Merge branch 'qt-fixups'

Various fixes and improvements for wxQt.

Closes #22932.

include/wx/qt/combobox.h

@@ -76,6 +76,8 @@ public:
     virtual void WriteText(const wxString &value) override;
     virtual void SetInsertionPoint(long insertion) override;
     virtual long GetInsertionPoint() const override;
+    virtual bool IsEditable() const override;
+    virtual void SetEditable(bool editable) override;
 
     virtual void Popup();
     virtual void Dismiss();

include/wx/qt/private/winevent.h

@@ -458,4 +458,28 @@ protected:
     }
 };
 
+// RAII wrapper for blockSignals(). It blocks signals in its constructor and in
+// the destructor it restores the state to what it was before the constructor ran.
+class wxQtEnsureSignalsBlocked
+{
+public:
+    // Use QObject instead of QWidget to avoid including <QWidget> from here.
+    wxQtEnsureSignalsBlocked(QObject *widget) :
+        m_widget(widget)
+    {
+        m_restore = m_widget->blockSignals(true);
+    }
+
+    ~wxQtEnsureSignalsBlocked()
+    {
+        m_widget->blockSignals(m_restore);
+    }
+
+private:
+    QObject* const m_widget;
+    bool m_restore;
+
+    wxDECLARE_NO_COPY_CLASS(wxQtEnsureSignalsBlocked);
+};
+
 #endif

src/qt/calctrl.cpp

@@ -137,9 +137,8 @@ bool wxCalendarCtrl::SetDate(const wxDateTime& date)
             wxQtConvertDate( date ) < m_qtCalendar->minimumDate() )
         return false;
 
-    m_qtCalendar->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtCalendar);
     m_qtCalendar->setSelectedDate(wxQtConvertDate(date));
-    m_qtCalendar->blockSignals(false);
 
     return true;
 }
@@ -158,10 +157,9 @@ bool wxCalendarCtrl::SetDateRange(const wxDateTime& lowerdate,
     if ( !m_qtCalendar )
         return false;
 
-    m_qtCalendar->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtCalendar);
     m_qtCalendar->setMinimumDate(wxQtConvertDate(lowerdate));
     m_qtCalendar->setMaximumDate(wxQtConvertDate(upperdate));
-    m_qtCalendar->blockSignals(false);
 
     return true;
 }

src/qt/checklst.cpp

@@ -9,6 +9,7 @@
 #include "wx/wxprec.h"
 
 #include "wx/checklst.h"
+#include "wx/qt/private/winevent.h"
 
 #include <QtWidgets/QListWidgetItem>
 
@@ -80,8 +81,11 @@ bool wxCheckListBox::IsChecked(unsigned int n) const
 
 void wxCheckListBox::Check(unsigned int n, bool check )
 {
+    // Prevent the emission of wxEVT_CHECKLISTBOX event by temporarily blocking all
+    // signals on m_qtListWidget object.
+    wxQtEnsureSignalsBlocked blocker(m_qtListWidget);
     QListWidgetItem* item = m_qtListWidget->item(n);
     wxCHECK_RET(item != nullptr, wxT("wrong listbox index") );
-    return item->setCheckState(check ? Qt::Checked : Qt::Unchecked);
+    item->setCheckState(check ? Qt::Checked : Qt::Unchecked);
 }
 

src/qt/choice.cpp

@@ -161,6 +161,8 @@ unsigned wxChoice::GetCount() const
 
 wxString wxChoice::GetString(unsigned int n) const
 {
+    wxCHECK_MSG(n < GetCount(), wxString(), "invalid index");
+
     return wxQtConvertString( m_qtComboBox->itemText(n) );
 }
 
@@ -172,9 +174,8 @@ void wxChoice::SetString(unsigned int n, const wxString& s)
 
 void wxChoice::SetSelection(int n)
 {
-    m_qtComboBox->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtComboBox);
     m_qtComboBox->setCurrentIndex(n);
-    m_qtComboBox->blockSignals(false);
 }
 
 int wxChoice::GetSelection() const

src/qt/combobox.cpp

@@ -190,6 +190,20 @@ bool wxComboBox::IsReadOnly() const
     return HasFlag( wxCB_READONLY );
 }
 
