[Feature] wordcloud 支持铺满画布

[xiaoluoHe]

What problem does this feature solve?

词云支持铺满画布

现在：

const spec = {
  type: 'wordCloud',
  nameField: 'name',
  valueField: 'value',
  padding:0,
  width:300,
  height:100,
  background:'pink',
  maskShape:'square',
    wordCloudConfig: {
    zoomToFit: {
      shrink: true,
      fontSizeLimitMin: 5
    }
  },
  data: {
    name: 'baseData',
    values: [
      {
        name: '螺蛳粉',
        value: 957
      },
      {
        name: '钵钵鸡',
        value: 942
      },
      {
        name: '板栗',
        value: 842
      },
      {
        name: '胡辣汤',
        value: 828
      },
      {
        name: '关东煮',
        value: 665
      },
      {
        name: '羊肉汤',
        value: 627
      },
      {
        name: '热干面',
        value: 574
      }
    ]
  }
};

What does the proposed API look like?

maskShape: 'rect'