Auto Layers

An auto layer keeps a glyph recipe live. FontLab generates its content from the recipe and can rebuild that content when the sources change. Choose it when the construction should be maintained automatically, rather than adjusted independently in each host glyph.

Auto Layer is a layer property. A glyph with at least one auto layer is an auto glyph; different masters can have different states. The workflow here concerns one working master, with broader-scope controls identified where they can affect your result.

Auto Layers as Live Composites

An ordinary component already follows changes to its source outline. An auto layer additionally retains the construction instructions: which parts to use, how to place them, and how to derive the resulting metrics and attachment data.

An auto layer is not hand-editable: its generated elements cannot be independently dragged or edited as ordinary contour content. The recipe owns that content. Edit the sources or the recipe, or turn Auto Layer off before taking manual control.

Keep metrics and placement related

For a base-plus-mark recipe, metrics normally derive from the base, with Nonspacing content excluded from the relevant bounds. A ligature construction instead combines the advances of its base groups. Explicit recipe metrics or supported metrics-expression overrides can change that result.

This makes the manual linking pattern—an accented glyph following its base—part of the generated construction. It does not mean every recipe must have the same width as its first component. Inspect the operators and metric instructions before deciding which width is correct.

Live regeneration also re-evaluates placement. Move a source attachment point and a recipe using that point can reposition the mark when the layer updates. Change a named position or numeric offset in the recipe and the next generation uses that instruction. This differs from a one-time, unanchored placement that merely retained the earlier offset.

An individually Anchored component can provide live attachment inside an otherwise manual layer. Use an auto layer when the whole recipe should manage the composition, not merely because one component needs to remain attached.

Inherit and consume anchors

Generated layers can collect source anchors at their transformed positions. The construction can consume the anchors used for attachment while retaining other useful anchors for subsequent marks. These are the same construction rules used by a one-time recipe build; an auto layer applies them again whenever it regenerates.

For a simple example, suppose a has top, while acutecomb has _top and an outgoing top. The recipe = a + acutecomb@top uses the incoming pair to place the acute. The outgoing top position can remain available for another mark. A mark without an outgoing top does not automatically provide a new top point above itself.

Ordinary same-name collection generally lets a later component supply the surviving position. Modern explicit mappings add more precise rules. With @top_2[_top], an outgoing top on the mark can be inherited as top_2, replacing the consumed base position. Further stacking can continue through that name. A conflicting mapping can report an error instead of silently choosing one of two incompatible names.

For ligature recipes with &, ordinary base anchors are numbered by logical base position: top_1, top_2, and so on. A base without a top anchor still occupies its position in that numbering. Marks do not count as extra bases. This preserves the distinction between the first and second letter's attachment sites.

Treat inherited positions as generated data. Source position expressions are not simply guaranteed to become identical independent expressions in the host: the build can retain suitable expressions, discard dependencies that do not transfer, or store the resulting transformed coordinates. Inspect the generated anchors when expression-driven sources or transforms are involved.

Independent mark-attachment anchors are therefore difficult to maintain directly in an auto layer. Do not assume a manually inserted same-named host anchor will always override generation. A rebuild can replace the generated anchor list. Put an authoritative attachment point in an appropriate source or explicit construction, or use a manual layer when the host needs independent anchors.

Appending #?noanchors suppresses anchor inheritance for that recipe's generated content:

= a + acutecomb@top #?noanchors

It is not limited to a final export switch, and it does not remove anchors from the source glyphs. Inspect the resulting layer before using it as a base for another construction.

Other source data

The generated drawing reuses source contours and other applicable source content. Metrics and anchors follow the rules above. Glyph guides and hints are also associated with source content, but their treatment depends on the construction path; do not assume every auto rebuild produces standalone host copies of every source guide and hint. Keep those references authoritative in the sources and inspect the generated and exported result where they matter.

The Elements panel makes the generated state visible: component names can appear subdued and their normal editing controls are restricted. A grayed component is not necessarily missing; check the recipe status and source availability.

Custom and Dynamic Auto Layers

The distinction is where the recipe comes from.

A custom auto layer stores an explicit recipe in the font's native working data. Once a particular source choice is recorded, adding another possible accent source or changing the local alias rules does not automatically substitute a different recipe. This is the more predictable choice when sharing a working font.

