react可视化编辑器 第五章 升级版 拖拽、缩放、转圈、移动

本章代码结构： 主入口Test.tsx , 组件：ResizeControl.tsx

本章花费俩天时间完成代码例子， 单独抽离代码 封装好一个 ResizeControl 组件， 拿来即用。

代码中const domObj = document.getElementById(resize-item-${startPos.id}) 这句是关键代码， 不然获取的dom节点有问题，导致多个红色div操作时候会重叠

• ResizeControl.tsx

/* eslint-disable no-case-declarations */
import { FC, useEffect, useRef, useState } from 'react';
import styles from './index.module.scss';
import type { Demo } from '../../pages/Test';

interface PropsType {
  children: JSX.Element | JSX.Element[];
  value: Demo;
  emitData: (val: Demo) => void;
}

// 获取旋转角度参数
function getRotate(transform: string) {
  // 假设 transform 是 "rotate(45deg)"
  // console.info('transform', transform);
  if (!transform) return 0;
  const match = /rotate\(([^)]+)\)/.exec(transform);
  const rotate = match ? parseFloat(match[1]) : 0;
  // console.info(890, rotate);
  return rotate;
}

const ResizeControl: FC<PropsType> = (props: PropsType) => {
  const { children, value, emitData } = props;

  const points = ['lt', 'tc', 'rt', 'rc', 'br', 'bc', 'bl', 'lc'];
  const [startPos, setStartPos] = useState<Demo>(value);
  const resizeItemRef = useRef(null);
  const isDown = useRef(false);
  const [direction, setDirection] = useState('');

  useEffect(() => {
    document.addEventListener('mouseup', handleMouseUp);
    document.addEventListener('mousemove', handleMouseMove);

    return () => {
      document.removeEventListener('mouseup', handleMouseUp);
      document.removeEventListener('mousemove', handleMouseMove);
    };
  }, [isDown, startPos]);

  // 鼠标被按下
  const onMouseDown = (e: React.MouseEvent<HTMLDivElement>) => {
    console.info('onMouseDown', e.currentTarget);
    e.stopPropagation();
    // e.preventDefault();

    // 获取 整个 resize-item 的dom节点
    const domObj = document.getElementById(`resize-item-${startPos.id}`);
    if (!domObj) return;
    resizeItemRef.current = domObj;
    if (!resizeItemRef.current) return;
    const { width, height, transform } = resizeItemRef.current.style;

    // 获取当前操作 dom  data-key
    const direction = e.currentTarget.getAttribute('data-key') || '';
    console.log('元素方向', direction);
    setDirection(direction);

    // 获取旋转角度
    const rotate = getRotate(transform);

    // 记录状态
    isDown.current = true;

    setStartPos({
      ...startPos,
      startX: e.clientX,
      startY: e.clientY,
      width: +width.replace(/px/, '') - 2,
      height: +height.replace(/px/, '') - 2,
      rotate,
    });
  };

  const handleMouseMove = (e: { clientX: number; clientY: number }) => {
    if (isDown.current && resizeItemRef.current) {
      const { rotate, startX, startY } = startPos;
      let { height, width, left, top } = startPos;
      // console.log('startPos', startPos);

      const curX = e.clientX;
      const curY = e.clientY;

      // 计算偏移量
      const offsetX = curX - startX;
      const offsetY = curY - startY;
      // console.info('offsetX', offsetX, offsetY);

      const rect = resizeItemRef.current.getBoundingClientRect();

      let nowRotate = 0;
      switch (direction) {
        // 右中
        case 'rc':
          width += offsetX;
          break;
        // 左中
        case 'lc':
          width -= offsetX;
          left += offsetX;
          break;
        // 底中
        case 'bc':
          height += offsetY;
          break;
        // 顶中
        case 'tc':
          height -= offsetY;
          top += offsetY;
          break;
        // 右上角
        case 'rt':
          height -= offsetY;
          top += offsetY;
          width += offsetX;
          break;
        // 左上角
        case 'lt':
          height -= offsetY;
          top += offsetY;
          width -= offsetX;
          left += offsetX;
          break;
        // 右下角
        case 'br':
          height += offsetY;
          width += offsetX;
          break;
        // 左下角
        case 'bl':
          height += offsetY;
          width -= offsetX;
          left += offsetX;
          break;

        case 'rotate':
          // 获取元素中心点位置
          const centerX = rect.left + rect.width / 2;
          const centerY = rect.top + rect.height / 2;

