dros/src/components/measures/MidlineMeasurementTool.ts

import { Point3, Point2, fromPoint3ToPoint2 } from './mathUtils';
import {
  utilities as csUtils,
  Types as CoreTypes,
  getEnabledElement,
} from '@cornerstonejs/core';

import {
  AnnotationTool,
  utilities,
  Types,
  annotation,
  drawing,
} from '@cornerstonejs/tools';

const {
  drawHandles,
  drawLinkedTextBox,
  drawLine: drawLineSvg,
} = drawing;

import {
  calculateMidpoint,
  vectorSubtract,
  vectorAdd,
  calculateDistance,
} from './mathUtils';
import {
  PublicToolProps,
  ToolProps,
  EventTypes,
  SVGDrawingHelper,
} from '@cornerstonejs/tools/dist/esm/types';

// 注解数据接口
interface MidlineMeasurementAnnotation extends Types.Annotation {
  data: {
    handles: {
      points: CoreTypes.Point3[];        // [A, B, C, D] - 4个点
      activeHandleIndex: number | null;
    };
    cachedStats?: {
      [targetId: string]: {
        midPointM1: CoreTypes.Point3;     // AB中点
        midPointM2: CoreTypes.Point3;     // CD中点
        midlineLength: number;            // 中线长度
      };
    };
  };
  // 选中状态
  isSelected?: boolean;
}

// 类型断言函数
function isMidlineMeasurementAnnotation(annotation: Types.Annotation): annotation is MidlineMeasurementAnnotation {
  return annotation.metadata?.toolName === 'MidlineMeasurementTool';
}

// 导出的注解数据接口
export interface ExportedMidlineData {
  points: CoreTypes.Point3[];           // [A, B, C, D] 4个点的世界坐标
  midline: {
    midPointM1: CoreTypes.Point3;       // AB中点
    midPointM2: CoreTypes.Point3;       // CD中点
    length: number;                     // 中线长度
  };
  metadata: {
    viewPlaneNormal: CoreTypes.Point3;
    viewUp: CoreTypes.Point3;
    FrameOfReferenceUID: string;
    referencedImageId: string;
  };
}

export default class MidlineMeasurementTool extends AnnotationTool {
  static toolName = 'MidlineMeasurementTool';

  editData: {
    annotation: Types.Annotation;
    viewportIdsToRender: string[];
    handleIndex?: number;
    newAnnotation?: boolean;
    hasMoved?: boolean;
    movingWholeTool?: boolean;           // 是否移动整个工具
    wholeToolOffset?: CoreTypes.Point2;  // 工具移动偏移量
  } | null = null;

  isDrawing: boolean = false;

  /**
   * 创建一个预设的注解，带有4个默认点
   * @param element HTML元素
   * @param viewport Viewport实例
   */
  static createDefaultAnnotation(
    element: HTMLDivElement,
    viewport: CoreTypes.IStackViewport | CoreTypes.IVolumeViewport
  ): MidlineMeasurementAnnotation {
    const enabledElement = getEnabledElement(element);
    if (!enabledElement) {
      throw new Error('Element is not enabled');
    }

    // 获取viewport的尺寸
    const canvas = viewport.canvas;
    const { width, height } = canvas;
    const centerX = width / 2;
    const centerY = height / 2;

    // 创建4个canvas坐标点
    // 线段AB: 水平线，在中心上方
    const lineAY = centerY - 100;
    const lineAStartX = centerX - 80;
    const lineAEndX = centerX + 80;

    // 线段CD: 水平线，在中心下方
    const lineCY = centerY + 100;
    const lineCStartX = centerX - 60;
    const lineCEndX = centerX + 60;

    const canvasPoints: CoreTypes.Point2[] = [
      // 线段AB: 点A, 点B
      [lineAStartX, lineAY],
      [lineAEndX, lineAY],
      // 线段CD: 点C, 点D
      [lineCStartX, lineCY],
      [lineCEndX, lineCY],
    ];

