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Big Blue Disk 27
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SKETCH16.TXT
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1988-11-04
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6KB
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118 lines
|A╔══════════════╗════════════════════════════════════════════════╔══════════════╗
|A║ |6Picture This |A║═══════════════════ ^1Sketch 16 |A══════════════════║ |6Picture This |A║
|A╚══════════════╝════════════════════════════════════════════════╚══════════════╝
^Cby
^CJohn Allen, Jr.
Most graphics programs for the IBM PC work in one or both of the medium-res
and high-res modes. Medium-res allows four colors on the screen at once, while
high-res gets better resolution at the expense of having only one foreground and
one background color.
But if there's a Medium and a High resolution mode, there ought to be a Low
Resolution mode too, right? If there wasn't, it would be as illogical as some
fast food places that presently offer "Medium" and "Large" soft drinks, without
any such thing as "Small." A "Medium" is only a "Medium" if there's something
on either side for it to be between.
Actually, there is a Low Resolution graphics mode. But, apparently IBM and
Microsoft thought little of it even at the time of first release, since no major
programming language supports it. It is, nonetheless, present on all Color
Graphics Adapter (CGA) cards. (Unfortunately, other adapters such as EGA's have
no such mode, and will produce bizarre displays with this program. For
instance, on my EGA system, you get vertical lines all across the screen cutting
into the picture.)
John Allen, one of our most talented submitters (he did Electronic Christmas
Card last issue, Dungeon of Shalan in this issue, and co-authored Video Pro
Titler back in #23), has created for us a program to let CGA users make use of
this little-known mode to make artistic creations. Being "low-res," its
pictures are very blocky. To make up for this, however, you get sixteen
different colors, which can all be on the screen at once, making this the most
colorful graphic mode you can get on a CGA.
I've been in the computer field long enough to remember how impressed I was
with Apple II low-res graphics ten years ago: 40-by-40 blocks with 16 colors.
This program gives you a not-quite-as-low-res mode with 80-by-100 blocks and 16
colors.
When you run it, you'll get a menu showing the available commands. Here
they are, and you'd better write them down or make a printout for your
reference: there's no on-screen help available once you're in graphics mode,
since Low-Res doesn't have the capability of easily showing text.
From the menu, the commands are:
D - Go into sketch mode: enters low-res graphic mode to let you do a picture or
resume working on a picture already in memory.
S - Save the picture that is presently in memory to a disk. There probably
isn't room on BIG BLUE DISK, so you should copy this program to your own disk
before you start saving images.
L - Load a picture that you previously saved. Some pictures are included on
disk for you to load: DRAG.SKE, SCENE.SKE, CITY.SCE, TITLE.SKE, and CAMARO.SKE.
There's no need for you to enter the extension, just the file name.
C - Clear the current image so you can start with a blank screen.
P - Print the image. (This may not work on all printer models.)
X - Exit the program and return to BIG BLUE DISK.
Once you're in sketch mode, you can use the arrow keys to move around. The
following other keys work:
Left Shift - Set point.
Right Shift - Reset point (clear it to black).
X - Mark the current location (use to set the first corner point for boxes).
R - Draw a rectangle from the marked point (set using X) to the current cursor
point, treating the two points as diagonally-opposite corners.
B - Draw a filled box. Just like a rectangle, only solidly filled in.
P - Paint from the current point outward to a border of any non-black color.
This causes the current area of the screen to be colored in.
F - Fill from the current point to a border that is the same color as the
current color. Any other colored points in the way will be wiped out.
U - Undo the last operation, handy if a Paint or Fill wipes out your whole
picture by mistake.
F1 through F8 - Set the color. F1 = black, F2 = blue, F3 = green, F4 = cyan,
F5 = red, F6 = magenta, F7 = brown, F8 = white.
Ctrl F1 through F* - Set the high intensity color corresponding to the above
colors.
Q (or ESC) - Return to the menu.
Remember, again: this program works only on CGA cards, not on EGA's, MDA's,
or any other non-CGA-compatible adapter. If your system produces vertical lines
all over the picture, or otherwise acts strangely, then your adapter is probably
not CGA-compatible, so this program won't work. This is apparently because IBM
decided that this graphics mode was so little-used that there was no need to
support it in newer adapters. It also will not work on PCjr computers; sorry.
Note: If you get garbage on your screen, indicating an incompatible display
adapter, it's a good idea to press ESC immediately to exit, and if that doesn't
clear up the screen, re-boot your system. There's the remote possibility that
leaving the system in an unsupported mode for an extended period can cause
damage to your monitor.
If this program will work on your adapter, we hope you can make artistic use
of it, exploring the capabilities of a graphics mode few know exists.
To run this program outside the BIG BLUE DISK menu, type: ^1SKETCH16^0.
DISK FILES THIS PROGRAM USES:
^FSKETCH16.COM
^FDRAG.SKE
^FSCENE.SKE
^FCITY.SKE
^FTITLE.SKE
^FCAMARO.SKE