\input texinfotimes
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Mostra
is an IFF ILBM viewer that can process any
IFF ILBM file; this means not only IFF ILBM FORMs,
but also nested ILBM, FTXT, FORMs, CATs, LISTs and
PROPs. It is well renowned in the Amiga community for both its
robustness and its flexibility.
Any design requires tradeoffs: Mostra
tries to give you a good
balance of program size, speed (optimized assembler decompression routines)
and features. It tries to be enough smart to have always reasonable
defaults, but also lets you force any aspect of the display, such as
resolution and video flags. While it is not possible to foresee every
possible race condition, Mostra
should be able to cope with any
reasonable ILBM file.
Version 2.0 has been completely rewritten with the Release 2 in mind (and with an eye towards 3.0). This means complete AGA support, localization, clipboard reading, display database access, selectable autoscroll, no need for arp.library, and more. The support for SHAM images has been dropped, because the new PCHG chunk supports much better line-by-line palette changes.
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Mostra
does not need any particular treatment when installed. However,
if you are interested in localization, you should take some care.
Localization means that Mostra
will try to give its messages in your
preferred language. It is a feature available under 2.1 and beyond. For it
to work, Mostra
has to be able to find out its catalogs. There
are two ways of doing this: either you copy the ‘Catalogs’ directory
coming with Mostra
’s distribution in the same directory where
Mostra
lives, or you copy the contents of the ‘Catalogs’
directory in your ‘Locale:Catalogs’ directory. The first solution
allows for easier maintenance, but with the second one you can move
Mostra
’s executable anywhere, and you will never have any problems.
If you decompress Mostra
’s archive, the ‘Catalogs’ directory
will be automatically created for you.
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Mostra
can be called both from the CLI and from the Workbench.
It is also a pure program, i.e., it can be made resident.
3.1 Command Line Usage | ||
3.2 Workbench Usage | ||
3.3 Keyboard Usage | ||
3.4 Options | ||
3.5 Examples |
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To get the command line syntax in AmigaDOS style, type ‘M ?’ followed by <RETURN>; this will produce the input template:
Mostra 2.0 Copyright (C) 1990-1994 Sebastiano Vigna Files/M,Clip/K/N,A=All/S,R=Repeat/S,Q=Quiet/S, NoFastDraw/S,C=Center/S,B=BlackBackground/S, Cycle/S,Secs/K/N,Fade/K/N,NO=NoStartup/S,Batch/K, LockPic/S,N=NoMouse/S,F=FreeMouse/S,LockKeys/S, NA=NoActivate/S,DB=DoubleBuffering/S,DM=DisplayMode/K, DC=DisplayClip/K,CAMG/K/N,W=Width/K/N,H=Height/K/N, AS=AutoScroll/S,HiRes/S,LoRes/S,SuperHiRes/S, Lace/S,NoLace/S,HAM/S,HalfBrite/S,FallBack/S, SMR=ScreenModeReq/S,FR=FileReq/S,PubScreen/K
(If you do not know how to read a template, take a look at the AmigaDOS manuals.)
Mostra
’s first argument is a list of patterns (or file names) as long
as you want; you will get every picture whose name matches one of the
patterns. The second argument specifies instead the number of a clipboard
unit to read (this will usually be 0). Note that you can specify both
arguments on the same line.
Alternatively, you can type only the ‘M’ character, and Mostra
will display the system file requester, allowing you to search for the picture
you want to show. Note that under version 2.1 and beyond you can select
multiple files using <SHIFT>-click.
For a detalied explanation of the keywords, see Options.
While showing each picture, Mostra
displays some information about the
file and the screen mode. First all the information IFF chunks (such as
ANNO, AUTH, et cetera) are printed, then the picture and the
display clip dimensions, followed by the size, depth and type of the screen,
are displayed.
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When Mostra
is called from Workbench without any argument icon, it will
pop up the file requester and will allow you to select the pictures to show.
Alternatively, you can <SHIFT>-select multiple icons together with
Mostra
’s one, or you can change the default tool of your pictures. For
details about this, see Startup Tool Types. Note that if you select an
IFF CAT or LIST you will have an automatic little slideshow.
