tdf#159452 sw content control, PDF export: fix checked checkboxes

Regression from commit 9bad5be0ffdcdee92d40162b598ed2ab2815e5d5 (sw
content controls, checkbox: add PDF export, 2022-09-13), we used to
export checkbox content controls as plain text, but once checkbox
content controls are exported as forms, the state of the checkboxes are
lost.

Writer content control checkboxes support custom values for the checked
and unchecked states, but the PDF export does not. On one hand,
PDFWriterImpl::createDefaultCheckBoxAppearance() assumes that the
checked state should be a checkmark, not the Writer default 'BALLOT BOX
WITH X' (U+2612). On the other hand, the PDF spec section 12.7.4.2.3
"Check Boxes" says that the checked state should be "Yes", which
explains why our checked state is not recognized by PDF readers.

Fix the problem by making the export of checked/unchecked states
conditional in SwContentControlPortion::DescribePDFControl(): the
checked state then shows up as expected.

Leave the unchecked case unchanged, the current markup there doesn't
cause problems.

(cherry picked from commit 256e2c679bcbb3ea446884d0ff4e3f8687b82ede)

Change-Id: I9063d8607c8cccfa080921af38b3cbfe40905115

0 files changed, 0 insertions, 0 deletions