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Diffstat (limited to 'Documentation/admin-guide/vga-softcursor.rst')
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diff --git a/Documentation/admin-guide/vga-softcursor.rst b/Documentation/admin-guide/vga-softcursor.rst new file mode 100644 index 000000000000..9eac6744b3a1 --- /dev/null +++ b/Documentation/admin-guide/vga-softcursor.rst @@ -0,0 +1,66 @@ +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 (and also work around some ugly bugs in +those miserable Trident cards [#f1]_. 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. + +.. [#f1] see ``#define TRIDENT_GLITCH`` in ``drivers/video/vgacon.c``. + +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' |