Functions:

tty tty_init(int sx, int sy, int resizable);

Creates a new vt100 terminal, of size sxXsy. If you want user input to be allowed to change that size, set resizable to non-zero.

int tty_resize(tty vt, int nsx, int nsy);

Resizes the vt to nsxXnsy. This works even on terminals marked as non-resizable since that prevents only user input from resizing, not you.

void tty_reset(tty vt);

Clears the screen and attributes.

void tty_free(tty vt);

Deallocates the vt and all its internal structures.

void tty_write(tty vt, const char *buf, int len);

Writes len bytes into the terminal, parsing them as vt100 codes.

void tty_printf(tty vt, const char *fmt, ...);

Does a printf into the terminal.

tty tty_copy(tty vt);

Allocates a new vt100 terminal, making it an exact copy of an existing one, including its internal state. Attached event callbacks are not copied.

uint32_t tty_color_convert(uint32_t c, uint32_t to);

Converts color values between modes: VT100_COLOR_OFF, VT100_COLOR_16, VT100_COLOR_256, VT100_COLOR_RGB.

Inside the terminal

You'll most likely be interested in the following fields of the structure:

tty {

int sx,sy; // screen size

int cx,cy; // cursor position

attrchar *scr; // screen buffer

int attr; // current attribute

char *title; // window title

scr is an array of character/attribute pairs, more exactly, each element is a struct "{ ucs ch; int attr; }". The array is a flat one of vt->sx*vt->sy elements, arranged row by row. A screen coordinate x,y is stored at x+y*vt->sy.

For other fields, please RTFS the header itself: tty.h

TTY event callbacks

Well, you have written some data to the terminal. Now you probably want to put it somewhere. What now? The tty structure has a number of event hooks that you can attach your functions to.

These hooks are callbacks inside the tty structure that you can set. The callback fields are:

void *l_data;

it's a place to put your private data in

void (*l_char)(tty vt, int x, int y, ucs ch, int attr, int width);

after a character has been written to the screen; the cursor advances by width which might be 1 (regular) or 2 (CJK "fullwidth")

void (*l_cursor)(tty vt, int x, int y);

after the cursor has moved

void (*l_clear)(tty vt, int x, int y, int len);

after a chunk of screen has been cleared

If an endpoint spills outside of the current line, it will go all the way to an end of screen.

If the cursor moves, you'll get a separate l_cursor, although it is already in place during the l_clear call.

void (*l_scroll)(tty vt, int nl);

after the region s1<=y<s2 is scrolled nl lines (nl<0 -> backwards, nl>0 -> forward).

There's no separare l_cursor event, cx and cy are already updated.

void (*l_flag)(tty vt, int f, int v);

when a flag changes to v. Flags that are likely to be of interest to you are:

void (*l_osc)(tty vt, int cmd, const char *str);

when a string command has been issued; most commands alter a color palette, but the most interesting one is 0: "set window title"

void (*l_resize)(tty vt, int sx, int sy);

after the terminal has been resized

void (*l_flush)(tty vt);

when a write chunk ends

void (*l_bell)(tty vt);

upon a beep

void (*l_free)(tty vt);

before the terminal is destroyed

Vt-on-vt redirection

For the case when you want the output go to a real terminal, there are:

void vtvt_attach(tty vt, FILE *f, int dump);

Attaches the FILE stream f to terminal vt. Usually, f will be stdout. Whenever the contents of vt changes, appropriate data will be written to the stream as well. If dump is non-zero, the current state will be drawn, otherwise, only subsequent changes will be shown.

The redirection will last until the terminal is destroyed by tty_free().

void vtvt_resize(tty vt, int sx, int sy);

Tells libtty that the real terminal has been resized (for resizing the virtual one, please use tty_resize()).

void vtvt_dump(tty vt);

Forces a full-screen redraw of the current contents of vt.