |
return 0; | |
} | |
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CFLAGS=-Wall | |
LDFLAGS=-lncurses | |
all: demo | |
clean: | |
rm -rf demo |
There is 100% CPU usage because there is no
usleep
being used, which is normally common in such loops.
While that would be an improvement over the original example, my advice is:
- In a curses-based program, don't use
usleep()
wherenapms()
will suffice.usleep()
introduces a POSIX dependency, whilenapms()
is native to curses, so the app may still be portable to non-POSIX systems. - Don't use
napms()
where a blockinggetch()
will do. Most curses apps will and should spend most of their time in an idle loop waiting on user input, so you may as well letgetch()
do the work of idling. In the case of this example, even resize events are reported as KEY_RESIZE key events by ncurses and PDCurses. And even in cases where a non-blockinggetch()
is needed, you can often rely on mechanisms likehalfdelay()
ortimeout()
instead of resorting to an explicitnapms()
.
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This version: https://gist.github.com/wmcbrine/f63e83d659cedd5181ae77c56907addb