Functions and modules#

Purpose and concepts#

function encapsulates computation or material composition. Component .lay files export variables/functions; the entry imports selected names and may rename them.

Minimal complete example#

Run this file directly with laymesh validate or laymesh render; it contains its own canvas and required definitions.

1# Minimal complete example: group2page=canvas(size=(100mm,75mm),background="#ffffff")3g=group()4a=g.add(rect(size=(35mm,20mm),fill="#e6f2f3"))5g.add(text("Reused"),target=a.center,anchor=center)6page.add(g,offset=(8mm,8mm))7page.add(g,offset=(55mm,38mm),rotation=15deg)

# Minimal complete example: group
page=canvas(size=(100mm,75mm),background="#ffffff")
g=group()
a=g.add(rect(size=(35mm,20mm),fill="#e6f2f3"))
g.add(text("Reused"),target=a.center,anchor=center)
page.add(g,offset=(8mm,8mm))
page.add(g,offset=(55mm,38mm),rotation=15deg)

1# Minimal complete example: group2page=canvas(size=(100mm,75mm),background="#ffffff")3g=group()4a=g.add(rect(size=(35mm,20mm),fill="#e6f2f3"))5g.add(text("Reused"),target=a.center,anchor=center)6page.add(g,offset=(8mm,8mm))7page.add(g,offset=(55mm,38mm),rotation=15deg)

# Minimal complete example: group
page=canvas(size=(100mm,75mm),background="#ffffff")
g=group()
a=g.add(rect(size=(35mm,20mm),fill="#e6f2f3"))
g.add(text("Reused"),target=a.center,anchor=center)
page.add(g,offset=(8mm,8mm))
page.add(g,offset=(55mm,38mm),rotation=15deg)

Dependencies

examples/manual/group.lay

Parameters and default behavior#

Unitless geometry uses the canvas unit; unitless type and stroke sizes use pt. Explicit call parameters override inherited/theme defaults. The linked interface reference lists accepted types, choices and defaults per parameter.

Composition#

Functions may accept sizes, titles or cap variables and return material or groups. Predefined variables also work in modules, with user/module bindings taking priority. Resource paths are relative to the module file.

8first = page.add(card("A"), target=page.top_left, offset=(8 mm, 29 mm))9page.add(card("B"), target=first.top_right, offset=(13 mm, 0 mm))

first = page.add(card("A"), target=page.top_left, offset=(8 mm, 29 mm))
page.add(card("B"), target=first.top_right, offset=(13 mm, 0 mm))

1# Gallery: containers / module-import2import { card } from "./card-component.lay"3page = canvas(name="Imported component", size=(120 mm, 80 mm), background="#f7f9fc")4font = "DejaVu Sans"5heading = text(content="Imported component", font_family=font, font_size=14 pt, color="#203864")6page.add(heading, target=page.top_left, offset=(7 mm, 5 mm))7# BEGIN DEMO8first = page.add(card("A"), target=page.top_left, offset=(8 mm, 29 mm))9page.add(card("B"), target=first.top_right, offset=(13 mm, 0 mm))10# END DEMO

# Gallery: containers / module-import
import { card } from "./card-component.lay"
page = canvas(name="Imported component", size=(120 mm, 80 mm), background="#f7f9fc")
font = "DejaVu Sans"
heading = text(content="Imported component", font_family=font, font_size=14 pt, color="#203864")
page.add(heading, target=page.top_left, offset=(7 mm, 5 mm))
# BEGIN DEMO
first = page.add(card("A"), target=page.top_left, offset=(8 mm, 29 mm))
page.add(card("B"), target=first.top_right, offset=(13 mm, 0 mm))
# END DEMO

1## @lang zh-CN2## 创建圆角卡片，并将标题放在中央。3## @param {string} label - 标题文字；支持行内公式。4## @returns {group} 可重复放置的卡片，宽 42mm、高 31mm。5## @example6## item = card("结果")7## @lang en8## Create a rounded card with a centered caption.9## @param {string} label - Caption text; supports inline mathematics.10## @returns {group} Reusable card material, 42mm wide and 31mm high.11## @example12## item = card("Result")13export function card(label) {14  item = group()15  plate = item.add(rect(size=(42 mm, 31 mm), border_radius=3 mm,16                        fill="#d8f0ec", border_color="#087f8c", border_width=0.5 mm),17                   target=item.top_left)18  item.add(text(content=label, font_family="DejaVu Sans",19                font_size=11 pt, color="#203864"),20           anchor=center, target=plate.center)21  return item22}

## @lang zh-CN
## 创建圆角卡片，并将标题放在中央。
## @param {string} label - 标题文字；支持行内公式。
## @returns {group} 可重复放置的卡片，宽 42mm、高 31mm。
## @example
## item = card("结果")
## @lang en
## Create a rounded card with a centered caption.
## @param {string} label - Caption text; supports inline mathematics.
## @returns {group} Reusable card material, 42mm wide and 31mm high.
## @example
## item = card("Result")
export function card(label) {
  item = group()
  plate = item.add(rect(size=(42 mm, 31 mm), border_radius=3 mm,
                        fill="#d8f0ec", border_color="#087f8c", border_width=0.5 mm),
                   target=item.top_left)
  item.add(text(content=label, font_family="DejaVu Sans",
                font_size=11 pt, color="#203864"),
           anchor=center, target=plate.center)
  return item
}

Dependencies

examples/gallery/containers/card-component.lay
examples/gallery/containers/module-import.lay

Common errors and limits#

Imports are read-only; cycles and missing exports error. Modules do not create or draw directly on the entry canvas. Create the entry canvas before using imported components.

Individual functions#

Detailed behavior and further examples#

Parameters#

Parameter	Purpose	Default or requirement
`import`	Import local components	Path relative to importing file
`function`	Define reusable functions	Components do not create an entry canvas

Common usage#

Imports must be local relative .lay paths. Modules use export for constants, materials, groups, or functions and may import further modules; imported names are read-only. The entry canvas must exist before imported values are used. A component module cannot create or draw on the entry canvas. Missing exports and import cycles are errors. See scripted.lay and card.lay.

Variables and expressions · Conditions and loops

Library documentation comments explain how to attach function and parameter help to your reusable components.

workflow#

Complete sources and executable verification fixtures for this workflow are listed in the feature coverage map. Follow this page’s input conditions and limits when composing features.