Cursor and Screen

Typedefs
typedef enum ConEraseMode	ConEraseMode
	Which portion of a line or screen to erase, relative to the current cursor position.

Enumerations
enum	ConEraseMode { CON_EraseToEnd , CON_EraseToStart , CON_EraseAll }
	Which portion of a line or screen to erase, relative to the current cursor position. More...

Functions
bool	conSetCursor (ConStream *con, uint16 row, uint16 col)
bool	conMoveCursor (ConStream *con, int16 drow, int16 dcol)
bool	conGetCursor (ConStream *con, uint16 *row, uint16 *col)
bool	conShowCursor (ConStream *con, bool show)
bool	conSaveCursor (ConStream *con)
bool	conRestoreCursor (ConStream *con)
bool	conEraseLine (ConStream *con, ConEraseMode mode)
bool	conEraseScreen (ConStream *con, ConEraseMode mode)
bool	conScroll (ConStream *con, int16 lines)
bool	conAltScreen (ConStream *con, bool enable)

Detailed Description

Enumeration Type Documentation

ConEraseMode

enum ConEraseMode

Which portion of a line or screen to erase, relative to the current cursor position.

Enumerator
CON_EraseToEnd	From the cursor to the end of the line/screen.
CON_EraseToStart	From the start of the line/screen to the cursor.
CON_EraseAll	The entire line/screen.

Definition at line 15 of file concursor.h.

Function Documentation

conAltScreen()

bool conAltScreen	(	ConStream *	con,
		bool	enable
	)

Switches to (or back from) the terminal's alternate screen buffer, if available (see ConCaps::altscreen). Only ever available under VT – the legacy Windows console has no equivalent, so this always fails there.

Parameters

con	Destination stream
enable	true to switch to the alternate screen, false to switch back

Returns

true on success

conEraseLine()

bool conEraseLine	(	ConStream *	con,
		ConEraseMode	mode
	)

Erases part or all of the current line. The cursor position does not change.

Parameters

con	Destination stream
mode	Which portion of the line to erase

Returns

true on success

conEraseScreen()

bool conEraseScreen	(	ConStream *	con,
		ConEraseMode	mode
	)

Erases part or all of the screen. The cursor position does not change.

Parameters

con	Destination stream
mode	Which portion of the screen to erase

Returns

true on success

conGetCursor()

bool conGetCursor	(	ConStream *	con,
		uint16 *	row,
		uint16 *	col
	)

Reports the cursor's current absolute position.

Only available when ConCaps::cursorquery is true – querying position under VT would require sending a DSR request and reading the reply from stdin, racing with any other input consumer and potentially hanging against a terminal that never answers, so this module never attempts it. Use conSaveCursor()/conRestoreCursor() instead, which is what most callers actually need and works under VT too.

Parameters

con	Stream to query
row	Receives the 0-based row
col	Receives the 0-based column

Returns

true on success; false if the stream cannot report its position

conMoveCursor()

bool conMoveCursor	(	ConStream *	con,
		int16	drow,
		int16	dcol
	)

Moves the cursor relative to its current position. Positive drow moves down, positive dcol moves right; either may be negative.

On a stream without ConCaps::cursorquery (most VT terminals), this still works even though conGetCursor() would fail – moving relative to the current position doesn't require knowing what that position is.

Parameters

con	Destination stream
drow	Rows to move (negative moves up)
dcol	Columns to move (negative moves left)

Returns

true on success

conRestoreCursor()

bool conRestoreCursor

(

ConStream *

con

)

Restores the cursor position most recently saved with conSaveCursor(). A no-op returning false if nothing has been saved.

Parameters

con	Stream to restore

Returns

true on success

conSaveCursor()

bool conSaveCursor

(

ConStream *

con

)

Saves the current cursor position for a later conRestoreCursor().

Only one position is remembered at a time; a second conSaveCursor() before a matching conRestoreCursor() overwrites the first.

Parameters

con	Stream whose cursor position to save

Returns

true on success

conScroll()

bool conScroll	(	ConStream *	con,
		int16	lines
	)

Scrolls the screen content. Positive lines scrolls up, revealing blank lines at the bottom; negative scrolls down, revealing blank lines at the top. The cursor position does not change.

Parameters

con	Destination stream
lines	Number of lines to scroll (negative scrolls down)

Returns

true on success

conSetCursor()

bool conSetCursor	(	ConStream *	con,
		uint16	row,
		uint16	col
	)

Moves the cursor to an absolute position.

A no-op returning false if the stream has no cursor capability (see ConCaps::cursor).

Parameters

con	Destination stream
row	0-based row
col	0-based column

Returns

true on success

conShowCursor()

bool conShowCursor	(	ConStream *	con,
		bool	show
	)

Shows or hides the cursor.

Parameters

con	Destination stream
show	true to show, false to hide

Returns

true on success