前端使用 Konva 实现可视化设计器（12）- 连接线 - 直线

这一章实现的连接线，目前仅支持直线连接，为了能够不影响原有的其它功能，尝试了2、3个实现思路，最终实测这个实现方式目前来说最为合适了。

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github源码

gitee源码

示例地址

相关定义

• 连接点
  
  

记录了连接点相关信息，并不作为素材而存在，仅记录信息，即导出导入的时候，并不会出现所谓的连接点节点。

它存放在节点身上，因此导出、导入自然而然就可以持久化了。

src/Render/draws/LinkDraw.ts

// 连接点
export interface LinkDrawPoint {
  id: string
  groupId: string
  visible: boolean
  pairs: LinkDrawPair[]
  x: number
  y: number
}

• 连接对
  
  

一个连接点，记录从该点出发的多条连接线信息，作为连接对信息存在。

src/Render/draws/LinkDraw.ts

// 连接对
export interface LinkDrawPair {
  id: string
  from: {
    groupId: string
    pointId: string
  }
  to: {
    groupId: string
    pointId: string
  }
}

• 连接点（锚点）
  
  

它是拖入素材的时候生成的真实节点，归属于所在的节点中，存在却不可见，关键作用是同步连接点真实坐标，尤其是节点发生 transform 时候，必须依赖它获得 transform 后连接点变化。

src/Render/handlers/DragOutsideHandlers.ts

// 略
		drop: (e: GlobalEventHandlersEventMap['drop']) => {
// 略

              const points = [
                // 左
                { x: 0, y: group.height() / 2 },
                // 右
                {
                  x: group.width(),
                  y: group.height() / 2
                },
                // 上
                { x: group.width() / 2, y: 0 },
                // 下
                {
                  x: group.width() / 2,
                  y: group.height()
                }
              ]

              // 连接点信息
              group.setAttrs({
                points: points.map(
                  (o) =>
                    ({
                      ...o,
                      id: nanoid(),
                      groupId: group.id(),
                      visible: true,
                      pairs: []
                    }) as LinkDrawPoint
                )
              })

              // 连接点（锚点）
              for (const point of group.getAttr('points') ?? []) {
                group.add(
                  new Konva.Circle({
                    name: 'link-anchor',
                    id: point.id,
                    x: point.x,
                    y: point.y,
                    radius: this.render.toStageValue(1),
                    stroke: 'rgba(0,0,255,1)',
                    strokeWidth: this.render.toStageValue(2),
                    visible: false
                  })
                )
              }

              group.on('mouseenter', () => {
                // 显示 连接点
                this.render.linkTool.pointsVisible(true, group)
              })

              // hover 框（多选时才显示）
              group.add(
                new Konva.Rect({
                  id: 'hoverRect',
                  width: image.width(),
                  height: image.height(),
                  fill: 'rgba(0,255,0,0.3)',
                  visible: false
                })
              )

              group.on('mouseleave', () => {
                // 隐藏 连接点
                this.render.linkTool.pointsVisible(false, group)

                // 隐藏 hover 框
                group.findOne('#hoverRect')?.visible(false)
              })

// 略
}
// 略

• 连接线
  
  

根据连接点信息，绘制的线条，也不作为素材而存在，导出导入的时候，也不会出现所谓的连接点节点。不过，在导出图片、SVG和用于预览框的时候，会直接利用线条节点导出、显示。

src/Render/tools/ImportExportTool.ts

// 略
  /**
   * 获得显示内容
   * @param withLink 是否包含线条
   * @returns
   */
  getView(withLink: boolean = false) {
  	// 复制画布
    const copy = this.render.stage.clone()
    // 提取 main layer 备用
    const main = copy.find('#main')[0] as Konva.Layer
    const cover = copy.find('#cover')[0] as Konva.Layer
    // 暂时清空所有 layer
    copy.removeChildren()

    // 提取节点
    let nodes = main.getChildren((node) => {
      return !this.render.ignore(node)
    })

    if (withLink) {
      nodes = nodes.concat(
        cover.getChildren((node) => {
          return node.name() === Draws.LinkDraw.name
        })
      )
    }

