CODEWITHSUNDEEP
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Fire Frost
Fire Frost

Reputation: 135

printw (ncurses) not displaying correct char in c

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

Upvotes: 0

Views: 1524

Answers (2)

Thomas Dickey
Thomas Dickey

Reputation: 54465

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;
}

Upvotes: 1

Fire Frost
Fire Frost

Reputation: 135

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

Upvotes: 0

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