G6实现node中文本过长点点点...替换显示，鼠标经过tooltip提示

文本点点点实现思路：因为G6是canvas，所以可以通过创建一个canvas文本并获取其宽度，对比node最大宽度来判断是否显示点点点... 再循环文本判断获取到最大宽度的文本

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getLableEllipsis(text, maxWidth, context) {
  let width = context.measureText(text).width

  if (width <= maxWidth) {
    return text
  }

  let ellipsis = '...'
  let ellipsisWidth = context.measureText(ellipsis).width

  let truncatedText = text
  while (width + ellipsisWidth > maxWidth) {
    truncatedText = truncatedText.slice(0, -1)
    width = context.measureText(truncatedText).width
  }
  return truncatedText + ellipsis
},
async init() {
  const canvas = document.createElement('canvas')
  const context = canvas.getContext('2d')
  const fontSize = 14
  context.font = `${fontSize}px Arial` // 根据你的实际字体样式进行设置
  let that = this
  G6.registerNode(
    'icon-node',
    {
      options: {
        size: [240, 80],
        stroke: '#d0d9e3',
        fill: '#f9fcfe'
      },
      draw(cfg, group) {
        const styles = this.getShapeStyle(cfg)
        const { labelCfg = {} } = cfg

        const w = styles.width
        const h = styles.height
        const keyShape = group.addShape('rect', {
          attrs: {
            ...styles,
            x: -w / 2,
            y: -h / 2,
            radius: 5,
            fill: '#f9fcfe',
            stroke: '#d0d9e3'
          }
        })
        if (cfg.label) {
          let label = cfg?.label || '--'
          const maxWidth = 200 //容器文本显示的最大宽度，超出用点点点...显示
          const textWidth = context.measureText(cfg.label).width //通过canvas测量文本宽度，因为G6文本就是canvas
          if (maxWidth < textWidth) {
            label = that.getLableEllipsis(label, maxWidth, context)
          }
          group.addShape('text', {
            attrs: {
              ...labelCfg.style,
              x: 0, // 居中
              y: -14,
              textAlign: 'center',
              textBaseline: 'middle',
              text: label,
              fill: '#000',
              fontSize: fontSize
            }
          })
          group.addShape('text', {
            attrs: {
              ...labelCfg.style,
              x: 0,
              y: 14,
              textAlign: 'center',
              textBaseline: 'middle',
              text: cfg?.accountId || '--',
              fontSize: fontSize,
              fill: '#000'
            }
          })
        }
        return keyShape
      },
      update: undefined
    },
    'rect'
  )
 }

canvas获取文本宽度 measureText

const canvas = document.createElement('canvas') 
const context = canvas.getContext('2d')
const textWidth = context.measureText('文本文本文本文本').width