printw (ncurses) not displaying correct char in c

Question

I'm using ncurses to do a sort of sim city simulator.

I have ascii map in a .txt and I need to load it on the terminal.

The loading is good but it doesn't display the right caracters(for some caracters only).

for example:

in .txt -> in terminal

│ -> �~T~B

═ -> �~U~P

( -> (

I'm using http://www.theasciicode.com.ar/ for the ascii map

bellow is the code to display the map in terminal

nt setUpMap(){

FILE *fp;
int c;

fp = fopen("./files/map.txt", "r+");

cbreak();

// Read and display data 

while ((c = fgetc(fp)) != EOF)
{
    switch(c){
        case 'p' :
            // todo : emoji
        break;
        default:
            printw("%c", c);
        break;
    }    
}

fclose(fp);

return 0;
}

example of the content of the .txt :

┌───────────────────────┐
│   []   []   []   []   │
│ []  []   []   []   [] │
│   []   []   []   []   │
│                       │
│   ┌──┐       ┌──┐     │
└───┘  └───────┘  └─────┘

output in terminal :

�~T~L�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@    �~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~P
�~T~B   []   []   []   []   �~T~B
�~T~B []  []   []   []   [] �~T~B
�~T~B   []   []   []   []   �~T~B
�~T~B                       �~T~B
�~T~B   �~T~L�~T~@�~T~@�~T~P       �~T~L�~T~@�~T~@�~T~P     �~T~B
�~T~T�~T~@�~T~@�~T~@�~T~X       �~T~T�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~@�~T~X      �~T~T�~T~@�~T~@�~T~@�~T~@�~T~@�~T~X

thanks for any ideas

I do not think that the code you posted shows us the error ... i suggest you to edit it and post more code, with a piece of the .txt file too. — Gam, Sep 28 '17 at 20:53
Maybe [this](https://stackoverflow.com/questions/34538814/print-unicode-characters-in-c-using-ncurses) can help ? — Quentin Laillé, Sep 29 '17 at 09:14
@QuentinLaillé so I have to do a switch on the input then output the right constant? — Fire Frost, Sep 29 '17 at 09:26
If you modify the printw() by `printw("%d\n", c);` is it the characters you wanted ? — Gam, Sep 29 '17 at 12:43

Thomas Dickey · Answer 1 · 2017-09-29T22:38:29.357

Generally speaking, curses will display POSIX character set printable characters as you intended. For anything else, there are additional steps (and limitations).

For ncurses, you'll have to initialize the locale to get it to print codes 160-255 as characters. That is mentioned in the ncurses manual's section on initialization.

But if your locale uses UTF-8 encoding (as the typical out-of-the-box "desktop" system does), then ncurses will expect the application to supply the bytes for UTF-8, e.g., using addch or addstr. printw might work in that case, although no one's commented on success (or failure) for that special case.

If the value is 128-159, some of those bytes (referring to addch) could be part of a UTF-8 encoded character, and depending on whether you initialized the locale in ncurses, you would get different results.

Either way (128-159 or 160-255), you'll get behavior as shown when ncurses prints those values in a terminal which displays UTF-8.

Other values in the 0-255 range are control characters.

Since your example uses fgetc, we need not consider values above 255.

Assuming that your example is in UTF-8, this program (linked with ncursesw, the wide-character library) would display the text as intended:

#include <curses.h>
#include <locale.h>

int
main(void)
{
    FILE *fp;
    int c;

    setlocale(LC_ALL, "");

    fp = fopen("./files/map.txt", "r");
    if (fp == 0)
        return 1;

    initscr();
    cbreak();
    noecho();

    // Read and display data 

    while ((c = fgetc(fp)) != EOF) {
        switch (c) {
        case 'p':
            // todo : emoji
            break;
        default:
            printw("%c", c);
            break;
        }
    }
    getch();
    endwin();

    fclose(fp);

    return 0;
}

I have tried to use setlocale like they say in initialization but it prints diffrent caracters now, │ -> M-3 — Fire Frost, Sep 29 '17 at 11:11

score 0 · Accepted Answer · answered Sep 29 '17 at 15:24

0

To use the extended ascii caracters, you need to use nursesw and not ncurses

you will need to apt-get ncursesw to use it

the include in your main still remains #<ncurses.h>

when you compile, you put -lncursesw

answered Sep 29 '17 at 15:24

Fire Frost

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printw (ncurses) not displaying correct char in c

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