Fix text annotation edit background should match frame background

Otherwise white text is not visible. Fix #10553.

(cherry-picked from 76c4cae)

Author: nyalldawson

src/app/qgsannotationwidget.cpp

@@ -54,6 +54,8 @@ QgsAnnotationWidget::QgsAnnotationWidget( QgsAnnotationItem* item, QWidget * par
     mBackgroundColorButton->setNoColorString( tr( "Transparent" ) );
     mBackgroundColorButton->setShowNoColor( true );
 
+    connect( mBackgroundColorButton, SIGNAL( colorChanged( QColor ) ), this, SIGNAL( backgroundColorChanged( QColor ) ) );
+
     const QgsMarkerSymbolV2* symbol = mItem->markerSymbol();
     if ( symbol )
     {

src/app/qgsannotationwidget.h

@@ -34,6 +34,11 @@ class APP_EXPORT QgsAnnotationWidget: public QWidget, private Ui::QgsAnnotationW
 
     void apply();
 
+  signals:
+
+    //! Emitted when the background color of the annotation is changed
+    void backgroundColorChanged( const QColor& color );
+
   private slots:
     void on_mMapMarkerButton_clicked();
 

src/app/qgstextannotationdialog.cpp

@@ -27,6 +27,8 @@ QgsTextAnnotationDialog::QgsTextAnnotationDialog( QgsTextAnnotationItem* item, Q
   mEmbeddedWidget = new QgsAnnotationWidget( mItem );
   mStackedWidget->addWidget( mEmbeddedWidget );
   mStackedWidget->setCurrentWidget( mEmbeddedWidget );
+  connect( mEmbeddedWidget, SIGNAL( backgroundColorChanged( QColor ) ), this, SLOT( backgroundColorChanged( QColor ) ) );
+  mTextEdit->setAttribute( Qt::WA_TranslucentBackground );
   if ( mItem )
   {
     mTextDocument = mItem->document();
@@ -56,6 +58,18 @@ QgsTextAnnotationDialog::~QgsTextAnnotationDialog()
   delete mTextDocument;
 }
 
+void QgsTextAnnotationDialog::showEvent( QShowEvent* )
+{
+  backgroundColorChanged( mItem ? mItem->frameBackgroundColor() : Qt::white );
+}
+
+void QgsTextAnnotationDialog::backgroundColorChanged( const QColor& color )
+{
+  QPalette p = mTextEdit->viewport()->palette();
+  p.setColor( QPalette::Base, color );
+  mTextEdit->viewport()->setPalette( p );
+}
+
 void QgsTextAnnotationDialog::applyTextToItem()
 {
   if ( mItem && mTextDocument )

src/app/qgstextannotationdialog.h

@@ -30,6 +30,10 @@ class APP_EXPORT QgsTextAnnotationDialog: public QDialog, private Ui::QgsTextAnn
     QgsTextAnnotationDialog( QgsTextAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
     ~QgsTextAnnotationDialog();
 
+  protected:
+
+    virtual void showEvent( QShowEvent * event ) override;
+
   private:
     QgsTextAnnotationItem* mItem;
     /** Text document (a clone of the annotation items document)*/
@@ -44,6 +48,7 @@ class APP_EXPORT QgsTextAnnotationDialog: public QDialog, private Ui::QgsTextAnn
     void on_mFontColorButton_colorChanged( const QColor& color );
     void setCurrentFontPropertiesToGui();
     void deleteItem();
+    void backgroundColorChanged( const QColor& color );
 };
 
 #endif // QGSTEXTANNOTATIONDIALOG_H