Inspect metadata for an embedded image

Reads dimensions, DPI, bits-per-pixel, and color space from a pdfium_obj of type "image". Wraps FPDFImageObj_GetImageMetadata (plus FPDFImageObj_GetImagePixelSize for the pixel dims when you only need width/height).

Usage

pdf_image_info(obj)

Arguments

obj

A pdfium_obj of type "image", typically returned by filtering pdf_page_objects() on type == "image".

Value

A named list with elements width, height (integer pixels), horizontal_dpi, vertical_dpi (numeric, may be 0 when the image has no explicit DPI), bits_per_pixel (integer), colorspace (character; one of "Unknown", "DeviceGray", "DeviceRGB", "DeviceCMYK", "CalGray", "CalRGB", "Lab", "ICCBased", "Separation", "DeviceN", "Indexed", "Pattern"), and marked_content_id (integer; -1 when absent).

See also

pdf_image_bitmap() for the decoded pixels, pdf_image_rendered() for the page-CTM-applied rendering, pdf_image_data() for the raw stream bytes.

Examples

fixture <- system.file("extdata", "fixtures", "image.pdf",
  package = "pdfium"
)
if (nzchar(fixture)) {
  doc <- pdf_doc_open(fixture)
  page <- pdf_page_load(doc, 1L)
  imgs <- Filter(function(o) o$type == "image", pdf_page_objects(page))
  if (length(imgs) > 0L) pdf_image_info(imgs[[1L]])
  pdf_page_close(page)
  pdf_doc_close(doc)
}