Set an explicit default width of 100% for README figs

[jennybc]

Meant to combat figs that run off the page for README.html that CRAN creates and hosts.

Suggests the use of, e.g.,

knitr::include_graphics("man/figures/i-already-exist.png")

for pre-made figs.

[hadley]

Do we really want them that wide?

[jennybc]

Hmmm ... I just saw this as a huge improvement over the status quo in some of my projects.

I'll explain how I got here, in case it's all dysfunction on my end:

• I often use quick and dirty measures to make a figure look better 😬. At the time of ggsave(), I make it physically larger than necessary, so that it looks nice and sharp wherever I need to use it later. Such as in a README. Ergo I need to specify figure width.
• I often put two figure side-by-side via fig.show = 'hold', out.width = '49%', which reinforced my choice of 49 + 49 = 98 ~= 100.

[hadley]

Hmmm, maybe I'm getting confused about how they're sized by default. Can you point me to the diff for the gapminder README? (which was the motivation IIRC)

[jennybc]

Sure:

jennybc/gapminder@dd232a2

It causes figures to be embedded via an <img> tag with explicit width vs. Markdown image syntax.

[jennybc]

Thanks! Even if 100% is not quite the thing, now the syntax is there in case someone wants to adjust, delete, or move to a specific chunk.