Windows in NCurses (Part 3)

#cpp #linux #ncurses

Hey there, if you haven't read Part-2 yet, I would suggest you read it first.

Ncurses provide one main window known as Standard Screen by default, defined as stdscr. It also allows you to make windows that divide the stdscr i.e Main Window.

A window may be as large as entire stdscr or as small as a single character

To declare a window you will have to use WINDOW typed object defined in ncurses.h. and newwin(int height, int width, int starty, int starty) function to initialize

For example,

WINDOW *win = newwin(10, 20, 1,10);
refresh(); // this will refresh "all" the screens

In the real world, you would be working with different windows. So if we want or refresh a specific window, we will be using wrefresh(WINDOW *) function of ncurses.h that takes a window and refresh memory contents related to that window only.

Like mvprintw() (in part 2) is for stdscr, you will have to use window specific function to print in particular window mvwprintw(WINDOW *, int y, int x, “String”, ….);

Ok now everything is done, except one, and that is borders. To add borders to screen there are two functions

box(WINDOW*, int v, int h): Function to add borders to window
- v is the value for vertical borders. Default is 0
- h is the value for horizontal borders. Default is 0
wborder(WINDOW*, int leftChar, int rightChar, int topChar, int bottomChar, int topLeftCorner, int topRightCorner, int bottomLeftCorner, int bottomRightCorner): The most precise function to add borders to a window

#include <ncurses.h>
using namespace std;

int main(int argc, char **argv)
{
    initscr();

    // creating a window;
    // with height = 15 and width = 10
    // also with start x axis 10 and start y axis = 20
    WINDOW *win = newwin(15, 17, 2, 10);
    refresh();

    // making box border with default border styles
    box(win, 0, 0);

    // move and print in window
    mvwprintw(win, 0, 1, "Greeter");
    mvwprintw(win, 1, 1, "Hello");

    // refreshing the window
    wrefresh(win);

    getch();
    endwin();
    return 0;
}

Top comments (3)

Peyton McGinnis • May 6 '20

Ahh, I remember my days in ncurses. I've tried and failed multiple times to write a decent wrapper around it in C++. My problem was always efficiently managing a custom WINDOW stack and allowing global keybindings.