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Merge pull request #190 from xexyl/1992-imc

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Formatting fixes in 1992/imc/README.md
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Landon Curt Noll authored and GitHub committed 2023-03-28 14:36:21 -07:00
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$ Best Output:
# Best Output:
Ian Collier
Oxford University
@@ -12,121 +12,137 @@ $ Best Output:
make all
### To run
## To run:
## Judges' comments
# text mode
./imc -text
The program is more interesting to run on workstations that can
make use of a Sun raster file. Others can make use of the -text
flag for character oriented output.
./imc
Of course, the source (layout) is self-documenting! :-)
## Judges' comments:
NOTE: The original winning source assumed that
exit returned a value which cause problems for some
systems where exit returned a void. The file imc.c
has been modified to avoid this problem.
The program is more interesting to run on workstations that can make use of a
Sun raster file. Others can make use of the -text flag for character oriented
output.
Of course, the source (layout) is self-documenting! :-)
NOTE: The original winning source assumed that exit returned a value which cause
problems for some systems where exit returned a void. The file imc.c has been
modified to avoid this problem.
## Author's comments
Portability
### Portability
This program depends upon the ASCII character set, and makes certain
assumptions about the architecture. It naughtily declares the first
argument to main as a long, and passes a pointer to long instead of char
to fwrite, giving a length value of 32 bytes for an array of 8 longs. I
guess that makes this program OK on most flavours of unix, but not on
PCs.
This program depends upon the ASCII character set, and makes certain
assumptions about the architecture. It naughtily declares the first
argument to main as a long, and passes a pointer to long instead of char
to fwrite, giving a length value of 32 bytes for an array of 8 longs. I
guess that makes this program OK on most flavours of unix, but not on
PCs.
About the program
### About the program
This program has several parameters; each of them has a default, so the
program runs happily without any parameters. If you supply an incorrect
parameter, an obfuscated error message results! :-) Should you want to
run the program without knowing what it does, then supplying the single
letter t as a parameter is a good move. Otherwise, direct the output
into a file. The resulting file is most useful on Sun OS, where the
"file" command will tell you what to do with it. For best results with
the t option, you may want to change the definition of the I macro :-)
Details appear later, though the formatting of the code is a large clue.
This program has several parameters; each of them has a default, so the
program runs happily without any parameters. If you supply an incorrect
parameter, an obfuscated error message results! :-) Should you want to
run the program without knowing what it does, then supplying the single
letter t as a parameter is a good move. Otherwise, direct the output
into a file. The resulting file is most useful on Sun OS, where the
`file` command will tell you what to do with it. For best results with
the t option, you may want to change the definition of the I macro :-)
Details appear later, though the formatting of the code is a large clue.
All the code in this program appears between the ";" and ")" in
"for(;;)". That isn't because I want to win the best one-liner, but
merely because it makes the code so much more impenetrable :-) In fact
running a pretty printer on the code hardly improves it at all. This
program has the obligatory macros with unmatched parentheses, and the
cleverly arranged macro names and parameters to spell out "Ian Colliers
Obfuscated C Code". If you expand macros, bear in mind that the more
complex ones are best left as macros, because they have well-defined and
nontrivial (IMHO) functions. These macros help to give the program's
parameter format its flexibility. The parameters are sorted out in a
unique way (based on an idea by Pete Bevin) which hides very effectively
their identities (and I think that using a variable called _ adds a nice
touch to the illegibility of the code). In this section of the code, the
data types of the numbers checked against is varied, and just because
you see a ',' doesn't mean it has anything to do with commas! So I hope
you will agree that this program is more than a little obfuscated...
All the code in this program appears between the `;` and `)` in
`for(;;)`. That isn't because I want to win the best one-liner, but
merely because it makes the code so much more impenetrable :-) In fact
running a pretty printer on the code hardly improves it at all. This
program has the obligatory macros with unmatched parentheses, and the
cleverly arranged macro names and parameters to spell out "Ian Colliers
Obfuscated C Code". If you expand macros, bear in mind that the more
complex ones are best left as macros, because they have well-defined and
nontrivial (IMHO) functions. These macros help to give the program's
parameter format its flexibility. The parameters are sorted out in a
unique way (based on an idea by Pete Bevin) which hides very effectively
their identities (and I think that using a variable called _ adds a nice
touch to the illegibility of the code). In this section of the code, the
data types of the numbers checked against is varied, and just because
you see a `,` doesn't mean it has anything to do with commas! So I hope
you will agree that this program is more than a little obfuscated...
This is a Mandelbrot/Julia drawer. Normally it produces a monochrome
Sun-format raster file. The version of xloadimage we have is able to
view such files, and so is Sun's screenload command. [Note: the header
contains eight 4-byte integers, the byte order in which depends upon the
machine. On Sun workstations they are stored MSB first].
This is a Mandelbrot/Julia drawer. Normally it produces a monochrome
Sun-format raster file. The version of xloadimage we have is able to
view such files, and so is Sun's screenload command. [Note: the header
contains eight 4-byte integers, the byte order in which depends upon the
machine. On Sun workstations they are stored MSB first].
