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FT_MDEFCRS()
Define the mouse cursor
------------------------------------------------------------------------------
Syntax
FT_MDEFCRS( <nCrsType>, <nScrMask>, <nCrsMask> ) -> NIL
Arguments
<nCrsType> is the cursor type. A value of 0 indicates the software cursor
(the default) and a value of 1 indicates the hardware cursor.
<nScrMask> is the screen mask for the software cursor or the first scan
line of the hardware cursor. See the description for more
information.
<nCrsMask> is the cursor mask for the software cursor of the last scan
line of the hardware cursor. See the description for more
information.
Returns
NIL
Description
In text mode the mouse cursor can either be a software generated or
the actual hardware cursor. This routine allows one choose between them.
The software cursor is the default and its effect on the character it
covers is determined by the screen mask and the cursor mask. Both of
these masks are 16 bit values (which in Clipper are passed as standard
numerical values). The 16 bit masks are arranged in a manner identical
to the way information is stored for each character cell on the screen.
The low order 8 bits represent the actual character displayed while the
high order bits represent the display atributes such as blinking,
intensity and forground and background colors. The mask is represented in
the diagram below:
Bit: |15 |14 12|11 |10 8|7 0|
Function:|blink |background|intensity|foreground|character|
Blinking and high intensity are on when the bit is 1. The background and
foreground indicate which colors are used for each. The software mouse
cursor uses these two values by taking the mask from the screen cell it
is on and performing a logical AND on each bit with the screen mask
value. The result is then logically XOR'ed with the cursor mask value.
Thus to keep the character the same but invert the foreground and
background colors the following values would be used:
Bit: |15 |14 12|11 |10 8|7 0|
Function:|blink |background|intensity|foreground|character|
screen: | 0 | 111 | 0 | 111 |11111111 | =30719
cursor: | 0 | 111 | 0 | 111 |00000000 | =30464
The hardware cursor is the text cursor provided by the video board. One
specifies the range of scan lines which are on using <nScrMask> and
<nCrsMask>. The range of values is dependant upon the type of monitor.
The first scan line is 0.
Source: MOUSE1.PRG
Author: Leo Letendre
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