Club Amiga de Montreal - CAM/CAM_CD_1.iso/files/279.lha/HR136/Readme

Text File | 1989-08-19 | 12.5 KB | 270 lines

                   *****  HR136 *****

             by Dick Bourne
             307 Silver Valley Rise NW
             Calgary, Alberta, Canada
                 T3B 4B1
           November 23, 1988

SHAREWARE NOTE: The world's cheapest shareware! Send me one dollar if you
find you can make good use of HR136 or the techniques described here. If
you can't afford that, pick out a grungy old no-name disk, and send me an
IFF picture which you created with HR136. If you can't afford either,
please say something nice about me to a fellow Amigan.

    Now that the Amiga's major competitors, Mac and IBM, both have
graphics boards available with 256 and more colors in hi-res, it's time for
Commodore or third-party hardware developers to make a move to this level.
Until they do, I've found a technique which allows me to use slightly more
than half of that number of colors in hi-res or even hi-res overscan! It
works well with all paint programs I know of which support hi-res,
including Deluxe Paint II (C), Express Paint 2.0 (C) and up, and Deluxe
Photolab (C).

WHAT IS HR136?

    Only a hi-res IFF file.....

    Only an IFF file, you say? But what a file! It contains in a neat
chart form every possible MIXTURE of the sixteen basic palette colors. The
size of the chart allows you to see clearly the hue, saturation and
luminance of the color mixtures, and to determine which two registers were
used to produce the resulting mix. The mixing pattern within each cell is
that of a checkerboard, and results in a very smooth blend on the hi-res
screen. Results can be even smoother when the signal is converted to NTSC
video, since the results are usually softer than on an RGB screen. However,
some color mixtures will "vibrate" or produce a moire pattern, especially
if the colors are fully saturated (rich) and opposite each other in the
color spectrum (complementary). Magenta and red are a pretty deadly example.
In cases like these, try adjusting your 16 register colors, reducing
saturation a bit or picking a similar color without the disturbing
"artifacts".

    Several variants are provided: HR136.mon has a monochrome (white,
greys and black) palette, HR136.def uses the default palette, and HR136.opt
uses a palette which I have optimized to produce the widest range of colors
possible. The mixing is equivalent to dithering, which some programs can
do automatically. Unfortunately, at this date there is no way to
automatically dither two colors which are not consecutive in the palette.

WHY EXACTLY 136 COLORS?

    I'm not a mathematician, but I still remember how to figure out
permutations. You might assume that 16 colors combined in all possible ways
might total 16 x 16 or 256, but this is not the case. You have 16 basic
colors available in hardware. Color 0 can combine with colors 1 - 15 for a
total of 15 new colors (if it combined with itself, you'd still just have
color 0!). Color 1 can combine with colors 2 - 15 for a total of 14 new
colors (You have already combined it with color 0). For each successive
color in the palette, there is one less combination to be made. The total,
then, is a permutation:

16+15+14+13+12+11+10+9+8+7+6+5+4+3+2+1+0 = 136! This equates to the 16 pure
register colors, plus 120 more.


HOW DO I USE HR136?

A. Deluxe Paint II:

1. Start the program in the hi-res mode.

2. Load HR136.opt (or one of the other two HR136 IFF files).

3. Press "j" to swap to the spare screen. Here you may draw a picture or
load a pre-drawn one. If you choose the latter route, your palette will be
reset to that of the loaded picture, and all of your color mixtures will
change, too. However, you will still likely find any tint that you need.

4. Once you have basically roughed out your drawing (making sure areas to be
filled with color are totally filled and enclosed) you may now begin to
refill areas with ANY of the 136 colors that HR136 can offer.

5. Press "j" to return to the HR136 screen.

6. Select the Magnify tool, and click the rectangle pointer on the mixture
you want to "paint"with. Now that the color area is enlarged, you will
clearly see the checkerboard pattern.

7. Select the Brush tool, and grab an area of color EXACTLY 2 dots by 2
dots within the magnified area.

8. Click with your RIGHT mouse button on the Fill tool. In the menu box
which appears, select "Pattern" and "From Brush" options. You will see the
color mixture fill the little window to the right of the box gadgets.

9. Click OK in the menu box.

10. Click on the Magnify tool again to close the magnified window.

11. Jump "j" to other screen.

12. Select Fill tool with the left mouse button.

13. Click with your pointer within the area to fill. If the effect is not
what you wish, press "u" to undo it. If color leaks out of the desired
area, press the spacebar to abort the process.

    Now return to step 5, and repeat the steps for a different color.
After a while it will become second nature. I found it took me only 10 -15
minutes to color - in a picture after the basic shapes were in place. I find
ANY of the 136 colors work well for computer-based displays, although
printed results may vary a lot. Video output needs to be checked carefully
and adjusted to avoid the problems alluded to in the introduction. I find
bright green mixed with red or magenta to be the worst combination when
used in conjunction with broadcast-quality equipment.

B. Express Paint:  (I've based my instructions on V2.0, but other
   versions will be similar.)

1. You load the program, select 640 x 400 for screen and page size, and
load one of the three HR136 IFF files.

2. Now you click on the scissors icon, and "snip" just within the cell
boundary of the colors you want, until you have made "cuts" of all the
colors you will need. The color cells have been constructed so that when
you use one to fill shapes with, there will be no breaks in the fill pattern.

3. A variation on this theme is to save each color cell to disk as
a cut that you can reload. I have done this for all the mixtures that
include color 0, and saved them in a drawer labelled "Cuts". Notice that
the name of each cut identifies the numbers of the two colors in the
mixture. Express Paint even allows you to create a file of loading
instructions that can preload cuts of your choice, but 120 cuts will take a
long time, and will eat up valuable memory. Be selective!

