Fix sizeHint for QAbstractSpinBox

The current size hint is not correct and the text is truncated
when using prefix/suffix.

Update QCommonStyle::sizeFromContents() to get the button
and frame widths into account for the QSpinBox width.

Update sizeFromContents() in the different styles to be
consistent with the change in QCommonStyle.

Update minimumSizeHint(), calculate it using the prefix and
data range. The SpinBox can shrunk over the suffix if any.

Task-number: QTBUG-28863

Change-Id: Ia742232edf8b11d0283e8136c2818928f8755103
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

3 files changed, 24 insertions, 31 deletions

diff --git a/src/widgets/widgets/qabstractspinbox.cpp b/src/widgets/widgets/qabstractspinbox.cpp
index 14d22c458b..c2b04ce461 100644
--- a/src/widgets/widgets/qabstractspinbox.cpp
+++ b/src/widgets/widgets/qabstractspinbox.cpp
@@ -825,14 +825,13 @@ QSize QAbstractSpinBox::sizeHint() const
         ensurePolished();
 
         const QFontMetrics fm(fontMetrics());
-        int h = d->edit->sizeHint().height() + 4;
+        int h = d->edit->sizeHint().height();
         int w = 0;
         QString s;
-        s = d->prefix + d->textFromValue(d->minimum) + d->suffix + QLatin1Char(' ');
-        s.truncate(18);
+        QString fixedContent =  d->prefix + d->suffix + QLatin1Char(' ');
+        s = d->textFromValue(d->minimum) + fixedContent;
         w = qMax(w, fm.width(s));
-        s = d->prefix + d->textFromValue(d->maximum) + d->suffix + QLatin1Char(' ');
-        s.truncate(18);
+        s = d->textFromValue(d->maximum) + fixedContent;
         w = qMax(w, fm.width(s));
         if (d->specialValueText.size()) {
             s = d->specialValueText;
@@ -857,27 +856,29 @@ QSize QAbstractSpinBox::minimumSizeHint() const
 {
     Q_D(const QAbstractSpinBox);
     if (d->cachedMinimumSizeHint.isEmpty()) {
+        //Use the prefix and range to calculate the minimumSizeHint
         ensurePolished();
 
         const QFontMetrics fm(fontMetrics());
         int h = d->edit->minimumSizeHint().height();
-        int w = fm.width(QLatin1String("1000"));
+        int w = 0;
+
+        QString s;
+        QString fixedContent =  d->prefix + QLatin1Char(' ');
+        s = d->textFromValue(d->minimum) + fixedContent;
+        w = qMax(w, fm.width(s));
+        s = d->textFromValue(d->maximum) + fixedContent;
+        w = qMax(w, fm.width(s));
+
+        if (d->specialValueText.size()) {
+            s = d->specialValueText;
+            w = qMax(w, fm.width(s));
+        }
         w += 2; // cursor blinking space
 
         QStyleOptionSpinBox opt;
         initStyleOption(&opt);
         QSize hint(w, h);
-        QSize extra(35, 6);
-        opt.rect.setSize(hint + extra);
-        extra += hint - style()->subControlRect(QStyle::CC_SpinBox, &opt,
-                                                QStyle::SC_SpinBoxEditField, this).size();
-        // get closer to final result by repeating the calculation
-        opt.rect.setSize(hint + extra);
-        extra += hint - style()->subControlRect(QStyle::CC_SpinBox, &opt,
-                                                QStyle::SC_SpinBoxEditField, this).size();
-        hint += extra;
-
-        opt.rect = rect();
 
         d->cachedMinimumSizeHint = style()->sizeFromContents(QStyle::CT_SpinBox, &opt, hint, this)
                                    .expandedTo(QApplication::globalStrut());
@@ -1724,7 +1725,8 @@ void QAbstractSpinBoxPrivate::setRange(const QVariant &min, const QVariant &max)
     clearCache();
     minimum = min;
     maximum = (variantCompare(min, max) < 0 ? max : min);
-    cachedSizeHint = QSize(); // minimumSizeHint doesn't care about min/max
+    cachedSizeHint = QSize();
+    cachedMinimumSizeHint = QSize(); // minimumSizeHint cares about min/max
 
     reset();
     if (!(bound(value) == value)) {
diff --git a/src/widgets/widgets/qdatetimeedit.cpp b/src/widgets/widgets/qdatetimeedit.cpp
index fb64850923..7ee2bf64fb 100644
--- a/src/widgets/widgets/qdatetimeedit.cpp
+++ b/src/widgets/widgets/qdatetimeedit.cpp
@@ -981,9 +981,9 @@ QSize QDateTimeEdit::sizeHint() const
         int h = d->edit->sizeHint().height();
         int w = 0;
         QString s;
-        s = d->textFromValue(d->minimum) + QLatin1String("   ");
+        s = d->textFromValue(d->minimum) + QLatin1Char(' ');
         w = qMax<int>(w, fm.width(s));
-        s = d->textFromValue(d->maximum) + QLatin1String("   ");
+        s = d->textFromValue(d->maximum) + QLatin1Char(' ');
         w = qMax<int>(w, fm.width(s));
         if (d->specialValueText.size()) {
             s = d->specialValueText;
@@ -1000,19 +1000,8 @@ QSize QDateTimeEdit::sizeHint() const
         } else
 #endif
         {
-            QSize extra(35, 6);
             QStyleOptionSpinBox opt;
             initStyleOption(&opt);
-            opt.rect.setSize(hint + extra);
-            extra += hint - style()->subControlRect(QStyle::CC_SpinBox, &opt,
-                                                QStyle::SC_SpinBoxEditField, this).size();
-            // get closer to final result by repeating the calculation
-            opt.rect.setSize(hint + extra);
-            extra += hint - style()->subControlRect(QStyle::CC_SpinBox, &opt,
-                                                QStyle::SC_SpinBoxEditField, this).size();
-            hint += extra;
-
-            opt.rect = rect();
             d->cachedSizeHint = style()->sizeFromContents(QStyle::CT_SpinBox, &opt, hint, this)
                                 .expandedTo(QApplication::globalStrut());
         }
@@ -1023,6 +1012,7 @@ QSize QDateTimeEdit::sizeHint() const
     return d->cachedSizeHint;
 }
 
+
 /*!
   \reimp
 */
diff --git a/src/widgets/widgets/qspinbox.cpp b/src/widgets/widgets/qspinbox.cpp
index e61c1c877a..b51bf4c078 100644
--- a/src/widgets/widgets/qspinbox.cpp
+++ b/src/widgets/widgets/qspinbox.cpp
@@ -268,6 +268,7 @@ void QSpinBox::setPrefix(const QString &prefix)
     d->updateEdit();
 
     d->cachedSizeHint = QSize();
+    d->cachedMinimumSizeHint = QSize(); // minimumSizeHint cares about the prefix
     updateGeometry();
 }