=> R0 = Reason code
Others vary according to reason code.
<= Vary according to reason code.
Euclid_MiscOp covers a number of general functions, some of which now have
their own dedicated entry. The list can be expanded if you wish, to include
functions to return pointers to internal tables/use of Euclid's internal
arithmetic calculations. Please apply in writing if you have some particular
need.
Euclid_MiscOp Reason Codes
R0 /Meaning/
0 Superceded by Euclid_Compress (Swap R3,R4;R0=0)
1 Superceded by Euclid_Expand (Swap R3,R4;R0=0)
2 Return the system Materials block pointer
3 Smooth the image
4 Check block size
The following two MiscOps are for handling the 16 colour modes:
5 Return dither pattern
6 Invalidate palette cache
Euclid_MiscOp 2
Return the system Materials block pointer.
=> R0 = 2
<= R0 ! System Materials table.
The pointer is for you to copy the table or to examine it for Material
names. If you Load or Append a file then the system automatically finds the
last Materials block in the picture structure and puts its pointer in at
Block+72. (Future versions of Euclid may also delete all other Materials
blocks - be warned!)
Euclid_MiscOp 3
Smooth the image
=> (Current graphics window.)
R0 = 3
R1 = Set to zero for future expansion.
<= -
Does a form of smoothing to the image. It is expected that this function
will be expanded to allow various other forms of image post-processing. Any
suggestions welcome. The current form only works in a 256-colour mode.
Euclid_MiscOp 4
Check block sizes
=> R0 = 4
R1 = Block identifier
<= R0 = Fixed header size
R1 = Variable section size
Returns a definitive value for the fixed/variable parts of a block
irrespective of what this manual says! Note that this call returns an error
for a bad id, so a function to return the varying part might be:
DEF FNVARY(ID%)
SYS"XEuclid_MiscOp",4,ID% TO F%,V%
=-(F%<256)*V%
Euclid_MiscOp 5
Return dither pattern
=> R0 = 5
R1 = Colour:
Bits 0-7 Red component
Bits 8-15 Green component
Bits 16-23 Blue component
<= R0 = Bytes for screen
The call would normally be in a sequence like:
SYS"Euclid_MiscOp",5,Colour% TO Byte%
A%=Byte%:B%=Byte%<<4 OR Byte%>>4:REM swap nibbles
VDU 23,2,A%,B%,A%,B%,A%,B%,A%,B%:GCOL 16,0
After this a good representation of the colour will occur using a checkerboard dither.
Euclid_MiscOp 6
Invalidate palette cache
=> R0 = 6
<= -
In order not to spend too long recalculating a suitable palette for the 16
colour modes, the module keeps a copy of the current palette after it has
calculated it. This cached palette is invalidated on a Mode change, but the
Module is unaware of palette changes, so this call must be used when an
application receives a 'Palette changed' message.
[sh-index] Back to list of manuals
|
| |
