feat: allow inner-drag-selecting with cmd/ctrl (#3603)

* feat: allow inner-drag-selecting with cmd/ctrl

* don't use  cursor when pressing cmd/ctrl

* ensure we reset deselected groups

* add tests

* add docs

* couple fixes around group selection

src/components/App.tsx

@@ -259,6 +259,7 @@ export type PointerDownState = Readonly<{
     hasBeenDuplicated: boolean;
     hasHitCommonBoundingBoxOfSelectedElements: boolean;
   };
+  withCmdOrCtrl: boolean;
   drag: {
     // Might change during the pointer interation
     hasOccurred: boolean;
@@ -2260,11 +2261,13 @@ class App extends React.Component<AppProps, AppState> {
     } else if (isOverScrollBar) {
       setCursor(this.canvas, CURSOR_TYPE.AUTO);
     } else if (
-      hitElement ||
-      this.isHittingCommonBoundingBoxOfSelectedElements(
-        scenePointer,
-        selectedElements,
-      )
+      // if using cmd/ctrl, we're not dragging
+      !event[KEYS.CTRL_OR_CMD] &&
+      (hitElement ||
+        this.isHittingCommonBoundingBoxOfSelectedElements(
+          scenePointer,
+          selectedElements,
+        ))
     ) {
       setCursor(this.canvas, CURSOR_TYPE.MOVE);
     } else {
@@ -2542,6 +2545,7 @@ class App extends React.Component<AppProps, AppState> {
 
     return {
       origin,
+      withCmdOrCtrl: event[KEYS.CTRL_OR_CMD],
       originInGrid: tupleToCoors(
         getGridPoint(origin.x, origin.y, this.state.gridSize),
       ),
@@ -2746,6 +2750,9 @@ class App extends React.Component<AppProps, AppState> {
         if (hitElement != null) {
           // on CMD/CTRL, drill down to hit element regardless of groups etc.
           if (event[KEYS.CTRL_OR_CMD]) {
+            if (!this.state.selectedElementIds[hitElement.id]) {
+              pointerDownState.hit.wasAddedToSelection = true;
+            }
             this.setState((prevState) => ({
               ...editGroupForSelectedElement(prevState, hitElement),
               previousSelectedElementIds: this.state.selectedElementIds,
@@ -3184,7 +3191,9 @@ class App extends React.Component<AppProps, AppState> {
           this.scene.getElements(),
           this.state,
         );
-        if (selectedElements.length > 0) {
+        // prevent dragging even if we're no longer holding cmd/ctrl otherwise
+        // it would have weird results (stuff jumping all over the screen)
+        if (selectedElements.length > 0 && !pointerDownState.withCmdOrCtrl) {
           const [dragX, dragY] = getGridPoint(
             pointerCoords.x - pointerDownState.drag.offset.x,
             pointerCoords.y - pointerDownState.drag.offset.y,
@@ -3326,11 +3335,25 @@ class App extends React.Component<AppProps, AppState> {
       if (this.state.elementType === "selection") {
         const elements = this.scene.getElements();
         if (!event.shiftKey && isSomeElementSelected(elements, this.state)) {
-          this.setState({
-            selectedElementIds: {},
-            selectedGroupIds: {},
-            editingGroupId: null,
-          });
+          if (pointerDownState.withCmdOrCtrl && pointerDownState.hit.element) {
+            this.setState((prevState) =>
+              selectGroupsForSelectedElements(
+                {
+                  ...prevState,
+                  selectedElementIds: {
+                    [pointerDownState.hit.element!.id]: true,
+                  },
+                },
+                this.scene.getElements(),
+              ),
+            );
+          } else {
+            this.setState({
+              selectedElementIds: {},
+              selectedGroupIds: {},
+              editingGroupId: null,
+            });
+          }
         }
         const elementsWithinSelection = getElementsWithinSelection(
           elements,
@@ -3346,6 +3369,14 @@ class App extends React.Component<AppProps, AppState> {
                   map[element.id] = true;
                   return map;
                 }, {} as any),
+                ...(pointerDownState.hit.element
+                  ? {
+                      // if using ctrl/cmd, select the hitElement only if we
+                      // haven't box-selected anything else
+                      [pointerDownState.hit.element
+                        .id]: !elementsWithinSelection.length,
+                    }
+                  : null),
               },
             },
             this.scene.getElements(),
@@ -3610,12 +3641,18 @@ class App extends React.Component<AppProps, AppState> {
             } else {
               // remove element from selection while
               // keeping prev elements selected
-              this.setState((prevState) => ({
-                selectedElementIds: {
-                  ...prevState.selectedElementIds,
-                  [hitElement!.id]: false,
-                },
-              }));
+              this.setState((prevState) =>
+                selectGroupsForSelectedElements(
+                  {
+                    ...prevState,
+                    selectedElementIds: {
+                      ...prevState.selectedElementIds,
+                      [hitElement!.id]: false,
+                    },
+                  },
+                  this.scene.getElements(),
+                ),
+              );
             }
           } else {
             // add element to selection while

