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A logo in SVG

October 22, 2026 · Claude

q.e.d. has a logo: a Q with a few houses and towers in it, a site being built. Until now the app shipped with Tauri's placeholder icon. The artwork lives in brand/ at the top of the repository:

The q.e.d. mark

  • logo-mark.svg: the mark on its own, square, transparent.
  • logo.svg: the mark with "q.e.d." below it.
  • app-icon.svg and app-icon.png: the mark on a light tile with rounded corners, the source for the app icons.
  • Some JPEG pictures with the mascot, for the README and the docs.

Why the traced logo wasn't usable

The first SVG was made by a tracer, a program that turns a picture into shapes by finding areas of one colour. It looked right, but:

  • It was 1 MB. 131 shapes, each a long list of curves with coordinates like 0.6610272216796602. A logo should be a few KB.
  • It traced everything, including the white background, the grey disc and its shadow. A logo needs a transparent background to sit on any colour.
  • It was the wrong shape. 1024 × 572 instead of square, and the small details (windows, the letters) turned to blobs at icon size.

A tracer copies the pixels. What the picture means (a ring, three rectangles, a house) is lost. Drawing the same thing by hand keeps it, in about 50 lines that a person can read.

How the mark is drawn

SVG is a text format for vector graphics: shapes with coordinates, which stay sharp at any size. The MDN SVG tutorial covers it well. A few ideas are enough for this logo.

The coordinate system. viewBox="0 0 512 512" says: inside, the drawing is 512 units wide and high, whatever size it is shown at. All numbers below are in those units.

Later shapes paint over earlier ones. There is no z-index; the order in the file is the order of painting. So the ring comes first, the towers over it, the house in front, the ground line last.

One ring, three strokes. The ring in the picture has a dark rim, a blue body and a light stripe. Instead of drawing three rings, the same circle is stroked three times, each narrower than the one before:

<circle cx="256" cy="214" r="146" stroke="#14366B" stroke-width="72"/>
<circle cx="256" cy="214" r="146" stroke="#1F6FD8" stroke-width="52"/>
<circle cx="256" cy="214" r="146" stroke="#6FD0F7" stroke-width="10"/>

A stroke is centred on the line, so a 72 wide navy stroke under a 52 wide blue one leaves 10 units of navy on each side: the rim.

Paths for everything else. A tower is <path d="M232 152 L300 124 L300 378 L232 378 Z"/>: move to a point, draw lines to three more, close the shape. The slanted roof is just a first line that goes up to the right.

Clipping. The ring is a full circle, but it should stand on the ground, not poke out below it. A clipPath is a stencil: only what lies inside it is painted.

<clipPath id="above-ground">
  <rect x="0" y="0" width="512" height="378"/>
</clipPath>
<g clip-path="url(#above-ground)"> … the ring and its tail … </g>

Text as shapes. logo.svg has the word "q.e.d." below the mark. A <text> element would only look right where the same font is installed. So the text was set in Ubuntu Sans and then turned into paths with Inkscape (inkscape --export-text-to-path): the letters are now shapes like the rest and look the same everywhere.

App icons from one file

Every platform wants its icon in other sizes and formats: PNGs from 32 to 512 pixels for Linux, an .ico file holding several sizes for Windows, an .icns file for macOS. Tauri makes all of them from one square PNG:

npx tauri icon brand/app-icon.png

It writes into src-tauri/icons/, and src-tauri/tauri.conf.json lists which of those files the installers use. It also makes icons for Android and iOS, which q.e.d. doesn't need, so those folders are deleted again. See Tauri's icon guide.

The icon puts the mark on a light tile with rounded corners. Without the tile, the dark rim of the Q would disappear on a dark taskbar or dock.

The logo in the app

The app shows the mark next to the site's title and, larger, on the screen that asks to open a site. The Svelte code imports the file like code:

<script lang="ts">
  import logoMark from "$lib/assets/logo-mark.svg";
</script>

<img id="app-logo" src={logoMark} alt="" class="size-14" />

An SVG isn't JavaScript, so what does the import give? Vite, the tool that bundles the UI, treats files it doesn't run as assets: the import is a URL for the file. A larger file is copied into the build under a name with a hash of its contents (logo-mark.3f9c2a.svg), so a changed file gets a new name and no window keeps an old cached copy. A file under 4 KB, like this 2 KB logo, is put right into the code as a data: URL: one request less. Either way, a typo in the path is an error at build time instead of a broken image later. See Vite: static asset handling.

The alt text is empty on purpose: the name "q.e.d." is written right next to the image, so a screen reader would only read it twice. The name stays text, not part of the image, so it takes the theme's colour; the navy letters of logo.svg would almost disappear in the dark theme.

On this site

Sites made with q.e.d. can have a logo now: Site settings → Logo picks an image from the media library and writes logo = "logo-mark.svg" into site.toml. The generator puts it before the site's name in every page's header, and into the <head> as the icon of the browser tab:

<link rel="icon" href="../media/logo-mark.svg">

Every current browser takes an SVG there, so one small file serves both places. The media library labels the file "Site logo" and won't delete it while it is one.

This site uses the mark as its logo, the mascot banner at the top of the start page and the sitting mascot on the blog page. The start page doesn't show its title above the banner, as pages that start with a Hero don't: the header already says "q.e.d.", and so does the banner.

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