Envelopes: type maps from its glyph outline bounds

An envelope mapped type from its laid-out box: ascent to descent for
point type, the frame for area type. The distorted glyphs then filled
less of the envelope than other art does, with room above the capitals
and below the baseline.

The envelope now maps type from the bounds of its glyph outlines,
underlines and strikethroughs when the type is on its own, in groups
and layers, or used as a clipping path. Inline graphics count by their
boxes. Rotated type and type in perspective map from their outlines as
they are drawn. Make with Mesh,
Make with Top Object and Reset with Mesh without Maintain Shape use
those bounds. Type that draws nothing keeps its laid-out box, and so
does type inside any other object, such as a blend, a repeat or a
symbol instance. Shrink Text to Fit type is measured as it is laid out
on the page.

vectorcraft-text's envelope_ink measures the type, and
register_envelope_ink registers it with the document crate. The engine
session, Renderer::new, live evaluation in vectorcraft-effects and the
.ai reader register it. The document crate keeps the measured boxes per
thread, by object and by a hash of the content, and measures again when
the type, the fonts, the hyphenation exceptions or the transform's
scale or rotation change.

This is VectorCraft's own rule. Envelopes of type made in VectorCraft
and in saved files map from the glyph outline bounds instead of the
type's laid-out box, so they redraw differently.

docs/mcp.md

@@ -6382,6 +6382,13 @@ envelopes, the path for a top-object envelope); the content keeps the envelope's
 opacity mask.
 Type inside an envelope distorts as its glyph outlines, run by run in each run's paint, on the canvas and in every
 export (SVG, PDF, EPS, EMF/WMF, DXF).
+An envelope maps type from the bounds of its glyph outlines, underlines and strikethroughs instead of its laid-out
+box (ascent to descent, or an area's frame) when the type is on its own, in groups and layers, or used as a clipping
+path. Inline graphics in the type count by their boxes. Rotated type and type in perspective map from the bounds of
+their outlines as they are drawn. `object.envelope.makeWithMesh`, `object.envelope.makeWithTopObject` and
+`object.envelope.resetWithMesh` with `maintainShape: false` use those bounds. Type that draws nothing keeps its
+laid-out box, and so does type inside any other object, such as a blend, a repeat or a symbol instance. This is
+VectorCraft's own rule, and envelopes of type in saved files redraw by it.
 Everything inside bends with the envelope: images as a raster mesh warp (cut into pieces by Fidelity, each a clipped
 image under its own affine map; SVG shares the pixels between the pieces), symbol instances as their symbol's art,
 and with Distort Appearance strokes (as their filled outlines) and geometry effects; with it, Distort Linear Gradients

docs/target-app-parity.md

@@ -1438,6 +1438,8 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
 
 - **Type drawn as glyph outlines:** under a geometry effect, in EMF and WMF export, in DXF export when it is written as outlines, flattened with Convert All Text to Outlines, and inside an envelope, type keeps its underline and strikethrough, the weight and dashes of its character strokes when it is scaled, and the placement of its gradients and patterns, as the canvas draws it. A group's or layer's own fills and strokes also paint the underline and strikethrough of the type in it.
 
+- **Envelopes of type map from the glyphs:** an envelope maps point type, area type, type in groups and layers and type used as a clipping path from the bounds of the glyph outlines, underlines and strikethroughs instead of the type's laid-out box (ascent to descent, or the area's frame), with inline graphics counted by their boxes; rotated type and type in perspective map from their outlines as drawn. Make with Mesh, Make with Top Object and Reset with Mesh without Maintain Shape use those bounds. Type that draws nothing keeps its laid-out box, and so does type inside any other object, such as a blend, a repeat or a symbol instance. This is VectorCraft's own rule; envelopes of type made in VectorCraft and in saved files redraw by it. Tests: `crates/engine/src/tests/envelope.rs`, and `tests/envelope_ink.rs` in `vectorcraft-eps`, `vectorcraft-render` and `vectorcraft-effects`. Scores and hours unchanged.
+
 - **Texture redraws (#1257):** Craquelure, Mosaic Tiles and Stained Glass compare squared distances when finding their nearest cells; rounding/tie boundaries use the original distance ordering. Brute-force candidate tests and three 1800×1500 viewport comparisons preserve the old pixels. A CMYK rectangle move at 190.07%/DPI 1.5 is reproducible with `cargo test -p vectorcraft-render texture_drag_perf -- --ignored --nocapture`; idle-machine Windows interaction is still unverified.
 
 - **Smart Blur modes:** Effect › Blur › Smart Blur… has a Mode menu with Normal, Edge Only and Overlay Edge (`blurMode`: `normal`, `edgeOnly` or `overlayEdge`; an effect saved without it draws as Normal). Edge Only draws the edges in white on black, and Overlay Edge draws them in white over the Normal blur. A pixel is on an edge when one of the pixels the search reads within Radius of it differs from it by more than Threshold in a channel and its channels, alpha included, add up to at least that pixel's. The search reads neighbors as the Normal blur does, kept within Radius, and always the four nearest pixels, so a color step gives a line about as wide as Radius, and at least one pixel wide, on the side with the larger sum (lines on both sides when the sums are equal). The white and the black keep each pixel's coverage. Behavior reference: [Summary of effects](https://helpx.adobe.com/illustrator/using/summary-effects.html).