  	// 略
  }
// 略

src/Render/draws/PreviewDraw.ts

  override draw() {
      // 略

      const main = this.render.stage.find('#main')[0] as Konva.Layer
      const cover = this.render.stage.find('#cover')[0] as Konva.Layer
      // 提取节点
      const nodes = [
        ...main.getChildren((node) => {
          return !this.render.ignore(node)
        }),
        // 补充连线
        ...cover.getChildren((node) => {
          return node.name() === Draws.LinkDraw.name
        })
      ]

      // 略
  }

• 连接线（临时）
  
  

起点鼠标按下 -> 拖动显示线条 -> 终点鼠标释放 -> 产生连接信息 LinkDrawPoint. LinkDrawPair

// 连接线（临时）
export interface LinkDrawState {
  linkingLine: {
    group: Konva.Group
    circle: Konva.Circle
    line: Konva.Line
  } | null
}

代码文件

新增几个关键的代码文件：

src/Render/draws/LinkDraw.ts

根据 连接点.链接对 绘制 连接点、连接线，及其相关的事件处理

它的绘制顺序，应该放在绘制 比例尺、预览框之前。

src/Render/handlers/LinkHandlers.ts

根据 连接线（临时）信息，绘制/移除 连接线（临时）

src/Render/tools/LinkTool.ts

移除连接线，控制 连接点 的显示/隐藏

移除连接线，实际上就是移除其 连接对 信息

// 略

export class LinkTool {
  // 略

  pointsVisible(visible: boolean, group?: Konva.Group) {
    if (group) {
      this.pointsVisibleEach(visible, group)
    } else {
      const groups = this.render.layer.find('.asset') as Konva.Group[]
      for (const group of groups) {
        this.pointsVisibleEach(visible, group)
      }
    }

    // 更新连线
    this.render.draws[Draws.LinkDraw.name].draw()
    // 更新预览
    this.render.draws[Draws.PreviewDraw.name].draw()
  }

  remove(line: Konva.Line) {
    const { groupId, pointId, pairId } = line.getAttrs()
    if (groupId && pointId && pairId) {
      const group = this.render.layer.findOne(`#${groupId}`) as Konva.Group
      if (group) {
        const points = (group.getAttr('points') ?? []) as LinkDrawPoint[]
        const point = points.find((o) => o.id === pointId)
        if (point) {
          const pairIndex = (point.pairs ?? ([] as LinkDrawPair[])).findIndex(
            (o) => o.id === pairId
          )
          if (pairIndex > -1) {
            point.pairs.splice(pairIndex, 1)
            group.setAttr('points', points)

            // 更新连线
            this.render.draws[Draws.LinkDraw.name].draw()
            // 更新预览
            this.render.draws[Draws.PreviewDraw.name].draw()
          }
        }
      }
    }
  }
}

关键逻辑

• 绘制 连接线（临时）
  
  

src/Render/draws/LinkDraw.ts

起点鼠标按下 'mousedown' -> 略 -> 终点鼠标释放 'mouseup'

// 略

export class LinkDraw extends Types.BaseDraw implements Types.Draw {
  // 略

  override draw() {
    this.clear()

    // stage 状态
    const stageState = this.render.getStageState()

    const groups = this.render.layer.find('.asset') as Konva.Group[]

    const points = groups.reduce((ps, group) => {
      return ps.concat(Array.isArray(group.getAttr('points')) ? group.getAttr('points') : [])
    }, [] as LinkDrawPoint[])

    const pairs = points.reduce((ps, point) => {
      return ps.concat(point.pairs ? point.pairs : [])
    }, [] as LinkDrawPair[])

    // 略

    // 连接点
    for (const point of points) {
      const group = groups.find((o) => o.id() === point.groupId)

      // 非 选择中
      if (group && !group.getAttr('selected')) {
        const anchor = this.render.layer.findOne(`#${point.id}`)

        if (anchor) {
          const circle = new Konva.Circle({
            id: point.id,
            groupId: group.id(),
            x: this.render.toStageValue(anchor.absolutePosition().x - stageState.x),
            y: this.render.toStageValue(anchor.absolutePosition().y - stageState.y),
            radius: this.render.toStageValue(this.option.size),
            stroke: 'rgba(255,0,0,0.2)',
            strokeWidth: this.render.toStageValue(1),
            name: 'link-point',
            opacity: point.visible ? 1 : 0
          })

