[linux-2.6-block.git] / Documentation / admin-guide / vga-softcursor.rst

Software cursor for VGA
=======================

by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
and Martin Mares <mj@atrey.karlin.mff.cuni.cz>

Linux now has some ability to manipulate cursor appearance.  Normally,
you can set the size of hardware cursor.  You can now play a few new
tricks: you can make your cursor look like a non-blinking red block,
make it inverse background of the character it's over or to highlight
that character and still choose whether the original hardware cursor
should remain visible or not.  There may be other things I have never
thought of.

The cursor appearance is controlled by a ``<ESC>[?1;2;3c`` escape sequence
where 1, 2 and 3 are parameters described below. If you omit any of them,
they will default to zeroes.

first Parameter
	specifies cursor size::

		0=default
		1=invisible
		2=underline,
		...
		8=full block
		+ 16 if you want the software cursor to be applied
		+ 32 if you want to always change the background color
		+ 64 if you dislike having the background the same as the
		     foreground.

	Highlights are ignored for the last two flags.

second parameter
	selects character attribute bits you want to change
	(by simply XORing them with the value of this parameter). On standard
	VGA, the high four bits specify background and the low four the
	foreground. In both groups, low three bits set color (as in normal
	color codes used by the console) and the most significant one turns
	on highlight (or sometimes blinking -- it depends on the configuration
	of your VGA).

third parameter
	consists of character attribute bits you want to set.

	Bit setting takes place before bit toggling, so you can simply clear a
	bit by including it in both the set mask and the toggle mask.

Examples
--------

To get normal blinking underline, use::

	echo -e '\033[?2c'

To get blinking block, use::

	echo -e '\033[?6c'

To get red non-blinking block, use::

	echo -e '\033[?17;0;64c'
Commit	Line	Data
27641b95 MCC	1	Software cursor for VGA
27641b95 MCC	2	=======================
1da177e4	3
27641b95 MCC	4	by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
	5	and Martin Mares <mj@atrey.karlin.mff.cuni.cz>
	6
5266e703 LT	7	Linux now has some ability to manipulate cursor appearance. Normally,
	8	you can set the size of hardware cursor. You can now play a few new
	9	tricks: you can make your cursor look like a non-blinking red block,
	10	make it inverse background of the character it's over or to highlight
	11	that character and still choose whether the original hardware cursor
	12	should remain visible or not. There may be other things I have never
	13	thought of.
1da177e4	14
27641b95	15	The cursor appearance is controlled by a ``<ESC>[?1;2;3c`` escape sequence
1da177e4 LT	16	where 1, 2 and 3 are parameters described below. If you omit any of them,
	17	they will default to zeroes.
	18
27641b95 MCC	19	first Parameter
	20	specifies cursor size::
	21
	22	0=default
	23	1=invisible
	24	2=underline,
	25	...
	26	8=full block
	27	+ 16 if you want the software cursor to be applied
	28	+ 32 if you want to always change the background color
	29	+ 64 if you dislike having the background the same as the
	30	foreground.
	31
	32	Highlights are ignored for the last two flags.
	33
	34	second parameter
	35	selects character attribute bits you want to change
	36	(by simply XORing them with the value of this parameter). On standard
	37	VGA, the high four bits specify background and the low four the
	38	foreground. In both groups, low three bits set color (as in normal
	39	color codes used by the console) and the most significant one turns
	40	on highlight (or sometimes blinking -- it depends on the configuration
	41	of your VGA).
	42
	43	third parameter
	44	consists of character attribute bits you want to set.
1da177e4	45
27641b95 MCC	46	Bit setting takes place before bit toggling, so you can simply clear a
27641b95 MCC	47	bit by including it in both the set mask and the toggle mask.
1da177e4	48
7358bb2f JC	49	Examples
7358bb2f JC	50	--------
1da177e4	51
27641b95 MCC	52	To get normal blinking underline, use::
	53
	54	echo -e '\033[?2c'
	55
	56	To get blinking block, use::
	57
	58	echo -e '\033[?6c'
	59
	60	To get red non-blinking block, use::
	61
	62	echo -e '\033[?17;0;64c'