# 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:

```bash
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

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