          // 略

          circle.on('mousedown', () => {
            this.render.selectionTool.selectingClear()

            const pos = this.render.stage.getPointerPosition()

            if (pos) {
              // 临时 连接线 画
              this.state.linkingLine = {
                group: group,
                circle: circle,
                line: new Konva.Line({
                  name: 'linking-line',
                  points: _.flatten([
                    [circle.x(), circle.y()],
                    [
                      this.render.toStageValue(pos.x - stageState.x),
                      this.render.toStageValue(pos.y - stageState.y)
                    ]
                  ]),
                  stroke: 'blue',
                  strokeWidth: 1
                })
              }

              this.layer.add(this.state.linkingLine.line)
            }
          })

          // 略
      }
    }
  }
}

src/Render/handlers/LinkHandlers.ts

拖动显示线条、移除 连接线（临时）

从起点到鼠标当前位置

  handlers = {
    stage: {
      mouseup: () => {
        const linkDrawState = (this.render.draws[Draws.LinkDraw.name] as Draws.LinkDraw).state

        // 临时 连接线 移除
        linkDrawState.linkingLine?.line.remove()
        linkDrawState.linkingLine = null
      },
      mousemove: () => {
        const linkDrawState = (this.render.draws[Draws.LinkDraw.name] as Draws.LinkDraw).state

        const pos = this.render.stage.getPointerPosition()

        if (pos) {
          // stage 状态
          const stageState = this.render.getStageState()

          // 临时 连接线 画
          if (linkDrawState.linkingLine) {
            const { circle, line } = linkDrawState.linkingLine
            line.points(
              _.flatten([
                [circle.x(), circle.y()],
                [
                  this.render.toStageValue(pos.x - stageState.x),
                  this.render.toStageValue(pos.y - stageState.y)
                ]
              ])
            )
          }
        }
      }
    }
  }

• 产生连接信息

src/Render/draws/LinkDraw.ts

// 略

export class LinkDraw extends Types.BaseDraw implements Types.Draw {
  // 略

  override draw() {
    this.clear()

    // stage 状态
    const stageState = this.render.getStageState()

    const groups = this.render.layer.find('.asset') as Konva.Group[]

    const points = groups.reduce((ps, group) => {
      return ps.concat(Array.isArray(group.getAttr('points')) ? group.getAttr('points') : [])
    }, [] as LinkDrawPoint[])

    const pairs = points.reduce((ps, point) => {
      return ps.concat(point.pairs ? point.pairs : [])
    }, [] as LinkDrawPair[])

    // 略

    // 连接点
    for (const point of points) {
      const group = groups.find((o) => o.id() === point.groupId)

      // 非 选择中
      if (group && !group.getAttr('selected')) {
        const anchor = this.render.layer.findOne(`#${point.id}`)

        if (anchor) {
          const circle = new Konva.Circle({
            id: point.id,
            groupId: group.id(),
            x: this.render.toStageValue(anchor.absolutePosition().x - stageState.x),
            y: this.render.toStageValue(anchor.absolutePosition().y - stageState.y),
            radius: this.render.toStageValue(this.option.size),
            stroke: 'rgba(255,0,0,0.2)',
            strokeWidth: this.render.toStageValue(1),
            name: 'link-point',
            opacity: point.visible ? 1 : 0
          })

          // 略

          circle.on('mouseup', () => {
            if (this.state.linkingLine) {
              const line = this.state.linkingLine
              // 不同连接点
              if (line.circle.id() !== circle.id()) {
                const toGroup = groups.find((o) => o.id() === circle.getAttr('groupId'))

                if (toGroup) {
                  const fromPoints = (
                    Array.isArray(line.group.getAttr('points')) ? line.group.getAttr('points') : []
                  ) as LinkDrawPoint[]

                  const fromPoint = fromPoints.find((o) => o.id === line.circle.id())

