CMap writing mode must be consistent

PDF/UA check FONT_WMODE_CONSISTENT · Fonts & text encoding · severity Medium · PDF/UA 8.4.5.4 CMaps · advanced check

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Advanced check. This is a file-internals rule. It is hidden from the standard report view and generally indicates a problem with the tool that produced the PDF rather than something an author did.

Why it matters#

Inconsistent WMode (writing direction) values cause text to be laid out or extracted in the wrong direction.

What you will see#

The WMode in a CMap dictionary disagrees with the WMode inside the embedded CMap stream.

How to fix#

Set the WMode entry in the embedded CMap's dictionary to the same value as the WMode defined inside the CMap stream itself (0 for horizontal, 1 for vertical). Regenerating the embedded CMap with a current tool keeps the two in sync.

Step-by-step guide#

1. Locate the embedded CMap streams flagged by the scan - these are fonts whose Encoding entry is a stream object rather than a predefined name. Find them with Acrobat's Preflight font inventory or Preflight > Options > Browse internal PDF structure.
2. Decode each CMap stream and read the writing-mode definition inside the CMap program (a line of the form /WMode 0 def or /WMode 1 def).
3. Set the WMode entry in the stream's PDF dictionary to the same integer: 0 for horizontal writing, 1 for vertical. Align the dictionary to the stream content, since the CMap program is what actually drives layout.
4. Alternatively, regenerate the PDF from the source application - a compliant exporter writes the dictionary entry and the CMap stream definition consistently in one pass.
5. Acrobat Pro has no UI for this edit; an inconsistent WMode means the CMap was written incorrectly by the producing application, and the reliable fix is re-exporting the document from its source with a compliant export pipeline.

Verify: Re-run the EQChecker advanced scan and confirm FONT_WMODE_CONSISTENT reports zero errors. Vertical-writing text, if any, should still lay out in the correct direction.

Note: Applies only to embedded CMaps - predefined CMaps are exempt. A missing WMode key in the stream dictionary defaults to 0, so a CMap program defining WMode 1 always needs an explicit dictionary entry of 1 to be consistent.

WCAG success criteria#

No WCAG success criterion maps cleanly to this check — it is a PDF/UA structural requirement. The PDF/UA clause above is the normative reference.

Standards#

This check contributes to the following standards:

PDF/UA