Fix "zoom" and "flash" features buttons have no effect when opening

filter mode in attribute form

(For reference: not a regression -- these buttons were originally
added for the "select by form" dialog only, and they've just never
been hooked up for use inside the attribute form itself!)

Fixes qgis#34506

python/gui/auto_generated/qgsmapcanvasutils.sip.in

@@ -0,0 +1,47 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsmapcanvasutils.h                                          *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+class QgsMapCanvasUtils
+{
+%Docstring
+Utility functions for working with QgsMapCanvas widgets.
+
+.. versionadded:: 3.14
+%End
+
+%TypeHeaderCode
+#include "qgsmapcanvasutils.h"
+%End
+  public:
+
+    static long zoomToMatchingFeatures( QgsMapCanvas *canvas, QgsVectorLayer *layer, const QString &filter );
+%Docstring
+Zooms a map ``canvas`` to features from the specified ``layer`` which match the given ``filter`` expression string.
+
+The total count of matching features will be returned.
+%End
+
+    static long flashMatchingFeatures( QgsMapCanvas *canvas, QgsVectorLayer *layer, const QString &filter );
+%Docstring
+Flashes features from the specified ``layer`` which match the given ``filter`` expression string with a map ``canvas``.
+
+The total count of matching features will be returned.
+%End
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsmapcanvasutils.h                                          *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/gui/gui_auto.sip

@@ -123,6 +123,7 @@
 %Include auto_generated/qgsmapcanvasitem.sip
 %Include auto_generated/qgsmapcanvassnappingutils.sip
 %Include auto_generated/qgsmapcanvastracer.sip
+%Include auto_generated/qgsmapcanvasutils.sip
 %Include auto_generated/qgsmaplayeractionregistry.sip
 %Include auto_generated/qgsmaplayercombobox.sip
 %Include auto_generated/qgsmaplayerconfigwidget.sip

src/app/qgsselectbyformdialog.cpp

@@ -22,7 +22,7 @@
 #include "qgsmessagebar.h"
 #include "qgsexpressioncontextutils.h"
 #include "qgsgui.h"
-
+#include "qgsmapcanvasutils.h"
 
 QgsSelectByFormDialog::QgsSelectByFormDialog( QgsVectorLayer *layer, const QgsAttributeEditorContext &context, QWidget *parent, Qt::WindowFlags fl )
   : QDialog( parent, fl )
@@ -65,35 +65,11 @@ void QgsSelectByFormDialog::setMapCanvas( QgsMapCanvas *canvas )
 
 void QgsSelectByFormDialog::zoomToFeatures( const QString &filter )
 {
-  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
-
-  QgsFeatureRequest request = QgsFeatureRequest().setFilterExpression( filter )
-                              .setExpressionContext( context )
-                              .setNoAttributes();
-
-  QgsFeatureIterator features = mLayer->getFeatures( request );
-
-  QgsRectangle bbox;
-  bbox.setMinimal();
-  QgsFeature feat;
-  int featureCount = 0;
-  while ( features.nextFeature( feat ) )
-  {
-    QgsGeometry geom = feat.geometry();
-    if ( geom.isNull() || geom.constGet()->isEmpty() )
-      continue;
-
-    QgsRectangle r = mMapCanvas->mapSettings().layerExtentToOutputExtent( mLayer, geom.boundingBox() );
-    bbox.combineExtentWith( r );
-    featureCount++;
-  }
-  features.close();
-
+  const long featureCount = QgsMapCanvasUtils::zoomToMatchingFeatures( mMapCanvas, mLayer, filter );
   QgsSettings settings;
   int timeout = settings.value( QStringLiteral( "qgis/messageTimeout" ), 5 ).toInt();
   if ( featureCount > 0 )
   {
-    mMapCanvas->zoomToFeatureExtent( bbox );
     if ( mMessageBar )
     {
       mMessageBar->pushMessage( QString(),
@@ -113,28 +89,10 @@ void QgsSelectByFormDialog::zoomToFeatures( const QString &filter )
 