    // 转换为world坐标
    const worldPoints = canvasPoints.map((canvasPoint) =>
      viewport.canvasToWorld(canvasPoint)
    );

    const camera = viewport.getCamera();
    const { viewPlaneNormal, viewUp } = camera;
    if (viewPlaneNormal === undefined) {
      throw new Error('viewPlaneNormal is undefined');
    }
    if (viewUp === undefined) {
      throw new Error('viewUp is undefined');
    }

    const annotationData = {
      invalidated: true,
      highlighted: false,
      metadata: {
        viewPlaneNormal: [...viewPlaneNormal] as CoreTypes.Point3,
        viewUp: [...viewUp] as CoreTypes.Point3,
        FrameOfReferenceUID: viewport.getFrameOfReferenceUID(),
        referencedImageId: viewport.getCurrentImageId?.() || '',
        toolName: MidlineMeasurementTool.toolName,
      },
      data: {
        label: '',
        handles: {
          points: worldPoints,
          activeHandleIndex: null,
        },
        cachedStats: {},
      },
    } as MidlineMeasurementAnnotation;

    return annotationData;
  }

  /**
   * 导出注解数据
   * @param annotation 要导出的注解
   * @returns 导出的数据对象
   */
  static exportAnnotationData(
    annotation: MidlineMeasurementAnnotation,
    viewport: CoreTypes.IStackViewport | CoreTypes.IVolumeViewport
  ): ExportedMidlineData | null {
    const targetId = `imageId:${viewport.getCurrentImageId?.() || ''}`;
    const cachedStats = annotation.data.cachedStats?.[targetId];

    if (!cachedStats) {
      return null;
    }

    return {
      points: [...annotation.data.handles.points],
      midline: {
        midPointM1: cachedStats.midPointM1,
        midPointM2: cachedStats.midPointM2,
        length: cachedStats.midlineLength,
      },
      metadata: {
        viewPlaneNormal: annotation.metadata?.viewPlaneNormal || [0, 0, 1],
        viewUp: annotation.metadata?.viewUp || [0, 1, 0],
        FrameOfReferenceUID: annotation.metadata?.FrameOfReferenceUID || '',
        referencedImageId: annotation.metadata?.referencedImageId || '',
      },
    };
  }

  /**
   * 从导出的数据恢复注解
   * @param exportedData 导出的数据
   * @param element HTML元素
   * @param viewport Viewport实例
   * @returns 恢复的注解
   */
  static restoreFromExportedData(
    exportedData: ExportedMidlineData,
    element: HTMLDivElement,
    viewport: CoreTypes.IStackViewport | CoreTypes.IVolumeViewport
  ): MidlineMeasurementAnnotation {
    const enabledElement = getEnabledElement(element);
    if (!enabledElement) {
      throw new Error('Element is not enabled');
    }

    const annotationData = {
      invalidated: true,
      highlighted: false,
      metadata: {
        ...exportedData.metadata,
        toolName: MidlineMeasurementTool.toolName,
      },
      data: {
        label: '',
        handles: {
          points: [...exportedData.points],
          activeHandleIndex: null,
        },
        cachedStats: {},
      },
    } as MidlineMeasurementAnnotation;

    return annotationData;
  }

  constructor(
    toolProps: PublicToolProps = {},
    defaultToolProps: ToolProps = {
      supportedInteractionTypes: ['Mouse', 'Touch'],
      configuration: {
        shadow: true,
        preventHandleOutsideImage: false,
      },
    }
  ) {
    super(toolProps, defaultToolProps);
  }

  /**
   * 添加新注解 - 禁用此功能，因为我们只使用预设的注解
   */
  addNewAnnotation(
    evt: EventTypes.InteractionEventType
  ): Types.Annotation {
    // 不创建新注解，直接返回空对象
    evt.preventDefault();
    return {} as Types.Annotation;
  }