                  if (fromPoint) {
                    const toPoints = (
                      Array.isArray(toGroup.getAttr('points')) ? toGroup.getAttr('points') : []
                    ) as LinkDrawPoint[]

                    const toPoint = toPoints.find((o) => o.id === circle.id())

                    if (toPoint) {
                      if (Array.isArray(fromPoint.pairs)) {
                        fromPoint.pairs = [
                          ...fromPoint.pairs,
                          {
                            id: nanoid(),
                            from: {
                              groupId: line.group.id(),
                              pointId: line.circle.id()
                            },
                            to: {
                              groupId: circle.getAttr('groupId'),
                              pointId: circle.id()
                            }
                          }
                        ]
                      }

                      // 更新历史
                      this.render.updateHistory()
                      this.draw()
                      // 更新预览
                      this.render.draws[Draws.PreviewDraw.name].draw()
                    }
                  }
                }
              }

              // 临时 连接线 移除
              this.state.linkingLine?.line.remove()
              this.state.linkingLine = null
            }
          })

          this.group.add(circle)
        }

        // 略
      }
    }
  }
}

• 绘制 连接线
  
  

src/Render/draws/LinkDraw.ts

这里就是利用了上面提到的 连接点（锚点），通过它的 absolutePosition 获得真实位置。

// 略

export class LinkDraw extends Types.BaseDraw implements Types.Draw {
  // 略

  override draw() {
    this.clear()

    // stage 状态
    const stageState = this.render.getStageState()

    const groups = this.render.layer.find('.asset') as Konva.Group[]

    const points = groups.reduce((ps, group) => {
      return ps.concat(Array.isArray(group.getAttr('points')) ? group.getAttr('points') : [])
    }, [] as LinkDrawPoint[])

    const pairs = points.reduce((ps, point) => {
      return ps.concat(point.pairs ? point.pairs : [])
    }, [] as LinkDrawPair[])

    // 连接线
    for (const pair of pairs) {
      const fromGroup = groups.find((o) => o.id() === pair.from.groupId)
      const fromPoint = points.find((o) => o.id === pair.from.pointId)

      const toGroup = groups.find((o) => o.id() === pair.to.groupId)
      const toPoint = points.find((o) => o.id === pair.to.pointId)

      if (fromGroup && toGroup && fromPoint && toPoint) {
        const fromAnchor = this.render.layer.findOne(`#${fromPoint.id}`)
        const toAnchor = this.render.layer.findOne(`#${toPoint.id}`)

        if (fromAnchor && toAnchor) {
          const line = new Konva.Line({
            name: 'link-line',
            // 用于删除连接线
            groupId: fromGroup.id(),
            pointId: fromPoint.id,
            pairId: pair.id,
            //
            points: _.flatten([
              [
                this.render.toStageValue(fromAnchor.absolutePosition().x - stageState.x),
                this.render.toStageValue(fromAnchor.absolutePosition().y - stageState.y)
              ],
              [
                this.render.toStageValue(toAnchor.absolutePosition().x - stageState.x),
                this.render.toStageValue(toAnchor.absolutePosition().y - stageState.y)
              ]
            ]),
            stroke: 'red',
            strokeWidth: 2
          })
          this.group.add(line)

          // 连接线 hover 效果
          line.on('mouseenter', () => {
            line.stroke('rgba(255,0,0,0.6)')
            document.body.style.cursor = 'pointer'
          })
          line.on('mouseleave', () => {
            line.stroke('red')
            document.body.style.cursor = 'default'
          })
        }
      }
    }

    // 略
  }
}

• 绘制 连接点

src/Render/draws/LinkDraw.ts

// 略

export class LinkDraw extends Types.BaseDraw implements Types.Draw {
 // 略

  override draw() {
    this.clear()

    // stage 状态
    const stageState = this.render.getStageState()

    const groups = this.render.layer.find('.asset') as Konva.Group[]

    const points = groups.reduce((ps, group) => {
      return ps.concat(Array.isArray(group.getAttr('points')) ? group.getAttr('points') : [])
    }, [] as LinkDrawPoint[])

    const pairs = points.reduce((ps, point) => {
      return ps.concat(point.pairs ? point.pairs : [])
    }, [] as LinkDrawPair[])

