R – How to resize and save plots in png format

Basically you have two options

scale_x_continuous(limits = c(-5000, 5000))

or

coord_cartesian(xlim = c(-5000, 5000)) 

Where the first removes all data points outside the given range and the second only adjusts the visible area. In most cases you would not see the difference, but if you fit anything to the data it would probably change the fitted values.

You can also use the shorthand function xlim (or ylim), which like the first option removes data points outside of the given range:

+ xlim(-5000, 5000)

For more information check the description of coord_cartesian.

The RStudio cheatsheet for ggplot2 makes this quite clear visually. Here is a small section of that cheatsheet:

Distributed under CC BY.

I can think of two solutions.

1. If your goal is to just save the list of plots as R objects, I recommend:

    saveRDS(object = pltlist, file = "file_path")

This way when you wish to reload in these graphs, you can just use readRDS(). You can then put them in cowplot or gridarrange. This command works for all lists and R Objects.

One caveat to this approach is if settings/labeling for ggplot2 is dependent upon things in the environment (not the data, but stuff like settings for point size, shape, or coloring) instead of the ggplot2 function used to make the graph), your graphs won't work until you restore your dependencies. One reason to save some dependencies is to modularize your scripts to make the graphs.

Another caveat is performance: From my experience, I found it is actually faster to read in the data and remake individual graphs than load in an RDS file of all the graphs when you have a large number of graphs (100+ graphs).

2. If your goal is to save an 'image' or 'picture' of each graph (single and/or multiplot as .png, .jpeg, etc.), and later adjust things in a grid manually outside of R such as powerpoint or photoshop, I recommend:

    filenames <- c("Filename_1", "Filename_2") #actual file names you want... 
    lapply(seq_along(pltlist), function(i) {
      ggsave(filename = filenames[i], plot = pltlist[[i]], ...) #use your settings here
    })

Settings I like for single plots:

    lapply(seq_along(pltlist), function(i) ggsave(
      plot = pltlist[[i]], 
      filename = paste0("plot_", i, "_", ".tiff"), #you can even paste in pltlist[[i]]$labels$title
      device = "tiff", width=180, height=180, units="mm", dpi=300, compression = "lzw", #compression for tiff
      path = paste0("../Blabla") #must be an existing directory.
    ))

You may want to do the manual approach if you're really OCD about the grid arrangement and you don't have too many of them to make for publications. Otherwise, when you do grid.arrange you'll want to do all the specifications there (adjusting font, increasing axis label size, custom colors, etc.), then adjust the width and height accordingly.