  /**
   * 处理 控制点/端点 选中回调
   */
  handleSelectedCallback(
    evt: EventTypes.InteractionEventType,
    annotation: Types.Annotation
  ): void {
    // 实现手柄选中逻辑
    if (isMidlineMeasurementAnnotation(annotation)) {
      annotation.highlighted = true;
    }
  }

  /**
   * 工具选中回调
   */
  toolSelectedCallback(
    evt: EventTypes.InteractionEventType,
    annotation: Types.Annotation
  ): void {
    // 实现工具选中逻辑
    if (isMidlineMeasurementAnnotation(annotation)) {
      annotation.highlighted = true;
      console.log(`选中了中线测量工具`);
    }
  }

  /**
   * 检查点是否靠近工具
   */
  isPointNearTool(
    element: HTMLDivElement,
    annotation: Types.Annotation,
    canvasCoords: CoreTypes.Point2,
    proximity: number
  ): boolean {
    if (!isMidlineMeasurementAnnotation(annotation)) {
      return false;
    }

    const enabledElement = getEnabledElement(element);
    if (!enabledElement) {
      return false;
    }
    const { viewport } = enabledElement;

    const points = annotation.data.handles.points;

    // 检查是否靠近任意一个手柄点
    for (let i = 0; i < points.length; i++) {
      const point = points[i];
      const canvasPoint = viewport.worldToCanvas(point);
      const distance = Math.sqrt(
        Math.pow(canvasPoint[0] - canvasCoords[0], 2) +
        Math.pow(canvasPoint[1] - canvasCoords[1], 2)
      );

      if (distance < proximity) {
        return true;
      }
    }

    // 检查是否靠近线段
    if (points.length >= 2) {
      for (let i = 0; i < points.length - 1; i += 2) {
        if (i + 1 < points.length) {
          const p1Canvas = viewport.worldToCanvas(points[i]);
          const p2Canvas = viewport.worldToCanvas(points[i + 1]);

          const dist = this._distanceToSegment(canvasCoords, p1Canvas, p2Canvas);
          if (dist < proximity) {
            return true;
          }
        }
      }
    }

    // 检查是否靠近中线
    if (points.length >= 4) {
      const midA = calculateMidpoint(points[0], points[1]);
      const midC = calculateMidpoint(points[2], points[3]);
      const midACanvas = viewport.worldToCanvas(midA);
      const midCCanvas = viewport.worldToCanvas(midC);

      const dist = this._distanceToSegment(canvasCoords, midACanvas, midCCanvas);
      if (dist < proximity) {
        return true;
      }
    }

    return false;
  }



  /**
   * 计算点到线段的距离
   */
  private _distanceToSegment(
    point: CoreTypes.Point2,
    lineStart: CoreTypes.Point2,
    lineEnd: CoreTypes.Point2
  ): number {
    const x = point[0];
    const y = point[1];
    const x1 = lineStart[0];
    const y1 = lineStart[1];
    const x2 = lineEnd[0];
    const y2 = lineEnd[1];

    const A = x - x1;
    const B = y - y1;
    const C = x2 - x1;
    const D = y2 - y1;

    const dot = A * C + B * D;
    const lenSq = C * C + D * D;
    let param = -1;

    if (lenSq !== 0) {
      param = dot / lenSq;
    }

    let xx, yy;

    if (param < 0) {
      xx = x1;
      yy = y1;
    } else if (param > 1) {
      xx = x2;
      yy = y2;
    } else {
      xx = x1 + param * C;
      yy = y1 + param * D;
    }

    const dx = x - xx;
    const dy = y - yy;

    return Math.sqrt(dx * dx + dy * dy);
  }

  /**
   * 取消操作
   */
  cancel(element: HTMLDivElement): string {
    if (this.isDrawing) {
      this.isDrawing = false;
      this._deactivateDraw(element);
      this._deactivateModify(element);

