如何在R中缩放图例框或放大图例框中的字体大小

我使用下面的代码来绘制一些伽马分布

par(mfrow=c(2, 2))
a = 0.5; b = 2
curve(dgamma(x, a, b), from=0.01, to=0.2, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=0.2, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=0.2, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), cex=0.5,ft.cex=1,
       c("a = 0.5, b = 2","a = 0.5, b = 1","a = 0.5, b = 0.5"))

a = 1; b = 2
curve(dgamma(x, a, b), from=0.01, to=4, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=4, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=4, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), cex=0.5,
       c("a = 1, b = 2","a = 1, b = 1","a = 1, b = 0.5"))

a = 2; b = 2
curve(dgamma(x, a, b), from=0.01, to=8, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=8, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=8, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), 
       c("a = 2, b = 2","a = 2, b = 1","a = 2, b = 0.5"))

a = 20; b = 2
curve(dgamma(x, a, b), from=0.01, to=70, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=70, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=70, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), 
       c("a = 20, b = 5","a = 20, b = 1","a = 20, b = 0.2"))
par(mfrow=c(1, 1))

如您所见，图例框的大小太大。我使用cex=0.5来缩小前两个子图中的图例框。然而，缩小盒子会使阅读文本变得困难。因此,

问题1：如何放大图例框中的文本

另一个问题是，当我增加左上角图表中标签的字体大小时，它超出了边距。因此,

问题2：如何增加左边距，使其不会从y型标签上砍下头部

最后，纵横比很奇怪。因此,

问题3：如何手动设置整个图形的宽度和高度？或者有没有办法缩小两行子图之间的空白

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谢谢

   par(mar=c(2,6,2,2), mfrow=c(2, 2))

这将设置底部、左侧、顶部和右侧边距。 只需放大左边距（以显示Y标签），缩小上下边距（以减少空白）

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这不能回答你的问题1。但是，因为您的数字会更大，因为您的空白更少，所以您的图例更适合。

如果您增加字体大小，我认为文本将不再适合图例框。因此，您需要调整cex，直到您可以阅读文本。在我的屏幕上，下面的脚本可以工作。如果在绘图区域内没有足够的空间，可以在绘图区域外放置de legend

par(mar=c(2.5,5,1,1), mfrow=c(2, 2))
a = 0.5; b = 2
curve(dgamma(x, a, b), from=0.01, to=0.2, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=0.2, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=0.2, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), cex=0.7, pt.cex(2), 
       c("a = 0.5, b = 2","a = 0.5, b = 1","a = 0.5, b = 0.5"))

a = 1; b = 2
curve(dgamma(x, a, b), from=0.01, to=4, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=4, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=4, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), cex=0.5,
       c("a = 1, b = 2","a = 1, b = 1","a = 1, b = 0.5"))

a = 2; b = 2
curve(dgamma(x, a, b), from=0.01, to=8, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=8, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=8, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), 
       c("a = 2, b = 2","a = 2, b = 1","a = 2, b = 0.5"))

a = 20; b = 2
curve(dgamma(x, a, b), from=0.01, to=70, ylab="p(x)", cex.lab=1.5)
b = 1
curve(dgamma(x, a, b), from=0.01, to=70, col=2, add=T)
b = 0.5
curve(dgamma(x, a, b), from=0.01, to=70, col=4, add=T)
legend("topright", bty="n", lty=1, lwd=1.5, col=c(1,2,4), 
       c("a = 20, b = 5","a = 20, b = 1","a = 20, b = 0.2"))
par(mfrow=c(1, 1))

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是的，它解决了第二季度和第三季度的问题。谢谢但是字体还是太小了。