src/groups.ts

@@ -67,10 +67,14 @@ export const selectGroupsForSelectedElements = (
   appState: AppState,
   elements: readonly NonDeleted<ExcalidrawElement>[],
 ): AppState => {
-  let nextAppState = { ...appState };
+  let nextAppState: AppState = { ...appState, selectedGroupIds: {} };
 
   const selectedElements = getSelectedElements(elements, appState);
 
+  if (!selectedElements.length) {
+    return { ...nextAppState, editingGroupId: null };
+  }
+
   for (const selectedElement of selectedElements) {
     let groupIds = selectedElement.groupIds;
     if (appState.editingGroupId) {

src/tests/helpers/api.ts

@@ -57,6 +57,7 @@ export class API {
     width = 100,
     height = width,
     isDeleted = false,
+    groupIds = [],
     ...rest
   }: {
     type: T;
@@ -66,6 +67,7 @@ export class API {
     width?: number;
     id?: string;
     isDeleted?: boolean;
+    groupIds?: string[];
     // generic element props
     strokeColor?: ExcalidrawGenericElement["strokeColor"];
     backgroundColor?: ExcalidrawGenericElement["backgroundColor"];
@@ -152,6 +154,9 @@ export class API {
     if (isDeleted) {
       element.isDeleted = isDeleted;
     }
+    if (groupIds) {
+      element.groupIds = groupIds;
+    }
     return element as any;
   };
 

src/tests/helpers/ui.ts

@@ -122,6 +122,9 @@ export class Pointer {
     };
   }
 
+  // incremental (moving by deltas)
+  // ---------------------------------------------------------------------------
+
   move(dx: number, dy: number) {
     if (dx !== 0 || dy !== 0) {
       this.clientX += dx;
@@ -150,6 +153,39 @@ export class Pointer {
     fireEvent.doubleClick(GlobalTestState.canvas, this.getEvent());
   }
 
+  // absolute coords
+  // ---------------------------------------------------------------------------
+
+  moveTo(x: number, y: number) {
+    this.clientX = x;
+    this.clientY = y;
+    fireEvent.pointerMove(GlobalTestState.canvas, this.getEvent());
+  }
+
+  downAt(x = this.clientX, y = this.clientY) {
+    this.clientX = x;
+    this.clientY = y;
+    fireEvent.pointerDown(GlobalTestState.canvas, this.getEvent());
+  }
+
+  upAt(x = this.clientX, y = this.clientY) {
+    this.clientX = x;
+    this.clientY = y;
+    fireEvent.pointerUp(GlobalTestState.canvas, this.getEvent());
+  }
+
+  clickAt(x: number, y: number) {
+    this.downAt(x, y);
+    this.upAt();
+  }
+
+  doubleClickAt(x: number, y: number) {
+    this.moveTo(x, y);
+    fireEvent.doubleClick(GlobalTestState.canvas, this.getEvent());
+  }
+
+  // ---------------------------------------------------------------------------
+
   select(
     /** if multiple elements supplied, they're shift-selected */
     elements: ExcalidrawElement | ExcalidrawElement[],

src/tests/selection.test.tsx

@@ -10,6 +10,9 @@ import ExcalidrawApp from "../excalidraw-app";
 import * as Renderer from "../renderer/renderScene";
 import { KEYS } from "../keys";
 import { reseed } from "../random";
+import { API } from "./helpers/api";
+import { Keyboard, Pointer } from "./helpers/ui";
+import { getSelectedElements } from "../scene";
 
 // Unmount ReactDOM from root
 ReactDOM.unmountComponentAtNode(document.getElementById("root")!);
@@ -23,6 +26,130 @@ beforeEach(() => {
 
 const { h } = window;
 
