Add support for a Non-Cumulative / Delta-Based Waterfall (Bridge Chart)

What is the problem or goal the end user is trying to solve or accomplish?

Users want to create a waterfall-style visualization where each bar represents an isolated positive/negative delta, without computing a running cumulative total.

This chart type is common in:

• Finance (variance analysis)

• Revenue bridges

• Budget vs actuals

• Component contribution analysis

The built-in Waterfall chart in Superset always applies a cumulative running total, which makes it impossible to reproduce this type of visualization.

How are they solving it currently?

Users currently rely on imperfect workarounds:

• Building a regular Bar Chart with conditional color formatting
  (green for positive deltas, red for negative deltas)

• Manually aligning bars to mimic a waterfall

• Precomputing offset values in SQL/dbt to simulate a fake “baseline”

• Using external BI tools (Excel, PowerBI) and embedding screenshots

These approaches do not replicate the intended visualization accurately and lack features like:

• Connector lines

• Zero-baseline deltas

• True waterfall styling without cumulation

What is the recommended solution by the Customer?

Add a new “Non-Cumulative / Delta / Bridge Waterfall Chart” option that:

• Uses raw delta values as-is (no running sum)

• Automatically colors positive/negative steps

• Supports connector lines between bars

• Allows flexible ordering/grouping

• Looks visually similar to common “bridge charts” used in financial analysis

Alternatively, enhance the existing Waterfall visualization with a toggle:

[ ] Enable cumulative running total
     (when disabled → show deltas only)

This would allow both chart types within the same visualization.