U-BW(1)

💅 U-BW(1) — the BRL-CAD glow-up where shorts become bytes ✨

okay so bestie, welcome to u-bw, straight out of the BRL-CAD fam 🫶 this is the page for the little tool that takes your chunky 16-bit numbers and serves them as cute lil 8-bit bytes. let's get into it 💖

---

✨ NAME ✨

u-bw — convert unsigned shorts to unsigned chars, aka 8-bit bw data 🎀

---

🦋 SYNOPSIS 🦋

u-bw [-l] < u_shorts > bwfile

---

🌸 DESCRIPTION 🌸

So here's the vibe: u-bw reads a stream of 16-bit unsigned short integers from standard input and writes a stream of 8-bit unsigned chars to standard output 😌 and what comes out is perfect for using as a bw(5) black and white image, or honestly any other unsigned char data stream you feel like feeding it 💅

By default, each unsigned short gets squished down to a single byte by taking the high-order byte — that's a right shift of 8 bits, bestie — which scales the full 0-65535 range down to 0-255. iconic behaviour, no notes 🔥

But if you pass -l, the low-order byte is the one that survives instead, which is effectively taking each value modulo 256. different byte, same energy ✨

🚨 real talk: both standard input and standard output must be redirected. if either one is a terminal, u-bw prints a usage message and exits. no terminal shenanigans allowed, periodt 💀

Data is processed in blocks of 512 values, so the byte ordering of the shorts is that of the host machine 🖥️ (yes, that means endianness of your machine is the main character here, iykyk).

---

💖 OPTIONS 💖

• -l — keep the low-order (least significant) byte of each unsigned short instead of the default high-order byte 🥰 this is equivalent to taking each input value modulo 256.

---

🌈 EXAMPLES 🌈

⭐ Example 1. Down-scale 16-bit samples to an 8-bit bw image

u-bw < heightfield.shorts > heightfield.bw
pix-fb -F /dev/X heightfield.bw

Convert a file of unsigned shorts (like, say, a 16-bit elevation or sensor grid 🌍) into 8-bit bw(5) data by taking the high byte of each sample — and then show it off on a framebuffer with pix-fb(1). main character energy, honestly 👑

⭐ Example 2. Keep the low byte to inspect fine detail

u-bw -l < data.shorts > low.bw

Retain the least significant byte of each short instead of the high byte — lowkey useful for examining the low-order bits of the source values 🔍🍓

---

🧚 SEE ALSO 🧚

brlcad(1), u-a(1), u-d(1), u-f(1), bw-d(1), bw(5)

---

👑 AUTHOR 👑

BRL-CAD Team 💜

---

🎀 COPYRIGHT 🎀

This software is Copyright (c) 1989-2026 by the United States Government as represented by U.S. Army Research Laboratory.

---

🙈 BUG REPORTS 🙈

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org 💌 (they're literally waiting to hear from you, bestie).

---

okay that's the whole page, mwah 💋 — this was U-BW(1) from BRL-CAD, and that's the whole sign-off from me, your favorite manual-writing bestie 🌸🦋 (page label's still U-BW(1) at the bottom too, don't worry, we keep the branding consistent 💅).