schema.json

The json block below contains the same structure with the same keys as the
json generated by qpdf. In the block below, the values are descriptions of
the meanings of those entries. The specific contract guaranteed by qpdf in
its json representation is explained in more detail in the manual. You can
specify a subset of top-level keys when you invoke qpdf, but the "version"
and "parameters" keys will always be present. Note that the "encrypt"
key's values will be populated for non-encrypted files. Some values will
be null, and others will have values that apply to unencrypted files.
{
  "acroform": {
    "fields": [
      {
        "alternativename": "alternative name of field -- this is the one usually shown to users",
        "annotation": {
          "annotationflags": "annotation flags from /F -- see pdf_annotation_flag_e in qpdf/Constants.h",
          "appearancestate": "appearance state -- can be used to determine value for checkboxes and radio buttons",
          "object": "reference to the annotation object"
        },
        "choices": "for choices fields, the list of choices presented to the user",
        "defaultvalue": "default value of field",
        "fieldflags": "form field flags from /Ff -- see pdf_form_field_flag_e in qpdf/Constants.h",
        "fieldtype": "field type",
        "fullname": "full name of field",
        "ischeckbox": "whether field is a checkbox",
        "ischoice": "whether field is a list, combo, or dropdown",
        "isradiobutton": "whether field is a radio button -- buttons in a single group share a parent",
        "istext": "whether field is a text field",
        "mappingname": "mapping name of field",
        "object": "reference to this form field",
        "pageposfrom1": "position of containing page numbered from 1",
        "parent": "reference to this field's parent",
        "partialname": "partial name of field",
        "quadding": "field quadding -- number indicating left, center, or right",
        "value": "value of field"
      }
    ],
    "hasacroform": "whether the document has interactive forms",
    "needappearances": "whether the form fields' appearance streams need to be regenerated"
  },
  "attachments": {
    "<attachment-key>": {
      "filespec": "object containing the file spec",
      "preferredcontents": "most preferred embedded file stream",
      "preferredname": "most preferred file name"
    }
  },
  "encrypt": {
    "capabilities": {
      "accessibility": "allow extraction for accessibility?",
      "extract": "allow extraction?",
      "moddifyannotations": "allow modifying annotations?",
      "modify": "allow all modifications?",
      "modifyassembly": "allow modifying document assembly?",
      "modifyforms": "allow modifying forms?",
      "modifyother": "allow other modifications?",
      "printhigh": "allow high resolution printing?",
      "printlow": "allow low resolution printing?"
    },
    "encrypted": "whether the document is encrypted",
    "ownerpasswordmatched": "whether supplied password matched owner password; always false for non-encrypted files",
    "parameters": {
      "P": "P value from Encrypt dictionary",
      "R": "R value from Encrypt dictionary",
      "V": "V value from Encrypt dictionary",
      "bits": "encryption key bit length",
      "filemethod": "encryption method for attachments",
      "key": "encryption key; will be null unless --show-encryption-key was specified",
      "method": "overall encryption method: none, mixed, RC4, AESv2, AESv3",
      "streammethod": "encryption method for streams",
      "stringmethod": "encryption method for string"
    },
    "userpasswordmatched": "whether supplied password matched user password; always false for non-encrypted files"
  },
  "objectinfo": {
    "<object-id>": {
      "stream": {
        "filter": "if stream, its filters, otherwise null",
        "is": "whether the object is a stream",
        "length": "if stream, its length, otherwise null"
      }
    }
  },
  "objects": "dictionary of original objects; keys are 'trailer' or 'n n R'",
  "outlines": [
    {
      "dest": "outline destination dictionary",
      "destpageposfrom1": "position of destination page in document numbered from 1; null if not known",
      "kids": "array of descendent outlines",
      "object": "reference to this outline",
      "open": "whether the outline is displayed expanded",
      "title": "outline title"
    }
  ],
  "pagelabels": [
    {
      "index": "starting page position starting from zero",
      "label": "page label dictionary"
    }
  ],
  "pages": [
    {
      "contents": [
        "reference to each content stream"
      ],
      "images": [
        {
          "bitspercomponent": "bits per component",
          "colorspace": "color space",
          "decodeparms": [
            "decode parameters for image data"
          ],
          "filter": [
            "filters applied to image data"
          ],
          "filterable": "whether image data can be decoded using the decode level qpdf was invoked with",
          "height": "image height",
          "name": "name of image in XObject table",
          "object": "reference to image stream",
          "width": "image width"
        }
      ],
      "label": "page label dictionary, or null if none",
      "object": "reference to original page object",
      "outlines": [
        {
          "dest": "outline destination dictionary",
          "object": "reference to outline that targets this page",
          "title": "outline title"
        }
      ],
      "pageposfrom1": "position of page in document numbering from 1"
    }
  ],
  "parameters": {
    "decodelevel": "decode level used to determine stream filterability"
  },
  "version": "JSON format serial number; increased for non-compatible changes"
}