konva实现photoshop中多选变形的功能

index.tsx

jsx 复制代码

import { useKeyPress } from 'ahooks'
import Konva from 'konva'
import React, { useState } from 'react'
import { Group, Layer, Rect, Stage, Transformer } from 'react-konva'
import { useShapeSelection } from './useShapeSelection'
import { useShapeTransformer } from './useShapeTransformer'

const INIT_SHAPES = [
  {
    id: 'rect',
    type: 'Rect',
    fill: 'red',
    width: 100,
    height: 100,
    x: 100,
    y: 100,
    scaleX: 1,
    scaleY: 1,
    skewX: 0,
    skewY: 0,
    rotation: 0
  },
  {
    id: 'circle',
    type: 'Circle',
    fill: 'blue',
    radius: 50,
    x: 300,
    y: 100,
    scaleX: 1,
    scaleY: 1,
    skewX: 0,
    skewY: 0,
    rotation: 0
  },
  {
    id: 'star',
    type: 'Star',
    fill: 'yellow',
    numPoints: 5,
    innerRadius: 30,
    outerRadius: 70,
    x: 200,
    y: 100,
    scaleX: 1,
    scaleY: 1,
    skewX: 0,
    skewY: 0,
    rotation: 0
  }
]

export default function View() {
  const [shapes, setShapes] = useState(INIT_SHAPES)

  // 使用自定义Hook处理选择逻辑
  const { selectedIds, handleShapeClick, handleStageClick } = useShapeSelection()

  // 使用自定义Hook处理变换逻辑
  const {
    transformerMode,
    stageRef,
    layerRef,
    groupRef,
    transformerRef,
    enableTransformerMode,
    confirmTransform,
    cancelTransform,
    handleGroupDragStart,
    handleTransformEnd,
    handleShapeDragEnd
  } = useShapeTransformer(shapes, setShapes, selectedIds)

  // 快捷键绑定
  useKeyPress(['ctrl.alt.t'], enableTransformerMode)
  useKeyPress(['enter'], confirmTransform)
  useKeyPress(['esc'], cancelTransform)

  const shapesElements = () => {
    return shapes.map((shape, index) => {
      const { id, type, ...props } = shape
      const isSelected = selectedIds.includes(id)

      return React.createElement(type, {
        key: id,
        id,
        draggable: !transformerMode,
        stroke: isSelected ? '#000' : undefined,
        strokeWidth: isSelected ? 4 : undefined,
        onClick: e => handleShapeClick(e, transformerMode),
        onDragEnd: e => handleShapeDragEnd(e, index),
        onTransformEnd: e => handleTransformEnd(e, index),
        onDragStart: (evt: Konva.KonvaEventObject<DragEvent>) => {
          // 取消冒泡
          evt.cancelBubble = true
        },
        ...props
      }) as React.ReactElement
    })
  }

  return (
    <div className='view-wrapper'>
      <div>selectedId: {selectedIds.join(', ')}</div>
      <div>Mode: {transformerMode ? '变形模式' : '普通模式'}</div>
      <div>快捷键: Ctrl+Alt+T(变形) | Enter(确认) | Esc(取消) | Shift+点击(多选)</div>

      <Stage ref={stageRef} width={800} height={600} onClick={handleStageClick}>
        <Layer ref={layerRef}>
          <Group ref={groupRef} draggable onDragStart={handleGroupDragStart}>
            <Rect width={800} height={600} fill='rgba(0, 0, 0, 0.1)' />
            {shapesElements()}
          </Group>
          <Transformer
            visible={transformerMode}
            ref={transformerRef}
            boundBoxFunc={(oldBox, newBox) => {
              // 限制最小尺寸
              if (newBox.width < 5 || newBox.height < 5) {
                return oldBox
              }
              return newBox
            }}
          />
        </Layer>
      </Stage>
    </div>
  )
}

useShapeSelection.ts

jsx 复制代码

import Konva from 'konva'
import cloneDeep from 'lodash.clonedeep'
import { useState } from 'react'

// 自定义Hook：处理图形选择逻辑
export const useShapeSelection = () => {
  const [selectedIds, setSelectedIds] = useState<string[]>([])

