feat(common): support transform z index (#817)

.changeset/four-dodos-sell.md

@@ -0,0 +1,6 @@
+---
+'@plait/common': minor
+'@plait/core': minor
+---
+
+support transform z index

packages/common/src/transforms/index.ts

@@ -1,3 +1,4 @@
 export * from './property';
 export * from './align';
 export * from './text';
+export * from './z-index';

packages/common/src/transforms/z-index.ts

@@ -0,0 +1,18 @@
+import { PlaitBoard } from '@plait/core';
+import { getOneMoveOptions, moveElementsToNewPath } from '../utils';
+
+const moveToTop = () => {};
+
+const moveToBottom = () => {};
+
+const moveUp = (board: PlaitBoard) => {
+    const moveOptions = getOneMoveOptions(board, 'up');
+    moveElementsToNewPath(board, moveOptions);
+};
+
+const moveDown = (board: PlaitBoard) => {
+    const moveOptions = getOneMoveOptions(board, 'down');
+    moveElementsToNewPath(board, moveOptions);
+};
+
+export const ZIndexTransforms = { moveUp, moveDown, moveToTop, moveToBottom };

packages/common/src/utils/index.ts

@@ -11,3 +11,4 @@ export * from './memorize';
 export * from './vector';
 export * from './math';
 export * from './drawing';
+export * from './z-index';

