Enum SystemChange 

pub enum SystemChange {
    TextSelectionClick {
        position: LogicalPosition,
        timestamp: Instant,
    },
    TextSelectionDrag {
        start_position: LogicalPosition,
        current_position: LogicalPosition,
    },
    ApplySelectionOp {
        target: DomNodeId,
        op: SelectionOp,
    },
    CopyToClipboard,
    CutToClipboard {
        target: DomNodeId,
    },
    PasteFromClipboard,
    SelectAllText,
    UndoTextEdit {
        target: DomNodeId,
    },
    RedoTextEdit {
        target: DomNodeId,
    },
    AddCursorAtClick {
        position: LogicalPosition,
    },
    SelectNextOccurrence {
        target: DomNodeId,
    },
    ApplyPendingTextInput,
    ApplyTextChangeset,
    ActivateNodeDrag {
        dom_id: DomId,
        node_id: NodeId,
    },
    ActivateWindowDrag,
    InitDragVisualState,
    SetDragOverState {
        target: DomNodeId,
        active: bool,
    },
    UpdateDropTarget {
        target: DomNodeId,
    },
    UpdateDragGpuTransform,
    DeactivateDrag,
    SetFocus {
        new_focus: Option<DomNodeId>,
        old_focus: Option<DomNodeId>,
    },
    ClearAllSelections,
    FinalizePendingFocusChanges,
    ScrollSelectionIntoView,
    ScrollNodeIntoView {
        target: DomNodeId,
    },
    ScrollCursorIntoViewAfterTextInput,
    StartAutoScrollTimer,
    StopAutoScrollTimer,
}

Framework-determined side effects (system changes).

Unlike CallbackChange (from user callbacks), these are determined by the framework’s event analysis: hit tests, gesture detection, focus rules, text selection, keyboard shortcuts, etc.

Both CallbackChange (user) and SystemChange (framework) are processed through exhaustive match on PlatformWindowV2 — adding a new variant causes a compile error in apply_system_change().

Variants

TextSelectionClick

Process a mouse click for text selection (single/double/triple click).

Fields

position: LogicalPosition

timestamp: Instant

TextSelectionDrag

Extend text selection via mouse drag.

Fields

start_position: LogicalPosition

current_position: LogicalPosition

ApplySelectionOp

Unified selection operation: cursor movement, selection extension, or deletion.

Replaces the old ArrowKeyNavigation and DeleteTextSelection variants. Every keyboard shortcut maps to a single SelectionOp — see its docs.

Fields

target: DomNodeId

op: SelectionOp

CopyToClipboard

Copy selected text to system clipboard (Ctrl+C / Cmd+C).

CutToClipboard

Cut selected text to clipboard and delete (Ctrl+X / Cmd+X).

Fields

target: DomNodeId

PasteFromClipboard

Paste text from system clipboard at cursor (Ctrl+V / Cmd+V).

SelectAllText

Select all text in focused node (Ctrl+A / Cmd+A).

UndoTextEdit

Undo last text edit (Ctrl+Z / Cmd+Z).

Fields

target: DomNodeId

RedoTextEdit

Redo last undone edit (Ctrl+Y / Ctrl+Shift+Z / Cmd+Shift+Z).

Fields

target: DomNodeId

AddCursorAtClick

Add a cursor at the clicked position (Ctrl+Click). The position will be hit-tested to find the text cursor location.

Fields

position: LogicalPosition

SelectNextOccurrence

Select the next occurrence of the current selection’s text (Ctrl+D). If the primary selection is a cursor, expand it to the word first.

Fields

target: DomNodeId

ApplyPendingTextInput

Apply pending text input from platform (keyboard/IME).

ApplyTextChangeset

Apply text changeset (incremental relayout).

ActivateNodeDrag

Activate node drag on a draggable element.

Fields

dom_id: DomId

node_id: NodeId

ActivateWindowDrag

Activate window drag (CSD titlebar).

InitDragVisualState

Set up drag visual state (:dragging pseudo-state, GPU transform key, DragDropManager sync).

SetDragOverState

Set :drag-over pseudo-state on a target node.

Fields

target: DomNodeId

active: bool

UpdateDropTarget

Update current drop target in drag context.

Fields

target: DomNodeId

UpdateDragGpuTransform

Update GPU transform for active node drag.

DeactivateDrag

End drag: clear pseudo-states, remove GPU keys, end drag session.

SetFocus

Change focus to a new target (or clear focus if None). Handles: set_focused_node, apply_focus_restyle, scroll_node_into_view, cursor_blink_timer start/stop.

Fields

new_focus: Option<DomNodeId>

old_focus: Option<DomNodeId>

ClearAllSelections

Clear all text selections.

FinalizePendingFocusChanges

Finalize pending focus changes (cursor initialization after layout).

ScrollSelectionIntoView

Scroll cursor/selection into view.

ScrollNodeIntoView

Scroll a specific node into view.

Fields

target: DomNodeId

ScrollCursorIntoViewAfterTextInput

Scroll cursor into view after text input (needs relayout first).

StartAutoScrollTimer

Start auto-scroll timer for drag-to-scroll (60Hz).

StopAutoScrollTimer

Cancel auto-scroll timer.

Trait Implementations

impl Clone for SystemChange

fn clone(&self) -> SystemChange

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SystemChange

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

Formats the value using the given formatter.

impl FromIterator<SystemChange> for SystemChangeVec

fn from_iter<T>(iter: T) -> Self

where T: IntoIterator<Item = SystemChange>,

Creates a value from an iterator.

impl PartialEq for SystemChange

fn eq(&self, other: &SystemChange) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for SystemChange