      const enabledElement = getEnabledElement(element);
      if (enabledElement) {
        const { renderingEngine } = enabledElement;
        const viewportIdsToRender =
          utilities.viewportFilters.getViewportIdsWithToolToRender(
            element,
            this.getToolName()
          );

        utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);
      }

      this.editData = null;
      return this.getToolName();
    }

    return '';
  }

  /**
   * 激活绘制模式
   */
  _activateDraw(element: HTMLDivElement): void {
    element.addEventListener(
      'CORNERSTONE_TOOLS_MOUSE_DRAG',
      this._dragCallback as EventListener
    );
    element.addEventListener(
      'CORNERSTONE_TOOLS_MOUSE_UP',
      this._endCallback as EventListener
    );
    element.addEventListener(
      'CORNERSTONE_TOOLS_MOUSE_CLICK',
      this._endCallback as EventListener
    );
  }

  /**
   * 取消激活绘制模式
   */
  _deactivateDraw(element: HTMLDivElement): void {
    element.removeEventListener(
      'CORNERSTONE_TOOLS_MOUSE_DRAG',
      this._dragCallback as EventListener
    );
    element.removeEventListener(
      'CORNERSTONE_TOOLS_MOUSE_UP',
      this._endCallback as EventListener
    );
    element.removeEventListener(
      'CORNERSTONE_TOOLS_MOUSE_CLICK',
      this._endCallback as EventListener
    );
  }

  /**
   * 激活修改模式
   */
  _activateModify(element: HTMLDivElement): void {
    element.addEventListener(
      'CORNERSTONE_TOOLS_MOUSE_DOWN',
      this._mouseDownModifyCallback as EventListener
    );
    element.addEventListener(
      'CORNERSTONE_TOOLS_MOUSE_DRAG',
      this._mouseDragModifyCallback as EventListener
    );
    element.addEventListener(
      'CORNERSTONE_TOOLS_MOUSE_UP',
      this._mouseUpModifyCallback as EventListener
    );
    element.addEventListener(
      'CORNERSTONE_TOOLS_MOUSE_MOVE',
      this._mouseMoveModifyCallback as EventListener
    );
    // 添加键盘事件监听用于删除功能
    element.addEventListener(
      'keydown',
      this._keyDownCallback as EventListener
    );
  }

  /**
   * 取消激活修改模式
   */
  _deactivateModify(element: HTMLDivElement): void {
    element.removeEventListener(
      'CORNERSTONE_TOOLS_MOUSE_DOWN',
      this._mouseDownModifyCallback as EventListener
    );
    element.removeEventListener(
      'CORNERSTONE_TOOLS_MOUSE_DRAG',
      this._mouseDragModifyCallback as EventListener
    );
    element.removeEventListener(
      'CORNERSTONE_TOOLS_MOUSE_UP',
      this._mouseUpModifyCallback as EventListener
    );
    element.removeEventListener(
      'CORNERSTONE_TOOLS_MOUSE_MOVE',
      this._mouseMoveModifyCallback as EventListener
    );
    // 移除键盘事件监听
    element.removeEventListener(
      'keydown',
      this._keyDownCallback as EventListener
    );
  }

  /**
   * 键盘按下回调 - 用于删除功能
   */
  _keyDownCallback = (evt: KeyboardEvent): void => {
    const element = evt.currentTarget as HTMLDivElement;

    if (evt.key === 'Delete' || evt.key === 'Backspace') {
      const enabledElement = getEnabledElement(element);
      if (!enabledElement) {
        return;
      }

      const annotations = annotation.state.getAnnotations(this.getToolName(), element);
      if (!annotations || annotations.length === 0) {
        return;
      }

      // 查找被选中的注解
      const selectedAnnotations = annotations.filter(
        (ann) => isMidlineMeasurementAnnotation(ann) && ann.highlighted
      );

      if (selectedAnnotations.length === 0) {
        return;
      }

      // 删除所有选中的注解
      for (const ann of selectedAnnotations) {
        annotation.state.removeAnnotation(ann.annotationUID!);
      }