+bool wxComboBox::IsEditable() const
+{
+    // Only editable combo boxes have a line edit.
+    QLineEdit* const lineEdit = m_qtComboBox->lineEdit();
+    return lineEdit && !lineEdit->isReadOnly();
+}
+
+void wxComboBox::SetEditable(bool editable)
+{
+    QLineEdit* const lineEdit = m_qtComboBox->lineEdit();
+    if ( lineEdit )
+        lineEdit->setReadOnly(!editable);
+}
+
 void wxComboBox::SetValue(const wxString& value)
 {
     SetActualValue( value );

src/qt/dc.cpp

@@ -373,6 +373,21 @@ void wxQtDCImpl::DoGetTextExtent(const wxString& string,
                              wxCoord *externalLeading,
                              const wxFont *theFont ) const
 {
+    if ( x )
+        *x = 0;
+    if ( y )
+        *y = 0;
+    if ( descent )
+        *descent = 0;
+    if ( externalLeading )
+        *externalLeading = 0;
+
+    // We can skip computing the string width and height if it is empty, but
+    // not its descent and/or external leading, which still needs to be
+    // returned even for an empty string.
+    if ( string.empty() && !descent && !externalLeading )
+        return;
+
     QFont f;
     if (theFont != nullptr)
         f = theFont->GetHandle();

src/qt/graphics.cpp

@@ -960,6 +960,21 @@ public:
         wxCHECK_RET( !m_font.IsNull(),
                      "wxQtContext::GetTextExtent - no valid font set" );
 
+        if ( width )
+            *width = 0;
+        if ( height )
+            *height = 0;
+        if ( descent )
+            *descent = 0;
+        if ( externalLeading )
+            *externalLeading = 0;
+
+        // We can skip computing the string width and height if it is empty, but
+        // not its descent and/or external leading, which still needs to be
+        // returned even for an empty string.
+        if ( str.empty() && !descent && !externalLeading )
+            return;
+
         EnsurePainterIsActive active(m_qtPainter);
 
         const wxQtFontData*

src/qt/listctrl.cpp

@@ -654,15 +654,15 @@ public:
 
         beginInsertColumns(QModelIndex(), newColumnIndex, newColumnIndex);
 
-        std::vector<ColumnItem>::iterator i = m_headers.begin();
-        std::advance(i, newColumnIndex);
-        m_headers.insert(i, newColumn);
+        std::vector<ColumnItem>::iterator it = m_headers.begin();
+        std::advance(it, newColumnIndex);
+        m_headers.insert(it, newColumn);
 
         const int numberOfRows = m_rows.size();
 
         for (int i = 0; i < numberOfRows; ++i )
         {
-            std::vector<ColumnItem>::iterator it = m_rows[i].m_columns.begin();
+            it = m_rows[i].m_columns.begin();
             std::advance(it, newColumnIndex);
             m_rows[i].m_columns.insert(it, newColumn);
         }

src/qt/notebook.cpp

@@ -178,15 +178,11 @@ bool wxNotebook::DeleteAllPages()
 
     // Block signals to not receive selection changed updates
     // which are sent by Qt after the selected page was deleted.
-    m_qtTabWidget->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtTabWidget);
 
     // Pages will be deleted one by one in the base class.
     // There's no need to explicitly clear() the Qt control.
-    bool deleted = wxNotebookBase::DeleteAllPages();
-
-    m_qtTabWidget->blockSignals(false);
-
-    return deleted;
+    return wxNotebookBase::DeleteAllPages();
 }
 
 int wxNotebook::SetSelection(size_t page)
@@ -206,13 +202,9 @@ int wxNotebook::ChangeSelection(size_t nPage)
 {
     // ChangeSelection() is not supposed to generate events, unlike
     // SetSelection().
-    m_qtTabWidget->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtTabWidget);
 
-    const int selOld = SetSelection(nPage);
-
-    m_qtTabWidget->blockSignals(false);
-
-    return selOld;
+    return SetSelection(nPage);
 }
 
 wxWindow *wxNotebook::DoRemovePage(size_t page)

src/qt/scrolbar.cpp

@@ -101,9 +101,10 @@ void wxScrollBar::SetScrollbar(int position, int WXUNUSED(thumbSize),
     {
         m_qtScrollBar->setRange( 0, range - pageSize );
         m_qtScrollBar->setPageStep( pageSize );
-        m_qtScrollBar->blockSignals(true);
-        m_qtScrollBar->setValue( position );
-        m_qtScrollBar->blockSignals(false);
+        {
+            wxQtEnsureSignalsBlocked blocker(m_qtScrollBar);
+            m_qtScrollBar->setValue( position );
+        }
         m_qtScrollBar->show();
     }
     else

src/qt/slider.cpp

@@ -77,9 +77,8 @@ bool wxSlider::Create(wxWindow *parent,
 
     m_qtSlider->setInvertedAppearance( style & wxSL_INVERSE );
 
-    m_qtSlider->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtSlider);
     SetRange( minValue, maxValue );
-    m_qtSlider->blockSignals(false);
     SetPageSize(wxMax(1, (maxValue - minValue) / 10));
 
