Layout

Reference: the pieces a page is built from, as a map from what a page looks like to the type that draws it. A service constructs a PageLayout and calls .build(request); the rest is what goes in its fields. The commonest shapes are re-exported from sextile; the full sets are in sextile.layout and sextile.formatting.

The page

PageLayout is the whole of a page, laid out down as many frames as it takes.

Field	What it is
title	what the header calls the page; None takes the registered title
parts	the content, in the order it appears down the frames
home	where 0 leads; unset is the service’s index, None offers no way home
numbered	whether the header shows the page number
shortcuts	Shortcut keys offered on every frame besides the digits and 0
item_noun	what A and D move between, as the footer says it
furniture	the bands round the content
next_page	where # leads once the frames have run out
hang_up	whether the line drops once the page has been shown

Parts: which frames content appears on

To draw	Use
a part on the first frame with room before it	OnOneFrame(drawable)
a part on every frame	OnEveryFrame(drawable)
a part broken across as many frames as it takes	Flow(drawable)
a picture positioned cell by cell	Custom(rows=, draw=)
a forced break between two parts	FrameBreak

Each wraps a Drawable. Part is the four wrappers together, which the layout walks onto frames itself.

Content shapes: what a part draws

To show	Use
numbered choices, chosen by a digit	Menu of MenuItem
lines exactly as given	Lines
a two-column reference	Listing
rows of figures	Figures
running text, wrapped	Prose
a sequence drawn your own way	a SequencePart subclass

RowSequencePart writes each entry along its rows; NumberedRowSequencePart draws the digit column too, for entries a reader chooses. Entry and MenuItem are what a shape is given.

Furniture: the bands round the content

Band	Type
the header row	Header
a rule	Rule
the prompt row	Footer
a band of your own	any Furnishing

DEFAULT_FURNITURE is the header, two rules and the footer; content_rows is the rows they leave a page. A Furnishing satisfies the protocol drawn with a FrameContext and docked to an Edge.

A part of your own

A Drawable implements place(canvas, space) -> Placed. Space is the room offered — its first_row, rows and choices — Claim is what the part took (its choices, what it named in the prompt, and any form), and Placed carries the rows drawn and the remainder for the next frame. CHOICES_PER_FRAME is nine, the digits a frame has.

A prompt drawn by hand

render_footer(items, FOOTER_WIDTH) composes the prompt row from FooterItems, shedding what will not fit in Priority order; movement(available, item=) gives the FooterItems for the movement keys a frame answers.

Why one import: PageLayout, the parts and the shapes come from sextile.layout and sextile.formatting, but the commonest are re-exported from sextile, so a plain page needs no second import line and the package split stays invisible.