html gif遮住了文字,在rmarkdown HTML输出中禁止GIF的替代文字

我正在使用RMarkdown文件中的gganimate包生成GIF。在前端使用output = github_document时，GIF会在输出(github-document-output)中按预期显示。但是，使用output = html_document时，GIF会生成alt文本，默认为块名称(html-document-output)。

有没有办法抑制这个自动标题？我尝试使用fig.cap chunk选项设置我自己的标题，但这不成功。

RMarkdown代码

---

output:

html_document: default

github_document: default

---

```{r}

knitr::opts_chunk$set(

collapse = TRUE,

comment = "#>",

fig.path = "output/test-fig-",

cache.path = "output/test-cache-"

)

```

```{r cache = FALSE}

library(knitr)

library(animation)

ani.options(autobrowse = FALSE, interval = 1)

opts_knit$set(animation.fun = function(x, options, format = "gif") {

x = c(knitr:::sans_ext(x), knitr:::file_ext(x))

fig.num = options$fig.num

format = sub("^[.]", "", format)

fig.fname = paste0(sub(paste0(fig.num, "$"), "*", x[1]),

".", x[2])

mov.fname = paste0(sub(paste0(fig.num, "$"), "", x[1]), ".",

format)

# order correctly

figs

figs

animation::im.convert(figs, output = mov.fname)

sprintf("", options$label, paste0(opts_knit$get("base.url"), mov.fname))

})

opts_chunk$set(cache = TRUE, message = FALSE, warning = FALSE, fig.show = "animate")

```

```{r pkgs, cache = FALSE}

library(gapminder)

library(ggplot2)

theme_set(theme_bw())

```

```{r setup}

p

geom_point() +

scale_x_log10()

```

```{r dependson = "setup"}

library(gganimate)

gg_animate(p)

```