Formatting minor y breaks in ggplot-CodePudding

I have the below chart:

library(ggplot2)
width = as.numeric(dff$time_terminal[1]-dff$time_terminal[2])*22.5
ggplot(data =dff, aes(x = time_terminal))  
  geom_rect(aes(xmin = time_terminal - width, xmax = time_terminal   width, ymin = pmin(open.ha, close.ha), ymax = pmax(open.ha, close.ha), fill = dir))  
  geom_linerange(aes(ymin=low, ymax=high))  
  geom_point(aes(y = close), size = 1) 
  labs(title = paste(min(df$time_terminal), max(df$time_terminal)), y = "Close", x = "")   
  theme_tq() 
  scale_y_continuous(breaks = seq(round(min(df$close),-1), max(df$close), by = 10)) 
  theme(legend.position="none")

How can I change the format of the minor y-axis break lines to be dotted for example, or of a lower width than the major breaks?

dff <- structure(list(time_terminal = structure(c(1663973640, 1663973700, 
1663973760, 1663973820, 1663973880, 1663973940), class = c("POSIXct", 
"POSIXt"), tzone = "UTC"), open.ha = c(12310.0220066959, 12308.473503348, 
12306.386751674, 12303.655875837, 12306.1654379185, 12308.9202189592
), high = c(12311.3, 12310.3, 12303.8, 12316.8, 12321.3, 12312.8
), low = c(12301.3, 12300.3, 12294.8, 12300.3, 12302.8, 12300.8
), close.ha = c(12306.925, 12304.3, 12300.925, 12308.675, 12311.675, 
12305.425), dir = c(FALSE, FALSE, FALSE, TRUE, TRUE, FALSE), 
    close = c(12303.8, 12303.3, 12302.3, 12315.3, 12306.3, 12301.8
    )), row.names = 23033:23038, class = "data.frame")

CodePudding user response：

To control the appearance of the minor breaks use the theme element panel.grid.minor. Here I have also made the major gridlines thicker for demonstration purposes and emphasis using panel.grid.major

ggplot(data = dff, aes(x = time_terminal))  
  geom_rect(aes(xmin = time_terminal - width, xmax = time_terminal   width, 
                ymin = pmin(open.ha, close.ha), ymax = pmax(open.ha, close.ha), 
                fill = dir))  
  geom_linerange(aes(ymin = low, ymax = high))  
  geom_point(aes(y = close), size = 1)  
  labs(title = paste(min(dff$time_terminal), max(dff$time_terminal)), 
       y = "Close", x = "")   
  tidyquant::theme_tq()  
  scale_y_continuous(breaks = seq(round(min(dff$close), -1), max(dff$close), 
                                  by = 10))  
  theme(legend.position = "none",
        panel.grid.major = element_line(size = 1),
        panel.grid.minor = element_line(linetype = 'dashed', size = 0.5))

If you want only the gridlines in the y axis to be affected, you can use the theme elements panel.grid.minor.y and panel.grid.major.y

CodePudding user response：

Those are controlled by the panel.grid.minor theme element. So add something like this to the plot:

theme(panel.grid.minor = element_line(color = "grey30", size = 0.1))

theme(panel.grid.minor = element_line(linetype = "dashed", size = 0.1))