chore(stack): remove stack only same sign

[susiwen8]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

According @100pah comment in 9317, ECharts only stack those value with same sign. I can't see why this rule was made, but seems this has cause a lot of question for areaStyle in stacked chart, also stack on different sign is reaonable for statistic. So I tried to lift this limitation, and done some experiment under line and bar, looks good for me.

Fixed issues

Close #9317 #9141 #13747 #15083 #14365

Details

Before: What was the problem?

After: How is it fixed in this PR?

Misc

• The API has been changed (apache/echarts-doc#xxx).
• This PR depends on ZRender changes (ecomfe/zrender#xxx).

Related test cases or examples to use the new APIs

NA.

Others

Merging options

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

Other information

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[pissang]

@susiwen8 It's an ancient rule that exists since echarts 1.0.

Check the case https://echarts.apache.org/examples/zh/editor.html?c=bar-negative. It will separate the stack of positive and negative values, usually more useful on the bar chart.

But seems it brings more issues than the benefits on the area chart.

[susiwen8]

@pissang It won't be the problem for stack bar. Maybe somewere has "accidently" fix this. No, still a issue for bar, in this case '收入' are not right.

[susiwen8]

@pissang I stand correct, bar chart stack with negative still ok, It has seperated positive and negative value, and final result are correct.

I have found some remaining issues.

1. value axis, the example above I have to set max to axis so the charts can display completly
2. To make negative stack work in bar, the first serie item mush have a negative value. Otherwise negative bar would disappear.

Beside issues listed above, looks like 'stack value with different sign' works on bar.

Test case for bar stack has added, you can check the option there.

[pissang]

@susiwen8 I'm not sure if it can work as before because this logic is completely removed.