Define and standardize axis properties across visualizations

[ohltyler]

Currently stroke width of axes is only supported at the vega level (ref). Ideally we can have this specified within the vega plugin via an extra field such that when it is post-processed in the vega parser or the vega view, we can update the compiled vega spec to include the user-configured value.

[ashwin-pc]

@ohltyler can you specify why we need this extra field? A little more context for this issue would help

[ohltyler]

@ohltyler can you specify why we need this extra field? A little more context for this issue would help

@opensearch-project/opensearch-ux has noticed the default stroke width of the axes for vega lite are lighter/thinner than that of vislib chart axes. They would like consistency. Perhaps even hardcoding something in the post-processing steps (vega parser, vega view) would make more sense, since this field isn't something currently configurable based on the existing chart configs.

[joshuarrrr]

@ohltyler This is on the roadmap as part of the Visualization Unification initiative.

I've added it as a subtask to #3368

I think the next step here is for @KrooshalUX to provide some general guidance on axis styling that we can then apply to all visualizations, and I've generalized the title accordingly.

As for the source code, to the best of my knowledge, this is where visLib sets the default line width to 1px (which appears to be used for both series lines and axes):

OpenSearch-Dashboards/src/plugins/vis_type_vislib/public/vislib/lib/axis/axis_config.js

Line 54 in 1728318

lineWidth: '1px',

But many specific chart types or layouts set that config to 2px.

As for vis_type_vega, axis styling should be supplied via a default config - https://vega.github.io/vega-lite/docs/axis.html#config

At the moment, I'd need to do more digging to see where that is specified, although I do know we inject additional config values in the parser:

OpenSearch-Dashboards/src/plugins/vis_type_vega/public/data_model/vega_parser.ts

Line 678 in 1728318

_setDefaultColors() {