      // 触发渲染更新
      const viewportIdsToRender =
        utilities.viewportFilters.getViewportIdsWithToolToRender(
          element,
          this.getToolName()
        );

      utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);

      evt.preventDefault();
      evt.stopPropagation();
    }
  };

  /**
   * 鼠标移动回调 - 用于修改模式，处理悬停检测
   */
  _mouseMoveModifyCallback = (evt: EventTypes.InteractionEventType): void => {
    const eventDetail = evt.detail;
    const { element, currentPoints } = eventDetail;

    if (!currentPoints || !currentPoints.canvas) {
      return;
    }
    const canvasCoords = currentPoints.canvas;

    const enabledElement = getEnabledElement(element);
    if (!enabledElement) {
      return;
    }

    const annotations = annotation.state.getAnnotations(this.getToolName(), element);
    if (!annotations || annotations.length === 0) {
      element.style.cursor = 'default';
      return;
    }

    let isHovering = false;

    // 检查是否悬停在手柄或线段上
    for (const ann of annotations) {
      if (!isMidlineMeasurementAnnotation(ann)) continue;

      // 检查是否靠近手柄
      const handle = this.getHandleNearImagePoint(element, ann, canvasCoords, 6);
      if (handle) {
        element.style.cursor = 'crosshair';
        ann.highlighted = true;
        isHovering = true;
        break;
      }

      // 检查是否靠近线段
      if (this.isPointNearTool(element, ann, canvasCoords, 10)) {
        element.style.cursor = 'crosshair';
        ann.highlighted = true;
        isHovering = true;
        break;
      }
    }

    // 如果没有悬停在任何地方，重置高亮
    if (!isHovering) {
      for (const ann of annotations) {
        if (isMidlineMeasurementAnnotation(ann)) {
          ann.highlighted = false;
        }
      }
      element.style.cursor = 'default';
    }

    // 触发渲染以更新高亮状态
    const viewportIdsToRender = utilities.viewportFilters.getViewportIdsWithToolToRender(
      element,
      this.getToolName()
    );
    utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);
  };

  /**
   * 鼠标按下回调 - 用于修改模式
   */
  _mouseDownModifyCallback = (evt: EventTypes.InteractionEventType): void => {
    const eventDetail = evt.detail;
    const { element, currentPoints } = eventDetail;
    const canvasCoords = currentPoints.canvas;

    const enabledElement = getEnabledElement(element);
    if (!enabledElement) {
      return;
    }

    const annotations = annotation.state.getAnnotations(this.getToolName(), element);
    if (!annotations || annotations.length === 0) {
      return;
    }

    // 查找最近的手柄
    for (const ann of annotations) {
      if (!isMidlineMeasurementAnnotation(ann)) continue;

      const handle = this.getHandleNearImagePoint(
        element,
        ann,
        canvasCoords,
        6
      );

      if (handle) {
        const viewportIdsToRender =
          utilities.viewportFilters.getViewportIdsWithToolToRender(
            element,
            this.getToolName()
          );

        this.editData = {
          annotation: ann,
          viewportIdsToRender,
          handleIndex: ann.data.handles.activeHandleIndex || 0,
          hasMoved: false,
        };

        ann.isSelected = true;
        ann.highlighted = true;
        utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);

        evt.preventDefault();
        evt.stopPropagation();
        return;
      }
    }

    // 检查是否点击在工具的其他位置（线段上）
    for (const ann of annotations) {
      if (!isMidlineMeasurementAnnotation(ann)) continue;

      if (this.isPointNearTool(element, ann, canvasCoords, 10)) {
        const viewportIdsToRender =
          utilities.viewportFilters.getViewportIdsWithToolToRender(
            element,
            this.getToolName()
          );

