Re: Graphs for Final Font Size

It may be a good idea to point out the two caveats mentioned above when
presenting the bytes reduction graphs in the evaluation report to avoid
misinterpreting those numbers as the reductions expected for a single font
viewed in isolation.

On Mon, Oct 12, 2020 at 2:32 PM Garret Rieger <grieger@google.com> wrote:

> Here's my attempt at creating a graph that has the total bytes transferred
> for a font across the three tested methods:
>
> https://github.com/w3c/PFE-analysis/pull/56/files
>
> Some notes:
>
>    - I stuck with the same style graph as used in the percentage graphs
>    as it lets us easily show distributions. I changed the line colour to blue
>    since there's no good/bad distinction on this graph.
>    - I derived the values on the graph by applying the percentage
>    reductions from the simulation results to the "worst case" woff2 font size
>    for each language group (the 95th percentile font size).
>    - This gives an estimate of the amount of bytes that would be
>    transferred for a font of that size.
>    - However, there are a couple important caveats:
>       - % reduction from the simulation is the reduction over a sequence
>       of page views and is *not representative of the reduction in bytes
>       transferred for loading a single page*. The reduction for a single
>       page is likely to be higher than for a sequence of page views.
>       - Similarly the reduction is the aggregate of all fonts on a given
>       page. So for something like CJK that means there could be latin or other
>       language fonts mixed in. Thus the percent reductions *are not
>       representative of the reductions you'd see for a single CJK font in
>       isolation*. Again I believe the reduction is actually larger for a
>       single CJK font on a single page.
>    - Unfortunately the simulation results were not recorded at the font
>    level but at the page view level, so there isn't a way to the true per font
>    reduction percentages out of the results we currently have.
>
>
> Next up I'm working on generating graphs of the font size distributions.
>
>