Screen Control

Screen control methods are thin wrappers around ANSI/VT commands for clearing, inserting, deleting, scrolling, and alternate-screen rendering. They emit output only when terminal commands are enabled.

#include <kaycxx/term.hpp>
 
using namespace kaycxx::term;
 
int main() {
    auto term = terminal();
 
    term.clear_screen();
}

Clearing

The clear methods erase visible terminal cells or the terminal scrollback buffer. They do not move the cursor unless the terminal itself has unusual behavior.

• clear_screen() clears the complete visible screen.
• clear_screen_to_end() clears from the cursor position to the end of the visible screen.
• clear_screen_to_start() clears from the beginning of the visible screen to the cursor position.
• clear_scrollback() clears the terminal's scrollback history when supported. This affects the off-screen history that the user can normally scroll back to, not just the currently visible cells.
• clear_line() clears the complete current line.
• clear_line_to_end() clears from the cursor position to the end of the current line.
• clear_line_to_start() clears from the beginning of the current line to the cursor position.

term.clear_screen();
term.clear_screen_to_end();
term.clear_screen_to_start();
term.clear_scrollback();
term.clear_line();
term.clear_line_to_end();
term.clear_line_to_start();

Lines and Cells

Line and cell operations edit terminal contents at the current cursor position. Counted variants do nothing when the count is zero or negative.

• insert_line() inserts one blank line at the current row. Existing lines in the active scrolling region move down.
• insert_lines(count) inserts multiple blank lines at the current row.
• delete_line() deletes one line at the current row. Lines below it move up.
• delete_lines(count) deletes multiple lines at the current row.
• clear_cell() replaces the cell at the cursor position with a blank cell. Text to the right is not shifted.
• clear_cells(count) replaces multiple cells starting at the cursor position with blank cells. Text to the right is not shifted.
• insert_cell() inserts one blank cell at the cursor position. Text to the right shifts right within the current line.
• insert_cells(count) inserts multiple blank cells at the cursor position.
• delete_cell() deletes one cell at the cursor position. Text to the right shifts left within the current line.
• delete_cells(count) deletes multiple cells at the cursor position.

term.insert_line();
term.insert_lines(3);
term.delete_line();
term.delete_lines(3);
 
term.clear_cell();
term.clear_cells(8);
term.insert_cell();
term.insert_cells(4);
term.delete_cell();
term.delete_cells(4);

Scrolling

The scroll region limits where scroll_up and scroll_down operate. Reset the region when the constrained area is no longer needed.

term.set_scroll_region(3, 20);
term.scroll_up();
term.scroll_down(2);
term.reset_scroll_region();

Alternate Screen

The alternate screen is useful for fullscreen terminal interfaces. It gives the program a separate screen buffer and usually restores the normal screen when leaving.

term.enter_alternate_screen();
term.clear_screen();
 
// Render fullscreen UI.
 
term.leave_alternate_screen();