        // 计算鼠标点击位置相对于工具的偏移量
        const points = ann.data.handles.points;
        if (points.length >= 4) {
          const midPoint = calculateMidpoint(points[0], points[1]);
          const midCanvas = enabledElement.viewport.worldToCanvas(midPoint);
          const wholeToolOffset: CoreTypes.Point2 = [
            canvasCoords[0] - midCanvas[0],
            canvasCoords[1] - midCanvas[1],
          ];

          this.editData = {
            annotation: ann,
            viewportIdsToRender,
            hasMoved: false,
            movingWholeTool: true,
            wholeToolOffset: wholeToolOffset,
          };

          ann.isSelected = true;
          ann.highlighted = true;
          utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);

          evt.preventDefault();
          evt.stopPropagation();
          return;
        }
      }
    }

    // 如果没有点击在工具上，取消所有工具的选中状态
    for (const ann of annotations) {
      if (isMidlineMeasurementAnnotation(ann)) {
        ann.isSelected = false;
        ann.highlighted = false;
      }
    }

    const viewportIdsToRender =
      utilities.viewportFilters.getViewportIdsWithToolToRender(
        element,
        this.getToolName()
      );

    utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);
  };

  /**
   * 鼠标拖拽回调 - 用于修改模式
   */
  _mouseDragModifyCallback = (evt: EventTypes.InteractionEventType): void => {
    if (!this.editData) {
      return;
    }

    const eventDetail = evt.detail;
    const { currentPoints } = eventDetail;
    const canvasCoords = currentPoints.canvas;

    const enabledElement = getEnabledElement(eventDetail.element);
    if (!enabledElement) {
      return;
    }

    const { annotation: ann, viewportIdsToRender, movingWholeTool } = this.editData;
    if (!isMidlineMeasurementAnnotation(ann)) return;

    const { data } = ann;

    // 如果正在移动整个工具
    if (movingWholeTool && this.editData.wholeToolOffset) {
      const newMidCanvas: CoreTypes.Point2 = [
        canvasCoords[0] - this.editData.wholeToolOffset[0],
        canvasCoords[1] - this.editData.wholeToolOffset[1],
      ];
      const newMidWorld = enabledElement.viewport.canvasToWorld(newMidCanvas);

      const points = data.handles.points;
      if (points.length >= 4) {
        const oldMid = calculateMidpoint(points[0], points[1]);
        const offset = vectorSubtract(newMidWorld, oldMid);

        // 移动所有点
        for (let i = 0; i < points.length; i++) {
          points[i] = vectorAdd(points[i], offset);
        }

        // 重新计算统计数据
        this._updateCachedStats(ann, enabledElement);
        this.editData.hasMoved = true;

        utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);
        evt.preventDefault();
        evt.stopPropagation();
        return;
      }
    }

    // 手柄拖拽
    const worldPos = currentPoints.world;
    const activeHandleIndex = data.handles.activeHandleIndex;

    if (activeHandleIndex !== null && activeHandleIndex >= 0 && activeHandleIndex < data.handles.points.length) {
      data.handles.points[activeHandleIndex] = worldPos;
      this._updateCachedStats(ann, enabledElement);
      this.editData.hasMoved = true;

      utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);
      evt.preventDefault();
      evt.stopPropagation();
    }
  };

  /**
   * 鼠标释放回调 - 用于修改模式
   */
  _mouseUpModifyCallback = (evt: EventTypes.InteractionEventType): void => {
    if (!this.editData) {
      return;
    }

    const { annotation: ann, hasMoved, movingWholeTool } = this.editData;
    if (!isMidlineMeasurementAnnotation(ann)) return;

    ann.data.handles.activeHandleIndex = null;

    // 如果没有拖拽且点击在线段上，则保持选中状态
    if (!hasMoved && movingWholeTool) {
      ann.highlighted = true;
    }

    const eventDetail = evt.detail;
    const { element } = eventDetail;

    const viewportIdsToRender =
      utilities.viewportFilters.getViewportIdsWithToolToRender(
        element,
        this.getToolName()
      );

    utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);

    this.editData = null;

    evt.preventDefault();
    evt.stopPropagation();
  };

