Support placing cursor in ligature with mouse or touch

We need to find out the closest element in the ligature to
the point we clicked (or tapped), currently we do this by
dividing the width of that ligature glyph evenly by the number
of characters it covered. We only support Common and Greek script
at this point, ligatures in other scripts are still handled as a
whole.

Task-number: QTBUG-19260
Reviewed-by: Eskil

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/auto/qtextlayout/tst_qtextlayout.cpp b/tests/auto/qtextlayout/tst_qtextlayout.cpp
index b5712fb..e68a65e 100644
--- a/tests/auto/qtextlayout/tst_qtextlayout.cpp
+++ b/tests/auto/qtextlayout/tst_qtextlayout.cpp
@@ -128,6 +128,7 @@ private slots:
     void textWidthWithStackedTextEngine();
     void textWidthWithLineSeparator();
     void cursorInLigatureWithMultipleLines();
+    void xToCursorForLigatures();
 
 private:
     QFont testFont;
@@ -1477,5 +1478,29 @@ void tst_QTextLayout::cursorInLigatureWithMultipleLines()
     QVERIFY(line.cursorToX(0) != line.cursorToX(1));
 }
 
+void tst_QTextLayout::xToCursorForLigatures()
+{
+#if !defined(Q_WS_MAC)
+    QSKIP("This test can not be run on Mac", SkipAll);
+#endif
+    QTextLayout layout("fi", QFont("Times", 20));
+    layout.beginLayout();
+    QTextLine line = layout.createLine();
+    layout.endLayout();
+
+    QVERIFY(line.xToCursor(0) != line.xToCursor(line.naturalTextWidth() / 2));
+
+    // U+0061 U+0308
+    QTextLayout layout2(QString::fromUtf8("\x61\xCC\x88"), QFont("Times", 20));
+
+    layout2.beginLayout();
+    line = layout2.createLine();
+    layout2.endLayout();
+
+    qreal width = line.naturalTextWidth();
+    QVERIFY(line.xToCursor(0) == line.xToCursor(width / 2) ||
+            line.xToCursor(width) == line.xToCursor(width / 2));
+}
+
 QTEST_MAIN(tst_QTextLayout)
 #include "tst_qtextlayout.moc"