provided that all the contents are distributed with the script.
What is this thing?
For some time, I've wanted a simple way to pan across photographs, producing
individual video frames. There may be offerings for the Amiga, but I haven't
spotted them (or possibly they cost too much
money, and I haven't evaluated the package!). It would be nice to scan in a
photo, somewhat larger than the desired size for the final image, specify a
start and end point for a pan across the photo,
and get frames as a result. That's what this AREXX script does.
I intend this script to be used to produce frames for Movie Shop/VLAB/Draco.
That doesn't mean it won't produce frames for say, an anim, or some other frame
playing program. It does mean I'm testing
it with Movie Shop, and you can be relatively certain it works satisfactorily
with that software. You can be less certain about it's functionality with other
software, but it may very well work satis
factorily for your purposes. For example, to create the demonstration anim, I
imported the frames pan created into DPaint V. Sharp eyed readers will note the
animation is stored with a PPaint ICON: t
hat's because I didn't want to create the need for anyone to have anything but
PPaint. I only put ten frames in this pan, to keep the distribution size small,
yet demostrate what it does. It really n
eeds about 150 frames to avoid the jerkiness.
What do I need?
Nothing that isn't or hasn't been available on Aminet. But I'll discuss that as
I explain how the program works, and its uses and limitations. Install PPaint
somewhere convenient, and copy the Pan.Re
xx script into the PPaint Rexx directory. You'll launch the script from the
Icon, so be sure it's present also. I have an assign for PPaint; it would be a
good idea if you did also.
How does it work?
As I said before, I'd wanted a panning program for some time. I have a small
video business, and I'd like to supplement the video I shoot with a pan of some
of the excellent stills my wife captures.
I considered reading in the IFF files, decoding the file, doing the pan, and
generating the frames, but it was all just too much work. I wasn't going to have
a pan tool in this lifetime. I decided to
base the tool around an existing program, which could already read and write
graphics files, and which could move around within a picture larger than the
screen.
PPaint does these things, and accepts AREXX commands. I found a few things I
wish it did do (or perhaps I don't yet understand how it does them). I wrote an
AREXX script which calls PPaint to do the
dirty work.
This is a BETA version, with all that implies. I could either wait around
until I tested many more cases, and resolved some of the problems I was having
understanding a couple of commands, or relea
se a working version with some limitations. I chose to do the latter. If this
script is of use to you, but something doesn't work as desired, let's work
together and improve the tool. By distributing
this as a Beta, you get the advantage of earlier availability, and influencing
what features get added. I get the benefit of additonal debuggers and idea
sources.
The script considers three cases: a vertical pan, a horizontal pan, and a
diagonal pan (the cases were treated separately for technical reasons). Most of
the time, I just need a horizontal pan. Nothi
ng fancy, no scaling, no variable pan rates, etc. Once in a while, I need a
vertical pan. And even less frequently, I need a diagonal pan. I've tested the
horizontal and vertical pans pretty thorough
ly; the diagonal pan has been tested less thoroughly.
First off, after installation and assigning PPaint, scan in a photo. I've
supplied a sample photo (Beach.jpg) for a horizontal scan with the archive. When
you scan your photos, I recommend you scan t
hem slightly larger than the largest dimensions you'll need*. Look at the photo
in PPaint. Decide where you want the scan to start and end. This beta version of
Pan is hard coded to produce 640x464 i
mages, which by some coincidence, is the size frames I have Movie Shop set to
accept.
What scanner or scanning software you use is entirely up to you. PeeCee stuff is
cheap (and almost worth what you pay for it), so I use one as a peripheral to my
Amigas, and scanned the image in it.
PPaint7.1 will read a fairly wide variety of image formats, so make life easy.
The output, though, will be IFF.
I look at the image in PPaint, enable the coordinate locator, and simply move
the cursor to what looks like a good center for the first image, note the
coordinates, then do the same for the end point
. You'll need these numbers later, so write them down!
The Pan.rexx script (screen grab 1) will launch PPaint, so it isn't necessary to
have it running before starting the script. However, PPaint has an annoying way
of interrupting your typing, if you do
n't already have it running. I haven't tested having PPaint already running
before starting the script under a variety of conditions, so if you have
trouble, you might try not starting PPaint first.
When you click on the Pan.rexx script, you'll get a requester. The second screen
grab shows most of the dialog Pan will have with you.
My source image happened to be located in an assign named 'Source:', and was
named 'Beach.jpg.' That's the sample image supplied. My destination path was
Video1:Beach. Video1 is a drive partition I u
se for (guess what?) videos, and Beach was a directory I set up earlier for this
pan. Note that no "/" is required after the path; Pan will add it. Be sure there
are no old frames in the destination
path whose names start "PIC..", or Pan may hiccup.
My earlier check showed that I wanted the pan to start at a center of 786, 232
(X,Y). That's well to the right of center. My end point was 320, 232 (X,Y). 320
is as far left as one can go in any imag
e; 232 is as far up as one can go.
I chose 10 as the number of frames. If this number is too small (several pixels
per step), the pan will be jerky. If it's too large, the whole thing is going to
move as slow as molasses in January. P
ick a number which matches your image. Pan will handle as many as 999 frames.
That's 30+ seconds in NTSC, or almost 40 seconds in PAL. Surely no one wants a
plan that long! If I were doing this parti
cular pan for use in a video, I'd probably pick 150 to 300 frames. Note that
this will produce 30 to 70 megabytes of images: you need a lot of memory to do
video and animations.
Pan pretty much takes over at this point. You'll see PPaint step along frame by
frame, saving frames to disk. Pan creates files in your stated path with the
names "PIC0001 .. PIC0999". When the fat l
ady is through singing, it will stop.
Limitations
I again emphasize that this is a Beta version. If there is enough interest and
positive suggestions, I will consider additional work on the script. Right now,
it:
* Is limited to 640x464 output
* Is limited to 256 colors
* Does not scale images and therefore:
* Does not zoom in or out
* It eats a lot of chip memory!
I admit I'd like the option of a different numbmer of colors, and I can see
easily why PAL users would like a different resolution. If there's enough
demand, it would not be difficult to add a PAL as
pect ratio. But a broad, user selectable ratio is harder to achieve.
The chip memory is a limitation of using PPaint as a base. I doubt the program
has much value on anything but an A4000 with 2mbyte of chip ram, and a lot of
disk storage (I have 2 mbytes of chip, 70
mbytes of fast, and 16gb of disk). Decreasing the number of colors would
decrease the amount of chip ram, but obviously have less dedsirable effects.
Have fun! Email me your ideas! I'd love to see any animations you produce.
*The size of your photo determines the amount of chip memory you'll need. But it
obviously must be larger than the pan distance, plus the frame size.
Elements in the Distribution:
Pan.rexx (the Arexx script)
Beach.jpg (the sample scanned image)
ArexxIcon (the screen grabbed copy of the Rexx startup icon)
ConsoleWindow (the screen grabbed copy of the script dialog)
readme (the thing you're reading!)
Beach.anim (an anim of the result - also runs under PPaint)
Credits
The PPaint startup part of the script is cloned directly from one of Cloanto's
PPaint Rexx scripts. I figure they should know how to start up their own program
better than anyone else, so why try to
compete?
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