  /**
   * 处理鼠标拖拽
   */
  _dragCallback = (evt: EventTypes.InteractionEventType): void => {
    this.isDrawing = true;
    const eventDetail = evt.detail;
    const { element } = eventDetail;

    const enabledElement = getEnabledElement(element);
    if (!enabledElement || !this.editData) {
      return;
    }

    const { annotation, viewportIdsToRender } = this.editData;
    if (!isMidlineMeasurementAnnotation(annotation)) return;

    const { data } = annotation;

    if (annotation) {
      const { currentPoints } = eventDetail;
      const worldPos = currentPoints.world;

      const points = data.handles.points;
      const activeHandleIndex = data.handles.activeHandleIndex;

      if (activeHandleIndex !== null && activeHandleIndex < points.length) {
        points[activeHandleIndex] = worldPos;
        this._updateCachedStats(
          annotation,
          enabledElement
        );
        this.editData!.hasMoved = true;
      }

      utilities.triggerAnnotationRenderForViewportIds(viewportIdsToRender);
    }
  };

  /**
   * 处理鼠标抬起/点击
   */
  _endCallback = (evt: EventTypes.InteractionEventType): void => {
    const eventDetail = evt.detail;
    const { element } = eventDetail;

    if (!this.editData) {
      return;
    }

    const { annotation, viewportIdsToRender, newAnnotation, hasMoved } =
      this.editData;
    if (!isMidlineMeasurementAnnotation(annotation)) return;

    const { data } = annotation;

    if (newAnnotation && !hasMoved) {
      const points = data.handles.points;

      if (points.length < 4) {
        const { currentPoints } = eventDetail;
        const worldPos = currentPoints.world;

        if (points.length > 0) {
          points[points.length - 1] = worldPos;
        }

        if (points.length < 4) {
          points.push(worldPos);
          data.handles.activeHandleIndex = points.length - 1;
        }

        if (points.length === 4) {
          this.isDrawing = false;
          data.handles.activeHandleIndex = null;
          annotation.highlighted = false;
          this.editData.newAnnotation = false;
          this._deactivateDraw(element);
        }

        const enabledElement = getEnabledElement(element);
        if (enabledElement) {
          this._updateCachedStats(
            annotation,
            enabledElement
          );

          const newViewportIdsToRender =
            utilities.viewportFilters.getViewportIdsWithToolToRender(
              element,
              this.getToolName()
            );
          utilities.triggerAnnotationRenderForViewportIds(newViewportIdsToRender);
        }
      }
    } else if (hasMoved) {
      this.editData.hasMoved = false;
    }
  };

  /**
   * 获取靠近图像点的手柄
   */
  getHandleNearImagePoint(
    element: HTMLDivElement,
    annotation: Types.Annotation,
    canvasCoords: CoreTypes.Point2,
    proximity: number
  ): Types.ToolHandle | undefined {
    if (!isMidlineMeasurementAnnotation(annotation)) return undefined;

    const enabledElement = getEnabledElement(element);
    if (!enabledElement) {
      return undefined;
    }
    const { viewport } = enabledElement;

    const points = annotation.data.handles.points;
    const handleProximity = Math.max(proximity, 15);

    for (let i = 0; i < points.length; i++) {
      const point = points[i];
      const canvasPoint = viewport.worldToCanvas(point);
      const distance = Math.sqrt(
        Math.pow(canvasPoint[0] - canvasCoords[0], 2) +
        Math.pow(canvasPoint[1] - canvasCoords[1], 2)
      );

      if (distance < handleProximity) {
        annotation.data.handles.activeHandleIndex = i;
        return {
          worldPosition: point,
        } as Types.ToolHandle;
      }
    }

    annotation.data.handles.activeHandleIndex = null;
    return undefined;
  }

  /**
   * 更新缓存的统计数据
   */
  _updateCachedStats(
    annotation: MidlineMeasurementAnnotation,
    enabledElement: CoreTypes.IEnabledElement
  ): void {
    const { viewport } = enabledElement;
    const { data } = annotation;
    const points = data.handles.points;