 #if 0 // there are not normally ticks for a wxSlider
@@ -105,16 +104,14 @@ int wxSlider::GetValue() const
 
 void wxSlider::SetValue(int value)
 {
-    m_qtSlider->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtSlider);
     m_qtSlider->setValue( value );
-    m_qtSlider->blockSignals(false);
 }
 
 void wxSlider::SetRange(int minValue, int maxValue)
 {
-    m_qtSlider->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtSlider);
     m_qtSlider->setRange( minValue, maxValue );
-    m_qtSlider->blockSignals(false);
 }
 
 int wxSlider::GetMin() const

src/qt/spinctrl.cpp

@@ -67,17 +67,15 @@ wxString wxSpinCtrlQt< T, Widget >::GetTextValue() const
 template< typename T, typename Widget >
 void wxSpinCtrlQt< T, Widget >::SetValue( T val )
 {
-    m_qtSpinBox->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtSpinBox);
     m_qtSpinBox->setValue( val );
-    m_qtSpinBox->blockSignals(false);
 }
 
 template< typename T, typename Widget >
 void wxSpinCtrlQt< T, Widget >::SetRange( T min, T max )
 {
-    m_qtSpinBox->blockSignals(true);
+    wxQtEnsureSignalsBlocked blocker(m_qtSpinBox);
     m_qtSpinBox->setRange( min, max );
-    m_qtSpinBox->blockSignals(false);
 }
 
 template< typename T, typename Widget >

src/qt/treectrl.cpp

@@ -357,9 +357,8 @@ private:
 
         if ( !changingEvent.IsAllowed() )
         {
-            blockSignals(true);
+            wxQtEnsureSignalsBlocked blocker(this);
             setCurrentItem(previous);
-            blockSignals(false);
             return;
         }
 
@@ -398,9 +397,8 @@ private:
 
         if ( !collapsingEvent.IsAllowed() )
         {
-            blockSignals(true);
+            wxQtEnsureSignalsBlocked blocker(this);
             item->setExpanded(true);
-            blockSignals(false);
             return;
         }
 
@@ -423,9 +421,8 @@ private:
 
         if ( !expandingEvent.IsAllowed() )
         {
-            blockSignals(true);
+            wxQtEnsureSignalsBlocked blocker(this);
             item->setExpanded(false);
-            blockSignals(false);
             return;
         }
 
@@ -1116,25 +1113,6 @@ void wxTreeCtrl::Delete(const wxTreeItemId& item)
     delete qTreeItem;
 }
 
-class wxQtEnsureSignalsBlocked
-{
-public:
-    wxQtEnsureSignalsBlocked(QWidget *widget) :
-        m_widget(widget)
-    {
-        m_restore = m_widget->blockSignals(true);
-    }
-
-    ~wxQtEnsureSignalsBlocked()
-    {
-        m_widget->blockSignals(m_restore);
-    }
-
-private:
-    QWidget *m_widget;
-    bool m_restore;
-};
-
 void wxTreeCtrl::DeleteChildren(const wxTreeItemId& item)
 {
     wxCHECK_RET(item.IsOk(), "invalid tree item");

src/qt/window.cpp

@@ -419,6 +419,9 @@ void wxWindowQt::PostCreation(bool generic)
 
     GetHandle()->setFont( wxWindowBase::GetFont().GetHandle() );
 
+    if ( !IsThisEnabled() )
+        DoEnable(false);
+
     // The window might have been hidden before Create() and it needs to remain
     // hidden in this case, so do it (unfortunately there doesn't seem to be
     // any way to create the window initially hidden with Qt).
@@ -474,7 +477,8 @@ wxString wxWindowQt::GetLabel() const
 
 void wxWindowQt::DoEnable(bool enable)
 {
-    GetHandle()->setEnabled(enable);
+    if ( GetHandle() )
+        GetHandle()->setEnabled(enable);
 }
 
 void wxWindowQt::SetFocus()
@@ -636,6 +640,21 @@ int wxWindowQt::GetCharWidth() const
 void wxWindowQt::DoGetTextExtent(const wxString& string, int *x, int *y, int *descent,
         int *externalLeading, const wxFont *font ) const
 {
+    if ( x )
+        *x = 0;
+    if ( y )
+        *y = 0;
+    if ( descent )
+        *descent = 0;
+    if ( externalLeading )
+        *externalLeading = 0;
+
+    // We can skip computing the string width and height if it is empty, but
+    // not its descent and/or external leading, which still needs to be
+    // returned even for an empty string.
+    if ( string.empty() && !descent && !externalLeading )
+        return;
+
     QFontMetrics fontMetrics( font != nullptr ? font->GetHandle() : GetHandle()->font() );
 
     if ( x != nullptr )
@@ -726,9 +745,10 @@ void wxWindowQt::SetScrollbar( int orientation, int pos, int thumbvisible, int r
     {
         scrollBar->setRange( 0, range - thumbvisible );
         scrollBar->setPageStep( thumbvisible );
-        scrollBar->blockSignals( true );
-        scrollBar->setValue(pos);
-        scrollBar->blockSignals( false );
+        {
+            wxQtEnsureSignalsBlocked blocker(scrollBar);
+            scrollBar->setValue(pos);
+        }
         scrollBar->show();
 
         if ( HasFlag(wxALWAYS_SHOW_SB) && (range == 0) )