CodeEditor

Remarks

Monospace by construction. A column is turned into an x by multiplying, which is what makes hit testing, the caret, the selection and the scroll width arithmetic rather than a per-line measurement — and it is what every code editor has ever done. ⚠ Given a proportional font the caret lands in the wrong place, and the theme therefore names one: a game that overrides code-editor's font-family with a proportional face has broken the caret, not the colours.

Virtualised on lines, like TreeView is on rows. A fifty-thousand-line shader is fifty thousand strings and about forty CodeLines. Folding is expressed in the same place: a collapsed region is lines missing from the row list, so nothing below has to know that folding exists.

⚠ Highlighting state is cached per line and invalidated from the edit downwards. A block comment opened on line 3 changes what line 4 000 is, so the state has to be carried forward — and recomputing the whole file on every keystroke is what makes a highlighter feel slow. Editing line n throws away the states from n on and nothing above it.

⚠ No undo. See CodeBuffer — an undo stack inside a text control can only undo typing, and every application that has one wants it to cover more than that. Changed is the seam.

Fields and properties (32)

• public const int Overscan

  How many lines are realised above and below the viewport.

• protected override string TagName

  The element name this type answers to when a caller does not choose one.

• protected override bool AcceptsFocus

  Whether the focus can rest on this kind of control at all.

• public CodeBuffer Buffer

  The text being edited.

• public ICodeTokenizer Tokenizer

  What turns a line into colours.

• public string Source

  The whole text, for the caller who does not want the buffer.

• public UiElement Gutter

  The column of numbers and markers down the left.

• public ScrollView Scroller

  The scroller the lines live in.

• public UiElement Lines

  Where the realised lines go.

• public UiElement Completion

  The autocomplete popup.

• public IReadOnlyList<CodeLine> Pool

  The lines that exist as elements, including the parked ones.

• public IReadOnlyList<int> Rows

  Which buffer line each visible row shows, folding taken out.

• public TextPosition Caret

  Where the caret is.

• public TextPosition Anchor

  The other end of the selection. Equal to the caret when nothing is selected.

• public bool HasSelection

  Whether anything is selected.

• public string SelectedText

  The selected text, or an empty string.

• public IReadOnlyList<CodeDiagnostic> Diagnostics

  What is being said about the file.

• public IReadOnlyList<CodeFold> Folds

  The regions that can be collapsed.

• public IReadOnlyList<CompletionItem> Completions

  What the popup is offering, filtered.

• public int CompletionIndex

  Which of them is highlighted.

• public bool IsCompleting

  Whether the popup is up.

• public int TabSize
• public bool AutoIndent
• public bool AutoFold
• public bool ReadOnly
• public Func<CodeEditor, string, IReadOnlyList<CompletionItem>>? CompletionProvider

  What to offer when a completion is asked for.

• public float RowHeight

  How tall one row of the virtualiser is.

• public float CharacterWidth

  How wide one character is.

• public static readonly UiPropertyKey TabSizeProperty

  Identity for TabSize.

• public static readonly UiPropertyKey AutoIndentProperty

  Identity for AutoIndent.

• public static readonly UiPropertyKey AutoFoldProperty

  Identity for AutoFold.

• public static readonly UiPropertyKey ReadOnlyProperty

  Identity for ReadOnly.

Events (3)

• public Action<CodeEditor>? CaretMoved

  Raised after the caret or the selection moves.

• public Action<CodeEditor>? TextChanged

  Raised after the text changes.

• public Action<CodeEditor, CompletionItem>? CompletionAccepted

  Raised when a completion is accepted.

Methods (22)

• protected override void OnCreated()

  Builds whatever this element is made of, once, as it joins a document.

• public void Refresh()

  Rebuilds the row list and realises the lines for it.

• public void SetDiagnostics(params ReadOnlySpan<CodeDiagnostic> items)

  Replaces what is being said about the file.

• public CodeFold? FoldAt(int line)

  The fold that starts on a line, if one does.

• public bool IsCollapsed(int line)

  Whether a fold is collapsed.

• public bool ToggleFold(int line)

  Collapses or expands the fold that starts on a line.

• public void SetFolds(params ReadOnlySpan<CodeFold> regions)

  Replaces the foldable regions, turning the automatic ones off.

• public int RowOf(int line)

  Which visible row a buffer line is on, or -1 if it is folded away.

• public Vector2 ToScreen(TextPosition position)

  Where a place in the text is, in document space.

• public TextPosition ToPosition(float x, float y)

  Which character a point is over.

• public void Move(TextPosition position, bool extend = false)

  Puts the caret somewhere, optionally dragging the selection with it.

• public void SelectAll()

  Selects everything.

• public void Insert(string text)

  Replaces the selection, or inserts at the caret if there is none.

• public void Erase(bool forward)

  Removes the selection, or one character either side of the caret.

• public void Reveal()

  Scrolls until the caret is on screen.

• public void ShowCompletion()

  Asks the provider what fits and shows the popup, if anything does.

• public void HideCompletion()

  Takes the popup down.

• public bool AcceptCompletion()

  Puts the highlighted completion in, replacing the word being typed.

• public void ClearTabSize()

  Unsets TabSize, so it takes its default or its ancestor's value again.

• public void ClearAutoIndent()

  Unsets AutoIndent, so it takes its default or its ancestor's value again.

• public void ClearAutoFold()

  Unsets AutoFold, so it takes its default or its ancestor's value again.

• public void ClearReadOnly()

  Unsets ReadOnly, so it takes its default or its ancestor's value again.

Used by (7)

• CodeEditorTestsVixen.Ui.Controls.Advanced.Tests
• CodeOverlayVixen.Ui.Controls.Advanced
• ResizeTestsVixen.Ui.Controls.Advanced.Tests
• CodeEditorViewVixen.Editor.AssetEditors
• ShaderGraphSurfaceTestsVixen.Editor.App.Tests
• ShaderGraphViewVixen.Editor.AssetEditors
• ShaderGraphViewTestsVixen.Editor.AssetEditors.Tests