A dynamic auto layer has no stored explicit recipe. It resolves its construction from the active implicit-recipe rules and available sources, including applicable fallback logic. Its result can change after reopening on another machine, changing alias.dat, or adding a newly preferred source.

A stored recipe improves reproducibility, but it does not freeze the source outlines or eliminate version and generation-setting differences. Share the required source glyphs as well as the recipe.

Read, edit, and reset the recipe

The recipe appears in the Glyph window controls and in Layers & Masters with layer properties shown. In the standard light appearance, dynamic recipes use gray text and custom recipes black editable text. Missing sources can produce a red warning state. Colors vary with the theme, so inspect the text, edit/reset control, and generated result as well.

The recipe widget shows an auto-layer construction. This example combines a with gravecomb at top.

In Layers & Masters, use Edit recipe to promote the displayed implicit construction to an explicit stored recipe. Edit it and press Return/Enter. A modern construction in this field starts with =, for example = a + acutecomb@top; it does not include the destination name as a Build Glyphs line does.

Use Reset recipe in that panel to remove the custom string and return to implicit resolution. Check the Auto Layer state afterward. Other recipe popups can couple their clear/reset action to turning off automatic generation, so do not assume every close-shaped icon is an identical operation.

Creating an auto layer or enabling Auto Layer on existing content can store the resolved recipe immediately. An empty field before enabling Auto Layer therefore does not guarantee that the resulting layer will remain dynamic. Inspect the resulting stored/custom state if dynamic lookup is what you intend.

Copy and reuse recipes

Copy recipe to masters in Layers & Masters copies the current recipe and relevant auto state to other master layers. Check the scope before using it: it can replace different recipes already present there.

To reuse constructions between glyph sets or fonts, select the glyphs in the Font window and choose Text > Copy Text As > Recipes. Inspect the copied text, then paste the desired lines into Build Glyphs > Custom. The receiving font needs the referenced source glyphs. If rebuilding existing targets, preserve their current content first.

Custom and dynamic are the same explicit-versus-implicit recipe choice used by one-time generation, now retained as a live property. They do not describe two different drawing formats.

Creating, Managing, and Freezing Auto Layers

Enabling Auto Layer can replace hand-built content. Save a native copy, open the intended glyph and layer, inspect the recipe, then enable Glyph > Auto Layer or the control in the property bar or Layers & Masters panel. Check warnings and the generated result; a missing usable recipe is not a dependable way to preserve arbitrary content under an automatic flag.

Scope and creation

Read the displayed Auto Layer or Auto Glyph command before applying it. Matching settings and modifiers can change current-layer versus all-master scope and propagate a recipe. Do not assume Alt always means all masters. Those synchronization workflows are taught in Editing across Masters.

For new constructions, use Font > Build Glyphs… > Create auto layers, choose the master scope, and review Rebuild existing glyphs before running the build. For ordinary missing-glyph creation, Preferences > Operations > New glyphs > Add components and Create auto layers govern recipe-based starting content. Missing sources still require attention.

Updating and finding auto layers

Font > Live Update > Live Auto Layers enables regeneration while editing sources; Live Metrics controls related spacing updates. These settings are retained with native data. If live rebuilding slows a large project, suspend it and use Font > Update Glyphs for a deliberate refresh. Inspect the affected glyphs afterward.

With structure icons enabled, a blue brick-like symbol identifies the displayed auto layer. The auto virtual tag and Sidebar property filters find glyphs containing auto layers; other masters can still be manual. The List view's Auto Layer column exposes auto state and recipe information. Check the active master before editing.

Freezing for manual work

Turn Auto Layer off to retain the generated construction as manual content. Component references can remain linked and individual Anchored states still matter. Choose Decompose separately when independent contours are required. Re-enabling Auto Layer can replace manual changes through regeneration.

A manual layer can be appropriate for independent host anchors or details the recipe cannot express. This trades automatic maintenance for local control. Before deleting sources, inspect dependent recipes; Preserve recipes can retain a recipe whose missing parts still need repair.

Export resolves live construction into the target format's supported structures; see The Export Process. Save the native source to preserve the recipe workflow, and inspect exported appearance and metrics separately.