4. At this point, click on the Eraser tool and then the option All.

5. Now you may load a pre-drawn picture, or draw your own. Use one of the
sixteen register colors to rough out the picture and fill all solid areas. Be
sure there are no places where color can "leak" beyond the desired
boundaries when you refill with color mixtures.

6. Select the "Fill" icon at the bottom of the screen.

7. In the right-screen tool area, select the Normal Fill icon (same design
as 6, above.) Now use the Up and Down arrows to scroll through your color
cuts until you see a shade you like. Or you may prefer to load a cut from
disk. With a little practise, you'll be able to visualize the resultant mix
of any two register colors.

8. Click with the left mouse button to the upper left of the area to be
filled, and drag the rubber-band box to the lower right of the area.
Release the button. You have created a containment area, so that any fill
that leaks out of its boundaries cannot destroy your whole picture.

9. Click within the area to be filled to finish the job. NOTE: You can not
"Undo" on versions lower than V3.0. You can only contain the damage. Also
you can not re-fill the area with another solid or pattern color unless you
erase the existing pattern - so be careful the first time!

Repeat from 7. to use other HR136 colors.

Note: Version 3.0 of Express Paint will allow you to keep HR136 on an
alternate screen, and make cuts of it as you wish. It also offers unlimited
"undos" if you make mistakes.

C. Deluxe Photolab "Paint" Program:

   This program has some nice features, but absolutely refuses to allow me
to open two hi-res screens, even with 3 megs of memory! Therefore, you will
have to keep a library of cuts similar to those explained in B. above.

1. Start the Paint program.

2. Pre-draw a new picture, filling in all solid areas with colors from the
standard palette. Be sure that you close any open space or "channel"
through which color could leak to an unwanted area during filling.

3. When you are ready, decide what tints you wish to use which are not in
the palette, and what color mixtures would likely produce them. For
example, if you need a very light pastel yellow, it would probably be
produced by mixing pure yellow and white.

4. Let's assume that color 1 is white and color 5 is yellow. Select Brush
Load from the top-of-screen menu and go into your Cuts (or "Brushes") menu.
If you have created 120 small cuts and labelled them as I indicated in B.
above, you'll select and load "1-5.cut". The brush that appears will be a
pastel yellow.

5. Click with the right mouse button on the Fill Icon in the Toolbox area -
(it's the one that looks like a paint bucket pouring).

6. A requester box will open. Notice gadgets for "Solid Color" and "Brush
Pattern". Click with your left mouse button in the second box.

7. Click with the left mouse button in the desired area to fill it with the
color mixture. If a mistake occurs, press "u" to undo or the spacebar to
abort the process.

Repeat from 3. for other HR136 colors you wish to use.

RELATIVE PROS AND CONS OF VARIOUS TECHNIQUES AND PROGRAMS:

1. The Deluxe Paint technique with the spare screen allows fast comparison
and selection of colors, but only one brush (cut) can be kept in memory.
You can save and load brushes from Ram: to avoid the need to zoom and
recapture them every time a certain color is needed, but that also takes
time. Deluxe Paint II is forgiving of errors, with an instant undo.

2. The Express Paint method allows rapid scrolling through the "cuts" colors
by use of the up/down arrows. This may become tedious, though, if you load a
large number of cuts! You also can get lost, and have no idea what register
combination you are viewing. A nice feature for multiple cuts would be to
have the file name visible in the title bar. Express Paint V2.0 also lacks
a true undo, but it is included in V3.0.

3. Deluxe Photolab's technique is the least friendly - there is no spare
screen in hi-res (though the program can support multiple screens when one
is of lower resolution) so you cannot keep HR136 handy for color selection.
Worse, brushes (cuts) must be loaded one at a time to be viewed or used.
However, the program will give you a second chance if you make a mistake,
following the Deluxe Paint approach of "u" to undo, and spacebar to abort a
fill.

GENERAL COMMENTS:

1. HR136 is not quite as good as a 256-color (8-bit) hi-res mode. Just
think of the number of colors a board like that could create using the
dot-mixing technique I've described! 256 + 255 + 254 .... + 2 + 1! The
scary thing is that third-party manufacturers for Mac II and IBM PS/2 are
pushing beyond 8-bit to 24- and 32-bit boards capable of millions of
on-screen colors. The hopeful aspect is that Amiga may still match or beat
their capabilities if Commodore and third party hardware manufacturers work
together effectively.

2. HR136 could become redundant if existing and new paint programs BUILD IN
an option which allows the user to step through all the two-color dithered
patterns, then draw or fill freely with them! Another elegant concept
would be the ability to fill over one pattern with another (a
"checkerboard detector" fill routine?). The hardware has the speed to do
it, developers!

3. You can't fill single-pixel lines with a pattern - but if you are
working in video, you should fatten up such lines anyway, so they don't
flicker or virtually disappear! Good video demands large, bold strokes,
shapes and fonts.

4. The dot-mixing technique does not produce solid-appearing shades in
lower-res, even when you record pictures to video; the patterns can still
be attractive, however.

5. Some medium-res color mixtures may work; use your own discretion.

6. Your IFF files will consume more disk space when HR136 colors are
used, if you save pictures in compacted form. (All three of the above paint
programs normally do). The reason for this is that you achieve greater
compaction when you have large solid areas, and less when you change colors
frequently within the same areas. Therefore, you should try to adjust the 16
register colors to the optimum settings for your LARGE areas, and use
color mixtures for the SMALLER areas whenever possible.

7. Anything which enlarges, shrinks or distorts an object in any way will
destroy the color mixing pattern. Do all such manipulation before filling
with a color mixture!

            ENJOY!