REG: Fix nbsp in QTextLayout

At some point since Qt 4.8, the nbsp character has acquired
the whitespace attribute, causing it to be treated exactly
like an ordinary space. To account for this, we add an extra
check in the layout code to avoid breaking on non-breaking
spaces even if they have the whiteSpace flag set.

This is a temporary fix for the regression. The line breaking
algorithm needs to be refactored and support Unicode tr14
properly, which it currently doesn't.

[ChangeLog][Text] Fixed lines breaking on non-breaking spaces.

Task-number: QTBUG-39832
Change-Id: Ibd7e1a11ce4b82c611ecda1542c8638a67bf3cae
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp b/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
index 26eaec0470..ec698e5db4 100644
--- a/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
+++ b/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
@@ -139,6 +139,7 @@ private slots:
     void cursorInLigatureWithMultipleLines();
     void xToCursorForLigatures();
     void cursorInNonStopChars();
+    void nbsp();
 
 private:
     QFont testFont;
@@ -2011,5 +2012,28 @@ void tst_QTextLayout::justifyTrailingSpaces()
     QVERIFY(qFuzzyIsNull(layout.lineAt(0).cursorToX(0)));
 }
 
+void tst_QTextLayout::nbsp()
+{
+    QString s = QString() + QChar(' ') + QChar('a') + QString(10, QChar::Nbsp) + QChar('a') + QChar(' ') + QChar('A');
+    QString text = s + s + s + s + s + s + s + s + s + s + s + s + s + s;
+    QTextLayout layout(text);
+    layout.setCacheEnabled(true);
+    layout.beginLayout();
+    layout.createLine();
+    layout.endLayout();
+
+    int naturalWidth = qCeil(layout.lineAt(0).naturalTextWidth());
+    int lineWidth = naturalWidth;
+
+    layout.beginLayout();
+    QTextLine line = layout.createLine();
+    while (lineWidth-- > naturalWidth / 2) {
+        line.setLineWidth(lineWidth);
+        QVERIFY(text.at(line.textLength()-1).unicode() != QChar::Nbsp);
+    }
+
+    layout.endLayout();
+}
+
 QTEST_MAIN(tst_QTextLayout)
 #include "tst_qtextlayout.moc"