packages/common/src/utils/z-index.ts

@@ -0,0 +1,167 @@
+import {
+    PlaitBoard,
+    getSelectedElements,
+    getSelectedGroups,
+    PlaitElement,
+    PlaitGroupElement,
+    findLastIndex,
+    getEditingGroup,
+    getGroupByElement,
+    PlaitGroup,
+    getElementsInGroup,
+    Transforms,
+    Path,
+    findIndex
+} from '@plait/core';
+
+export interface ZIndexMoveOption {
+    element: PlaitElement;
+    newPath: Path;
+}
+
+export const moveElementsToNewPath = (board: PlaitBoard, zIndexMoveOption: ZIndexMoveOption[]) => {
+    zIndexMoveOption
+        .map(item => {
+            const path = PlaitBoard.findPath(board, item.element);
+            const ref = board.pathRef(path);
+            return () => {
+                ref.current && Transforms.moveNode(board, ref.current, item.newPath);
+                ref.unref();
+            };
+        })
+        .forEach(action => {
+            action();
+        });
+};
+
+export const getOneMoveOptions = (board: PlaitBoard, direction: 'down' | 'up'): ZIndexMoveOption[] => {
+    const indicesToMove = getIndicesToMove(board);
+    let groupedIndices = toContiguousGroups(board, indicesToMove);
+    if (direction === 'up') {
+        groupedIndices = groupedIndices.reverse();
+    }
+    let moveContents: ZIndexMoveOption[] = [];
+    groupedIndices.forEach((indices, i) => {
+        const leadingIndex = indices[0];
+        const trailingIndex = indices[indices.length - 1];
+        const boundaryIndex = direction === 'down' ? leadingIndex : trailingIndex;
+        const targetIndex = getTargetIndex(board, boundaryIndex, direction);
+        if (targetIndex === -1 || boundaryIndex === targetIndex) {
+            return;
+        }
+        if (direction === 'down') {
+            moveContents.push(
+                ...indices.reverse().map(path => {
+                    return {
+                        element: board.children[path],
+                        newPath: [targetIndex]
+                    };
+                })
+            );
+        } else {
+            moveContents.push(
+                ...indices.map(path => {
+                    return {
+                        element: board.children[path],
+                        newPath: [targetIndex]
+                    };
+                })
+            );
+        }
+    });
+
+    return moveContents;
+};
+
+const getIndicesToMove = (board: PlaitBoard) => {
+    const selectedElements = [...getSelectedElements(board), ...getSelectedGroups(board)];
+    return selectedElements
+        .map(item => {
+            return board.children.indexOf(item);
+        })
+        .sort((a, b) => {
+            return a - b;
+        });
+};
+
+const toContiguousGroups = (board: PlaitBoard, array: number[]) => {
+    let cursor = 0;
+    return array.reduce((acc, value, index) => {
+        if (index > 0) {
+            const currentElement = board.children[value];
+            const previousElement = board.children[array[index - 1]];
+            const isInSameGroup = currentElement.groupId === previousElement.groupId;
+            const isContain = currentElement.id === previousElement.groupId || currentElement.groupId === previousElement.id;
+            if (array[index - 1] !== value - 1 || (!isInSameGroup && !isContain)) {
+                cursor = ++cursor;
+            }
+        }
+        (acc[cursor] || (acc[cursor] = [])).push(value);
+        return acc;
+    }, [] as number[][]);
+};
+
+/**
+ * Returns next candidate index that's available to be moved to. Currently that
+ *  is a non-deleted element, and not inside a group (unless we're editing it).
+ */
+const getTargetIndex = (board: PlaitBoard, boundaryIndex: number, direction: 'down' | 'up') => {
+    if ((boundaryIndex === 0 && direction === 'down') || (boundaryIndex === board.children.length - 1 && direction === 'up')) {
+        return -1;
+    }
+    const indexFilter = (element: PlaitElement) => {
+        if (element.isDeleted || PlaitGroupElement.isGroup(element)) {
+            return false;
+        }
+        return true;
+    };
+    const candidateIndex =
+        direction === 'down'
+            ? findLastIndex(board.children, el => indexFilter(el), Math.max(0, boundaryIndex - 1))
+            : findIndex(board.children, el => indexFilter(el), boundaryIndex + 1);
+
+    const nextElement = board.children[candidateIndex];
+    if (!nextElement) {
+        return -1;
+    }
+
+    if (!nextElement.groupId) {
+        return candidateIndex;
+    }
+
+    const elements = [...board.children];
+    const sourceElement = elements[boundaryIndex];
+    const editingGroup = getEditingGroup(board, sourceElement);
+    const nextElementGroups = (getGroupByElement(board, nextElement, true) || []) as PlaitGroup[];
+    // candidate element is a sibling in current editing group → return
+    if (editingGroup && sourceElement?.groupId !== nextElement?.groupId) {
+        // candidate element is outside current editing group → prevent
+        if (!(nextElementGroups as PlaitGroup[]).find(item => item.id === editingGroup.id)) {
+            return -1;
+        }
+    }
+    let siblingGroup: PlaitGroup;
+    if (editingGroup) {
+        siblingGroup = nextElementGroups[nextElementGroups.indexOf(editingGroup) - 1];
+    } else {
+        siblingGroup = nextElementGroups[nextElementGroups.length - 1];
+    }
+    if (siblingGroup) {
+        let elementsInSiblingGroup = getElementsInGroup(board, siblingGroup, true, true);
+        if (elementsInSiblingGroup.length) {
+            elementsInSiblingGroup = [...elementsInSiblingGroup, siblingGroup];
+            elementsInSiblingGroup.sort((a, b) => {
+                const indexA = board.children.findIndex(child => child.id === a.id);
+                const indexB = board.children.findIndex(child => child.id === b.id);
+                return indexA - indexB;
+            });
+            // assumes getElementsInGroup() returned elements are sorted
+            // by zIndex (ascending)
+            return direction === 'down'
+                ? elements.indexOf(elementsInSiblingGroup[0])
+                : elements.indexOf(elementsInSiblingGroup[elementsInSiblingGroup.length - 1]);
+        }
+    }
+
+    return candidateIndex;
+};

