[plots][layout] Implement axes invertion setting for Qgs2DXyPlot as well as bar and line charts (Request in QGIS)

[qgis-bot]

Request for documentation

From pull request qgis/QGIS#64960
Author: @nirvn
QGIS version: 4.0

[plots][layout] Implement axes invertion setting for Qgs2DXyPlot as well as bar and line charts

PR Description:

Description

This PR completes work that was underway within the Qgs2DXyPlot class to allow for flipping the X/Y axis "on the fly" to allow for horizontal bar charts (and more). The PR also fixes some logic within the Qgs2DXyPlot's handling of Y-axis intervals (since those had not been tested before).

This is how the UI/UX looks like:

Screencast.From.2026-02-17.14-20-28.mp4

This was the last foundational functionality I think deserves to be in our first QGIS' "charts" release. If there are no strong objections, I'd like to merge this despite the feature freeze to insure we can ship the best possible charting functionality out of the box for QGIS 4.0.

Commits tagged with [need-docs] or [FEATURE]

[DelazJ]

Belongs to https://docs.qgis.org/testing/en/docs/user_manual/print_layout/layout_items/layout_chart.html#main-properties

[BhattacharjeeSutapa]

@DelazJ please assign me for this.