No wrapping wanted in a legend of a ggplot graph

Question

If I run the following R code:

    g <- ggplot(results_table, aes(x = factor(results_table$Criteria, as.character(results_table$Criteria)), 
                               y = Pct*100)) + 
  geom_bar(aes (fill = factor(results_table$Criteria, as.character(results_table$Criteria))),
           stat = "identity", width = 1) + 
  scale_fill_manual(values=Palcolor) +
  theme_classic() + 
  theme(legend.position = "bottom", legend.title=element_blank(), axis.line.x=element_blank(), 
        axis.line.y=element_blank(), axis.ticks.x = element_blank(), axis.ticks.y = element_blank(), 
        axis.text.x = element_blank(), axis.text.y = element_blank(), 
        axis.title.x = element_text(margin = margin(t = -0.3, unit = "cm"),size = 9)) + 
  guides(fill = guide_legend(nrow = 4, byrow = TRUE)) +
  xlab("% of \nOrganizations") + 
  ylab("") + 
  geom_text(aes(label = paste0(sprintf("%0.1f", round(Pct*100, digits = 1)),"%"), vjust = -0.8, 
                hjust = 0.5), size = 3.2, color = "black") 

it produces the following graph:

first question: I would like to have the legend's labels in one line, then no wrapping. Second question: I would like to have smaller squares. How can I proceed?

Answer 1

Updated to include removal of line breaks from legend text to prevent wrapping, and functions to allow maximum space for legend presentation.

library(tibble)
library(ggplot2)
library(dplyr)
library(stringr)

data

tib <- tibble(v1 = letters[1:7],
              v2 = 7:1,
              g = c("long legend text, blah di blah blah blah, blah di blah  blah blah 1",
                    "long legend text, blah di blah blah blah, blah di blah  blah blah 2",
                    "long legend text, blah di blah blah blah\nwith a line break 3",
                    "long legend text, blah di blah blah blah, blah di blah  blah blah 4",
                    "long legend text, blah di blah blah blah, blah di blah  blah blah 5",
                    "long legend text, blah di blah blah blah\nwith a line break 6",
                    "long legend text, blah di blah blah blah, blah di blah  blah blah 7"))

data wrangle

# remove line break with base r
tib$g <- gsub("\\n", "", tib$g)

# or with dplyr and stringr
tib <- mutate(tib, g = str_remove(g, "\\n"))
  

plot

ggplot(tib, aes(v1, v2, fill = g)) +
  geom_col()+
  labs(fill = NULL)+
  theme(legend.position = "bottom",
        legend.key.size = unit(3, "mm"), #smaller squares
        legend.box.margin = margin(t = 0, r = 0, b = 0, l = 0, unit = "mm"), #maximise legend extents
        legend.text = element_text(size = 8))+ #modify text size to fit  
  guides(fill = guide_legend(nrow = 4, byrow = TRUE))

^{Created on 2020-05-14 by the reprex package (v0.3.0)}