Archive Magazine CD 1995/Archive Magazine CD 1995.iso/text/hints/volume_03/issue_06

Text File | 1995-02-16 | 7.1 KB | 208 lines

•   !chars − which is available as !1stchars with FWPlus version 2 and
is also available on SID + Archive BBS + various PD discs, can be used
for “mousing” text into !Draw applications.
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•   !Draw − You can use the cursor keys for fine positioning when
drawing Bezier curves or lines.
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•   !Madness − I was always very disappointed with this Demo − until I
looked at the !RunImage file and found a variable called madspeed% −
guess what changing it to 1 does? Rob Davison
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•   !system on floppies − Those of you without hard discs will have
!system on various of your floppies. The trouble is that when you change
to other discs, even if they have !system on them, you will be asked to
insert the disc containing !system that the com-puter saw first of all.
To get round this, double click on !system on the current disc before
trying to launch applications from the disc.
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•   Art Nouveau − Fills approximating to graduated, logarithmic,
circular etc can easily be ‘designed’ and saved to disc. For example:
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Approx circle fill − Set a small grid size and switch it on. Draw
several concentric filled circles, selecting each shade as you go. Smear
the edges with ‘colour merge’ if you don’t want the bands of colour to
show. Pick it up as a brush and use with: brush, effects1, distort x (or
y). Some of the effect that Pro-Artisan and Atelier have as features can
be cobbled together with a little effort using Art Nouveau (at half the
price!). D P Allen.
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•   Beware the SUM! − If you rely on indentation in your programs to
keep a check on the structure of the various loops, beware that SUM(A())
will cause an extra indent. Is there any way round this? Fred Hartley,
Hayes.
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•   Booting − When booting the Archimedes up it is tempting to just
refer to applications assuming their path starts at the root ($). e.g.
!Edit − can be installed on the desktop using just !Edit in a boot file.
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However, this will not ensure the appropriate system variable is set up
with the full pathname. Again using !Edit as example, you would get just
− Edit$Dir = !Edit
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To avoid this put the full name in the desktop boot file, e.g.
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*Run adfs:HardDisc.$.!Edit
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Only of much use if, like me, you decide to set the directory yourself
while using Desktop (despite what Acorn advise!). Ian Pollock
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•   Graph-Box − superb program but I find it very annoying that it
‘dies’ when you close the window. The following changes will give
Graphbox an icon on the iconbar. It will only ‘die’ when you click
<menu> followed by ‘quit’ as Edit and Draw etc. This lets you clear some
valuable desktop space to write a letter or whatever. while still having
Graphbox available on the icon bar.
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*BASIC
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LOAD “!GraphBox.!RunImage”
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 220 WHEN 3:PROCclosew(!q%):IF!q%=
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w_graphbox% THEN mainclosed%=TRUE
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 560 quit%=FALSE:mainclosed%=FALSE
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4590 WHEN0:PROCclosew(w_graphbox%)
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:quit%=TRUE
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5291 Icon%=sprites%:!Icon%=TRUE:
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DIM Spritename% 14:$Spritename%=
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“!graphbox”:Icon%!4=0:Icon%!8=0:
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Icon%!12=64:Icon%!16=68:Icon%!20=
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(&311A OR (7<<28))
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5292 Icon%!24=Spritename%:Icon%!28=1:
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Icon%!32=12:SYS “Wimp_CreateIcon”
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,,Icon% TO graph_iconbar%
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5445 READ t$:m_iconbar%=FNcrmenu(t$)
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5447 DATA “#Graphbox,Info>w_pinfo%,
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Quit“
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5710 REM quit%=TRUE
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6395 IF mh%=-2 AND mb%=4 OR mb%=1024
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 AND mi%=graph_icnbar% THEN PROCgetw
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(w_graphbox%):PROCfront(w_graphbox%
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,420,150):mainclosed%=FALSE
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7375 WHEN-2:IFmi%=graph_icnbar% THEN
