Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Create correct stacked area chart when it contains time series, regardless of them being disjunct.

Fixed issues

• ECharts "Stacked Area Chart" does not work for not-synced time series data. #15742

Details

Before: What was the problem?

When stacking time series, echarts decided to use stacking by index.
This causes it to place data in places where it is not: Index 0 for one time series is not necessarily the same point in time as index 0 for another time series.

After: How does it behave after the fixing?

For time series, stacking is set to stacking by dimension and an inverted index is created, allowing stacking to use the time value instead of the index for stacking. It reuses the mechanism for ordinal stacking.

Document Info

One of the following should be checked.

• This PR doesn't relate to document changes
• The document should be updated later
• The document changes have been made in apache/echarts-doc#xxx

Misc

ZRender Changes

• This PR depends on ZRender changes (ecomfe/zrender#xxx).

Related test cases or examples to use the new APIs

I added a visual test line-stack-disjunct-timeseries.html.
Please advise whether this should be put in an existing test or can be left stand alone.

All existing visual tests that pass for 6.0.0-beta.1 pass for this PR, however some seem to be flaky. With several runs the flaky ones also pass.

Others

Merging options

• Please squash the commits into a single one when merging.

Other information

I have not tested the performance of this on a large dataset.