strwidth错误（words [i]，cex = size [i]，...）：无效的'cex'值

Question

我正在使用tm和wordcloud软件包。我正试图从DTM制作一个词云。这是代码：

ocs <- Corpus(VectorSource(text))
trans <- content_transformer(function(x, pattern) gsub(pattern," ",x))
Docs <- tm_map(Docs, trans, "/")
Docs <- tm_map(Docs, trans, "@")
Docs <- tm_map(Docs, trans, "//|")
Docs <- tm_map(Docs, content_transformer(tolower))
Docs <- tm_map(Docs, removeNumbers)
Docs <- tm_map(Docs, removeWords, stopwords("english"))
Docs <- tm_map(Docs, removePunctuation)
Docs <- tm_map(Docs, stripWhitespace)
Docs <- tm_map(Docs, stemDocument)
Docs <- tm_map(Docs, wordLength)
dtm <- TermDocumentMatrix(Docs)
mat <- as.matrix(dtm)
v <- sort(rowSums(mat), decreasing = TRUE)
Data <- data.frame(word = names(v), freq = v)
set.seed(1056)
wordcloud(words = Data$word, freq = Data$freq, min.freq = 1,
      max.words = 200, random.order = FALSE, rot.per = 0.35,
      colors = brewer.pal(8,"Dark2"))

发现错误：strwidth错误（words [i]，cex = size [i]，...）：无效的'cex'值。有人可以告诉我错误的解决方法吗？