tst_QTextMarkdownWriter: test both ways of setting font characteristics

We have explicit QFont properties, and QTextFormat::setProperty().
Setting FontFixedPitch doesn't necessarily affect the view (QTextEdit or
Qt Quick Text/TextEdit); and setting the font to the one we get from
QFontDatabase::systemFont(QFontDatabase::FixedFont) is also unreliable,
because the "monospace" fallback might actually be proportional.
QTextMarkdownWriter checks for both to decide whether to use backticks;
so markdown writing works if an editor UI makes the format monospace
both ways to be safe. But in the opposite case that the main font is
actually a monospace font, it's always been broken.

The rest of the QTextCharFormat properties are generally working, to
the extent that they are applicable to Markdown. But we lacked explicit
test coverage: so far we were just reading Markdown or HTML and writing
Markdown to test the writer.

Also amend an old comment about writing underlines: writing was always
possible, and since f5c7799f59ba53c634906b11e2135190093bf87b reading is
supported too. So the underline support is symmetric (except that we
don't heed the QTextDocument::MarkdownFeatures argument to the writer
ctor: we probably should do that some day).

Pick-to: 6.7
Task-number: QTBUG-54623
Task-number: QTBUG-75648
Task-number: QTBUG-75649
Task-number: QTBUG-79900
Task-number: QTBUG-99676
Task-number: QTBUG-103484
Change-Id: Iacb4ed0ea59030570702d4eadfdadfad872065c6
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/gui/text/qtextmarkdownwriter.cpp b/src/gui/text/qtextmarkdownwriter.cpp
index 011658d2d9..64dd88d82c 100644
--- a/src/gui/text/qtextmarkdownwriter.cpp
+++ b/src/gui/text/qtextmarkdownwriter.cpp
@@ -588,9 +588,9 @@ int QTextMarkdownWriter::writeBlock(const QTextBlock &block, bool wrap, bool ign
                             endingMarkers = true;
                     }
                     if (fontInfo.underline() != underline) {
-                        // Markdown doesn't support underline, but the parser will treat a single underline
-                        // the same as a single asterisk, and the marked fragment will be rendered in italics.
-                        // That will have to do.
+                        // CommonMark specifies underline as another way to get emphasis (italics):
+                        // https://spec.commonmark.org/0.31.2/#example-148
+                        // but md4c allows us to distinguish them; so we support underlining (in GitHub dialect).
                         markers += u'_';
                         underline = fontInfo.underline();
                         if (!underline)