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twMDefCrs( nCurType, nScrMask, nCurMask )
----------------------------------------------------------------------------
There are two types of mouse cursor in text mode, a hardware and a
software cursor. The hardware cursor is based on the number of
scan lines displayed in a pixel, much like the normal cursor. If
you choose the hardware cursor, you should shape it differently
from the normal text cursor in order to distinguish between the
two. The software cursor is depends on a screen and cursor mask
passed to it in nScrMask and nCurMask.
The software cursor is most common since it may be defined in more
ways than the hardware cursor. The attribute and character bytes
at the mouse cursor's location are ANDed with the screen mask and
XORed with the cursor mask to determine the form it will take. The
standard default is to reverse the character's attributes:
Bit 15 8 7 0
Screen Mask: 01110111 11111111 - 77FFh
Cursor Mask: 01110111 00000000 - 7700h
| |
| +----- ASCII character
+-------------- Attribute byte
For the attribute byte, bit 15 sets blinking or non-blinking.
12-14 sets background colour.
11 sets high or medium intensity.
For the character byte, 0 - 7 is th ASCII character code.
To leave the ASCII character unchanged,
the screen mask must be xxFF, and
the cursor mask must be xx00.
Arguments:
nCurType - 'N' 0 for software cursor.
1 for hardware cursor.
nScrMask - 'N' Screen mask for software cursor or starting scan
line for hardware cursor.
nCurMask - 'N' Cursor mask for software cursor or ending scan line
for hardware cursor.
Return:
Nothing.
Example:
twMDefCrs( 0, ( 119 * 256 ) + 255, ( 119 * 256 )) yields the
default mouse cursor definition.
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Written by Dave Pearson