          // 旋转前的角度
          const rotateDegreeBefore =
            Math.atan2(startY - centerY, startX - centerX) / (Math.PI / 180);

          // 旋转后的角度
          const rotateDegreeAfter =
            Math.atan2(curY - centerY, curX - centerX) / (Math.PI / 180);

          // 获取旋转的角度值
          nowRotate = rotateDegreeAfter - rotateDegreeBefore + rotate;
          resizeItemRef.current.style.transform = `rotate(${nowRotate}deg)`;
          break;

        case 'move':
          left += offsetX;
          top += offsetY;

          // 获取父元素的边界 (打开注释， 可验证边界条件判断)
          // const parent = resizeItemRef.current.parentElement;
          // if (!parent) return;
          // const parentRect = parent.getBoundingClientRect();
          // // 限制div不超过父元素的边界
          // const maxTop = parentRect.height - height;
          // const maxLeft = parentRect.width - width;

          // left = Math.min(Math.max(left, 0), maxLeft);
          // top = Math.min(Math.max(top, 0), maxTop);
          break;
      }

      // console.log('-----', width, height);

      resizeItemRef.current.style.width = width + 'px';
      resizeItemRef.current.style.height = height + 'px';
      resizeItemRef.current.style.left = left + 'px';
      resizeItemRef.current.style.top = top + 'px';

      const newPos = {
        ...startPos,
        height,
        width,
        startX: curX, 
        startY: curY,
        left,
        top,
        rotate: nowRotate,
      };

      emitData(newPos);
      setStartPos(newPos);
    }
  };

  if (!children) return null;

  const handleMouseUp = () => {
    console.info('clear。。。。');
    isDown.current = false;
    resizeItemRef.current = null;
  };

  return (
    <div
      className={styles['resize-item']}
      style={{
        left: `${startPos.left}px`,
        top: `${startPos.top}px`,
        width: `${startPos.width + 2}px`,
        height: `${startPos.height + 2}px`,
      }}
      id={`resize-item-${startPos.id}`}
    >
      {points.map((item, index) => (
        <div
          key={index}
          data-key={item}
          onMouseDown={onMouseDown}
          className={[
            styles['resize-control-btn'],
            styles[`resize-control-${item}`],
          ].join(' ')}
        ></div>
      ))}
      <div
        className={styles['resize-control-rotator']}
        onMouseDown={onMouseDown}
        data-key={'rotate'}
      >
        转
      </div>
      <div
        data-key={'move'}
        onMouseDown={(e) => onMouseDown(e)}
        style={{ width: '100%', height: '100%', background: 'yellow' }}
      >
        {/* <span style={{ wordBreak: 'break-all', fontSize: '10px' }}>
          {JSON.stringify(startPos)}
        </span> */}
        {children}
      </div>
    </div>
  );
};
export default ResizeControl;

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• ResizeControl/index.module.scss

.resize-item {
  cursor: move;
  position: absolute;
  z-index: 2;
  border: 1px dashed yellow;
  box-sizing: border-box;
}

$width_height: 4px; // 建议偶数

.resize-control-btn {
  position: absolute;
  width: $width_height;
  height: $width_height;
  background: yellow;
  // user-select: none; // 注意禁止鼠标选中控制点元素，不然拖拽事件可能会因此被中断
  z-index: 1;
}

.resize-control-btn.resize-control-lt {
  cursor: nw-resize;
  top: $width_height / -2;
  left: $width_height / -2;
}
.resize-control-btn.resize-control-tc {
  cursor: ns-resize;
  top: $width_height / -2;
  left: 50%;
  margin-left: $width_height / -2;
}
.resize-control-btn.resize-control-rt {
  cursor: ne-resize;
  top: $width_height / -2;
  right: $width_height / -2;
}
.resize-control-btn.resize-control-rc {
  cursor: ew-resize;
  top: 50%;
  margin-top: $width_height / -2;
  right: $width_height / -2;
}
.resize-control-btn.resize-control-br {
  cursor: se-resize;
  bottom: $width_height / -2;
  right: $width_height / -2;
}
.resize-control-btn.resize-control-bc {
  cursor: ns-resize;
  bottom: $width_height / -2;
  left: 50%;
  margin-left: $width_height / -2;
}
.resize-control-btn.resize-control-bl {
  cursor: sw-resize;
  bottom: $width_height / -2;
  left: $width_height / -2;
}
.resize-control-btn.resize-control-lc {
  cursor: ew-resize;
  top: 50%;
  margin-top: $width_height / -2;
  left: $width_height / -2;
}

