Struct DragSession 

pub struct DragSession {

    pub session_id: DragSessionId,
    pub pointer_id: PointerId,
    pub source_window: AppWindowId,
    pub current_window: AppWindowId,
    pub cross_window_hover: bool,
    pub kind: DragKindId,
    pub start_position: Point,
    pub position: Point,
    pub cursor_grab_offset: Option<Point>,
    pub follow_window: Option<AppWindowId>,
    pub moving_window: Option<AppWindowId>,
    pub window_under_moving_window: Option<AppWindowId>,
    pub window_under_moving_window_source: WindowUnderCursorSource,
    pub transparent_payload_applied: bool,
    pub transparent_payload_hit_test_passthrough_applied: bool,
    pub window_under_cursor_source: WindowUnderCursorSource,
    pub diag_cursor_screen_pos_raw_physical_px: Option<Point>,
    pub diag_cursor_screen_pos_used_physical_px: Option<Point>,
    pub diag_cursor_screen_pos_was_clamped: bool,
    pub diag_cursor_override_active: bool,
    pub diag_current_window_outer_pos_physical_px: Option<Point>,
    pub diag_current_window_decoration_offset_physical_px: Option<Point>,
    pub diag_current_window_client_origin_screen_physical_px: Option<Point>,
    pub diag_current_window_client_origin_source_platform: bool,
    pub diag_current_window_scale_factor_x1000: Option<u32>,
    pub diag_current_window_local_pos_from_screen_logical_px: Option<Point>,
    pub dragging: bool,
    pub phase: DragPhase,
    /* private fields */
}

Fields

session_id: DragSessionId

pointer_id: PointerId

source_window: AppWindowId

current_window: AppWindowId

cross_window_hover: bool

kind: DragKindId

start_position: Point

position: Point

cursor_grab_offset: Option<Point>

Cursor grab offset in window-local logical coordinates.

Runners may use this to keep an OS window under the cursor during docking interactions (ImGui-style multi-viewport behavior), without needing to downcast the typed payload.

follow_window: Option<AppWindowId>

If set, requests the runner to treat this drag as a “move the OS window” interaction for the given window id, while still allowing cross-window docking hover/drop routing.

moving_window: Option<AppWindowId>

Best-effort diagnostics hint: OS window currently being moved by the runner for this drag session (ImGui-style “follow window” multi-viewport behavior).

This is intentionally diagnostics-only: it does not request follow behavior; it records what the runner is currently doing.

window_under_moving_window: Option<AppWindowId>

Best-effort diagnostics hint: when Self::moving_window is set, the window considered “under” the moving window at the current cursor position.

This exists to support ImGui-style terminology where HoveredWindow and HoveredWindowUnderMovingWindow can differ during a viewport drag. Fret currently keeps current_window as the runner-selected hover/drop target; this field makes it possible to gate and evolve “peek-behind” behavior without reinterpreting current_window.

window_under_moving_window_source: WindowUnderCursorSource

Best-effort diagnostics hint: which mechanism was used to select Self::window_under_moving_window.

transparent_payload_applied: bool

Best-effort diagnostics hint: true when the runner has applied an ImGui-style “transparent payload” treatment to the moving dock window (e.g. reduced opacity and/or click-through hit-test passthrough while following the cursor).

transparent_payload_hit_test_passthrough_applied: bool

Best-effort diagnostics hint: true when the runner successfully applied click-through hit-test passthrough to the moving dock window while transparent payload is enabled.

This is a result signal (applied by the OS/window backend), not a request. When false, the runner either did not attempt passthrough or the platform/backend rejected it.

window_under_cursor_source: WindowUnderCursorSource

Best-effort diagnostics hint: which mechanism was used to select the hovered window during cross-window drag routing (OS-backed vs heuristic).

diag_cursor_screen_pos_raw_physical_px: Option<Point>

Best-effort diagnostics hint: raw cursor position in screen-space physical pixels, as observed by the runner.

diag_cursor_screen_pos_used_physical_px: Option<Point>

Best-effort diagnostics hint: cursor position in screen-space physical pixels used for local position conversion (may be clamped during scripted injection).

diag_cursor_screen_pos_was_clamped: bool

True when Self::diag_cursor_screen_pos_used_physical_px differs from Self::diag_cursor_screen_pos_raw_physical_px due to runner-side clamping.

diag_cursor_override_active: bool

True when diagnostics cursor override/input isolation is active while recording the cursor conversion hints.

diag_current_window_outer_pos_physical_px: Option<Point>

Best-effort diagnostics hint: outer window position (top-left) in screen-space physical pixels for Self::current_window at the time routing was computed.

diag_current_window_decoration_offset_physical_px: Option<Point>

Best-effort diagnostics hint: window decoration offset (client origin relative to outer origin) in physical pixels for Self::current_window.

diag_current_window_client_origin_screen_physical_px: Option<Point>

Best-effort diagnostics hint: computed client origin in screen-space physical pixels for Self::current_window at the time routing was computed.

diag_current_window_client_origin_source_platform: bool

True when the runner obtained the client origin from a platform API (e.g. Win32 HWND), rather than falling back to outer_position + surface_position.

diag_current_window_scale_factor_x1000: Option<u32>

Best-effort diagnostics hint: scale factor (DPI) of Self::current_window used by the runner to convert screen physical pixels into window-local logical pixels.

diag_current_window_local_pos_from_screen_logical_px: Option<Point>

Best-effort diagnostics hint: local cursor position derived from the screen-space cursor position + client origin + scale factor.

dragging: bool

phase: DragPhase

Implementations

impl DragSession

pub fn new<T: Any>( session_id: DragSessionId, pointer_id: PointerId, source_window: AppWindowId, kind: DragKindId, start_position: Point, payload: T, ) -> Self

pub fn new_cross_window<T: Any>( session_id: DragSessionId, pointer_id: PointerId, source_window: AppWindowId, kind: DragKindId, start_position: Point, payload: T, ) -> Self

pub fn payload<T: Any>(&self) -> Option<&T>

pub fn payload_mut<T: Any>(&mut self) -> Option<&mut T>

pub fn into_payload(self) -> Box<dyn Any>

Trait Implementations

impl Debug for DragSession

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

Formats the value using the given formatter.