The program may be asked to produce text output instead of a raster
file. Then the characters defined in the I macro will be used to create
up to 16 different shades of grey. Quite a respectable picture can be
gained by printing a 130x110 output on a dot matrix 132 column printer
with the linefeed set to 7 points. Text output also gives a good picture
when used in an X window with small characters having a square aspect
ratio.
The program may be asked to produce text output instead of a raster
file. Then the characters defined in the I macro will be used to create
up to 16 different shades of grey. Quite a respectable picture can be
gained by printing a 130x110 output on a dot matrix 132 column printer
with the linefeed set to 7 points. Text output also gives a good picture
when used in an X window with small characters having a square aspect
ratio.
The options accepted by the program follow. Each option is a letter; it
may be preceded with a minus sign (or any character in [!-/]) and may be
followed by other letters, so for example
m -m mask *mail
all mean the same thing. Most options may be followed by one or two
numbers. These numbers may be separated from each other and from the
option by a space, or may be joined to each other with a comma, or may
be appended to the single-letter option, so
-s100,200 size 100,200 -size123 100 200 s100 200
all mean the same (note that in "-size123" all characters following the
initial s are ignored). Numbers need not be specified, as each has a
default value. In all cases except "j" and "t", and "s" whenever it
appears before "t", specifying an option without numbers has no effect.
(specifying "-s -t" has the effect of producing text with the default
raster size; not a good idea!). The options are:
The options accepted by the program follow. Each option is a letter; it
may be preceded with a minus sign (or any character in `[!-/]`) and may be
followed by other letters, so for example
-centre x y (float x,y) Centre the picture at x+iy in the complex
plane (default x=0 y=0)
-factor f (float f) Use f pixels per unit of the plane (default
f=x/4 where x is the width)
-julia x y (float x,y) Draw a julia set. Use x+iy as the constant
to add after squaring (default x=0 y=0)
-limit l (int l) Use l iterations maximum (default l=128)
-mask m (int m) Use m as a mask in deciding the colour of each
pixel (see below) (default m=1)
-size x y (int x,y) Produce an x-by-y output (default for raster
x=768 y=768; default for text x=63 y=23)
-text Produce text instead of raster.
The colour of each point is determined by taking the bit-and of the
number of iterations and the mask. For a raster, the point is black
(1-bit) if the result is zero, white otherwise. For text, the result of
the operation determines the grey-ness of the character produced, with a
blank for zero going up to a star for the maximum value. For a
four-colour picture, for example, use a mask with two bits set (e.g. 3),
and for a 16-colour picture use a mask with four bits set (e.g. 15). For
a picture with coarse detail, use a mask which ends with several zero
bits (e.g. 8).
m -m mask *mail
While the program is creating your picture, it displays dots on the
standard error to indicate its progess (one dot per pixel line).
Here are a couple of good pictures to draw:
all mean the same thing. Most options may be followed by one or two
numbers. These numbers may be separated from each other and from the
option by a space, or may be joined to each other with a comma, or may
be appended to the single-letter option, so
imc -s 512,512 -f 600000 -l 512 -m 16 -c.00805,.74274 > screen1.ras
imc -s512,512 -j-.523,-.535 > screen2.ras
-s100,200 size 100,200 -size123 100 200 s100 200
all mean the same (note that in `-size123` all characters following the
initial `s` are ignored). Numbers need not be specified, as each has a
default value. In all cases except `j` and `t`, and `s` whenever it
appears before `t`, specifying an option without numbers has no effect.
(specifying `-s -t` has the effect of producing text with the default
raster size; not a good idea!).
### Options
The options of this program are:
-centre x y (float x,y) Centre the picture at x+iy in the complex
plane (default x=0 y=0)
-factor f (float f) Use f pixels per unit of the plane (default
f=x/4 where x is the width)
-julia x y (float x,y) Draw a julia set. Use x+iy as the constant
to add after squaring (default x=0 y=0)
-limit l (int l) Use l iterations maximum (default l=128)
-mask m (int m) Use m as a mask in deciding the colour of each
pixel (see below) (default m=1)
-size x y (int x,y) Produce an x-by-y output (default for raster
x=768 y=768; default for text x=63 y=23)
-text Produce text instead of raster.
The colour of each point is determined by taking the bit-and of the
number of iterations and the mask. For a raster, the point is black
(1-bit) if the result is zero, white otherwise. For text, the result of
the operation determines the greyness of the character produced, with a
blank for zero going up to a star for the maximum value. For a
four-colour picture, for example, use a mask with two bits set (e.g. 3),
and for a 16-colour picture use a mask with four bits set (e.g. 15). For
a picture with coarse detail, use a mask which ends with several zero
bits (e.g. 8).
While the program is creating your picture, it displays dots on the
standard error to indicate its progress (one dot per pixel line).
### Example pictures to try
Here are a couple of good pictures to draw:
./imc -s 512,512 -f 600000 -l 512 -m 16 -c.00805,.74274 > screen1.ras
./imc -s512,512 -j-.523,-.535 > screen2.ras
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