Exporting Diagrams

Every diagram ends up somewhere — a blog post, a slide, a README, a social card. This page covers choosing a format, controlling the background and colors, and the one thing you can’t control yet.

The shortest version:

dgmo diagram.dgmo                      # → diagram.png in the current directory
dgmo diagram.dgmo -o diagram.svg       # → SVG

Format is inferred from the extension you give -o. .svg produces SVG; anything else produces PNG. With no -o at all you get <input>.png next to where you ran the command. Piping in from stdin with no -o writes PNG to stdout, which is how you feed a diagram straight into another tool:

cat diagram.dgmo | dgmo > diagram.png

PNG or SVG

Going where	Use	Why
Blog post, docs page	SVG	Scales to any screen, stays crisp on retina, small file
Slides (Keynote, Google Slides, PowerPoint)	SVG if the tool accepts it, else PNG	Slides get projected and resized; vector survives it
Social (X, LinkedIn, Slack)	PNG	Most social platforms won’t accept or preview SVG at all
GitHub README, wiki, issue	SVG or PNG	Both render; SVG looks better and stays sharp
Print, posters, anything large	SVG	The only format that scales up without going soft

The default is PNG because it works everywhere. Reach for SVG whenever the destination accepts it — it’s smaller, sharper, and immune to the resolution limit described below.

One caveat for SVG: text is rendered as real text in a specific font. If the viewing environment doesn’t have that font, letters may shift slightly. PNG bakes the type in, so it always looks exactly as rendered. If pixel-exact typography matters more than sharpness, use PNG.

Backgrounds and themes

--theme controls the background and the ink:

dgmo diagram.dgmo --theme light         # default — light background
dgmo diagram.dgmo --theme dark          # dark background, light ink
dgmo diagram.dgmo --theme transparent   # no background at all

transparent is the one to know about. It produces a diagram with no background fill — a genuinely transparent PNG (real alpha channel) or an SVG with no background. Drop it onto any surface and it takes on whatever is behind it: a colored slide, a patterned header, a page whose background you don’t control.

dgmo diagram.dgmo --theme transparent -o diagram.png

This is what you want for slides almost every time. A light-theme PNG on a slide gives you a white rectangle floating on your deck; a transparent one just shows the diagram.

The honest caveat: transparent uses the light theme’s ink — dark text, dark strokes. It’s built to sit on a light or mid-tone surface. On a dark slide the text will be nearly invisible. There is no “dark transparent” combination today; --theme dark always paints its own dark background. If your destination is dark, export with --theme dark and accept the background, or place the dark-theme image on a matching dark surface so the seam doesn’t show.

Palettes

--palette picks the color set. This is what “the active palette” means everywhere else in the docs — it’s set at render time, not in the diagram source.

dgmo diagram.dgmo --palette nord
dgmo diagram.dgmo --palette catppuccin --theme dark

The palettes that ship:

Palette	Character
`slate`	The default — muted, professional, safe on any background
`nord`	Cool arctic blues and soft frost tones
`atlas`	Warm earth tones, parchment feel
`blueprint`	Deep technical blues, drafting-table look
`catppuccin`	Bright saturated pastels, high contrast
`tidewater`	Desaturated coastal blues and greens
`tokyo-night`	Vivid neons, strongest in dark theme

slate is used if you don’t pass anything. An unknown name is rejected with the valid list, so you can always jog your memory with a deliberate typo — or just run dgmo --help.

Palette and theme are independent: every palette has a light and a dark rendering, and any palette can be exported transparent. See Colors for what each of the named colors looks like in every palette.

Output size

Output size is not currently controllable. There is no --width, --height, --scale, or --dpi flag — passing one is an error, not a silently-ignored option.

What you get instead: the diagram is laid out at a natural size determined by its content, and PNG export renders that at 2x. A diagram whose natural size is 1200x800 comes out as a 2400x1600 PNG. That is retina-sharp for normal document and slide use, and it’s plenty for most social cards.

Where it bites is anything large — a poster, a wide banner, a diagram blown up to fill a projected slide. At those sizes 2x PNG will start to look soft and you have no flag to push it further.

Use SVG when you need to scale. SVG has no resolution at all; it renders sharp at any size, and every downstream tool that accepts it can resize it losslessly. If you must have a large raster, export SVG and convert it at whatever size you want with a separate image tool.

A resolution flag doesn’t exist yet. SVG is the workaround, and for most destinations it’s the better answer anyway.

To hand someone a diagram without exporting a file at all:

dgmo share diagram.dgmo

This prints a URL that opens the diagram in the online editor, and copies it to your clipboard at the same time. The whole diagram is encoded in the URL itself — nothing is uploaded and no account is involved, so the link works for anyone who clicks it.

dgmo share diagram.dgmo --no-copy    # print only, don't touch the clipboard
dgmo share diagram.dgmo --json       # structured output for scripts

Share links are ideal for review — paste one into a pull request, a chat message, or a ticket and the other person sees the rendered diagram and can edit it. Because the source is packed into the URL, very large diagrams can exceed the URL length limit; if that happens, export a file instead.

Doing it for a whole directory

dgmo renders one file per invocation — there is no glob or batch mode. Use a shell loop:

for f in *.dgmo; do
  dgmo "$f" -o "${f%.dgmo}.svg"
done

See Diagrams in your repo for the CI-ready version of this, plus how to check diagrams for errors before they ship.

Then: Diagrams in your repo · Colors · How DGMO thinks