fix: z-index inconsistencies during addition / deletion in frames (#6914)

Co-authored-by: Marcel Mraz <marcel.mraz@adacta-fintech.com>
Co-authored-by: dwelle <luzar.david@gmail.com>

src/components/App.tsx

@@ -6501,7 +6501,7 @@ class App extends React.Component<AppProps, AppState> {
             }
 
             nextElements = updateFrameMembershipOfSelectedElements(
-              this.scene.getElementsIncludingDeleted(),
+              nextElements,
               this.state,
               this,
             );

src/frame.test.tsx

@@ -1,9 +1,10 @@
+import { ExcalidrawElement } from "./element/types";
 import {
   convertToExcalidrawElements,
   Excalidraw,
 } from "./packages/excalidraw/index";
 import { API } from "./tests/helpers/api";
-import { Pointer } from "./tests/helpers/ui";
+import { Keyboard, Pointer } from "./tests/helpers/ui";
 import { render } from "./tests/test-utils";
 
 const { h } = window;
@@ -28,8 +29,225 @@ describe("adding elements to frames", () => {
     }, []);
   };
 
-  describe("resizing frame over elements", () => {
-    const testElements = async (
+  function resizeFrameOverElement(
+    frame: ExcalidrawElement,
+    element: ExcalidrawElement,
+  ) {
+    mouse.clickAt(0, 0);
+    mouse.downAt(frame.x + frame.width, frame.y + frame.height);
+    mouse.moveTo(
+      element.x + element.width + 50,
+      element.y + element.height + 50,
+    );
+    mouse.up();
+  }
+
+  function dragElementIntoFrame(
+    frame: ExcalidrawElement,
+    element: ExcalidrawElement,
+  ) {
+    mouse.clickAt(element.x, element.y);
+    mouse.downAt(element.x + element.width / 2, element.y + element.height / 2);
+    mouse.moveTo(frame.x + frame.width / 2, frame.y + frame.height / 2);
+    mouse.up();
+  }
+
+  function selectElementAndDuplicate(
+    element: ExcalidrawElement,
+    moveTo: [number, number] = [element.x + 25, element.y + 25],
+  ) {
+    const [x, y] = [
+      element.x + element.width / 2,
+      element.y + element.height / 2,
+    ];
+
+    Keyboard.withModifierKeys({ alt: true }, () => {
+      mouse.downAt(x, y);
+      mouse.moveTo(moveTo[0], moveTo[1]);
+      mouse.up();
+    });
+  }
+
+  function expectEqualIds(expected: ExcalidrawElement[]) {
+    expect(h.elements.map((x) => x.id)).toEqual(expected.map((x) => x.id));
+  }
+
+  let frame: ExcalidrawElement;
+  let rect1: ExcalidrawElement;
+  let rect2: ExcalidrawElement;
+  let rect3: ExcalidrawElement;
+  let rect4: ExcalidrawElement;
+  let text: ExcalidrawElement;
+  let arrow: ExcalidrawElement;
+
+  beforeEach(async () => {
+    await render(<Excalidraw />);
+
+    frame = API.createElement({ id: "id0", type: "frame", x: 0, width: 150 });
+    rect1 = API.createElement({
+      id: "id1",
+      type: "rectangle",
+      x: -1000,
+    });
+    rect2 = API.createElement({
+      id: "id2",
+      type: "rectangle",
+      x: 200,
+      width: 50,
+    });
+    rect3 = API.createElement({
+      id: "id3",
+      type: "rectangle",
+      x: 400,
+      width: 50,
+    });
+    rect4 = API.createElement({
+      id: "id4",
+      type: "rectangle",
+      x: 1000,
+      width: 50,
+    });
+    text = API.createElement({
+      id: "id5",
+      type: "text",
+      x: 100,
+    });
+    arrow = API.createElement({
+      id: "id6",
+      type: "arrow",
+      x: 100,
+      boundElements: [{ id: text.id, type: "text" }],
+    });
+  });
+
+  const commonTestCases = async (
+    func: typeof resizeFrameOverElement | typeof dragElementIntoFrame,
+  ) => {
+    describe("when frame is in a layer below", async () => {
+      it("should add an element", async () => {
+        h.elements = [frame, rect2];
+
+        func(frame, rect2);
+
+        expect(h.elements[0].frameId).toBe(frame.id);
+        expectEqualIds([rect2, frame]);
+      });
+
+      it("should add elements", async () => {
+        h.elements = [frame, rect2, rect3];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect2, rect3, frame]);
+      });
+
+      it("should add elements when there are other other elements in between", async () => {
+        h.elements = [frame, rect1, rect2, rect4, rect3];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect2, rect3, frame, rect1, rect4]);
+      });
+
+      it("should add elements when there are other elements in between and the order is reversed", async () => {
+        h.elements = [frame, rect3, rect4, rect2, rect1];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect2, rect3, frame, rect4, rect1]);
+      });
+    });
+
+    describe("when frame is in a layer above", async () => {
+      it("should add an element", async () => {
+        h.elements = [rect2, frame];
+
+        func(frame, rect2);
+
+        expect(h.elements[0].frameId).toBe(frame.id);
+        expectEqualIds([rect2, frame]);
+      });
+
+      it("should add elements", async () => {
+        h.elements = [rect2, rect3, frame];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect3, rect2, frame]);
+      });
+
+      it("should add elements when there are other other elements in between", async () => {
+        h.elements = [rect1, rect2, rect4, rect3, frame];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect1, rect4, rect3, rect2, frame]);
+      });
+
+      it("should add elements when there are other elements in between and the order is reversed", async () => {
+        h.elements = [rect3, rect4, rect2, rect1, frame];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect4, rect1, rect3, rect2, frame]);
+      });
+    });
+
+    describe("when frame is in an inner layer", async () => {
+      it("should add elements", async () => {
+        h.elements = [rect2, frame, rect3];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect2, rect3, frame]);
+      });
+
+      it("should add elements when there are other other elements in between", async () => {
+        h.elements = [rect2, rect1, frame, rect4, rect3];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect1, rect2, rect3, frame, rect4]);
+      });
+
+      it("should add elements when there are other elements in between and the order is reversed", async () => {
+        h.elements = [rect3, rect4, frame, rect2, rect1];
+
+        func(frame, rect2);
+        func(frame, rect3);
+
+        expect(rect2.frameId).toBe(frame.id);
+        expect(rect3.frameId).toBe(frame.id);
+        expectEqualIds([rect4, rect3, rect2, frame, rect1]);
+      });
+    });
+  };
+
+  const resizingTest = async (
     containerType: "arrow" | "rectangle",
     initialOrder: ElementType[],
     expectedOrder: ElementType[],
@@ -61,50 +279,51 @@ describe("adding elements to frames", () => {
 
