PDFix Actions for Accessibility

PDFix Actions for Accessibility

PDFix Actions for accessibility provide a flexible, no-code method for fixing accessibility issues using batch commands. For more information about batch commands, please follow actions.

Users can assemble a set of actions in a JSON file. These actions are executed sequentially on an opened PDF document.

Make Accessible for Non-Tagged Documents

The Make Accessible command is a set of actions designed to fix common accessibility issues in non-tagged PDF documents. By default, it uses a configuration that includes a sequence of actions such as cleaning up the previous structure, flattening form XObjects, embedding fonts, autotagging, updating metadata, creating bookmarks from headings, and applying other necessary fixes to ensure PDF/UA compliance.

Executing the Make Accessible Command

Using the Command-Line:

./pdfix_app make-accessible -i "input.pdf" -o "output.pdf"

Programmatically in Python:

pdfix = GetPdfix()
doc = pdfix.OpenDoc("path/to/doc.pdf", "")
cmd = doc.GetCommand()
cmdStm = pdfix.CreateMemStream()
command.SaveCommandsToStream(kActionMakeAccessible, cmdStm, kDataFormatJson, kSaveFull)
cmd.LoadParamsFromStream(cmdStm, kDataFormatJson)
cmdStm.Destroy()
command.Run()
doc.Save("path/to/out.pdf", kSaveFull)

See the complete code examples below.

Customizing the Make Accessible Command

Some documents require a customized set of actions. For example, if the document:

Contains transparent elements → flattening form XObjects may visually alter the document.
Is a PDF 2.0 file → updating metadata must be tailored for this version.

Users can create a custom JSON file with appropriate actions and parameters. A list of all available actions is provided here actions.

Executing with a Custom Configuration

Using the Command-Line:

./pdfix_app make-accessible -i "input.pdf" -o "output.pdf" -c "path/to/custom/command.json"

Programmatically in Python:

pdfix = GetPdfix()
doc = pdfix.OpenDoc("path/to/doc.pdf", "")
cmd = doc.GetCommand()
cmdStm = pdfix.CreateFileStream("path/to/custom/command.json", kReadOnly)
cmd.LoadParamsFromStream(cmdStm, kDataFormatJson)
cmdStm.Destroy()
command.Run()
doc.Save("path/to/out.pdf", kSaveFull)

See the complete code examples below.

Example of a Custom Command to Auto-Tag, Set Document Language, and Apply PDF/UA Identifier

{
  "actions": [
    {
      "name": "add-tags"
    },
    {
      "name": "set_lang",
      "params": [
        {
          "name": "lang",
          "value": "en-US"
        }
      ]      
    },
    {
      "name": "set_pdf_ua_standard",
      "params": [
        {
          "name": "path",
          "value": "1"
        }
      ]
    }
  ]
}

Fixing Accessibility Issues in Tagged PDF Documents

Tagged PDFs may require a different set of commands, addressing accessibility issues identified in a validation report.

These actions may include:

Fixing headings
Adding missing spaces
Generating alt text or table summaries
Fixing lists
Deleting unnecessary tags
Other necessary corrections

The approach remains the same as with the Make Accessible command, excluding methods that clear or re-tag the document structure.

Example: Fixing Missing Document Title, Annotation Contents, Lists, and Invalid MCIDs

{
  "actions": [
    {
      "name": "set_title",
      "params": [
        {
          "name": "title_type",
          "value": "2"              # Retrieve title from the file name
        }
      ]      
    },
    {
      "name": "set_annot_contents",
      "params": [
        {
          "name": "annot_types",
          "value": "Link|Widget"
        },
        {
          "name": "alt_type",
          "value": "1"              # Use text from annotation bounding box
        }
      ]
    },
    {
      "name": "fix_list_tag"
    },
    {
      "name": "artifact_content",
      "params": [
        {
          "name": "object_types",
          "value": {
            "template": {
              "object_update": [
                {
                  "query": {
                    "$and": [
                      {
                        "$0_artifact": "false"
                      },
                      {
                        "$0_mcid": "-1"
                      }
                    ],
                    "param": [
                      "pds_object"
                    ]
                  },
                  "statement": "$if"
                }
              ]
            }
          }      
        },
        {
          "name": "artifact_type",
          "value": "0"              # Mark as an artifact
        }
      ]
    },
    {
      "name": "remove_content_marks",
      "params": [
        {
          "name": "object_types",
          "value": ".*"             # All tag types
        },
        {
          "name": "flags",
          "value": "0"              # Invalid MCIDs
        }
      ]
    }
  ]
}

For more available actions and parameter options, check actions.

Code Examples

Links to full code examples:

PDFix Documentation