Check Char at Current/Given Position in Pdcurses/Ncurses

Check char at current/given position in PDCurses/NCurses

The inch family of functions should do that:

chtype inch(void);
chtype winch(WINDOW *win);
chtype mvinch(int y, int x);
chtype mvwinch(WINDOW *win, int y, int x);

Reading changes from screen

Curses keeps an internal map of the window, you can interrogate it with:

 chtype inch(void);
 chtype winch(WINDOW *win);
 chtype mvinch(int y, int x);
 chtype mvwinch(WINDOW *win, int y, int x);

You'll have to read each position in the window.

The chtype contains the character and flags for effects like bold etc

How to implement a scroll or list box in NCurses/PdCurses? ( C )

scrollok doesn't magically create a scroll box, it just allows the window to be scrolled up. You do not even need scrollok for your purpose. Just

• maintain an index i to the topmost name which is to be displayed (initially 0)
• print height h names from index i to min(i+h-1, i_max) to the window, starting at the topmost line
• when user presses "N", if i+h ≤ i_max then set i to i+h, clear window box, go to print
• when user presses "P", if i > 0 then set i to i-h, clear window box, go to print

How to implement a scroll or list box in NCurses/PdCurses? ( C )

scrollok doesn't magically create a scroll box, it just allows the window to be scrolled up. You do not even need scrollok for your purpose. Just

• maintain an index i to the topmost name which is to be displayed (initially 0)
• print height h names from index i to min(i+h-1, i_max) to the window, starting at the topmost line
• when user presses "N", if i+h ≤ i_max then set i to i+h, clear window box, go to print
• when user presses "P", if i > 0 then set i to i-h, clear window box, go to print

printw() won't print a single character from a uint8_t array

You need to get rid of the carriage return (CR) characters (\r).

When you output a CR, ncurses resets the cursor to the first column in the same row. Then when you output a NL (\n), ncurses erases from the cursor position to the end of the row before advancing the cursor to the next row. That effectively deletes the entire row that was just printed.

This behaviour is documented, for what it's worth. From man waddch (emphasis added):

If ch is a tab, newline, or backspace, the cursor is moved appropriately within the window. Backspace moves the cursor one character left; at the left edge of a window it does nothing. Newline does a clrtoeol, then moves the cursor to the window left margin on the next line, scrolling the window if on the last line. Tabs are considered to be at every eighth column. The tab interval may be altered by setting the TABSIZE variable.

The response to a carriage return is documented in the ncurses waddch manpage, at the end of the PORTABILITY section:

If ch is a carriage return, the cursor is moved to the beginning of the current row of the window. This is true of other implementations, but is not documented.

(Thanks to Thomas Dickey for pointing to the PORTABILITY section.)

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