feat(ssr): add useViewBox opts in renderToSVGString

[pissang]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Add useViewBox opt in renderToSVGString method to make the generated SVG responsive.

Related PR: #15880 (comment)

Fixed issues

#16127 (comment)

Details

Before: What was the problem?

The generated SVG has no viewBox attribute and is not responsive.

After: How is it fixed in this PR?

Use a useViewBox opt (default to be true) to add viewBox attribute. It's responsive now when width and height are changed.

This allows use to configure width and height in the CSS.

.chart svg {
  width: 100%;
  height: 100%;
}

Misc

• The API has been changed (apache/echarts-doc#xxx).
• This PR depends on ZRender changes (feat(ssr): add useViewBox opt ecomfe/zrender#861).

[echarts-bot]

Thanks for your contribution!
The community will review it ASAP. In the meanwhile, please checkout the coding standard and Wiki about How to make a pull request.

The pull request is marked to be PR: author is committer because you are a committer of this project.

Document changes are required in this PR. Please also make a PR to apache/echarts-doc for document changes and update the issue id in the PR description. When the doc PR is merged, the maintainers will remove the PR: awaiting doc label.

This PR depends on ZRender changes. Please update the ZRender dependency to the latest nightly version including this change, which takes place everyday at 8:00 UTC (16:00 Beijing Time).
You can use npm i zrender@npm:zrender-nightly@dev to update package.json.
If you have any question about this, please leave a comment and we will give you extra help on this.

[echarts-bot]

Congratulations! Your PR has been merged. Thanks for your contribution! 👍