Omacalc

An engineering calculator built with Qt Quick and C++ that automatically follows the Omarchy theme and system dark/light mode.

This is an engineering edition of omacom-io/omacalc, the dead-simple calculator that ships with Omarchy. It keeps the look and the theme integration and adds a full expression engine.

Install

Build from source (the omacalc package in the Omarchy repository installs the original, simple calculator):

sudo pacman -S --needed base-devel qt6-base qt6-declarative
git clone https://github.com/yaghofgm/omacalc-engineering
cd omacalc-engineering
bin/build            # produces build/omacalc
bin/test             # optional: runs the test suite

To make it the calculator your launcher and Omarchy's calculator keys open, install it into /usr/local/bin, which comes before /usr/bin on the path:

sudo install -Dm755 build/omacalc /usr/local/bin/omacalc

This leaves the packaged /usr/bin/omacalc alone; remove /usr/local/bin/omacalc to go back to it. Rebuild and re-run the install line to update.

Usage

Omacalc is an engineering calculator: type an expression, watch the result preview as you type, and press Enter to commit it to the history. The keypad covers the same ground for the mouse, with a 2nd key for the alternate functions shown in each key's corner.

• Arithmetic with real precedence, parentheses (left open ones close themselves), ^ or ** for powers, and implicit multiplication that binds tighter than ×/÷: 2πf, 3(4 + 5), 1/2π = 1/(2π).
• SI prefixes on numbers: 4.7k, 10u/10µ, 100n, 5p, 1M, 3G. The ENG display mode shows results the same way, so they paste back in.
• Parallel combinations: 10k ∥ 4.7k (or ||, or par(a, b, …)).
• Complex numbers for impedances and phasors: 3 + 4j, 1/(j 2π·1k·1µ), polar entry 5∠53.13 (type @ for ∠), and RECT/POLAR display.
• Trig in DEG or RAD, with 30° always meaning degrees; inverse and hyperbolic functions; exact results at the usual angles (sin(180°) is 0).
• Logs, roots and friends: ln, log, log(x, b), log2, √, ∛, root(x, n), exp, n!, nCr, nPr, gamma, gcd, lcm, rounding, and db/dbp/undb/undbp for decibels.
• Statistics: sum, mean, median, stdev, var, min, max, hypot.
• Programmer: 0xFF, 0b1010, 0o17 literals; &, |, xor, ~, <<, >>; DEC/HEX/BIN/OCT display.
• Constants: π, e, j, c, h, hbar, kB, q, ε0/eps0, μ0/mu0, Z0, VT, NA, R, g, and more. Physical constants give way to your own variables, so R = 10k just works.
• Variables and functions that persist between sessions: R1 = 10k, fc(r, c) = 1/(2π r c), then fc(R1, 100n). ans is the last result, and starting a line with an operator continues from it.

Press F1 (or click ?) for the full reference of functions and constants.

Keyboard:

• Enter calculates, Esc clears, ↑/↓ walk the history.
• Ctrl+C copies the result (or the selection).
• Ctrl+D DEG/RAD, Ctrl+E NORM/SCI/ENG, Ctrl+B DEC/HEX/BIN/OCT, Ctrl+P RECT/POLAR, Ctrl+L clears the history, Ctrl+Q quits.
• Click a history expression to edit it, or its result to insert it. Select part of the input and press a function key to wrap it.

Colors follow the current Omarchy theme (~/.local/state/omarchy/current/theme/colors.toml) and re-tint live when the theme changes. Text follows the desktop text size — omarchy display text size, or GNOME's text-scaling-factor.

Requirements

• Qt 6: qt6-base, qt6-declarative
• xdg-desktop-portal and a portal backend

The iA Writer Mono font is bundled under the SIL Open Font License 1.1; see fonts/OFL.txt. The font is copyright Information Architects Inc. and based on IBM Plex, copyright IBM Corp.