     const container = h.elements[1];
 
-      mouse.clickAt(0, 0);
-      mouse.downAt(frame.x + frame.width, frame.y + frame.height);
-      mouse.moveTo(
-        container.x + container.width + 100,
-        container.y + container.height + 100,
-      );
-      mouse.up();
+    resizeFrameOverElement(frame, container);
     assertOrder(h.elements, expectedOrder);
 
     expect(h.elements[0].frameId).toBe(frame.id);
     expect(h.elements[1].frameId).toBe(frame.id);
   };
 
-    it("resizing over text containers / labelled arrows", async () => {
-      await testElements(
+  describe("resizing frame over elements", async () => {
+    await commonTestCases(resizeFrameOverElement);
+
+    it("resizing over text containers and labelled arrows", async () => {
+      await resizingTest(
         "rectangle",
         ["frame", "rectangle", "text"],
         ["rectangle", "text", "frame"],
       );
-      await testElements(
+      await resizingTest(
         "rectangle",
         ["frame", "text", "rectangle"],
         ["rectangle", "text", "frame"],
       );
-      await testElements(
+      await resizingTest(
         "rectangle",
         ["rectangle", "text", "frame"],
         ["rectangle", "text", "frame"],
       );
-      await testElements(
+      await resizingTest(
         "rectangle",
         ["text", "rectangle", "frame"],
-        ["text", "rectangle", "frame"],
+        ["rectangle", "text", "frame"],
       );
-
-      await testElements(
+      await resizingTest(
         "arrow",
         ["frame", "arrow", "text"],
         ["arrow", "text", "frame"],
       );
-      await testElements(
+      await resizingTest(
         "arrow",
         ["text", "arrow", "frame"],
-        ["text", "arrow", "frame"],
+        ["arrow", "text", "frame"],
+      );
+      await resizingTest(
+        "arrow",
+        ["frame", "arrow", "text"],
+        ["arrow", "text", "frame"],
       );
 