.resize-control-rotator {
  position: absolute;
  cursor: pointer;
  bottom: -20px;
  left: 50%;
  margin-left: -10px;
  width: 20px;
  text-align: center;
  font-size: 10px;
  background: red;
}

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• 主入口 Test.tsx

import React, { useState, DragEvent, useRef, useEffect } from 'react';
import ResizeControl from '../../components/ResizeControl';

export interface Demo {
  id: number;

  left: number;
  top: number;

  startX: number;
  startY: number;

  width: number;
  height: number;

  rotate: number;
}

// 获取元素旋转角度
function getDomRotate(transform: string) {
  // 假设 transform 是 "rotate(45deg)"
  // console.info('transform', transform);
  const match = /rotate\(([^)]+)\)/.exec(transform);
  const rotate = match ? parseFloat(match[1]) : 0;
  // console.info(890, rotate);
  return rotate;
}

const App: React.FC = () => {
  const [demos, setDemos] = useState<Demo[]>([]);
  const divRef = useRef<HTMLDivElement | null>(null);
  const [activeDomId, setActiveDomId] = useState(0);

  const handleDragStart = (e: DragEvent<HTMLDivElement>, id: number) => {
    e.dataTransfer.setData('id', id.toString());

    // 鼠标偏移量
    const offsetX = e.clientX - e.currentTarget.getBoundingClientRect().left;
    const offsetY = e.clientY - e.currentTarget.getBoundingClientRect().top;
    e.dataTransfer.setData('offsetX', offsetX.toString());
    e.dataTransfer.setData('offsetY', offsetY.toString());

    divRef.current = e.currentTarget;
  };

  const handleDrop = (e: DragEvent<HTMLDivElement>) => {
    e.preventDefault();
    console.info('鼠标释放位置', e.clientX, e.clientY);

    const contentDom = document.getElementById('content');
    if (!contentDom) return;
    const contentStyle = contentDom.getBoundingClientRect();
    // console.info('contentStyle', contentStyle);
    const { left, top } = contentStyle;
    const offsetX = +e.dataTransfer.getData('offsetX') || 0;
    const offsetY = +e.dataTransfer.getData('offsetY') || 0;
    // console.info('offsetX', offsetX, offsetY);

    const newLeft = e.clientX - left - offsetX;
    const newTop = e.clientY - top - offsetY;

    if (!divRef.current) return;
    const { width, height, transform } = divRef.current.style;

    // 元素旋转角度
    let rotate = 0;
    if (!transform) {
      rotate = 0;
    } else {
      rotate = getDomRotate(transform);
    }

    const newDemo: Demo = {
      id: e.dataTransfer.getData('id'),
      startX: e.clientX,
      startY: e.clientY,
      left: newLeft,
      top: newTop,
      width: +width.replace(/px/, ''),
      height: +height.replace(/px/, ''),
      rotate,
    };
    setDemos([...demos, newDemo]);
  };

  const handleDragOver = (e: DragEvent<HTMLDivElement>) => {
    e.preventDefault();
  };

  return (
    <div>
      <div
        id="demo"
        draggable
        onDragStart={(e) => handleDragStart(e, +new Date())}
        style={{
          width: '100px',
          height: '100px',
          backgroundColor: 'red',
          margin: '30px',
          cursor: 'pointer',
        }}
      >
        demo2
      </div>
      <div
        id="content"
        onDrop={handleDrop}
        onDragOver={handleDragOver}
        style={{
          width: '300px',
          height: '300px',
          margin: '30px',
          backgroundColor: 'blue',
          position: 'relative',
        }}
      >
        {demos.map((demo) => (
          <ResizeControl
            key={demo.id}
            value={demo}
            emitData={(data) => {
              setDemos((prevDemos) =>
                prevDemos.map((a) => {
                  return a.id == data.id ? data : a;
                })
              );
            }}
          >
            {/* 当前 div 组件 */}
            <div
              style={{
                backgroundColor: 'red',
                width: '100%',
                height: '100%',
              }}
            >
              {/* <span style={{ wordBreak: 'break-all', fontSize: '10px' }}>
                {JSON.stringify(demo)}
              </span> */}
            </div>
          </ResizeControl>
        ))}
      </div>
    </div>
  );
};

export default App;

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