I am trying to get a plot to occupy the whole of a landscape page. I am using Rmarkdown and knitting a pdf document. I have also tried to change the chunk option and no luck, please help before I pull my hair out. I tried to modify the size in ggsave, it is not changing the size the whole plot. I have tried to modify aspect/ratio, I have tried to modify the chunk, no luck either.

image_path <- "C:/PATH TO IMAGES"

image_files <- c(
  "2021 Summer.jpg", 
  "2021 Autum.jpg", 
  "2021 Winter.jpg", 
  "2021 Spring.jpg",  
  "2022 Summer.jpg", 
  "2022 Autum.jpg", 
  "2022 Winter.jpg", 
  "2022 Spring.jpg", 
  "2023 Summer.jpg", 
  "2023 Autum.jpg", 
  "2023 Winter.jpg", 
  "2023 Spring.jpg"
)



# Loop through each image file
#for (filename in image_files) {
  # Read the image
  #image_path_full <- file.path(image_path, filename)
  #image <- image_read(image_path_full)
  
  # Rotate the image 90 degrees clockwise
  #rotated_image <- image_rotate(image, degrees = -90)
  
  # Show the rotated image (optional)
  #plot(as.raster(rotated_image))
#}

#print("Images rotated successfully.")


# Function to create a plot for each image file with year label
create_image_plot <- function(file, year_label) {
  image <- readJPEG(file.path(image_path, file))
  aspect_ratio <- dim(image)[2] / dim(image)[1]
  ggplot() +
    annotation_custom(grid::rasterGrob(image, width = unit(0.8, "npc"), height = unit(0.8 * aspect_ratio, "npc")), 
                      xmin = -Inf, xmax = Inf, ymin = -Inf, ymax = Inf) +
    labs(subtitle = year_label) +
    theme_void() +
    theme(plot.margin = margin(0),
          plot.subtitle = element_text(hjust = 0.5))  # Center the year label
}
# Create a list to hold the image grobs
image_grobs <- mapply(create_image_plot, file = image_files, year_label = substr(image_files, 1, 4), SIMPLIFY = FALSE)

# Create a list of legend plots
legends <- lapply(c("Summer", "Autumn", "Winter", "Spring"), function(season) {
  ggplot() +
    geom_blank() +
    labs(title = season) +
    theme_void() +
    theme(legend.position = "none", plot.title = element_text(hjust = 0.5)) 
})

# Combine legends into one plot
legend_plot <- grid.arrange(
  grobs = legends,
  nrow = 1,
  widths = rep(1, 4)
)

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{r echo=FALSE, warning=FALSE, message=FALSE, fig.align='center',fig.width=10, fig.height=8, fig.cap = paste("Soil Adjusted Vegetation Index (SAVI) imagery at the ", Carbon_Project, " between 2021 and 2023 for each season."), dpi=800}

# Arrange the plots and legend in a grid
combined_plot <- grid.arrange(
  legend_plot,
  arrangeGrob(
    do.call(arrangeGrob, c(image_grobs[c(1, 5, 9)], ncol = 1)),  
    do.call(arrangeGrob, c(image_grobs[c(2, 6, 10)], ncol = 1)),  
    do.call(arrangeGrob, c(image_grobs[c(3, 7, 11)], ncol = 1)),  
    do.call(arrangeGrob, c(image_grobs[c(4, 8, 12)], ncol = 1)),  
    ncol = 4
  ),
  nrow = 3,
  heights = unit(c(0.15, rep(1, 2)), "null")
)

# Save the combined plot as an image
ggsave("combined_plot.png", combined_plot)

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