       // FIXME failing in tests (it fails to add elements to frame for some
@@ -118,11 +337,104 @@ describe("adding elements to frames", () => {
       //   ["arrow", "text", "frame"],
       //   ["arrow", "text", "frame"],
       // );
-      // await testElements(
-      //   "arrow",
-      //   ["frame", "text", "arrow"],
-      //   ["text", "arrow", "frame"],
-      // );
+    });
+
+    it("should add arrow bound with text when frame is in a layer below", async () => {
+      h.elements = [frame, arrow, text];
+
+      resizeFrameOverElement(frame, arrow);
+
+      expect(arrow.frameId).toBe(frame.id);
+      expect(text.frameId).toBe(frame.id);
+      expectEqualIds([arrow, text, frame]);
+    });
+
+    it("should add arrow bound with text when frame is in a layer above", async () => {
+      h.elements = [arrow, text, frame];
+
+      resizeFrameOverElement(frame, arrow);
+
+      expect(arrow.frameId).toBe(frame.id);
+      expect(text.frameId).toBe(frame.id);
+      expectEqualIds([arrow, text, frame]);
+    });
+
+    it("should add arrow bound with text when frame is in an inner layer", async () => {
+      h.elements = [arrow, frame, text];
+
+      resizeFrameOverElement(frame, arrow);
+
+      expect(arrow.frameId).toBe(frame.id);
+      expect(text.frameId).toBe(frame.id);
+      expectEqualIds([arrow, text, frame]);
+    });
+  });
+
+  describe("resizing frame over elements but downwards", async () => {
+    it("should add elements when frame is in a layer below", async () => {
+      h.elements = [frame, rect1, rect2, rect3, rect4];
+
+      resizeFrameOverElement(frame, rect4);
+      resizeFrameOverElement(frame, rect3);
+
+      expect(rect2.frameId).toBe(frame.id);
+      expect(rect3.frameId).toBe(frame.id);
+      expectEqualIds([rect2, rect3, frame, rect4, rect1]);
+    });
+
+    it("should add elements when frame is in a layer above", async () => {
+      h.elements = [rect1, rect2, rect3, rect4, frame];
+
+      resizeFrameOverElement(frame, rect4);
+      resizeFrameOverElement(frame, rect3);
+
+      expect(rect2.frameId).toBe(frame.id);
+      expect(rect3.frameId).toBe(frame.id);
+      expectEqualIds([rect1, rect2, rect3, frame, rect4]);
+    });
+
+    it("should add elements when frame is in an inner layer", async () => {
+      h.elements = [rect1, rect2, frame, rect3, rect4];
+
+      resizeFrameOverElement(frame, rect4);
+      resizeFrameOverElement(frame, rect3);
+
+      expect(rect2.frameId).toBe(frame.id);
+      expect(rect3.frameId).toBe(frame.id);
+      expectEqualIds([rect1, rect2, rect3, frame, rect4]);
+    });
+  });
+
+  describe("dragging elements into the frame", async () => {
+    await commonTestCases(dragElementIntoFrame);
+
+    it("should drag element inside, duplicate it and keep it in frame", () => {
+      h.elements = [frame, rect2];
+
+      dragElementIntoFrame(frame, rect2);
+
+      const rect2_copy = { ...rect2, id: `${rect2.id}_copy` };
+
+      selectElementAndDuplicate(rect2);
+
+      expect(rect2_copy.frameId).toBe(frame.id);
+      expect(rect2.frameId).toBe(frame.id);
+      expectEqualIds([rect2_copy, rect2, frame]);
+    });
+
+    it("should drag element inside, duplicate it and remove it from frame", () => {
+      h.elements = [frame, rect2];
+
+      dragElementIntoFrame(frame, rect2);
+
+      const rect2_copy = { ...rect2, id: `${rect2.id}_copy` };
+
+      // move the rect2 outside the frame
+      selectElementAndDuplicate(rect2, [-1000, -1000]);
+
+      expect(rect2_copy.frameId).toBe(frame.id);
+      expect(rect2.frameId).toBe(null);
+      expectEqualIds([rect2_copy, frame, rect2]);
     });
   });
 });

