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claude 36631c7709 svg-maker: svgc - .svgd text format -> SVG for agent-helm sharing

Line-based DSL (shapes, text, groups, color vars) with strict
validation and line-numbered errors, SVG emitter with visibility
defaults, truecolor terminal preview (same half-block technique as
spritec), info with bbox + outside-canvas warnings. Verified
end-to-end: svgc build -> helmd share -> visible through the hub.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011KikHkfCiC3yELbsMN8fT9

2026-08-07 00:37:51 +02:00

3.1 KiB

Raw Blame History

svg-maker — `svgc`, vector graphics for agents

Builds SVG images from a line-based text format (.svgd) that an agent can author directly, verify without a GUI (terminal preview

measurements) and show to a human through agent-helm (helmd share out.svg). Built for "graphical elements": status cards, diagrams, icons, simple illustrations.

Usage

svgc build <file.svgd> [-o out.svg] [--preview] [--width N]
svgc preview <file.svgd> [--width N]     truecolor half-block render
svgc info <file.svgd>                    counts, colors, bbox, warnings
svgc example                             annotated example to start from

Typical agent flow:

svgc example > card.svgd        # start from the example
# ...edit card.svgd...
svgc build card.svgd --preview  # writes card.svg + shows what it looks like
helmd share card.svg --note "status card"   # display it in agent-helm

build prints an info block after writing — element counts, colors, the drawing's bounding box and warnings for anything outside the canvas — so mistakes surface as text even without the preview. Errors carry line numbers (card.svgd: line 7: "four" is not a number — rect needs: rect <x> <y> <w> <h>).

The .svgd format

One element per line, # comments, key=value attributes last:

canvas 240 120                       # required: width height
bg #12161f                           # optional background
def accent #4f9cf9                   # named color, use as $accent

rect 10 10 60 40 fill=$accent rx=6
circle 120 40 20 fill=#3fca7c stroke=white stroke-width=2
ellipse 60 90 30 12 fill=gray
line 10 100 190 100 stroke=red width=3
polyline 10,20 30,40 50,10 stroke=white
polygon 20,80 40,60 60,80 fill=#e0a63f
path M10,10 L50,50 Q70,20 90,50 Z stroke=white
text 100 60 "Hello agent-helm" size=14 fill=white anchor=middle bold
group stroke=gray stroke-width=1     # group attrs are inherited
  line 0 0 10 10
end

Piece	Notes
`canvas w h`	required first; becomes the viewBox and image size
`bg color`	background rect
`def name color`	color variable; `$name` in any fill/stroke
attributes	`fill stroke stroke-width` (alias `width`) `opacity fill-opacity stroke-opacity rx ry anchor size font dash linecap linejoin transform id` + flags `bold italic`
colors	`#rgb`, `#rrggbb`, CSS names, `none`; unknown attribute keys are errors
`path`	subset `M L H V C Q Z`, absolute + relative, commas or spaces
`transform`	raw SVG transform with commas: `transform=rotate(45,50,50)`

Friendly defaults: line/polyline/path get a visible stroke if you give none, polyline gets fill=none — no invisible elements, no accidental filled blobs.

Preview fidelity

The preview rasterizes the same shape model the emitter writes: fills, strokes, opacity and group inheritance are honored. Two approximations: rx rounded corners render square, and text renders as its baseline box (real glyphs are a font problem — check text in the real render via agent-helm). info always reflects true geometry.

Build & test

go test ./...
go build -o build/svgc .

3.1 KiB Raw Blame History

svg-maker — svgc, vector graphics for agents