Generate HTML Report for Batch Comparison Results

Creates a standalone HTML report summarizing batch image comparison results. Includes pass/fail statistics, failure reasons, diff statistics, and thumbnails of the worst offenders.

Usage

batch_report(
  object,
  output_file = NULL,
  title = "odiffr Comparison Report",
  embed = FALSE,
  relative_paths = FALSE,
  n_worst = 10,
  show_all = FALSE,
  images = c("diff", "all"),
  ...
)

Arguments

object: An odiffr_batch object from compare_images_batch() or compare_image_dirs().
output_file: Path to write the HTML file. If NULL, returns HTML as a character string. The file is written as UTF-8 and its parent directory is created if it does not exist.
title: Report title. Default: "odiffr Comparison Report".
embed: If TRUE, embed diff images as base64 data URIs for a fully self-contained file. If FALSE (default), link to image files on disk using file:// URIs.
relative_paths: If TRUE and output_file is specified, use paths relative to the report location for image src attributes. This makes reports portable without embedding. Paths are percent-encoded so that file names containing spaces, #, ? or % work. If no relative path can be built (e.g. different drives on Windows), a file:// URI is used instead. Ignored when embed = TRUE. Default: FALSE.
n_worst: Number of worst offenders to display. Default: 10.
show_all: If TRUE, include a table of all comparisons. Default: FALSE.
images: Which images to show for each comparison: "diff" (default) shows only the diff image; "all" shows the baseline (img1), current (img2) and diff images side by side, each with a caption. Clicking a thumbnail shows the full-size image (a link to the file for linked reports, an in-page zoom for embedded ones).
...: Additional arguments passed to summary.odiffr_batch().

Value

If output_file is NULL, returns the HTML as a character string (invisibly). If output_file is specified, writes the file and returns the file path (invisibly).

Details

Diff image thumbnails (or embedded images when embed = TRUE) are only shown for comparisons where a diff_output file was created. This requires using diff_dir in compare_images_batch() or compare_image_dirs(). Comparisons without diff images will show "No diff" in the preview column.

With images = "all", baseline and current images are linked or embedded in the same way as diff images (embed, relative_paths). Embedded images get a MIME type based on their file extension (PNG, JPEG, WebP, BMP or TIFF; note that most browsers cannot display TIFF). Images that are not files on disk (for example "<magick-image>" inputs) or that no longer exist are shown as a placeholder. The report stays a single HTML file with inline CSS and no JavaScript.

Failures without pixel statistics (layout differences, errors, or baseline images with no current counterpart) show "-" for the diff percentage and pixel count. If the results contain an error column, its message is shown in the Reason column. An empty batch produces a valid report with a pass rate of "-".

Examples

if (FALSE) { # \dontrun{
results <- compare_image_dirs("baseline/", "current/", diff_dir = "diffs/")

# Generate report file
batch_report(results, output_file = "report.html")

# Self-contained report with embedded images
batch_report(results, output_file = "report.html", embed = TRUE)

# Baseline, current and diff images side by side
batch_report(results, output_file = "report.html", images = "all")

# Get HTML as string
html <- batch_report(results)
} # }