# bbcat
Dependency-free terminal viewer for CP437 ANSI and ansimation, DarkDraw DDW,
DIZ, ADF, RIPscrip, and XBin art. It writes colored UTF-8 by default, with
optional Kitty graphics and PNG output.
Browse and download BBS art packs at [16colo.rs](https://16colo.rs/).
## Install
```console
cargo install bbcat
```
To build from source, run `cargo build --release`.
## Usage
```console
bbcat [OPTIONS] [FILE]...
```
Pass one or more files, use `-` for standard input, or omit the filename to
read standard input. Use `--` before a filename that begins with `-`.
```console
bbcat art.ans FILE_ID.DIZ
bbcat < art.ans
bbcat --kitty scene.xb
bbcat --output preview.png art.adf
bbcat --output - art.ans > preview.png
bbcat --2x --kitty art.ans
bbcat --sauce art.ans
bbcat --baud 4x animation.ans
```
## Output modes
| UTF-8 | default | Converts CP437 characters to Unicode and emits 24-bit ANSI colors. |
| Kitty | `--kitty` | Renders bitmap glyphs through Kitty graphics, cropping at the terminal's right edge. |
| PNG | `-o FILE`, `--output FILE` | Writes one indexed-color PNG; use `-` to write it to standard output. |
Kitty mode requires terminal stdout and a terminal that answers bbcat's Kitty
graphics protocol probe. [Kitty](https://sw.kovidgoyal.net/kitty/) and
[Ghostty](https://ghostty.org/) are supported on Linux and macOS, along with
[iTerm2](https://iterm2.com/) on macOS. Long images are emitted in strips so
they remain available in terminal scrollback. Add `--fit` to scale the complete
image to the terminal width instead of cropping. If that would make the image
shorter than one terminal row, bbcat reports the minimum required terminal
width.
PNG mode requires exactly one input file. Use `--output -` to pipe or redirect
the PNG from standard output. PNG mode cannot be combined with `--kitty`,
`--slow`, `--delay`, or `--baud`.
UTF-8 output is intended for character art using the standard CP437 glyph set.
Use Kitty or PNG output for RIPscrip, XBin 512-character fonts, or artwork whose
embedded bitmap font must be reproduced exactly.
## Animation
bbcat recognizes ansimation from repeated ANSI screen rewrites and DarkDraw
DDW animation frames, then plays them automatically when standard output is a
terminal. Playback defaults to `1X`. Use `--baud RATE` to choose an animation
frame rate or set the row-reveal speed for static ANSI and text:
```console
bbcat --baud 2400 animation.ans
bbcat --baud 57600 animation.ans
bbcat --baud 2x animation.ans
bbcat --baud 4x animation.ans
```
`2400`, `9600`, `14400`, `28800`, `38400`, `57600`, `115200` (`1X`), `2X`
(230400), and `4X` (460800) are suggested familiar rates; run `bbcat --baud`
to print the list. Any positive numeric rate is accepted, as is an `Nx`
multiplier of 115200 (for example, `3X` is 345600). Animated playback uses each
frame's source byte count to determine how long it remains visible. DDW uses
its source-defined per-frame duration at `1X`, scaled proportionally by the
selected rate. Static art uses the same smooth row reveal as `--slow`: `1X` is
25 milliseconds per row, with lower rates slower and higher rates faster.
Terminals with
synchronized-output support reveal each redraw atomically to avoid visible
row-by-row tearing. Animation playback preserves CP437 text and source-defined
16-color, 256-color, and true-color SGR sequences. An animation that explicitly
homes to the terminal's top-left clears the canvas before playback; relative
animations leave the terminal intact. Both retain their final frame and return
the shell prompt below it.
Redirected UTF-8 output and Kitty or PNG output render the last visible state
instead of replaying the animation. Supplying `--baud` explicitly replays an
animation or uses the static row reveal even when UTF-8 output is redirected.
`--baud` cannot be combined with Kitty, PNG, `--slow`, or `--delay`.
## Slow mode
```console
bbcat --slow art.ans
bbcat --delay 50 art.ans
bbcat --kitty --slow art.ans
```
`--slow` reveals one character row at a time with a 25 millisecond delay.
`--delay MS` enables slow mode with a custom delay from 1 through 10,000
milliseconds. Both UTF-8 and Kitty modes flush each row before waiting; Kitty
mode automatically uses one image strip per character row.
Slow mode is not supported with ANSI animation, PNG output, or RIPscrip raster
graphics. Use `--baud` for baud-paced ANSI/text output. In Kitty slow mode,
`--chunk-lines` has no effect.
## SAUCE metadata
Use `--sauce` to show an artwork's available SAUCE title, author, group, and
creation date as a compact gallery-style caption below the rendered art. Files
without descriptive SAUCE metadata render without a caption. The option works
with UTF-8 and Kitty output, including multiple input files, but cannot be
combined with PNG output.
