Repaint QProgressBar when minimum or maximum changed

The implementation of QProgressBar::setMinimum and setMaximum did not
repaint the widget. This caused the widget to be shown incorrectly in
case you call setMinimum or setMaximum but not setValue.

Task-number: QTBUG-22121

Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

2 files changed, 49 insertions, 4 deletions

diff --git a/src/gui/widgets/qprogressbar.cpp b/src/gui/widgets/qprogressbar.cpp
index 1b0a1a1..c583a78 100644
--- a/src/gui/widgets/qprogressbar.cpp
+++ b/src/gui/widgets/qprogressbar.cpp
@@ -341,11 +341,17 @@ int QProgressBar::value() const
 void QProgressBar::setRange(int minimum, int maximum)
 {
     Q_D(QProgressBar);
-    d->minimum = minimum;
-    d->maximum = qMax(minimum, maximum);
-    if ( d->value <(d->minimum-1) || d->value > d->maximum)
-        reset();
+    if (minimum != d->minimum || maximum != d->maximum) {
+        d->minimum = minimum;
+        d->maximum = qMax(minimum, maximum);
+
+        if (d->value < (d->minimum - 1) || d->value > d->maximum)
+            reset();
+        else
+            update();
+    }
 }
+
 /*!
     \property QProgressBar::textVisible
     \brief whether the current completed percentage should be displayed
diff --git a/tests/auto/qprogressbar/tst_qprogressbar.cpp b/tests/auto/qprogressbar/tst_qprogressbar.cpp
index 04b7ce7..878cce8 100644
--- a/tests/auto/qprogressbar/tst_qprogressbar.cpp
+++ b/tests/auto/qprogressbar/tst_qprogressbar.cpp
@@ -63,6 +63,7 @@ private slots:
     void text();
     void format();
     void setValueRepaint();
+    void setMinMaxRepaint();
     void sizeHint();
     void formatedText_data();
     void formatedText();
@@ -216,6 +217,44 @@ void tst_QProgressBar::setValueRepaint()
     }
 }
 
+void tst_QProgressBar::setMinMaxRepaint()
+{
+    ProgressBar pbar;
+    pbar.setMinimum(0);
+    pbar.setMaximum(10);
+    pbar.setFormat("%v");
+    pbar.show();
+    QTest::qWaitForWindowShown(&pbar);
+
+    QApplication::processEvents();
+
+    // No repaint when setting minimum to the current minimum
+    pbar.repainted = false;
+    pbar.setMinimum(0);
+    QTest::qWait(50);
+    QTRY_VERIFY(!pbar.repainted);
+
+    // No repaint when setting maximum to the current maximum
+    pbar.repainted = false;
+    pbar.setMaximum(10);
+    QTest::qWait(50);
+    QTRY_VERIFY(!pbar.repainted);
+
+    // Repaint when setting minimum
+    for (int i = 9; i >= 0; i--) {
+        pbar.repainted = false;
+        pbar.setMinimum(i);
+        QTRY_VERIFY(pbar.repainted);
+    }
+
+    // Repaint when setting maximum
+    for (int i = 0; i < 10; ++i) {
+        pbar.repainted = false;
+        pbar.setMaximum(i);
+        QTRY_VERIFY(pbar.repainted);
+    }
+}
+
 void tst_QProgressBar::sizeHint()
 {
     ProgressBar bar;