Struct Projection 

pub struct Projection { /* private fields */ }

The display order of one view at one store version.

A projection has two orders. Self::rows lists every data row that passes the view, as if everything were expanded. The lines shown (Self::line, Self::len) are what the body paints: in a flat view the same rows; with grouping also group captions and footers, without the rows of collapsed groups; in a tree, the rows whose ancestors are all expanded. Display positions index the lines.

Implementations

impl Projection

pub fn len(&self) -> usize

The number of shown lines: group captions, data rows and group footers. In a flat view, the number of displayed rows.

pub fn is_empty(&self) -> bool

Returns true if no line is shown.

pub fn line(&self, display_ix: usize) -> Option<DisplayRow>

The line at a display position.

pub fn row(&self, display_ix: usize) -> Option<RowId>

The data row at a display position; None on a group caption or footer.

pub fn display_ix(&self, id: RowId) -> Option<usize>

The display position of a data row; None if the view filters it out or a collapsed group or tree row hides it.

pub fn order_ix(&self, id: RowId) -> Option<usize>

The position of a row in Self::rows, shown or in a collapsed group; None if the view filters it out.

pub fn row_count(&self) -> usize

The live rows of Self::rows when the projection was built: fading rows are not counted. In a flat view without fading rows, the number of displayed rows.

pub fn groups(&self) -> GroupTable<'_>

The group table; empty without grouping.

pub fn group_line(&self, group: GroupId) -> Option<usize>

The display position of a group’s caption; None while a collapsed ancestor hides it.

pub fn totals(&self) -> AggregateRow<'_>

The aggregates of the whole view, for the totals row; empty without aggregates.

pub fn is_grouped(&self) -> bool

Returns true if the view is grouped.

pub fn is_tree(&self) -> bool

Returns true if the view is a tree.

pub fn expanded_lines(&self) -> impl Iterator<Item = DisplayRow> + '_

The lines as if every group and tree row were expanded, as an export of everything writes them: group footers by GroupInfo::has_footer, tree rows at their depths. In a flat view, the shown lines. Walks the groups or the tree without listing the lines.

impl Projection

pub fn group_stamps(&self, group: GroupId) -> Option<&[Stamp]>

The change stamps of a group’s aggregates while any is hot, indexed by ColumnIx: one per column up to the last aggregated one, Stamp::NONE for a column whose aggregate did not change. The view sets them as aggregates change; a new group has none, its caption shows it (Self::caption_stamp).

pub fn totals_stamps(&self) -> Option<&[Stamp]>

The change stamps of the totals while any is hot, indexed by ColumnIx as Self::group_stamps.

pub fn caption_stamp(&self, group: GroupId) -> Option<Stamp>

The stamp of a group’s caption while it is hot: RowChange::Inserted for a new group, RowChange::Updated without a direction when its live row count changed.

impl Projection

pub fn branch(&self, id: RowId) -> Option<Branch>

The tree row with shown children; None for a leaf, a row the view does not show, and outside a tree.

pub fn tree_cycles(&self) -> usize

The rows of a tree shown as roots because their parents formed a cycle; 0 outside a tree. A row that is its own parent is a root but not a cycle.

impl Projection

pub fn store_version(&self) -> u64

The store version the projection was built from.

pub fn rows(&self) -> &[RowId]

Every data row that passes the view, in order as if every group and tree row were expanded: the rows of a group follow each other. In a flat view these are the displayed rows.

pub fn contains(&self, id: RowId) -> bool

Returns true if the row passes the view, displayed or not: a row of a collapsed group passes too, so commands may act on it when it is selected.

Trait Implementations

impl Debug for Projection

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Projection

fn default() -> Projection

Returns the “default value” for a type.