Graphics Plus/Graphics Plus.iso/amiga/opalvisn/dropshdw.lha/DropShadow.readme

Text File | 1993-05-03 | 5.4 KB | 113 lines

Automatic Drop Shadow Maker AREXX script for OpalPaint v2.0 & above
By Greg Niles, Centaur Development


This script automates the process of creating transparent drop shadows for
brushes in OpalPaint, for those who might need or want such a thing ;-))

Actually, making drop shadows manually in OpalPaint is very easy; it's just
that doing a lot of them really can use some automation, so the idea for
this script was born.  In the meantime, I added some things I use often for
drop shadows, such as feathering.

*****************  Installing Drop Shadow Maker *******************

Pretty simple, really.  First, copy the file "DropShadow.oprx" into your
"OpalPaint:Rexx" directory, or "REXX:" logical device; OpalPaint searches
these locations for ARexx scripts in this order.  For simplicity's sake, I
recommend you keep all your OpalPaint ARexx scripts in the "OpalPaint:Rexx"
directory.

After you've copied the script, run OpalPaint.  Go to the Extras menu and
click on the "ARexx Controls" button.  You should see a few text boxes and
a gadget at the lower center of the window that toggles between the
different qualifiers for function keys.  Click in the box of your choice
and type "DropShadow" (you don't need the quotes or the .oprx extension).
Now, the script is assigned to the corresponding key on your keyboard.

*****************  How To Use Drop Shadow Maker *******************

Press the key assigned to the Drop Shadow macro.  All you need to do at
this point is follow the directions.

First, Drop Shadow Maker will ask which brush you would like to apply a
drop shadow to: B1, B2, or B3.  Type 1, 2, or 3 to use the corresponding
brush.

Next, the script will ask you how much "feathering", or fuzziness, you
would like for your brush.  Feathering add realism to your drop shadows
by creating "soft" shadows instead of harsh, computer-looking ones.
Typing 0 will create a hard-edged shadow, while larger numbers will create
shadows that are more and more blurry.  5 is a good number to use for most
applications, keep in mind that this number is in pixels, so the larger the
number, the more the drop shadow shrinks.

Next, you are presented with a slider for the amount of transparency of the
drop shadow.  Adjust this to your liking.

At this point, OpalPaint will do a few operations on its own.  You will
notice that a new screen will appear and your selected brush will be pasted
down in the center of the new screen.  After these operations are
completed, the script will then ask you for the position of the drop
shadow; place the brush where you want the drop shadow to appear and click
the left mouse button.

Once that's done, the script goes through a few more steps on its own, and
presents you with a requested when it's done.  At this point, you will have
a version of your original brush with a soft-edged, semi-transparent drop
shadow (if you selected that) incorporated directly into the brush.  Paste
it over anything you want, and the effect will still be there.

***********************  How it Works  *************************

The drop shadows are possible due to OpalPaint's 256-level alpha channel
capability.  All brushes in OpalPaint are actually 32-bit, because when
you do any resizing, warping, or feathering to a brush, you actually
modify the transparency of portions of the brush.  Also, picking up a brush
when there is an underlying alpha channel attached to the picture can be
used in the brush itself, by specifying "Use Alpha" in the Cutout Brush
Options menu.

Here's what the ARexx script does:

After receiving input from the user, the brush is pasted in the center of a
spare screen AND into the alpha channel in the exact same position.  Before
pasting, the alpha channel is reversed so that pasting into the alpha
channel cuts a transparent hole into the background picture (which happens
to be black).  Then, after feathering the brush by the specified number of
pixels and asking for the position of the drop shadow, the script pastes
the feathered version of the brush into the alpha channel only.  Then, the
brush is picked up in Paint Mode, with alpha channel turned on, so that
black surrounding the brush is also picked up, but semi-transparent
according the alpha channel.  Now, the brush has a drop shadow attached to
it.

*********************  A few hints  **************************

OpalPaint automatically defaults to a black pattern when drawing the alpha
channel.  If you want to see what the program is doing while it's working
(It doesn't slow anything down, and it helps to visualize the alpha mode)
change the pattern to something else by right-clicking the AL button for
work mode BEFORE running the script.  I usually use one of the "wallpaper"
patterns.

Don't use feathering amounts over 10 pixels, unless your brush is really
large; remember, the feather command actually works INWARD, so your brush
actually gets smaller with more feathering.

Keep a backup of your brush BEFORE you run this script, as once you've
applied the drop shadow, you CANNOT undo it.

The script creates a spare page in order to make the drop shadow, so if you
are running low on memory, don't forget to delete the spare page after the
brush has been created.

***************************************************************


We'd love to see some of the results of this script.  If you have any
interesting pictures or AREXX scripts for OpalPaint, be sure to upload
them to our OpalVision BBS - [phone].

Greg Niles, Centaur Development