Flamegraph / Pyroscope prototype

[janpaul123]

Checklist copy-pasted from my recent livestream

Goals

• Publish Pyroscope case study
  • Implement Zaplib flamegraph in Pyroscope open source project (JP)
  • Benchmark Zaplib implementation against existing implementation (Steve)

Tasks

Not fun:

• Text rendering looks bad on non-retina screen
• Fix spaces in example_text
• Fix rect border / coordinates deferred to Fix 2d canvas / signed distance fields rendering discrepancies #181 + test_shader_2d_primitives in CI + small fixes #182

Rote:

• "Focus rectangle" highlighting
• Temporarily disable scrolling / panning

Fun:

• Integration into Pyroscope
  • Hello world integration (toolchain, tests, etc)
  • Headers (OR Allow single-threaded usage #65)
  • Rendering at proper location
  • Transfer data
  • Popover when hovering (keep in DOM)
  • Highlighting when selecting item in the side table
  • Search highlighting
  • Focus subtree
• Rendering in Node.js https://github.com/pyroscope-io/pyroscope/blob/main/packages/pyroscope-flamegraph/src/index.node.ts#L2
• Head first vs tail first
  • No ellipsis at all
  • Cut off letters or not?
• Diff view
• Flamegraph as a library
  • Packaging wasm
  • Refactor Zaplib to operate on instances, rather than exported global functions #146
  • Anyone using this will have to fix their headers (docs; logs; etc) (OR Allow single-threaded usage #65)

Future improvements:

• Bring back scrolling / panning
  • Fix scrolling behavior when zoomed in a lot
  • Scrolling around current mouse position
• Ellipsis glyph
  • Figure out why it doesn't render currently
• Better font