Groups and reuse#

Purpose and concepts#

group is a reusable container with local coordinates. Populate it, then place it on a page. Internal targets refer to existing instances in that group; placement replays these dependencies.

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#

Combine a panel, title and connector in a group, then reuse, rotate or resize it. fuse instead merges two already placed vector instances in the same container into a new outline; the inputs leave drawing and can no longer be referenced.

7card = group()8base = card.add(rect(size=(38 mm, 28 mm), border_radius=3 mm, fill="#d8f0ec",9                     border_color="#087f8c", border_width=0.5 mm), target=card.top_left)10card.add(ellipse(size=(10 mm, 10 mm), fill="#f2ab47"),11         anchor=center, target=base.center)12first = page.add(card, target=page.top_left, offset=(8 mm, 30 mm))13page.add(card,size=(52 mm, 38 mm), target=first.top_right,14         offset=(11 mm, -3 mm))

card = group()
base = card.add(rect(size=(38 mm, 28 mm), border_radius=3 mm, fill="#d8f0ec",
                     border_color="#087f8c", border_width=0.5 mm), target=card.top_left)
card.add(ellipse(size=(10 mm, 10 mm), fill="#f2ab47"),
         anchor=center, target=base.center)
first = page.add(card, target=page.top_left, offset=(8 mm, 30 mm))
page.add(card,size=(52 mm, 38 mm), target=first.top_right,
         offset=(11 mm, -3 mm))

1# Gallery: containers / group-reuse2page = canvas(name="Reusable group", size=(120 mm, 80 mm), background="#f7f9fc")3font = "DejaVu Sans"4heading = text(content="Reusable group", font_family=font, font_size=14 pt, color="#203864")5page.add(heading, target=page.top_left, offset=(7 mm, 5 mm))6# BEGIN DEMO7card = group()8base = card.add(rect(size=(38 mm, 28 mm), border_radius=3 mm, fill="#d8f0ec",9                     border_color="#087f8c", border_width=0.5 mm), target=card.top_left)10card.add(ellipse(size=(10 mm, 10 mm), fill="#f2ab47"),11         anchor=center, target=base.center)12first = page.add(card, target=page.top_left, offset=(8 mm, 30 mm))13page.add(card,size=(52 mm, 38 mm), target=first.top_right,14         offset=(11 mm, -3 mm))15# END DEMO

# Gallery: containers / group-reuse
page = canvas(name="Reusable group", size=(120 mm, 80 mm), background="#f7f9fc")
font = "DejaVu Sans"
heading = text(content="Reusable group", font_family=font, font_size=14 pt, color="#203864")
page.add(heading, target=page.top_left, offset=(7 mm, 5 mm))
# BEGIN DEMO
card = group()
base = card.add(rect(size=(38 mm, 28 mm), border_radius=3 mm, fill="#d8f0ec",
                     border_color="#087f8c", border_width=0.5 mm), target=card.top_left)
card.add(ellipse(size=(10 mm, 10 mm), fill="#f2ab47"),
         anchor=center, target=base.center)
first = page.add(card, target=page.top_left, offset=(8 mm, 30 mm))
page.add(card,size=(52 mm, 38 mm), target=first.top_right,
         offset=(11 mm, -3 mm))
# END DEMO

Dependencies

examples/gallery/containers/group-reuse.lay

Common errors and limits#

First placement seals a group. It cannot contain itself, and anchors from different containers cannot be mixed directly. fuse rejects images, text and groups and is not a public general-purpose Boolean API.

Individual functions#

group#

Create a reusable container with local coordinates. Populate it before placement; first placement seals contents and reuse replays internal positioning dependencies.

Returns: material

Minimal complete source · Composition source · All parameters

fuse#

Fuse visible outlines of two placed vector instances in one container; inputs leave drawing and references. Connecting a gap requires positive bridge_width; images/text/groups are unsupported.

Returns: instance

Minimal complete source · Composition source · All parameters

Detailed behavior and further examples#

Parameters#

Parameter	Purpose	Default or requirement
`width / height`	Group instance dimensions	Optional; scales children too
`target / offset`	Placement in the container	Use local coordinates inside a group

Common usage#

Finish group contents before placing the group on a canvas. Groups can be reused and nested; group scaling also scales children, including text and strokes.

Complete parameters and rules

Units and dimensions · Placement and anchors · Transforms and drawing order

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.