metric: First meaningful paint (1.0)

Ideally, the first paint where the user feels that the primary content is visible

This means paints with only the topnav don’t qualify. Any primary text must be visible (and not waiting for fonts). If an image is critical to the page (e.g. e-commerce product page), then first meaningful paint requires it to be visible.

Manual evaluation: Network Tab in DevTools timeline. Reload with screenshots/filmstrip enabled. Select the first screenshot with a meaningful view.

Input:

• Use ksakamoto’s work:
  • First meaningful paint? - Google Groups
  • First Meaningful Paint - manual evaluation
  • Time-to-first-X-paint metrics: status and refinement plans
  • "Is it useful?" metric (aka. First meaningful paint): layout-based approach - Google Groups

Audit Scoring

• Metric’s value is milliseconds from navigationStarted until this paint hit swapBuffers from GPU/browser threads.
• Goal: first meaningful paint delivered from first 14K of the HTML document in 1000ms (on the reference device/network class)
• Metric’s score will be expressed as n/100.
  • 100/100 score is fMP in <= 1000ms
  • 90/100 is ~= 3000ms
  • TBD: Determine curve of score down to 0/100.

[umaar]

Just a heads up: in the report.html, I get a -1 for Fast first paint of content (target value: 1,000ms ) - for airhorner.

[paulirish]

early work was done a while ago. #618 picks up the remaining stuff.