feat(iced): implement transform drag messages and handlers

hcie-iced-app/crates/hcie-iced-gui/src/app.rs

@@ -201,6 +201,10 @@ pub struct IcedDocument {
     pub selection_transform: Option<SelectionTransform>,
     /// Transform handle being dragged
     pub transform_drag_handle: TransformHandle,
+    /// Transform drag start position in canvas coordinates
+    pub transform_drag_start: Option<(f32, f32)>,
+    /// Original transform state before drag (for undo)
+    pub transform_original: Option<SelectionTransform>,
     /// Internal clipboard for copy/paste operations
     pub internal_clipboard: Option<SelectionTransform>,
     /// Selection mask (alpha channel) for the current selection
@@ -375,6 +379,13 @@ pub enum Message {
     SelectionDragMove(f32, f32),
     SelectionDragEnd,
 
+    // ── Selection transform ─────────────────────────────
+    TransformDragStart(f32, f32),
+    TransformDragMove(f32, f32),
+    TransformDragEnd,
+    TransformApply,
+    TransformCancel,
+
     // ── Vector tools ────────────────────────────────────
     VectorDrawStart(f32, f32),
     VectorDrawMove(f32, f32),
@@ -527,6 +538,8 @@ impl HcieIcedApp {
             full_upload: std::cell::RefCell::new(true),
             selection_transform: None,
             transform_drag_handle: TransformHandle::None,
+            transform_drag_start: None,
+            transform_original: None,
             internal_clipboard: None,
             selection_mask: None,
             selection_bounds: None,
@@ -1809,6 +1822,8 @@ impl HcieIcedApp {
                     full_upload: std::cell::RefCell::new(true),
                     selection_transform: None,
                     transform_drag_handle: TransformHandle::None,
+                    transform_drag_start: None,
+                    transform_original: None,
                     internal_clipboard: None,
                     selection_mask: None,
                     selection_bounds: None,
@@ -1929,6 +1944,100 @@ impl HcieIcedApp {
                 }
             }
 
+            // ── Selection transform ────────────────────────
+            Message::TransformDragStart(x, y) => {
+                let doc = &mut self.documents[self.active_doc];
+                if let Some(ref tr) = doc.selection_transform {
+                    let original = tr.clone();
+                    doc.transform_drag_start = Some((x, y));
+                    doc.transform_original = Some(original);
+                }
+            }
+            Message::TransformDragMove(x, y) => {
+                let doc = &mut self.documents[self.active_doc];
+                if let (Some(start), Some(ref mut tr)) = (doc.transform_drag_start, &mut doc.selection_transform) {
+                    let dx = x - start.0;
+                    let dy = y - start.1;
+
+                    match doc.transform_drag_handle {
+                        TransformHandle::Move => {
+                            tr.pos = iced::Vector::new(tr.pos.x + dx, tr.pos.y + dy);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::TopLeft => {
+                            tr.pos = iced::Vector::new(tr.pos.x + dx, tr.pos.y + dy);
+                            tr.size = iced::Vector::new(tr.size.x - dx, tr.size.y - dy);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::TopRight => {
+                            tr.size = iced::Vector::new(tr.size.x + dx, tr.size.y - dy);
+                            tr.pos = iced::Vector::new(tr.pos.x, tr.pos.y + dy);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::BottomLeft => {
+                            tr.size = iced::Vector::new(tr.size.x - dx, tr.size.y + dy);
+                            tr.pos = iced::Vector::new(tr.pos.x + dx, tr.pos.y);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::BottomRight => {
+                            tr.size = iced::Vector::new(tr.size.x + dx, tr.size.y + dy);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::Top => {
+                            tr.pos = iced::Vector::new(tr.pos.x, tr.pos.y + dy);
+                            tr.size = iced::Vector::new(tr.size.x, tr.size.y - dy);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::Bottom => {
+                            tr.size = iced::Vector::new(tr.size.x, tr.size.y + dy);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::Left => {
+                            tr.pos = iced::Vector::new(tr.pos.x + dx, tr.pos.y);
+                            tr.size = iced::Vector::new(tr.size.x - dx, tr.size.y);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::Right => {
+                            tr.size = iced::Vector::new(tr.size.x + dx, tr.size.y);
+                            doc.transform_drag_start = Some((x, y));
+                        }
+                        TransformHandle::Rotate => {
+                            // Calculate rotation from center
+                            let center_x = tr.pos.x + tr.size.x / 2.0;
+                            let center_y = tr.pos.y + tr.size.y / 2.0;
+                            let angle = (y - center_y).atan2(x - center_x);
+                            tr.rotation = angle;
+                        }
+                        TransformHandle::None => {}
+                    }
+                }
+            }
+            Message::TransformDragEnd => {
+                let doc = &mut self.documents[self.active_doc];
+                doc.transform_drag_start = None;
+                doc.transform_original = None;
+            }
+            Message::TransformApply => {
+                let doc = &mut self.documents[self.active_doc];
+                if let Some(_tr) = doc.selection_transform.take() {
+                    // TODO: Apply transform to layer pixels
+                    // For now, just clear the transform
+                    doc.transform_drag_handle = TransformHandle::None;
+                    return Task::perform(async {}, |_| Message::CompositeRefresh);
+                }
+            }
+            Message::TransformCancel => {
+                let doc = &mut self.documents[self.active_doc];
+                // Restore original transform if we have it
+                if let Some(original) = doc.transform_original.take() {
+                    doc.selection_transform = Some(original);
+                } else {
+                    doc.selection_transform = None;
+                }
+                doc.transform_drag_start = None;
+                doc.transform_drag_handle = TransformHandle::None;
+            }
+
             // ── Vector tools ──────────────────────────────
             Message::VectorDrawStart(x, y) => {
                 self.documents[self.active_doc].vector_draw = Some(((x, y), (x, y)));
@@ -2230,6 +2339,8 @@ impl HcieIcedApp {
                     full_upload: std::cell::RefCell::new(true),
                     selection_transform: None,
                     transform_drag_handle: TransformHandle::None,
+                    transform_drag_start: None,
+                    transform_original: None,
                     internal_clipboard: None,
                     selection_mask: None,
                     selection_bounds: None,