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 PROCpop(m_iconbar%,-1)
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8219 IF menu%=m_iconbar% my%+=64
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8545 WHEN m_iconbar%:IF !mlist%=1
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 THEN quit%=TRUE
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16505 IFmainclosed%=TRUE PROCfront
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(w_graphbox%,420,150):
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mainclosed%=FALSE
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SAVE “!GraphBox.!RunImage”
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NOTE: Graphbox claims what you have in your next slot up to a max of
640k but as the program needs only a minimum of around 200k to run,
there’s space for a very big graph! Before loading Graphbox, drag the
‘next’ slot down to about 330k to free some more space. You can edit the
!run file and change the -max to reconfigure it more permanently. Rob
Davison
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•   Installing Alerion − Here are the steps you must take in order to
install RISC-OS Alerion onto your hard disc:
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(i) create a RAM disc with at least 432k
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(ii) copy the !Alerion directory into the RAM disc
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(iii) alter the RAM disc !Boot file in the !Alerion directory so that it
reads:
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IconSprites <Obey$Dir>.!Sprites
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(iv) also alter the !Run file so that reads:
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Set Alerion$Dir <Obey$Dir>
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RMClear
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RMLoad MemAlloc
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RMSize 320k
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ScreenSize 160k
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RMKill MemAlloc
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Run <Alerion$Dir>.!RunImage
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(v) copy the !Alerion directory from the RAM disc to your hard disc.
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•   Rounding Errors − Try typing P.STR$(0.6) in BASIC. If you are
putting the string of a variable into a writeable menu option when
programming a wimp system and this rounding error comes up, the
resulting string can overwrite some of the data structure for your menu.
The result is often an “Abort on data transfer”! This can be quite hard
to track down so be careful. DIMming the block to 5 bytes will stop a
crash but will leave the user with a 0.6666666669 to edit instead of
0.6. This can be a bit disconcerting. To solve it, set @% to round to
e.g. 2 decimal places before doing the STR$ and reset @% afterwards −
see 400 series BASIC Guide pp277-278 for details. Rob Davison
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•   Screen modes & memory claiming − If your program has a proper RISC-
OS front end, it can change modes without worrying about screen memory.
If there is enough in ‘free’ and ‘next’ it will be shunted to screen
memory and the mode selected. Rob Davison
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•   Synthesiser MIDI modes − The answer to Gerald Fitton’s problem
(issue 2.12 p 18) that his Korg synthesiser plays all channels no matter
what he does, is that his synthesiser is not in the correct MIDI mode.
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All MIDI devices operate under modes. These are as below:
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   MIDI mode 1:   OMNI On/Poly
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   MIDI mode 2:   OMNI On/Mono
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   MIDI mode 3:   OMNI Off/Poly
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   MIDI mode 4:   OMNI Off/Mono
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OMNI On/Off selects whether the device receives on all MIDI channels
(OMNI On) or only on one MIDI channel (OMNI Off). Poly means that the
device will be able to play two or more notes at the same time and Mono
means that it will only be able to play one at a time. The Korg will
almost certainly be in MIDI mode 1, which is how most synthesisers are
set up when they are sent from the shop. The answer is to change the
MIDI mode to 3 or 4 and to set the Korg to receive on the same MIDI
channel as Maestro is sending.
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•   Wimp Resizing − I have written a program which needs a large area of
memory as store for data. The program works in the desktop and claims
memory via SYS “Wimp_SlotSize”. Initially, I used the BASIC statement
“END=HIMEM + value%” but this also changes the address of HIMEM. Loops,
procedures and local variables are stored just below HIMEM so my data
was being overwritten. I tried lowering HIMEM immediately afterwards but
things still went wrong so I use “Wimp_SlotSize” directly. BASIC is
ignorant of the new memory area and it can therefore be safely used as a
store. Use a variable “Claimer%’ and exit the Wimp_Poll loop if it’s not
zero then call Wimp_SlotSize. R.D.
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