Struct BlockLayouts 

pub struct BlockLayouts(/* private fields */);

Where each block’s text landed, recorded as it painted.

A caret has to be placeable by pointer, and only paint knows where a glyph ended up. An editor hands one of these in, the renderer fills it, and the next click resolves against it. Read-only callers pass nothing and pay nothing.

Implementations

impl BlockLayouts

pub fn hit(&self, point: Point<Pixels>) -> Option<(Cursor, Affinity)>

The position under point.

Falls back to the nearest text vertically, so clicking the margin beside a line — or below the last one — still lands somewhere useful rather than doing nothing.

pub fn position( &self, at: Cursor, affinity: Affinity, ) -> Option<(Point<Pixels>, Pixels)>

Where a position painted last frame, on the row affinity names at a soft wrap, and how tall its line is.

Vertical motion is geometry rather than arithmetic on line numbers, so a wrapped row and a hard newline are the same case and neither needs counting — the rule ui::TextField arrived at.

pub fn row_start(&self, at: Cursor, affinity: Affinity) -> Option<Cursor>

The start of the painted row holding at.

pub fn row_end( &self, at: Cursor, affinity: Affinity, ) -> Option<(Cursor, Affinity)>

The end of the painted row holding at, and the affinity that keeps a caret there on that row.

pub fn wraps_at(&self, at: Cursor) -> bool

Whether at is a soft wrap last frame: the end of one painted row and the start of the next.

pub fn rects(&self, selection: Selection) -> Vec<Bounds<Pixels>>

The painted rows of a range, in document order — what a bar centred over a selection is placed against, and what a highlight of a caller’s own is drawn from.

One rect per visual row rather than one box: a selection that wraps or crosses blocks has no single box, and a caller given one would paint over the gaps.

pub fn step_row( &self, at: Cursor, affinity: Affinity, x: Pixels, down: bool, ) -> Option<(Cursor, Affinity)>

The position one painted row above or below at nearest x. Walks the recorded runs in paint order — which is document order.

Not a hit test: the gap between blocks belongs to no run, so a probe there answers with whichever run is nearest — and at a boundary that is the block being left, whose bottom edge is zero pixels away while the next block’s top is a whole gap.

pub fn over_text(&self, point: Point<Pixels>) -> bool

Whether point is inside painted text.

Self::hit answers with the nearest run wherever it is asked, which is what a click wants and what a pointer must not have: an I-beam belongs where a caret would land, not everywhere an editor’s box reaches.

pub fn block_at(&self, point: Point<Pixels>) -> Option<usize>

The block under point, for a gutter handle and a drop target.

pub fn first_row(&self, ix: usize) -> Option<(Pixels, Pixels)>

Where a block’s first painted row sits, and how tall that row is — what a mark in the gutter has to line up with.

Self::block_bounds is not that: it spans every row the block holds, and a heading’s single row is taller than a paragraph’s, so anything placed from the top of the box rides above the text it points at. None for a block that paints no text at all, a rule being the one that does.

pub fn block_bounds(&self, ix: usize) -> Option<Bounds<Pixels>>

Where a block painted last frame, in window coordinates.

pub fn language_bounds(&self, ix: usize) -> Option<Bounds<Pixels>>

Where a fenced block’s language label painted — the box a host hangs its picker on. Recorded rather than derived: the word’s width is the text system’s answer, and padding arithmetic would be wrong the first time any of it changed.

pub fn painted_bounds(&self, ix: usize) -> Option<Bounds<Pixels>>

Where a resizable painted block painted last frame — a painted fence, or an embed card — and None for any other block.

pub fn picture_bounds(&self, ix: usize) -> Option<Bounds<Pixels>>

Where an image block’s picture painted, which BlockLayouts::block_bounds does not give: that box spans the column and takes in the caption, so a handle placed from it sits off the edge of any picture narrower than the page.

pub fn checkbox_bounds(&self, ix: usize) -> Option<Bounds<Pixels>>

Where a task block’s checkbox painted, which is the box itself and not the marker column it sits in — a press outside it is a press on the gutter, and belongs to whatever handles one.

pub fn cell_bounds(&self, ix: usize, part: Part) -> Option<Bounds<Pixels>>

Where a table cell painted, padding included.

pub fn cell_at(&self, point: Point<Pixels>) -> Option<(usize, Part)>

The table cell under point: its block and part.

pub fn reveal(&self, range: Selection)

Scrolls the document until the start of range shows, centring it when it does not.

Answered over the next few frames by a document rendered with these layouts and an Editing::scroll; without one the request is dropped at the next frame. A later call replaces an earlier one.

pub fn reveal_with(&self, range: Selection, mode: RevealMode)

Self::reveal, placing the start of range by mode.

pub fn top(&self, at: Cursor) -> Option<Pixels>

Where at sits down the window, as last frame placed it: the top of its row where that row painted, else the top of the item holding it — a block, or a line of the source — measured or guessed. None before the column has been laid out.

Off screen the answer is a guess until the item is built, and moves when it is measured.

Trait Implementations

impl Clone for BlockLayouts

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for BlockLayouts

fn default() -> Self

Returns the “default value” for a type.