src/frame.ts

@@ -468,14 +468,39 @@ export const addElementsToFrame = (
     }
   }
 
-  let nextElements = allElements.slice();
+  const allElementsIndex = allElements.reduce(
+    (acc: Record<string, number>, element, index) => {
+      acc[element.id] = index;
+      return acc;
+    },
+    {},
+  );
+
+  const frameIndex = allElementsIndex[frame.id];
+  // need to be calculated before the mutation below occurs
+  const leftFrameBoundaryIndex = findIndex(
+    allElements,
+    (e) => e.frameId === frame.id,
+  );
+
+  const existingFrameChildren = allElements.filter(
+    (element) => element.frameId === frame.id,
+  );
+
+  const addedFrameChildren_left: ExcalidrawElement[] = [];
+  const addedFrameChildren_right: ExcalidrawElement[] = [];
 
-  const frameBoundary = findIndex(nextElements, (e) => e.frameId === frame.id);
   for (const element of omitGroupsContainingFrames(
     allElements,
     _elementsToAdd,
   )) {
     if (element.frameId !== frame.id && !isFrameElement(element)) {
+      if (allElementsIndex[element.id] > frameIndex) {
+        addedFrameChildren_right.push(element);
+      } else {
+        addedFrameChildren_left.push(element);
+      }
+
       mutateElement(
         element,
         {
@@ -483,27 +508,34 @@ export const addElementsToFrame = (
         },
         false,
       );
+    }
+  }
 
-      const frameIndex = findIndex(nextElements, (e) => e.id === frame.id);
-      const elementIndex = findIndex(nextElements, (e) => e.id === element.id);
+  const frameElement = allElements[frameIndex];
+  const nextFrameChildren = addedFrameChildren_left
+    .concat(existingFrameChildren)
+    .concat(addedFrameChildren_right);
 
-      if (elementIndex < frameBoundary) {
-        nextElements = [
-          ...nextElements.slice(0, elementIndex),
-          ...nextElements.slice(elementIndex + 1, frameBoundary),
-          element,
-          ...nextElements.slice(frameBoundary),
-        ];
-      } else if (elementIndex > frameIndex) {
-        nextElements = [
-          ...nextElements.slice(0, frameIndex),
-          element,
-          ...nextElements.slice(frameIndex, elementIndex),
-          ...nextElements.slice(elementIndex + 1),
-        ];
-      }
-    }
-  }
+  const nextFrameChildrenMap = nextFrameChildren.reduce(
+    (acc: Record<string, boolean>, element) => {
+      acc[element.id] = true;
+      return acc;
+    },
+    {},
+  );
+
+  const nextOtherElements_left = allElements
+    .slice(0, leftFrameBoundaryIndex >= 0 ? leftFrameBoundaryIndex : frameIndex)
+    .filter((element) => !nextFrameChildrenMap[element.id]);
+
+  const nextOtherElement_right = allElements
+    .slice(frameIndex + 1)
+    .filter((element) => !nextFrameChildrenMap[element.id]);
+
+  const nextElements = nextOtherElements_left
+    .concat(nextFrameChildren)
+    .concat([frameElement])
+    .concat(nextOtherElement_right);
 
   return nextElements;
 };
@@ -518,6 +550,7 @@ export const removeElementsFromFrame = (
   for (const element of elementsToRemove) {
     if (element.frameId) {
       _elementsToRemove.push(element);
+
       const boundTextElement = getBoundTextElement(element);
       if (boundTextElement) {
         _elementsToRemove.push(boundTextElement);
@@ -566,7 +599,7 @@ export const replaceAllElementsInFrame = (
   );
 };
 
-/** does not mutate elements, but return new ones */
+/** does not mutate elements, but returns new ones */
 export const updateFrameMembershipOfSelectedElements = (
   allElements: ExcalidrawElementsIncludingDeleted,
   appState: AppState,