  // 处理图形点击选择
  const handleShapeClick = (e: Konva.KonvaEventObject<MouseEvent>, isTransformerMode: boolean) => {
    if (isTransformerMode) return

    const node = e.target as Konva.Shape
    const id = node.id()
    const isShiftPressed = e.evt.shiftKey

    setSelectedIds(prev => {
      const newSelectedIds = cloneDeep(prev)
      const index = newSelectedIds.indexOf(id)

      if (index === -1) {
        // 如果按住Shift键，则添加到已选中列表；否则替换已选中列表
        return isShiftPressed ? [...newSelectedIds, id] : [id]
      } else {
        // 如果已经选中，则取消选中
        newSelectedIds.splice(index, 1)
        return newSelectedIds
      }
    })
  }

  // 处理舞台点击，清除选择
  const handleStageClick = (e: Konva.KonvaEventObject<MouseEvent>) => {
    if (e.target === e.target.getStage()) {
      setSelectedIds([])
    }
  }

  return { selectedIds, setSelectedIds, handleShapeClick, handleStageClick }
}

useShapeTransformer.ts

jsx 复制代码

import Konva from 'konva'
import cloneDeep from 'lodash.clonedeep'
import { useRef, useState } from 'react'

// 自定义Hook：处理图形变换逻辑
export const useShapeTransformer = (shapes, setShapes, selectedIds) => {
  const [transformerMode, setTransformerMode] = useState(false)
  const beforeTransformShapeRef = useRef([])

  const stageRef = useRef<Konva.Stage>(null)
  const layerRef = useRef<Konva.Layer>(null)
  const groupRef = useRef<Konva.Group>(null)
  const transformerRef = useRef<Konva.Transformer>(null)

  // 开启变形模式
  const enableTransformerMode = () => {
    if (selectedIds.length === 0) return
    // 记录当前shapes, 用于撤销
    beforeTransformShapeRef.current = cloneDeep(shapes)
    setTransformerMode(true)
    transformerRef.current.nodes(selectedIds.map(id => stageRef.current.findOne(`#${id}`)))
  }

  // 确认变形
  const confirmTransform = () => {
    if (!transformerMode) return

    setTransformerMode(false)
    transformerRef.current.nodes([])
  }

  // 取消变形
  const cancelTransform = () => {
    if (!transformerMode) return

    setTransformerMode(false)
    setShapes(beforeTransformShapeRef.current)
    transformerRef.current.nodes([])
  }

  // 处理组拖拽结束事件
  const handleGroupDragStart = () => {
    groupRef.current.stopDrag()
    if (!transformerMode) return
    // 停止所有图形的拖拽，只允许选中的图形拖拽
    shapes.forEach(shape => {
      if (selectedIds.includes(shape.id)) {
        stageRef.current.findOne(`#${shape.id}`).startDrag()
      } else {
        stageRef.current.findOne(`#${shape.id}`).stopDrag()
      }
    })
  }

  // 处理变换结束事件
  const handleTransformEnd = (e: Konva.KonvaEventObject<DragEvent>, index: number) => {
    const node = e.target as Konva.Shape

    if (!node) return
    const { x, y, width, height, scaleX, scaleY, rotation } = node.attrs

    // 更新所有选中图形的属性
    setShapes(prevShapes => {
      const newShapes = cloneDeep(prevShapes)
      newShapes[index] = {
        ...newShapes[index],
        x: x,
        y: y,
        width,
        height,
        scaleX,
        scaleY,
        rotation: rotation
      }
      return newShapes
    })
  }

  // 处理图形拖拽结束事件
  const handleShapeDragEnd = (e: Konva.KonvaEventObject<DragEvent>, index: number) => {
    const node = e.target as Konva.Shape
    const { x, y } = node.position()

    setShapes(prevShapes => {
      const newShapes = cloneDeep(prevShapes)
      newShapes[index] = {
        ...newShapes[index],
        x,
        y
      }
      return newShapes
    })
  }

  return {
    transformerMode,
    stageRef,
    layerRef,
    groupRef,
    transformerRef,
    enableTransformerMode,
    confirmTransform,
    cancelTransform,
    handleGroupDragStart,
    handleTransformEnd,
    handleShapeDragEnd
  }
}