Correct way to straighten smoothed lines for ThemeRiver chart (question)

Description

Echarts has great chart type ThemeRiver (also known as streamgraph) but this type has no options smooth or smoothMonotone like in other chart types. It does not allow to straighten the lines.

I found (probably) place in code where this options inlined but it cannot be changed from official API. Rewrite this code directly will cause a problem with the future updates.

What problem does this feature solve?

Smooth lines in charts need for best looking but when you need greater accuracy the only way — to straighten the lines.

What does the proposed API look like?

The best option to do as in other types of diagrams:

Workaround

Is there possible to overload the process function without changes source code? Something like the plugin or extension API. Maybe I can intercept the lines drawing …

[creadone]

@creadone I’m trying to achieve the same thing with having straight lines, please would you be able to share how you managed to achieve it?

I was in a hurry and took the side of darkness - fixed it in the source 🤦 But it’s was really fast, take a look on micro changes. https://gist.github.com/creadone/d91447c21429d7a96e26415ba4e55f0c/revisions

diff --git a/assets/js/plugins/echarts/echarts.js b/assets/js/plugins/echarts/echarts.js
index 3d7ffca..daf6eb4 100644
--- a/assets/js/plugins/echarts/echarts.js
+++ b/assets/js/plugins/echarts/echarts.js
@@ -69072,9 +69072,9 @@ extendChartView({
      shape: {
       points: points0,
       stackedOnPoints: points1,
-     smooth: 0.4,
-     stackedOnSmooth: 0.4,
-     smoothConstraint: false
+    smooth: 0,
+    stackedOnSmooth: 0,
+    smoothConstraint: true
  },
  z2: 0
});

[etjenkins]

@creadone Thank you so much for that and for being so fast to reply! Really appreciate it 👍