Enhance Support for Custom Axes and 2D Plotting

[pperanich]

Is your feature request related to a problem? Please describe.

I'm currently using the rerun viewer to visualize time series data. However, I'm facing challenges when trying to visualize the frequency spectrum of a time series signal. The SeriesLine plot is limited by requiring the x-axis to be a time axis, which isn't suitable for frequency spectrum data where the x-axis should represent frequency. Additionally, the LineStrip2D plot lacks axes and grids, and the BarChart lacks support for custom x-values, making these options less ideal for frequency spectrum visualization.

Describe the solution you'd like

I propose the introduction of a new plot type or an enhancement to the existing SeriesLine plot that allows for frequency spectrum visualization. Key features should include:

• Support for custom x-values, enabling the x-axis to represent frequency bins instead of time.
• Axes and grid support.
• The ability to plot the data as a continuous line strip or as points (e.g., using SeriesPoint), with customizable markers.

Describe alternatives you've considered

• Using the BarChart with custom x-values (once available) to represent the frequency spectrum.
• Using LineStrip2D without any axes information.

Additional context

The ability to visualize frequency spectra directly within rerun would significantly enhance its utility for multi-modal time series analysis.

[Wumpf]

Related to:

• https://github.com/rerun-io/rerun/issues/5622
• https://github.com/rerun-io/rerun/issues/1387

I was sure there was already a ticket on general 2D plotting itself, but couldn't find it, so might as well be the first! :)