refactor word cloud mark

[hustcc]

• refactor word cloud mark
• test case
• demo

[pearmini]

需要生成基准图片？

[coveralls]

Pull Request Test Coverage Report for Build 8749775624

Details

• 11 of 22 (50.0%) changed or added relevant lines in 5 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.06%) to 86.371%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/data/wordCloud.ts	3	5	60.0%
src/mark/wordCloud.ts	1	3	33.33%
src/shape/text/tag.ts	5	12	41.67%

Files with Coverage Reduction	New Missed Lines	%
src/data/wordCloud.ts	1	12.9%

Totals
Change from base Build 8611256665:	-0.06%
Covered Lines:	10293
Relevant Lines:	11544

---

💛 - Coveralls

[hustcc]

试过，也生成不出来，因为他用到 canvas 去计算词云布局的，使用了 mock canvas，导致计算出来的位置不正确。

[pearmini]

试过，也生成不出来，因为他用到 canvas 去计算词云布局的，使用了 mock canvas，导致计算出来的位置不正确。

哦，对，词云没有去测试，因为是随机的。

[hustcc]

以前词云图为什么出来就是不好看，或者会有一些遮挡，核心问题是布局结果和绘图配置不一致，主要有：

• textAlign
• textBaseline
• rotate
• x y 坐标系方向