packages/core/src/utils/group.ts

@@ -233,3 +233,18 @@ export const canRemoveGroup = (board: PlaitBoard, elements?: PlaitElement[]) =>
     const selectedElements = elements || getSelectedElements(board);
     return selectedElements.length > 0 && selectedGroups.length > 0;
 };
+
+
+export const getEditingGroup = (board: PlaitBoard, element: PlaitElement) => {
+    const groups = getGroupByElement(board, element, true) as PlaitGroup[];
+    let editingGroup = null;
+    if (groups?.length) {
+        for (let i = 0; i < groups?.length; i++) {
+            if (!isSelectedAllElementsInGroup(board, groups[i])) {
+                editingGroup = groups[i];
+                break;
+            }
+        }
+    }
+    return editingGroup;
+};

packages/core/src/utils/helper.ts

@@ -1,4 +1,4 @@
-import { PlaitElement } from "../interfaces";
+import { PlaitElement } from '../interfaces';
 
 export function isNullOrUndefined(value: any) {
     return value === null || value === undefined;
@@ -37,3 +37,40 @@ export function uniqueById(elements: PlaitElement[]) {
 
     return Array.from(uniqueMap.values());
 }
+
+export const findLastIndex = <T>(
+    array: readonly T[],
+    cb: (element: T, index: number, array: readonly T[]) => boolean,
+    fromIndex: number = array.length - 1
+) => {
+    if (fromIndex < 0) {
+        fromIndex = array.length + fromIndex;
+    }
+    fromIndex = Math.min(array.length - 1, Math.max(fromIndex, 0));
+    let index = fromIndex + 1;
+    while (--index > -1) {
+        if (cb(array[index], index, array)) {
+            return index;
+        }
+    }
+    return -1;
+};
+
+export const findIndex = <T>(
+    array: readonly T[],
+    cb: (element: T, index: number, array: readonly T[]) => boolean,
+    fromIndex: number = 0
+) => {
+    // fromIndex = 2
+    if (fromIndex < 0) {
+        fromIndex = array.length + fromIndex;
+    }
+    fromIndex = Math.min(array.length, Math.max(fromIndex, 0));
+    let index = fromIndex - 1;
+    while (++index < array.length) {
+        if (cb(array[index], index, array)) {
+            return index;
+        }
+    }
+    return -1;
+};

src/app/editor/editor.component.html

@@ -17,6 +17,8 @@
 </plait-board>
 
 <div #contextMenu class="context-menu">
+    <div class="context-menu-item" (pointerup)="moveUp($event)">上移一层</div>
+    <div class="context-menu-item" (pointerup)="moveDown($event)">下移一层</div>
     <div class="context-menu-item" *ngIf="showAddGroup" (pointerup)="addGroup($event)">成组</div>
     <div class="context-menu-item" *ngIf="showRemoveGroup" (pointerup)="removeGroup($event)">取消成组</div>
     <div class="context-menu-item" (pointerup)="copy($event)">复制</div>

src/app/editor/editor.component.ts

@@ -37,7 +37,7 @@ import { withCommonPlugin } from '../plugins/with-common';
 import { AppMenuComponent } from '../components/menu/menu.component';
 import { NgIf } from '@angular/common';
 import { mockTurningPointData } from './mock-turning-point-data';
-import { withGroup } from '@plait/common';
+import { withGroup, ZIndexTransforms } from '@plait/common';
 
 const LOCAL_STORAGE_KEY = 'plait-board-data';
 
@@ -169,6 +169,18 @@ export class BasicEditorComponent implements OnInit {
         BoardTransforms.updateThemeColor(this.board, value as ThemeColorMode);
     }
 
+    moveUp(event: MouseEvent) {
+        event.stopPropagation();
+        event.preventDefault();
+        ZIndexTransforms.moveUp(this.board);
+    }
+
+    moveDown(event: MouseEvent) {
+        event.stopPropagation();
+        event.preventDefault();
+        ZIndexTransforms.moveDown(this.board);
+    }
+
     copy(event: MouseEvent) {
         event.stopPropagation();
         event.preventDefault();