feat(transform): add transform session commands

editor/initial-state.ts

@@ -12,6 +12,7 @@ export const initialEditorState: EditorState = {
     layerIds: [],
   },
   tools: initialToolState,
+  transformSession: undefined,
 };
 
 export function createInitialAppState(name = "Untitled"): AppState {

editor/state.ts

@@ -2,6 +2,7 @@ import type { ImageDocument } from "@core/document";
 import type { Angle, Size, Vec2D } from "@core/geometry";
 import type { ArtboardId, LayerId } from "@core/id";
 import type { ToolState } from "./tools";
+import type { TransformSession } from "./transform";
 
 export type ViewportState = {
   center: Vec2D;
@@ -19,6 +20,7 @@ export type EditorState = {
   viewport: ViewportState;
   selection: SelectionState;
   tools: ToolState;
+  transformSession?: TransformSession;
 };
 
 export type AppState = {

editor/transform.ts

@@ -0,0 +1,16 @@
+import type { Rect, Vec2D } from "@core/geometry";
+import type { ArtboardId } from "@core/id";
+
+export type TransformHandle = "body" | "n" | "ne" | "e" | "se" | "s" | "sw" | "w" | "nw";
+
+export type TransformTarget = {
+  type: "artboard";
+  id: ArtboardId;
+};
+
+export type TransformSession = {
+  target: TransformTarget;
+  handle: TransformHandle;
+  startPoint: Vec2D;
+  initialBounds: Rect;
+};