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Merge pull request #244 from xexyl/2018-bellard

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Landon Curt Noll authored and GitHub committed 2023-04-01 14:16:43 -07:00
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2018/bellard/.gitignore
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lena.ppm lena.ppm
prog prog
small.jpg small.jpg
fruits.ppm
lena512.ppm
vintage_cars.ppm
2018/bellard/README.md
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# Most inflationary # Most inflationary
Fabrice Bellard Fabrice Bellard
<https://bellard.org/> <https://bellard.org/>
## To build: ## To build:
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```sh ```sh
eog lena.ppm # On Linux eog lena.ppm # On Linux
preview lena.ppm # On MacOS open -a Preview lena.ppm # On macOS
pngtopnm < Lenna.png | pnmscale 0.25 | cjpeg -arithmetic -dct float -quality 14 > small.jpg pngtopnm < Lenna.png | pnmscale 0.25 | cjpeg -arithmetic -dct float -quality 14 > small.jpg
``` ```
@@ -27,22 +27,25 @@ pngtopnm < Lenna.png | pnmscale 0.25 | cjpeg -arithmetic -dct float -quality 14
## Judges' comments: ## Judges' comments:
The file `small.jpg` will be approximately of the same size as the raw image data The file `small.jpg` will be approximately of the same size as the raw image
in the program. Compare the level of the detail and the artifacts of data in the program. Compare the level of the detail and the artifacts of
`small.jpg` and `lena.ppm`. `small.jpg` and `lena.ppm`.
Compressing images is just a matter of simple arithmetic and some magic, isn't it? Compressing images is just a matter of simple arithmetic and some magic, isn't
it?
We could understand some of the arithmetic but none of the magic. We could understand some of the arithmetic but none of the magic.
Deciphering the mechanism used for data encoding to make use Deciphering the mechanism used for data encoding to make use of whitespace,
of whitespace, braces and semicolons should be a slightly easier task. braces and semicolons should be a slightly easier task.
## Author's comments: ## Author's comments:
This program outputs a 128x128 RGB image file to the standard output Warning: the program is not protected against invalid input.
using the portable pixmap file format (PPM). It contains the famous
"Lena" image which is used in many image compression tests. This program outputs a 128x128 RGB image file to the standard output using the
portable pixmap file format (PPM). It contains the famous "Lena" image which is
used in many image compression tests.
The uncompressed image is 12 times larger than the source code of the The uncompressed image is 12 times larger than the source code of the
program which includes the image data and the complete decoder. The program which includes the image data and the complete decoder. The
@@ -73,8 +76,8 @@ input. Examples:
``` ```
The original images for [fruits][1] and [vintage cars][2] come from The original images for [fruits][1] and [vintage cars][2] come from
Wikipedia and were resized to a width of 1024 pixels. Warning: the Wikipedia and were resized to a width of 1024 pixels.
program is not protected against invalid input.
The program should be portable on any Unix system. On Windows the line The program should be portable on any Unix system. On Windows the line
`_setmode(0, 32768); _setmode(1, 32768);` must be added at the start of `_setmode(0, 32768); _setmode(1, 32768);` must be added at the start of