+const mouse = new Pointer("mouse");
+
+const assertSelectedIds = (ids: string[]) => {
+  expect(
+    getSelectedElements(h.app.getSceneElements(), h.state).map((el) => el.id),
+  ).toEqual(ids);
+};
+
+describe("inner box-selection", () => {
+  beforeEach(async () => {
+    await render(<ExcalidrawApp />);
+  });
+  it("selecting elements visually nested inside another", async () => {
+    const rect1 = API.createElement({
+      type: "rectangle",
+      x: 0,
+      y: 0,
+      width: 300,
+      height: 300,
+      backgroundColor: "red",
+      fillStyle: "solid",
+    });
+    const rect2 = API.createElement({
+      type: "rectangle",
+      x: 50,
+      y: 50,
+      width: 50,
+      height: 50,
+    });
+    const rect3 = API.createElement({
+      type: "rectangle",
+      x: 150,
+      y: 150,
+      width: 50,
+      height: 50,
+    });
+    h.elements = [rect1, rect2, rect3];
+    Keyboard.withModifierKeys({ ctrl: true }, () => {
+      mouse.downAt(40, 40);
+      mouse.moveTo(290, 290);
+      mouse.up();
+
+      assertSelectedIds([rect2.id, rect3.id]);
+    });
+  });
+
+  it("selecting grouped elements visually nested inside another", async () => {
+    const rect1 = API.createElement({
+      type: "rectangle",
+      x: 0,
+      y: 0,
+      width: 300,
+      height: 300,
+      backgroundColor: "red",
+      fillStyle: "solid",
+    });
+    const rect2 = API.createElement({
+      type: "rectangle",
+      x: 50,
+      y: 50,
+      width: 50,
+      height: 50,
+      groupIds: ["A"],
+    });
+    const rect3 = API.createElement({
+      type: "rectangle",
+      x: 150,
+      y: 150,
+      width: 50,
+      height: 50,
+      groupIds: ["A"],
+    });
+    h.elements = [rect1, rect2, rect3];
+
+    Keyboard.withModifierKeys({ ctrl: true }, () => {
+      mouse.downAt(40, 40);
+      mouse.moveTo(rect2.x + rect2.width + 10, rect2.y + rect2.height + 10);
+      mouse.up();
+
+      assertSelectedIds([rect2.id, rect3.id]);
+      expect(h.state.selectedGroupIds).toEqual({ A: true });
+    });
+  });
+
+  it("selecting & deselecting grouped elements visually nested inside another", async () => {
+    const rect1 = API.createElement({
+      type: "rectangle",
+      x: 0,
+      y: 0,
+      width: 300,
+      height: 300,
+      backgroundColor: "red",
+      fillStyle: "solid",
+    });
+    const rect2 = API.createElement({
+      type: "rectangle",
+      x: 50,
+      y: 50,
+      width: 50,
+      height: 50,
+      groupIds: ["A"],
+    });
+    const rect3 = API.createElement({
+      type: "rectangle",
+      x: 150,
+      y: 150,
+      width: 50,
+      height: 50,
+      groupIds: ["A"],
+    });
+    h.elements = [rect1, rect2, rect3];
+    Keyboard.withModifierKeys({ ctrl: true }, () => {
+      mouse.downAt(rect2.x - 20, rect2.x - 20);
+      mouse.moveTo(rect2.x + rect2.width + 10, rect2.y + rect2.height + 10);
+      assertSelectedIds([rect2.id, rect3.id]);
+      expect(h.state.selectedGroupIds).toEqual({ A: true });
+      mouse.moveTo(rect2.x - 10, rect2.y - 10);
+      assertSelectedIds([rect1.id]);
+      expect(h.state.selectedGroupIds).toEqual({});
+      mouse.up();
+    });
+  });
+});
+
 describe("selection element", () => {
   it("create selection element on pointer down", async () => {
     const { getByToolName, container } = await render(<ExcalidrawApp />);

src/tests/zindex.test.tsx

@@ -56,9 +56,8 @@ const populateElements = (
         y,
         width,
         height,
+        groupIds,
       });
-      // @ts-ignore
-      element.groupIds = groupIds;
       if (isSelected) {
         selectedElementIds[element.id] = true;
       }