QTextLayout: fix maximumWidth() for a text containing line separator

When laying out, we need to increase layout's maximum width _only_
if the previous line was not explicitly wrapped by a line or paragraph
separator, or if the current line's width is greater than the
previously accumulated layout's maximum width.

Fixes: QTBUG-89557
Fixes: QTBUG-104986
Pick-to: 6.2 6.4
Change-Id: Ib7cc4b9dda8f20166dcbd5cfd3b56424bb33d14a
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp b/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
index def7c88593..25906ebf32 100644
--- a/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
+++ b/tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp
@@ -125,6 +125,7 @@ private slots:
     void softHyphens_data();
     void softHyphens();
     void min_maximumWidth();
+    void min_maximumWidthWithLineSeparator();
 
 private:
     QFont testFont;
@@ -2683,5 +2684,32 @@ void tst_QTextLayout::min_maximumWidth()
     }
 }
 
+void tst_QTextLayout::min_maximumWidthWithLineSeparator()
+{
+    QTextLayout referenceLayout("text", testFont);
+
+    QString multilineText("text\ntext\ntext");
+    multilineText.replace('\n', QChar::LineSeparator);
+    QTextLayout layout(multilineText, testFont);
+
+    for (int wrapMode = QTextOption::NoWrap; wrapMode <= QTextOption::WrapAtWordBoundaryOrAnywhere; ++wrapMode) {
+        QTextOption opt;
+        opt.setWrapMode((QTextOption::WrapMode)wrapMode);
+
+        referenceLayout.setTextOption(opt);
+        referenceLayout.beginLayout();
+        while (referenceLayout.createLine().isValid()) { }
+        referenceLayout.endLayout();
+
+        layout.setTextOption(opt);
+        layout.beginLayout();
+        while (layout.createLine().isValid()) { }
+        layout.endLayout();
+
+        QCOMPARE(layout.minimumWidth(), referenceLayout.minimumWidth());
+        QCOMPARE(layout.maximumWidth(), referenceLayout.maximumWidth());
+    }
+}
+
 QTEST_MAIN(tst_QTextLayout)
 #include "tst_qtextlayout.moc"