CanvasBuilder reference

CanvasBuilder collects content and timeline intent, then produces the internal representation consumed by CanvasScene.

builder = CanvasBuilder(title="My Explanation")
tape = builder.add_tape("main")
# author content and actions
super().__init__(dsl=builder.build(), **kwargs)

Most builder methods are chainable and return the builder rather than an element identifier. Pass an explicit id= when a later action must reference an element.

Content

Method	Purpose
`add_text(text, ...)`	General text, including styled inline runs
`add_heading(text, ...)`	Short heading with non-wrapping defaults
`add_body(text, ...)`	Explanatory text with wrapping defaults
`add_observation(text, ...)`	Semantic explanatory alias
`add_math(latex, ...)`	Typeset LaTeX content
`add_3d(equation, ...)`	Mathematical 3D surface
`add_solid(shape, ...)`	Generic volumetric solid
`add_raw(element)`	Low-level escape hatch

Tape builders expose the corresponding content methods while binding elements to their tape.

Inline runs

tape.add_text([
    "The ",
    builder.run("active region", color="#8d82ff", highlight=True),
    " remains searchable.",
])

Run style supports properties such as color, highlight, underline, bold, italic, font size, and opacity.

Layout

Method	Purpose
`add_tape(name)`	Create and return a `TapeBuilder`
`add_flex_row(items, ...)`	Lay independently addressable items in a row
`add_flex_column(items, ...)`	Lay independently addressable items in a column
`text_spec(...)`	Text item specification for flex
`math_spec(...)`	Math item specification for flex
`element_spec(...)`	Custom element specification for flex
`last_flex_ids`	IDs produced by the most recent flex container

Camera and observation

Method	Purpose
`add_camera_focus(id, ...)`	Isolate or overlay-focus an existing element
`add_camera_move(dy, ...)`	Legacy explicit tape movement
`add_camera_keyframe(target=..., ...)`	General 3D observation keyframe
`scroll_tape(local_y, ...)`	Enter tape-scroll mode explicitly
`observe_object(target, ...)`	Observe a world object
`add_camera_inspect(id, path=..., ...)`	Inspect a 3D object along a path

3D objects

Method	Purpose
`add_object(kind, ...)`	Register a generic world object
`add_solid(shape, ...)`	Place a built-in volumetric solid
`add_solid_lift(id, ...)`	Raise a solid above its tape
`solid_label(...)`	Create a camera-facing label specification
`add_3d(equation, ...)`	Place a mathematical surface in tape flow

Focus example

tape.add_math(r"E = mc^2", id="energy")

builder.add_camera_focus(
    "energy",
    mode="isolate",
    zoom=2.0,
    dim_opacity=0.1,
    run_time=1.1,
    hold_time=1.2,
    reset_zoom=True,
)

Internal API boundary

SheetDSL, raw canvas elements, and JSON loading are intended for engine tests, debugging, and specialized escape hatches. New product authoring should remain reachable through CanvasBuilder.

For exact signatures in the current source, see canvas/builder.py.