Base R中解决RMarkdown转PDF时柱状图分类X轴标签截断问题

方案1：用正确参数调整X轴标签字体大小 #

你之前使用的cex.axis是控制坐标轴数值刻度（比如Y轴的0、10、20这类数值）的字体大小，而barplot的X轴分类标签需要用cex.names参数来调整：

# 提取t1的列名作为X轴标签（适用于t1为矩阵/表格的情况）
x_labels <- colnames(t1)

barplot(t1,
        legend = TRUE, 
        main="Commitment to Conserving Water vs. Age of Voice and Familiarity of Imagery", 
        xlab = "Voice - Familiarity Level", 
        ylab = "Number of Participants",
        ylim = c(0,40), 
        beside = TRUE,
        cex.names = 0.8,  # 缩小标签字体，可根据需求调整数值
        names.arg = x_labels)  # 显式指定X轴标签，确保对应正确

方案2：旋转X轴标签并调整边距 #

如果缩小字体仍无法完整显示，可以将标签旋转，同时加大图形底部边距给标签留出空间：

# 调整图形边距：mar参数顺序为「下、左、上、右」，默认是c(5,4,4,2)+0.1，这里加大底部边距
par(mar = c(8, 4, 4, 2) + 0.1)

barplot(t1,
        legend = TRUE, 
        main="Commitment to Conserving Water vs. Age of Voice and Familiarity of Imagery", 
        xlab = "Voice - Familiarity Level", 
        ylab = "Number of Participants",
        ylim = c(0,40), 
        beside = TRUE,
        cex.names = 0.8,
        las = 2)  # las=2让X轴标签垂直竖排，避免横向截断

# 若需要倾斜标签（比如45度），可手动绘制标签：
bar_pos <- barplot(t1,
                   legend = TRUE, 
                   main="Commitment to Conserving Water vs. Age of Voice and Familiarity of Imagery", 
                   xlab = "Voice - Familiarity Level", 
                   ylab = "Number of Participants",
                   ylim = c(0,40), 
                   beside = TRUE,
                   xaxt = "n")  # 关闭默认X轴标签绘制
text(bar_pos, par("usr")[3]-1,  # 设置标签位置：柱状图中心，Y轴底部下方1单位
     labels = colnames(t1), 
     srt = 45,  # 旋转45度
     adj = 1,  # 标签右对齐
     cex = 0.8)

方案3：给长标签手动换行 #

如果标签过长，可通过\n将标签拆分为多行，减少横向长度：

# 自动替换分隔符为换行（这里以" - "为例），也可手动修改标签
x_labels <- gsub(" - ", "\n", colnames(t1))

barplot(t1,
        legend = TRUE, 
        main="Commitment to Conserving Water vs. Age of Voice and Familiarity of Imagery", 
        xlab = "Voice - Familiarity Level", 
        ylab = "Number of Participants",
        ylim = c(0,40), 
        beside = TRUE,
        names.arg = x_labels,
        cex.names = 0.9)

内容的提问来源于stack exchange，提问作者Crystal