When Mostra
is called from Workbench, it never outputs diagnostic or
error messages. If you have problem in displaying a picture, you may want to
try from the CLI. This can raise a problem if the ‘Repeat’ option is
used, and ‘BlackBackground’ is not specified (see section Options). In this
case, if none of the specified files and icons is an IFF picture, since no
window will be ever opened Mostra
will continue to endlessly scan the
argument list, and the only way of stopping it will be by sending a break
signal using the status
and the break
commands from the CLI,
or some task handling utility.
All the options available on the command line are available through tool types.
See section Options, and Startup Tool Types. You can also peek at the tool
types of Mostra
’s icon.
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Once you are looking at the picture you selected, you can exit by moving the mouse pointer to the very top of the screen and pressing the right button (you can also press the <RETURN>, <SPACE> or <ESCAPE> keys). You can drag or depth arrange the screen with the left mouse button (the gadget(s) are invisible, but they really are there!). <TAB> will toggle on/off color cycling. <SHIFT>-<TAB> will do the same, but it will also reset the palette to its initial value. To stop pattern matching or IFF scanning use <CTRL>-C at any moment.
If the screen size is less than the size of the picture, you can move around
with cursor keys alone (moving by 8 pixels) or in combination with the
<SHIFT> (a screenful minus 16 pixels), <ALT> (which brings you to
the borders), or <CTRL> (16 pixels) keys. A noteworthy feature of
Mostra
is that the picture is not decrunched all at one time
in a very large chunk of memory; instead, a fast assembler routine decrunches
the file in real-time every time you move (the routine could be faster, but it
has lots of controls to get rid of damaged IFF BODY chunks; safety
always first). This is not as fast as the memory-eating method, but I think
it’s much better. Very large pictures (like 800x900) will be shown in a
full screen (generated on the fly at Workbench size) in which you can move around.
Overscan pictures will retain their size of it’s not greater than the video
overscan available for the picture video mode (for instance, 362x283 lo-res
pixels in PAL, or 362x241 in NTSC). Small brushes will be shown in a
minimum 128x128 pixel screen. Of course, moving vertically with multi-palette
pictures involves a high system overhead, since Copper lists are continuously
built and deleted.
A weird effect of this method is that you can see pictures that can’t even be
loaded into your Amiga. Let’s suppose you have a really crunched
picture; the BODY chunk and a 256x256 lo-res screen could take much less
space than the decrunched picture, so you could create pictures that only
Mostra
could let you see in all of their parts. Why you would want to do
this, well, that’s another matter.
If you own a large amount of Chip memory, you can also consider using the
‘AutoScroll’ keyword, that will force Mostra
to decrunch the
whole picture in one gulp, and to use the system screen scrolling features.
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This list describes all the options available in Mostra
. The letters
between parentheses denote availability of a shortening. Options can be put
anywhere on the command line, or in tool types (see section Startup Tool Types).
All (A)
forces a recursive scan of all of the subdirectories during the wildcard search.
Repeat (R)
will endlessly restart from the first picture when it has finished with the
last one; this includes repeating the wildcard search, checking for the
clipboard, and opening the file requester, if any of these options has been
specified. If you used the FileReq
line argument, the Cancel
gadget will break the loop.
Quiet (Q)
turns off all messages except in case of error.
NoFastDraw
leaves the program at priority 0; by default, Mostra
will surround
the BODY decrunching operations with a SetTaskPri(1)
. This will
not lock the system, but in a multitasking situation Mostra
will
perform quickly when needed. If your program has already a priority greater
than one, Mostra
will leave it untouched.
Center (C)
will force the screen to be centered. Note that the centering is based on your Overscan preferences.
BlackBackground (B)
will create a 1-bitplane black screen that will stay until you saw the last picture. This is for aesthetic purposes only (note that almost no Chip memory will be used).
Cycle
will automatically activate color cycling on every picture. Usually this happens only by request, through <TAB>.
Secs
must be followed by a number between 0 and 1000. Mostra
will display
each picture for the number of seconds specified, but you can skip using the
mouse or the keyboard as usual (see section Keyboard Usage) or stop the show with
<CTRL>-C. Cursor keys are disabled.
Fade
lets you specify a speed for pictures to fade in and out. Valid numbers are 1 to 4, with four the slowest. Note that HAM pictures can’t be faded.
NoMouse (N)
will hide the mouse pointer while Mostra
is displaying a picture.
FreeMouse (F)
will let you pass from one picture to another by clicking either of the mouse buttons at any position on the screen.
LockKeys
will discard any input from the keyboard during the display. You must use
the mouse to pass to the following picture. Note that if FreeMouse
is not activated, the only way to go is clicking the right mouse button
while the mouse pointer is at the top of the screen.