## 2x scaling
```console
bbcat --2x --kitty scene.xb
bbcat --kitty --fit wide.ans
bbcat --2x --output large.png drawing.rip
bbcat --2x --kitty --slow art.ans
```
`--2x` doubles both graphical output dimensions. Kitty mode crops the doubled
bitmap at the terminal width unless `--fit` is present; PNG mode writes an image
with twice the width and height. It works with every supported input format and
can be combined with Kitty slow mode. Slow-mode delays remain per original
artwork row.
Scaling is intentionally unavailable in UTF-8 mode: repeating text characters
would change strings and distort line art. Use `--kitty` or `--output FILE` with
`--2x`.
When UTF-8 output goes directly to a terminal, rows wider than the terminal are
cropped to its current column count. Redirected or piped UTF-8 output preserves
the full artwork width. Kitty crops at terminal width by default; `--fit` scales
the complete image down when at least one terminal row remains. PNG output
always retains its full dimensions.
## Formats
- ANSI and plain CP437 text, including `.ANS`, `.DIZ`, `.ASC`, `.NFO`, `.MEM`,
and `.TXT`. ANSI cursor movement, erasing, standard and bright colors,
inverse video, blink/iCE colors, wrapping, SAUCE dimensions, and baud-paced
ansimation are handled. Ansimation playback also preserves 256-color and
true-color SGR sequences.
- DarkDraw (`.DDW`) UTF-8 JSON Lines text art and animation. Base and
frame-specific objects are painted in source order; reusable group references
are expanded recursively at their positioned frame. Each DDW frame uses its
declared duration. A `Dimensions` metadata record is used when present;
otherwise bbcat infers the canvas from the positioned text. Terminal playback
preserves Unicode glyphs and 16- and 256-color styles; Kitty and PNG output
show the final frame with a CP437/VGA approximation where necessary.
- XBin (`.XB`) with embedded palettes, 8- or 16-color backgrounds, embedded
fonts up to 32 pixels high, 256- and 512-character modes, and XBin RLE.
- ArtWorx Data Format (`.ADF`) version 1 with its embedded palette and 8x16
font. ADF is fixed at 80 columns.
- RIPscrip (`.RIP`) level-one vector graphics, including its bitmap and
proportional BGI stroke fonts. RIPscrip is rendered to a 640x350 canvas and
requires Kitty or PNG output.
SAUCE metadata is used for content length, canvas dimensions, iCE color mode,
and named IBM VGA50, Amiga MicroKnight, Amiga Topaz 2+, and Empathy bitmap
fonts when present. Kitty and PNG output reproduce their exact glyph shapes;
UTF-8 output remains a terminal-font approximation. A DOS EOF marker terminates
plain ANSI/text input.
Common raster image inputs such as PNG, GIF, JPEG, WebP, TIFF, ICO, BMP, and
QOI are rejected by content with an explanatory error instead of being parsed
as character art. Malformed, truncated, oversized, or unsupported BBS inputs
also produce a non-zero exit status and a filename-scoped error. With multiple
inputs, bbcat reports a rejected file and continues with the remaining files.
## Options
| `-w COLS`, `--width COLS` | Override text width. ANSI/text accepts declared widths through 10,000 columns; untagged plain text is inferred through 1,000. DDW and XBin must match their declared width; an untagged DDW may be widened but not narrowed. ADF must be 80, and RIPscrip must be 640. |
| `--chunk-lines ROWS` | Set the number of character rows in each Kitty image strip, from 1 through 256. The default is `$LINES - 1`, clamped to 1 through 64, or 24 when `$LINES` is unavailable. |
| `--kitty` | Use Kitty graphics instead of colored UTF-8. |
| `--fit` | Scale complete Kitty output to terminal width instead of cropping. Errors if the result would be shorter than one terminal row. |
| `--slow` | Reveal one character row at a time using a 25 ms delay. |
| `--delay MS` | Enable slow mode with a delay from 1 through 10,000 ms per row. |
| `--baud RATE` | Play ANSI animation by source-byte timing or DDW animation by native frame timing, or set static ANSI/text row-reveal speed. `1X` is the same 25 ms/row as `--slow`; rates scale it proportionally. Run `--baud` alone for familiar suggested values. |
| `--2x` | Double Kitty or PNG output width and height. Requires `--kitty` or `--output FILE`. |
| `--sauce` | Show the available SAUCE title, author, group, and creation date below the artwork. |
| `-o FILE`, `--output FILE` | Write an indexed-color PNG. Use `-` for standard output; requires exactly one input. |
| `-h`, `--help` | Print command help. |
| `-V`, `--version` | Print the bbcat version. |
bbcat has no runtime dependencies and does not require a particular Rust
version beyond what is needed to compile the current Rust edition.