Support the markdown underline extension

MarkdownDialectGitHub now includes this feature, so *emph* is italicized
and _emph_ is underlined. This is a better fit for QTextDocument capabilities;
until now, _underlined_ markdown could be read, but would be rendered with
italics, because in CommonMark, *emphasis* and _emphasis_ are the same.
But QTextMarkdownWriter already writes underlining and italics distinctly
in this way.

[ChangeLog][QtGui][Text] By default (with MarkdownDialectGitHub), markdown
_underline_ and *italic* text styles are now distinct.

Fixes: QTBUG-84429
Change-Id: Ifc6defa4852abe831949baa4ce28bae5f1a82265
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

2 files changed, 18 insertions, 8 deletions

diff --git a/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp b/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
index bc9dc1b695..d652db0699 100644
--- a/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
+++ b/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
@@ -69,9 +69,10 @@ public:
         Normal = 0x0,
         Italic = 0x1,
         Bold = 0x02,
-        Strikeout = 0x04,
-        Mono = 0x08,
-        Link = 0x10
+        Underlined = 0x04,
+        Strikeout = 0x08,
+        Mono = 0x10,
+        Link = 0x20
     };
     Q_DECLARE_FLAGS(CharFormats, CharFormat)
 };
@@ -252,6 +253,12 @@ void tst_QTextMarkdownImporter::nestedSpans_data()
     QTest::newRow("bold italic")
             << "before ***bold italic*** after"
             << 1 << (Bold | Italic);
+    QTest::newRow("bold underlined")
+            << "before **_bold underlined_** after"
+            << 1 << (Bold | Underlined);
+    QTest::newRow("italic underlined")
+            << "before *_italic underlined_* after"
+            << 1 << (Italic | Underlined);
     QTest::newRow("bold strikeout")
             << "before **~~bold strikeout~~** after"
             << 1 << (Bold | Strikeout);
@@ -322,12 +329,14 @@ void tst_QTextMarkdownImporter::nestedSpans()
         QTextCharFormat fmt = cur.charFormat();
         qCDebug(lcTests) << "word" << wordToCheck << cur.selectedText() << "font" << fmt.font()
                          << "weight" << fmt.fontWeight() << "italic" << fmt.fontItalic()
+                         << "underlined" << fmt.fontUnderline()
                          << "strikeout" << fmt.fontStrikeOut() << "anchor" << fmt.isAnchor()
                          << "monospace" << QFontInfo(fmt.font()).fixedPitch() // depends on installed fonts (QTBUG-75649)
                                         << fmt.fontFixedPitch() // returns false even when font family is "monospace"
                                         << fmt.hasProperty(QTextFormat::FontFixedPitch); // works
         QCOMPARE(fmt.fontWeight() > QFont::Normal, expectedFormat.testFlag(Bold));
         QCOMPARE(fmt.fontItalic(), expectedFormat.testFlag(Italic));
+        QCOMPARE(fmt.fontUnderline(), expectedFormat.testFlag(Underlined));
         QCOMPARE(fmt.fontStrikeOut(), expectedFormat.testFlag(Strikeout));
         QCOMPARE(fmt.isAnchor(), expectedFormat.testFlag(Link));
         QCOMPARE(fmt.hasProperty(QTextFormat::FontFixedPitch), expectedFormat.testFlag(Mono));
diff --git a/tests/auto/gui/text/qtextmarkdownwriter/data/example.md b/tests/auto/gui/text/qtextmarkdownwriter/data/example.md
index 0c3f34e09d..a9a157f25a 100644
--- a/tests/auto/gui/text/qtextmarkdownwriter/data/example.md
+++ b/tests/auto/gui/text/qtextmarkdownwriter/data/example.md
@@ -11,10 +11,11 @@ comments in each of the following sections to encourage you to experiment.
 
 ## Font and Paragraph Styles
 
-QTextEdit supports **bold**, *italic*, and ~~strikethrough~~ font styles, and can
-display multicolored text. Font families such as Times New Roman and `Courier`
-can also be used directly.  *If you place the cursor in a region of styled text,
-the controls in the tool bars will change to reflect the current style.*
+QTextEdit supports **bold**, *italic*, _underline_ and ~~strikethrough~~ font
+styles, and can display multicolored text. Font families such as Times New
+Roman and `Courier` can also be used directly. *If you place the cursor in a
+region of styled text, the controls in the tool bars will change to reflect the
+current style.*
 
 Paragraphs can be formatted so that the text is left-aligned, right-aligned,
 centered, or fully justified.
@@ -70,7 +71,7 @@ column spans, text formatting within cells, and size constraints for columns.
 |9:00 - 11:00 |Introduction to Qt                                                                      |||
 |11:00 - 13:00|Using qmake                         |Object-oriented Programming|Layouts in Qt            |
 |13:00 - 15:00|Qt Designer Tutorial                |Extreme Programming        |Writing Custom Styles    |
-|15:00 - 17:00|Qt Linguist and Internationalization|                           |                         |
+|15:00 - 17:00|Qt Linguist and Internationalization|Test-Driven Development    |                         |
 
 *Try adding text to the cells in the table and experiment with the alignment of
 the paragraphs.*