LockPic
will lock the picture displayed. You won’t be able to scroll around, but the memory in which the file is loaded will be immediately freed after the decompression, thus minimizing the memory usage.
NoActivate (NA)
will inhibit the activation of the picture screens, so you can keep on typing on your current screen.
DoubleBuffering (DB)
sets a double buffering show mode: while a new picture is being loaded you will see the old one, no Workbench pop-up or black screens. It eats lots of memory, too.
DisplayMode (DM)
sets a specific display mode from the graphic database. For instance, you
can ask to display your picture in ‘NTCS:Lores’. Note that under 2.1
and beyond the database entries are localized, so that you need to
know the name of the display mode in the first language currently selected
in the locale preferences. This option is the safest and most precise way of
forcing a display mode (but see also the ScreeModeReq
option).
DisplayClip (DC)
sets a specific display clip from the graphic database. For instance, you
can ask to display the maximum available amount with ‘VIDEO’. Allowed
values are ‘TEXT’, ‘GRAPHICS’, ‘MAX’ and ‘VIDEO’. Note
that these entries are not localized. Under 3.0, in particular, the
‘VIDEO’ display clip allows you to see 736 pixel width pictures in
PAL and NTSC (see also the ScreeModeReq
option).
CAMG
sets a specific display ID, expressed as a decimal number. This option is mainly useful for developers. It has the same effect as a CAMG ILBM chunk.
Width (W)
Height (H)
want an argument that specifies a dimension of the viewing screen. However,
Mostra
is an intelligent program, and will almost always find the
correct screen by itself. The minimum allowed dimension is 128; smaller values
will be silently increased to this value. Note that if ‘AutoScroll’
was specified, only the display clip dimensions are changed—the screen will
retain its full size.
AutoScroll (AS)
sets the automatic scrolling feature. The whole picture has to be decompressed in a big chunk of Chip memory, but then you can scan through it very smoothly by moving the mouse towards the edges of the video (exactly like in a Workbench which is bigger than your screen size). It works also with multipalette pictures (but in rare occasions, some glitches may be visible in certain scroll positions).
HiRes
LoRes
SuperHiRes
Lace
NoLace
HAM
HalfBrite
force all screens to have the respective mode bit set (note that if
Mostra
finds a six bitplane picture with no CAMG chunk, it won’t
set the HAM
flag by default). These flags are dumb, that is, they
will do exactly what you say, even if it is meaningless. However, if you use
both HalfBrite
and HAM
together, only the former will take
place. You should avoid in general the use of these options, and rather ask
for a specific display mode with ‘DisplayMode’, ‘DisplayClip’ and
‘ScreenModeReq’.
FallBack
forces Mostra
to try to guess the best display mode with which it can
display a picture in case its natural (or user specified) display mode is not
available.
ScreenModeReq (SMR)
forces Mostra
to open the screen mode requester on the public screen
specified by the ‘PubScreen’ option, allowing you to specify a display
mode, display clip, screen size and optional autoscroll. This option is
functional only under 2.1 and beyond. Note that the selections made in the
requester will supersede all the related keywords (such as ‘Width’,
‘AutoScroll’ et cetera). However, if the keywords are specified
they will be used in order to initialize the requester fields.
FileReq (FR)
tells Mostra
to open the system file requester on the public screen
specified by the ‘PubScreen’ option. Note that you can specify this option
together with file names and clip numbers. Mostra
will turn its
attention to file names, clips and input from the file requester, in this order.
PubScreen
specifies a public screen to open the file and screen mode requesters on. The screen is moved to front before opening the requester. This option is functional only under 2.1 and beyond.
The NoStartup
and Batch
options will be discussed later, in
Startup Files.
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And now, some examples:
M MyPics:#? Secs 5 Fade 1 NoMouse BlackBackground Repeat Center All
will generate a slide show of the pictures in the ‘MyPics:’ directory and in all its subdirectories, centered and with no mouse pointer hanging around. In order to stop the slide show, you must press <CTRL>-C.
M df0:#?.image df0:pictures/#?.pic DisplayMode PAL:Hires
will show the files ending with ‘.image’ in the directory ‘df0:’
and the files ending with ‘.pic’ in the directory ‘df0:pictures’.
Mostra
will be forced to use high resolution screens.
