Trait View 

pub trait View {
    // Required methods
    fn open(
        &mut self,
        ctx: &Context,
        bytes: &[u8],
        path: &Path,
    ) -> Result<(), String>;
    fn close(&mut self);
    fn is_open(&self) -> bool;
    fn title(&self) -> Option<String>;
    fn document_mut(&mut self) -> Option<&mut Document>;
    fn central(&mut self, ui: &mut Ui, zoom: f32, editing: &mut Editing);

    // Provided methods
    fn reindex(&mut self) { ... }
    fn caret(&self) -> Option<Caret> { ... }
    fn restore_caret(&mut self, _caret: Caret) { ... }
    fn menus(&mut self, _ui: &mut Ui, _editing: &Editing) { ... }
    fn presenting(&self) -> bool { ... }
    fn find(&mut self, _query: &str) -> usize { ... }
    fn can_replace(&self, _editing: &Editing) -> bool { ... }
    fn replace(
        &mut self,
        _with: &str,
        _all: bool,
        _editing: &mut Editing,
    ) -> Replaced { ... }
    fn show_match(&mut self, _index: usize) { ... }
    fn side(&mut self, _ui: &mut Ui) -> bool { ... }
    fn view_menu(&mut self, _ui: &mut Ui) { ... }
    fn file_menu(&mut self, _ui: &mut Ui, _path: Option<&Path>) { ... }
    fn take_notice(&mut self) -> Option<Notice> { ... }
}

What the shell needs from the view that draws a particular format.

Required Methods

fn open( &mut self, ctx: &Context, bytes: &[u8], path: &Path, ) -> Result<(), String>

Take a document’s bytes. The path is for the window’s title and for reloading, and is never read from here: this is given the bytes.

The context is for the work a new document makes necessary before it can be drawn — loading the font faces its styles name, which rebuilds egui’s glyph atlas and so belongs to opening rather than to drawing.

Errors

A message to show the person, already translated.

fn close(&mut self)

Forget the document.

fn is_open(&self) -> bool

Whether a document is open.

fn title(&self) -> Option<String>

What the document calls itself, for the window’s title.

fn document_mut(&mut self) -> Option<&mut Document>

The document, for saving and for undo. None while nothing is open.

fn central(&mut self, ui: &mut Ui, zoom: f32, editing: &mut Editing)

Draw the document. The shell has already put a scroll area or a panel around whatever this needs. The editing state says whether edit mode is on and takes the snapshot an edit records before it changes the tree.

Provided Methods

fn reindex(&mut self)

The content tree was replaced under the document, by undo or redo. A view that derives anything from the tree rebuilds it here.

fn caret(&self) -> Option<Caret>

Where the caret is, for a view that has one, so that an undo can bring it back there.

fn restore_caret(&mut self, _caret: Caret)

Put the caret where an undo or a redo says it was, after Self::reindex.

fn menus(&mut self, _ui: &mut Ui, _editing: &Editing)

Draw the view’s own menus, after Edit: each a menu_button of its own. A command chosen is kept by the view and applied when it next draws its page, where the document and the editing state are.

fn presenting(&self) -> bool

Whether the view is showing the document full screen and nothing else, as a slideshow does: the shell takes its menu, its panels and its keys away until it is not.

fn find(&mut self, _query: &str) -> usize

Look for text in the document and keep what is found, to draw highlighted; an empty query forgets the search. Answers how many matches there are. Asked again whenever the query or the text changes, and the current match is kept if there are still that many.

fn can_replace(&self, _editing: &Editing) -> bool

Whether the search bar offers to replace: where the document can be changed now.

fn replace( &mut self, _with: &str, _all: bool, _editing: &mut Editing, ) -> Replaced

Replace the current match, or every match, with a text, as one step to undo, and answer how many were replaced and how many left alone.

fn show_match(&mut self, _index: usize)

Make one of the matches the current one, and bring it into view.

fn side(&mut self, _ui: &mut Ui) -> bool

Draw the panel beside the document — an outline, a sheet list, a slide list — and answer whether there is one to draw.

fn view_menu(&mut self, _ui: &mut Ui)

Add the application’s own items to the View menu.

fn file_menu(&mut self, _ui: &mut Ui, _path: Option<&Path>)

Add the application’s own items to the File menu, after saving: what the document can be written out as. Given the file the document was read from, which is where such a file is offered to go.

fn take_notice(&mut self) -> Option<Notice>

Something the view has to tell the person, for the bar at the foot of the window, once.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors