size argument passed to annotations not respected?

I understand this issue has a chance of being an off-topic implementation issue. If so, please accept my sincere apologies in advance. Frank Harrell reported he is unable to change size of the annotated text using the code below.

require(plotly)
p <- plot_ly()
p <- add_markers(p,x=~1:2, y=~1:2)
p <- add_annotations(p, x=~c(1.1, 2.1), y=~c(1.2, 2.4),
                     text=~c('XXX','YYY'), size=~c(7,20))
p

I was unable to account for size of text using the 'old' method using 'layout' (as discussed in #744).

ann <- data.frame(x = c(1.1, 2.1),
                  y = c(1.2, 2.4),
                  size = c(10, 20),
                  text = c("XXX", "YYY"))
xy <- data.frame(x = c(1, 2), y = c(1, 2))

a <- vector("list", nrow(ann))

for (i in 1:nrow(ann)) {
  a[[i]] <- list(
    x = ann$x[i],
    y = ann$y[i],
    text = ann$text[i],
    xref = "x", yref = "y",
    showarrow = TRUE,
    size = ann$size[i]
  )
}

plot_ly(xy, x = ~x, y = ~y) %>%
  add_markers() %>%
  layout(annotations = a)

@cpsievert suggested using add_annotations but I'm a bit lost on how to pass on the size argument. Based on the documentation and some examples scattered over the internet, I tried

plot_ly(xy, x = ~x, y = ~y) %>%
  add_markers() %>%
  add_annotations(text = ~text, font = list(size = ~size), data = ann)

with no luck. Is there something I'm doing wrong?

まず、font = list(size = ~size) の形式と以前のレイアウト方式を含め、提供されている add_annotations の例を再現します。add_annotations のエントリポイントをたどってアノテーションのサイズがどのように渡されるかを確認し、次に、アノテーションが要求された行ごとのサイズでレンダリングされることを検証します。