    // 略

    // 连接点
    for (const point of points) {
      const group = groups.find((o) => o.id() === point.groupId)

      // 非 选择中
      if (group && !group.getAttr('selected')) {
        const anchor = this.render.layer.findOne(`#${point.id}`)

        if (anchor) {
          const circle = new Konva.Circle({
            id: point.id,
            groupId: group.id(),
            x: this.render.toStageValue(anchor.absolutePosition().x - stageState.x),
            y: this.render.toStageValue(anchor.absolutePosition().y - stageState.y),
            radius: this.render.toStageValue(this.option.size),
            stroke: 'rgba(255,0,0,0.2)',
            strokeWidth: this.render.toStageValue(1),
            name: 'link-point',
            opacity: point.visible ? 1 : 0
          })

          // hover 效果
          circle.on('mouseenter', () => {
            circle.stroke('rgba(255,0,0,0.5)')
            circle.opacity(1)
            document.body.style.cursor = 'pointer'
          })
          circle.on('mouseleave', () => {
            circle.stroke('rgba(255,0,0,0.2)')
            circle.opacity(0)
            document.body.style.cursor = 'default'
          })

          // 略
      }
    }
  }
}

• 复制

有几个关键：

1. 更新 id，包括：节点、连接点、锚点、连接对
2. 重新绑定相关事件

src/Render/tools/CopyTool.ts

// 略

export class CopyTool {
  // 略

  /**
   * 复制粘贴
   * @param nodes 节点数组
   * @param skip 跳过检查
   * @returns 复制的元素
   */
  copy(nodes: Konva.Node[]) {
    const clones: Konva.Group[] = []

    for (const node of nodes) {
      if (node instanceof Konva.Transformer) {
        // 复制已选择
        const backup = [...this.render.selectionTool.selectingNodes]
        this.render.selectionTool.selectingClear()
        this.copy(backup)

        return
      } else {
        // 复制未选择（先记录，后处理）
        clones.push(node.clone())
      }
    }

    // 处理克隆节点

    // 新旧 id 映射
    const groupIdChanges: { [index: string]: string } = {}
    const pointIdChanges: { [index: string]: string } = {}

    // 新 id、新事件
    for (const copy of clones) {
      const gid = nanoid()
      groupIdChanges[copy.id()] = gid
      copy.id(gid)

      const pointsClone = _.cloneDeep(copy.getAttr('points') ?? [])
      copy.setAttr('points', pointsClone)

      for (const point of pointsClone) {
        const pid = nanoid()
        pointIdChanges[point.id] = pid

        const anchor = copy.findOne(`#${point.id}`)
        anchor?.id(pid)

        point.id = pid

        point.groupId = copy.id()
        point.visible = false
      }

      copy.off('mouseenter')
      copy.on('mouseenter', () => {
        // 显示 连接点
        this.render.linkTool.pointsVisible(true, copy)
      })
      copy.off('mouseleave')
      copy.on('mouseleave', () => {
        // 隐藏 连接点
        this.render.linkTool.pointsVisible(false, copy)

        // 隐藏 hover 框
        copy.findOne('#hoverRect')?.visible(false)
      })

      // 使新节点产生偏移
      copy.setAttrs({
        x: copy.x() + this.render.toStageValue(this.render.bgSize) * this.pasteCount,
        y: copy.y() + this.render.toStageValue(this.render.bgSize) * this.pasteCount
      })
    }

    // pairs 新 id
    for (const copy of clones) {
      const points = copy.getAttr('points') ?? []
      for (const point of points) {
        for (const pair of point.pairs) {
          // id 换新
          pair.id = nanoid()
          pair.from.groupId = groupIdChanges[pair.from.groupId]
          pair.from.pointId = pointIdChanges[pair.from.pointId]
          pair.to.groupId = groupIdChanges[pair.to.groupId]
          pair.to.pointId = pointIdChanges[pair.to.pointId]
        }
      }
    }

    // 略
  }
}

接下来，计划实现下面这些功能：

• 连接线 - 折线（头疼）
• 等等。。。

More Stars please！勾勾手指~

源码

gitee源码

示例地址