add DragSwitch

Signed-off-by: kernelkind <kernelkind@gmail.com>

crates/notedeck_columns/src/drag.rs

@@ -0,0 +1,103 @@
+#[derive(Default, Clone, Debug)]
+pub struct DragSwitch {
+    state: Option<DragState>,
+}
+
+#[derive(Clone, Debug)]
+struct DragState {
+    start_pos: egui::Pos2,
+    cur_direction: DragDirection,
+}
+
+impl DragSwitch {
+    /// should call BEFORE both drag directions get rendered
+    pub fn update(&mut self, horizontal: egui::Id, vertical: egui::Id, ctx: &egui::Context) {
+        let horiz_being_dragged = ctx.is_being_dragged(horizontal);
+        let vert_being_dragged = ctx.is_being_dragged(vertical);
+
+        if !horiz_being_dragged && !vert_being_dragged {
+            self.state = None;
+            return;
+        }
+
+        let Some(state) = &mut self.state else {
+            return;
+        };
+
+        let Some(cur_pos) = ctx.pointer_interact_pos() else {
+            return;
+        };
+
+        let dx = (state.start_pos.x - cur_pos.x).abs();
+        let dy = (state.start_pos.y - cur_pos.y).abs();
+
+        let new_direction = if dx > dy {
+            DragDirection::Horizontal
+        } else {
+            DragDirection::Vertical
+        };
+
+        if new_direction == DragDirection::Horizontal
+            && state.cur_direction == DragDirection::Vertical
+        {
+            // drag is occuring mostly in the horizontal direction
+            ctx.set_dragged_id(horizontal);
+            let new_dir = DragDirection::Horizontal;
+            state.cur_direction = new_dir;
+        } else if new_direction == DragDirection::Vertical
+            && state.cur_direction == DragDirection::Horizontal
+        {
+            // drag is occuring mostly in the vertical direction
+            let new_dir = DragDirection::Vertical;
+            state.cur_direction = new_dir;
+            ctx.set_dragged_id(vertical);
+        }
+    }
+
+    /// should call AFTER both drag directions rendered
+    pub fn check_for_drag_start(
+        &mut self,
+        ctx: &egui::Context,
+        horizontal: egui::Id,
+        vertical: egui::Id,
+    ) {
+        let Some(drag_id) = ctx.drag_started_id() else {
+            return;
+        };
+
+        let cur_direction = if drag_id == horizontal {
+            DragDirection::Horizontal
+        } else if drag_id == vertical {
+            DragDirection::Vertical
+        } else {
+            return;
+        };
+
+        let Some(cur_pos) = ctx.pointer_interact_pos() else {
+            return;
+        };
+
+        self.state = Some(DragState {
+            start_pos: cur_pos,
+            cur_direction,
+        });
+    }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+enum DragDirection {
+    Horizontal,
+    Vertical,
+}
+
+pub fn get_drag_id(ui: &egui::Ui, scroll_id: egui::Id) -> egui::Id {
+    ui.id().with(egui::Id::new(scroll_id)).with("area")
+}
+
+// unfortunately a Frame makes a new id for the Ui
+pub fn get_drag_id_through_frame(ui: &egui::Ui, scroll_id: egui::Id) -> egui::Id {
+    ui.id()
+        .with(egui::Id::new("child"))
+        .with(egui::Id::new(scroll_id))
+        .with("area")
+}

crates/notedeck_columns/src/lib.rs

@@ -12,6 +12,7 @@ pub mod column;
 mod deck_state;
 mod decks;
 mod draft;
+mod drag;
 mod key_parsing;
 pub mod login_manager;
 mod media_upload;