# Constants

Import these from `@grafloria/renderer`.

## Constants

### `AVG_CHAR_WIDTH_EM`

The average glyph advance, as a fraction of font-size.

THE SAME CONSTANT `LabelRenderer.estimateTextWidth` uses. It is a rough mean for
proportional Latin text — and it being rough is fine, because the renderer sizes
label backgrounds with it too. What matters is that the two AGREE: a bbox derived
from a different estimate than the one that placed the text would crop labels the
renderer thought it had left room for.

```ts
const AVG_CHAR_WIDTH_EM: 0.6
```

### `DEFAULT_MAX_OUTPUT_SIZE`

The default cap on an exported raster's pixel size, per side.

```ts
const DEFAULT_MAX_OUTPUT_SIZE: 4000
```

### `GRAFLORIA_MODEL_KEY`

The PNG text-chunk keyword, and the SVG element name.

NOT `grafloria-diagram`: that is already the CSS class on the exported root
(`class="grafloria-diagram"`), so "does this file carry a model?" would answer YES for
every export we have ever produced.

```ts
const GRAFLORIA_MODEL_KEY: "grafloria-model"
```

### `GRAFLORIA_NS`

The XML namespace the embedded model lives in.

```ts
const GRAFLORIA_NS: "https://grafloria.dev/ns/diagram"
```

### `IMAGE_NOT_INLINED_WARNING`

Companion caveat from `resolveImageHref` — same lifecycle as {@link IMAGE_PDF_WARNING}.

```ts
const IMAGE_NOT_INLINED_WARNING: string
```

### `IMAGE_PDF_WARNING`

The capture-time verdict on an external image, EXPORTED because the async export path
revises it: `await export(…)` fetches external URLs (environment fetch, then
`ExportOptions.assetFetcher`) and STRIPS this warning from any capture whose images it
embedded — see `stripResolvedImageWarnings`. The synchronous entry points cannot fetch,
so for them this text is the whole truth, and it names the way out.

```ts
const IMAGE_PDF_WARNING: string
```

### `PAGE_SIZES`

Page sizes in POINTS (1/72"), which is PDF's only unit.

```ts
const PAGE_SIZES: { readonly a4: { readonly width: 595.28; readonly height: 841.89; }; readonly letter: { readonly width: 612; readonly height: 792; }; readonly legal: { readonly width: 612; readonly height: 1008; }; readonly a3: { readonly width: 841.89; readonly height: 1190.55; }; readonly tabloid: { readonly width: 792; readonly height: 1224; }; }
```

### `SVG_XMLNS`

```ts
const SVG_XMLNS: "http://www.w3.org/2000/svg"
```

### `utf8`

UTF-8, implemented rather than borrowed.

`TextEncoder`/`TextDecoder` are NOT reliably global: they are absent in jsdom (which
is what the renderer's own tests run in) and were late to Node. Sniffing for them and
falling back would give two code paths that can disagree about a surrogate pair — in a
module whose entire job is lossless bytes. So: one path, always, everywhere.

```ts
const utf8: { encode(text: string): Uint8Array<ArrayBufferLike>; decode(bytes: Uint8Array<ArrayBufferLike>): string; }
```

### `XML_DECLARATION`

The XML prolog. Required by strict XML parsers and by most SVG→PDF toolchains.

```ts
const XML_DECLARATION: "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>"
```