我尝试使用png格式将R图保存为透明背景。我已经遵循stackoverflow上的一些推荐方法,但每次仍然得到白色背景。我的测试数据如下:
structure(list(wd = c(7.5, 22.5, 37.5, 52.5, 67.5, 82.5, 97.5,
112.5, 127.5, 142.5, 157.5, 172.5, 187.5, 202.5, 217.5, 232.5,
247.5, 262.5, 277.5, 292.5, 307.5, 322.5, 337.5, 352.5), MP1 = c(17.6,
21, 20.5, 26.5, 32.7, 38.3, 40.7, 41.8, 41.6, 44.4, 52.4, 62.5,
70.7, 74.4, 71.1, 66.9, 66.9, 69.4, 69.4, 67.4, 63.4, 55.9, 43.9,
33.9)), .Names = c("wd", "MP1"), class = "data.frame", row.names = c(NA,
-24L))
我尝试了两种方法,但是都无法去除背景。
方法1:
library(ggplot2)
library(cairo)
ggplot(dat, aes(wd, MP1)) +
coord_polar( start = 0, direction = 1) +
xlab("")+
ylab("")+
scale_x_continuous(limits = c(0, 360), expand = c(0, 0), breaks = seq(0, 360-1, by = 90), labels=c("North", "East","South", "West")) +
geom_vline(xintercept = seq(0, 360-1, by = 15), colour = "grey90", size = 0.2) +
geom_bar(width=15, stat='identity', fill= "cyan", colour= "white") +
theme_bw() +
theme(panel.border = element_blank(),
legend.key = element_blank(),
axis.ticks = element_blank(),
axis.text.y = element_blank(),
axis.text.x = element_blank(),
panel.grid = element_blank())
Cairo(width = 640, height = 480, file="test.png", type="png",
bg = "transparent")
dev.off()
方法2:
png("test.png", width = 4 * 800,
height = 4 * 800, res = 600)
ggplot(dat, aes(wd, MP1)) +
coord_polar( start = 0, direction = 1) +
xlab("")+
ylab("")+
scale_x_continuous(limits = c(0, 360), expand = c(0, 0), breaks = seq(0, 360-1, by = 90), labels=c("North", "East","South", "West")) +
geom_vline(xintercept = seq(0, 360-1, by = 15), colour = "grey90", size = 0.2) +
geom_bar(width=15, stat='identity', fill= "cyan", colour= "white") +
theme_bw() +
theme(panel.border = element_blank(),
legend.key = element_blank(),
axis.ticks = element_blank(),
axis.text.y = element_blank(),
axis.text.x = element_blank(),
panel.grid = element_blank(),
plot.background = element_rect(fill = NULL,colour = NA))
dev.off()
很遗憾,这两种方法都不能给我透明的背景色,如果我将其添加到ArcGIS或Microsoft Word文档中,仍然会显示白色背景。我非常感谢任何可能的建议,因为我没有收到任何错误消息,但却没有得到透明的背景色。提前致谢。