Create side-by-side comparisons of published and reproduced figures

Combines each published figure with the corresponding reproduced figure into one image, with a label below each, so that differences can be seen at a glance in the certificate. Both images are scaled to the same width; only the first page or frame of an image file is used. PDF and SVG figures are rendered at a resolution that fits width. The font size of long labels is reduced so that they fit. Include the comparisons in the certificate with render_figure_comparisons.

Usage

compare_figures(
  published,
  reproduced,
  output_dir = "comparison",
  names = sprintf("comparison-%d.jpg", seq_along(published)),
  labels = c("Published", "Reproduced"),
  layout = c("vertical", "horizontal"),
  width = 1600,
  quality = 85
)

Arguments

published: Paths to the published figures, e.g., from extract_pdf_figures.
reproduced: Paths to the reproduced figures, in the same order.
output_dir: Directory to write the comparison images to; created if missing.
names: File names of the comparison images, ending in .jpg, .jpeg, or .png; default comparison-1.jpg, comparison-2.jpg, etc.
labels: Labels for the published and the reproduced figure.
layout: "vertical" (default) puts the published figure above the reproduced one, "horizontal" puts them side by side.
width: Width in pixels to which each figure is scaled.
quality: JPEG quality of the comparison images.

Value

A data frame with the columns published, reproduced, and file, invisibly.

Details

Make sure the license of the published figures allows their reuse, e.g., CC BY, and attribute them in labels.

Examples

if (FALSE) { # \dontrun{
comparisons <- compare_figures(
  published = figures$file[1:2],
  reproduced = c("outputs/Figure 1.png", "outputs/Figure 2.png"),
  labels = c("Published (Author et al., 2026, CC BY 4.0)", "Reproduced (CODECHECK)"))
} # }