    const targetId = this.getTargetId(viewport);
    if (!targetId) {
      return;
    }

    if (!data.cachedStats) {
      data.cachedStats = {};
    }

    if (!data.cachedStats[targetId]) {
      data.cachedStats[targetId] = {
        midPointM1: [0, 0, 0] as CoreTypes.Point3,
        midPointM2: [0, 0, 0] as CoreTypes.Point3,
        midlineLength: 0,
      };
    }

    const stats = data.cachedStats[targetId];

    if (points.length >= 4) {
      // 计算中点
      const midPointM1 = calculateMidpoint(points[0], points[1]);
      const midPointM2 = calculateMidpoint(points[2], points[3]);

      // 计算中线长度
      const midlineLength = calculateDistance(midPointM1, midPointM2);

      // 存储计算结果
      stats.midPointM1 = midPointM1;
      stats.midPointM2 = midPointM2;
      stats.midlineLength = midlineLength;
    }
  }

  /**
   * 渲染注解
   */
  renderAnnotation = (
    enabledElement: CoreTypes.IEnabledElement,
    svgDrawingHelper: SVGDrawingHelper
  ): boolean => {
    let renderStatus = false;
    const { viewport } = enabledElement;
    const { element } = viewport;

    let annotations = annotation.state.getAnnotations(this.getToolName(), element);

    if (!annotations?.length) {
      return renderStatus;
    }

    for (let i = 0; i < annotations.length; i++) {
      const annotation = annotations[i];
      if (!isMidlineMeasurementAnnotation(annotation)) continue;

      const { annotationUID, data } = annotation;
      const points = data.handles.points;

      if (points.length < 4) {
        continue;
      }

      const targetId = this.getTargetId(viewport);
      const cachedStats = targetId ? data.cachedStats?.[targetId] : undefined;

      // 转换所有点为canvas坐标
      const canvasPoints = points.map((p) => viewport.worldToCanvas(p));

      // 绘制线段AB (蓝色)
      if (annotationUID) {
        const lineABUID = `${annotationUID}-lineAB`;
        drawLineSvg(
          svgDrawingHelper,
          annotationUID,
          lineABUID,
          canvasPoints[0],
          canvasPoints[1],
          {
            color: 'rgb(0, 0, 255)',
            width: 2,
          }
        );
      }

      // 绘制线段CD (红色)
      if (annotationUID) {
        const lineCDUID = `${annotationUID}-lineCD`;
        drawLineSvg(
          svgDrawingHelper,
          annotationUID,
          lineCDUID,
          canvasPoints[2],
          canvasPoints[3],
          {
            color: 'rgb(255, 0, 0)',
            width: 2,
          }
        );
      }

      // 绘制中线 (绿色)
      if (cachedStats?.midPointM1 && cachedStats?.midPointM2 && annotationUID) {
        const midM1Canvas = viewport.worldToCanvas(cachedStats.midPointM1);
        const midM2Canvas = viewport.worldToCanvas(cachedStats.midPointM2);

        const midlineUID = `${annotationUID}-midline`;
        drawLineSvg(
          svgDrawingHelper,
          annotationUID,
          midlineUID,
          midM1Canvas,
          midM2Canvas,
          {
            color: 'rgb(0, 255, 0)',
            width: 2,
          }
        );
      }



      // 绘制手柄点
      if (annotationUID) {
        const handleGroupUID = '0';
        const handleRadius = annotation.highlighted ? 12 : 8;
        drawHandles(
          svgDrawingHelper,
          annotationUID,
          handleGroupUID,
          canvasPoints,
          {
            color: 'rgb(255, 255, 255)',
            handleRadius: handleRadius,
          }
        );
      }

      renderStatus = true;
    }

    return renderStatus;
  };
}