Tracking Issue for timing report SVG render backend

[weihanglo]

Summary

Original issue: #8850
Implementation: #15091

This changes Cargo timing report renderer from HTML canvas to SVG, improving the performance of rendering large dependency graph, as well as hovering dependency lines.

Currently canvas is still the default, and there is a toggle switching between them during the call-for-testing period

Unresolved Issues

• Call-for-testing
• Remove legacy canvas renderer
• Understand our minimum supported browser version
• Should we switch to HTML template library for better maintainability?
  • Cons: bloating Cargo its own binary size and compile time
• Should we switch to a frontend framework for better maintainability?
  • Cons: editing HTML/JS directly will be harder

Future Extensions

• A detailed view when hover on dependency lines: Experiment: Render timing pipeline in SVG #15091 (comment)

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

[eth3lbert]

I've experimented with a simple detail view as shown below:

The content and style of the details can be adjusted based on any feedback provided. Hopefully, this will mitigate the inconvenience for those who need to track 'unblocked' or 'unblocked-by' units in a large graph.

[eth3lbert]

Regarding the issue described in #15091 (comment), another idea is to introduce a dep-line lock mode. Specifically, when a unit is clicked, we would only highlight its dep-lines, even if the user hovers over other units. This should help mitigate the issue, although I'm not sure if it would be useful in the end. 🤔