M dh0:hirespic PAL:Lores AutoScroll
will show a hi-res picture in lo-res (zooming in). You can move around with the mouse.
Width
and Height
can be useful when you have a picture that
cannot be displayed because there’s not enough Chip RAM. In such a
case, try:
M pic Width 128 Height 128
This will usually allow you to at least get a peek at something.
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For maximum flexibility, Mostra
allows you to use startup files
and startup tool types, with which you can configure the program to
suit your tastes.
4.1 Startup Files | ||
4.2 Startup Tool Types | ||
4.3 Startup Examples |
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There is a standard startup file called ‘S:Startup-Mostra’. Mostra
will search for it whenever it is launched. The format of this file is
exactly the same as Mostra
’s command line format minus the
command name. Commands may be spread out over several lines or gathered
together onto a single line. Every switch or keyword in the startup file will
act as a default, and will be toggled or superseded by any command line
arguments. Command line switches will act as toggles (if your startup file has
the keyword All
and you say M * All
, you won’t go into
subdirectories), while keywords simply assert the new value (if you have
Fade 1
in your startup file and you say Fade 3
in the command
line, your pictures will be faded at speed 3).
Two options concern startup files:
NoStartup (NO)
inhibits the search for startup files, useful if you have one and you want to specify your options from scratch.
Batch
wants a complete path/filename that Mostra
will use as startup file.
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From the Workbench side, you can write the startup options in the tool types of
Mostra
’s icon, and Mostra
will use them. You have to fill each
tool type with an option (previous releases would allow even multiple options
on the same line, but this is in contrast with Commodore’s guidelines). Please
note that ‘Fade=1’, ‘Width=352’ are valid, but ‘FreeMouse=ON’ is
not; use only ‘FreeMouse’.
These options supersede or toggle the options specified in the startup file exactly as command line options. See section Startup Files. If you have no startup file, this does no matter.
You can also add tool types to a picture icon, and they will supersede or
toggle again the settings specified by the startup file and by Mostra
’s
icon tool types.
You can also prepare an icon with no related file, but having a tool type such as ‘Files=PICS:#?’. Double clicking on the icon will show all the pictures in ‘PICS:’.
The previous version of Mostra
had a feature called style icons,
by which a selected pattern of preferences, contained in the tool types of an
icon, was applicable to a series of icons. This is no longer possible (and the
need for the ‘STARTUP’ keyword is gone), but under Release 2 you can
easily create a hard link to Mostra
, and give it a new icon with new
tool types, and a ‘Files’ tool type. This will produce the same effect.
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Now, examples, by means of common problems:
Simple: create a project icon for each group, and add a tool type like
‘FILES=PICS:Group1/*’, plus all the tool types you would like to apply to
the pictures; then set the default tool to C:M
(or wherever you put it)
and double-click (of course, this must be done with every group icon). Don’t
give the icons the same name as a directory, or Mostra
will collapse in
confusion.
Set a Mostra
tool type to ‘BlackBackground’.
Create a series of hard links to Mostra
(they behave like copies
of the program, but they take almost no space on your disk).
You can give icons to the hard links, and put different options in the
tool types of each icon. Then, using different icons will start Mostra
with different settings.
You need a psycho-analyst, not Mostra
.
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I would like to thank the people that encouraged me someway or helped me to find bugs, in particular Warren Block, Tom Rokicki, Steve Tibbett, Christopher A. Wichura, Loren Wilton and all the other beta testers, which are really too many to mention.
The catalog files were provided by Reinhard Spisser, Stefan Becker, Martin Taillefer and Tomi Blinnikka.
Mostra
is Copyright © 1990-1994 Sebastiano Vigna and it’s not
public domain: it is shareware. You should send me $20 (or more, why not?) if
you find it useful. Please don’t send checks drawn on a US bank, they’re almost
impossible to cash. I’d prefer currency, postal money orders or checks drawn on
an italian bank (in this order). Mostra
is freely distributable as long
as all of its files are included in their original form without additions,
deletions, or modifications of any kind, and only a nominal fee is charged for
its distribution. This software is provided “AS IS” without warranty of any
kind, either expressed or implied. By using Mostra
, you agree to accept
the entire risk as to the quality and performance of the program.
Comments, complaints, desiderata are welcome.
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Sebastiano Vigna Via California 22 I-20144 Milano MI BIX: svigna@bix.com INTERNET: vigna@dsi.unimi.it
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