Module varc 

Outlines from variable composites in VARC.

A variable composite glyph is a tree of components. Each component is a transformed glyph drawn at its own location in the font’s variation space, and may itself be a composite. The leaves are glyphs from the font’s base outline source, glyf or CFF. They are drawn by the OutlineGlyphs that produced the composite.

The working memory a VarcGlyph needs depends on its nesting depth and its largest leaf. The tree is walked to measure them the first time the size is needed, and the result is kept. Drawing splits that memory into typed slices, as the glyf loader does, so a composite needs no memory beyond that buffer.

Structs

DrawContext 🔒

Data shared by every glyph in one draw.

GlyphStack 🔒

The composites being walked, outermost first, used to detect cycles.

Layout 🔒

The size of a composite’s working memory and how it is split.

Leaves 🔒

Draws the leaves of a composite from the base source.

Level 🔒

The runs for one level, with the remaining runs for the levels below it.

Levels 🔒

The unused runs of coordinates and scalars.

Measured 🔒

What measuring a composite’s tree found, kept in atomics so an outline stays cheap to clone and safe to share.

Memory 🔒

The working memory for one draw, split by a Layout.

Outline 🔒

A glyph in the VARC table, with its working memory size computed. A composite glyph, ready to draw.

Outlines 🔒

Provides access to the variable composite glyphs in a font.

ScalarCache 🔒

The scalar for each region at one location, computed on first use.

Scratch 🔒

Slices that each level uses in turn, and the number of edges left to walk.

VarcGlyph

A variable composite glyph from a Font.

Walk 🔒

The state of a sizing walk.

Constants

TRANSFORM_FIELD_COUNT 🔒

The maximum number of fields that one transform can vary.

Traits

VarcContext 🔒

Provides the data that Outlines::draw needs from outside the table.

Functions

apply_transform_variations 🔒

axis_values 🔒

Writes the axis values of component to out, one per axis index.

compute_tuple_deltas 🔒

Sums the deltas at coords for the tuple identified by var_idx into out.

eval_condition 🔒

expand_coords 🔒

Copies coords into out, which holds one value per axis.

linear_scale 🔒

Returns the factor that scales font units to ppem.

scale_matrix 🔒

split 🔒

Splits len elements off the front of slice, or None if it is too short.