 void QgsSelectByFormDialog::flashFeatures( const QString &filter )
 {
-  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
-
-  QgsFeatureRequest request = QgsFeatureRequest().setFilterExpression( filter )
-                              .setExpressionContext( context )
-                              .setNoAttributes();
-
-  QgsFeatureIterator features = mLayer->getFeatures( request );
-  QgsFeature feat;
-  QList< QgsGeometry > geoms;
-  while ( features.nextFeature( feat ) )
-  {
-    if ( feat.hasGeometry() )
-      geoms << feat.geometry();
-  }
-
+  const long featureCount = QgsMapCanvasUtils::flashMatchingFeatures( mMapCanvas, mLayer, filter );
   QgsSettings settings;
   int timeout = settings.value( QStringLiteral( "qgis/messageTimeout" ), 5 ).toInt();
-  if ( !geoms.empty() )
-  {
-    mMapCanvas->flashGeometries( geoms, mLayer->crs() );
-  }
-  else if ( mMessageBar )
+  if ( featureCount == 0 && mMessageBar )
   {
     mMessageBar->pushMessage( QString(),
                               tr( "No matching features found" ),

src/gui/CMakeLists.txt

@@ -450,6 +450,7 @@ SET(QGIS_GUI_SRCS
   qgsmapcanvasmap.cpp
   qgsmapcanvassnappingutils.cpp
   qgsmapcanvastracer.cpp
+  qgsmapcanvasutils.cpp
   qgsmaplayeractionregistry.cpp
   qgsmaplayercombobox.cpp
   qgsmaplayerconfigwidgetfactory.cpp
@@ -681,6 +682,7 @@ SET(QGIS_GUI_HDRS
   qgsmapcanvasmap.h
   qgsmapcanvassnappingutils.h
   qgsmapcanvastracer.h
+  qgsmapcanvasutils.h
   qgsmaplayeractionregistry.h
   qgsmaplayercombobox.h
   qgsmaplayerconfigwidget.h

src/gui/attributetable/qgsdualview.cpp

@@ -43,6 +43,7 @@
 #include "qgsexpressioncontextutils.h"
 #include "qgsshortcutsmanager.h"
 #include "qgsfieldconditionalformatwidget.h"
+#include "qgsmapcanvasutils.h"
 
 
 QgsDualView::QgsDualView( QWidget *parent )
@@ -149,6 +150,21 @@ void QgsDualView::init( QgsVectorLayer *layer, QgsMapCanvas *mapCanvas, const Qg
   connect( mAttributeForm, &QgsAttributeForm::widgetValueChanged, this, &QgsDualView::featureFormAttributeChanged );
   connect( mAttributeForm, &QgsAttributeForm::modeChanged, this, &QgsDualView::formModeChanged );
   connect( mAttributeForm, &QgsAttributeForm::filterExpressionSet, this, &QgsDualView::filterExpressionSet );
+  connect( mAttributeForm, &QgsAttributeForm::flashFeatures, this, [ = ]( const QString & filter )
+  {
+    if ( QgsMapCanvas *canvas = mFilterModel->mapCanvas() )
+    {
+      QgsMapCanvasUtils::flashMatchingFeatures( canvas, mLayer, filter );
+    }
+  } );
+  connect( mAttributeForm, &QgsAttributeForm::zoomToFeatures, this, [ = ]( const QString & filter )
+  {
+    if ( QgsMapCanvas *canvas = mFilterModel->mapCanvas() )
+    {
+      QgsMapCanvasUtils::zoomToMatchingFeatures( canvas, mLayer, filter );
+    }
+  } );
+
   connect( mMasterModel, &QgsAttributeTableModel::modelChanged, mAttributeForm, &QgsAttributeForm::refreshFeature );
   connect( mFilterModel, &QgsAttributeTableFilterModel::sortColumnChanged, this, &QgsDualView::onSortColumnChanged );
 

src/gui/qgsmapcanvasutils.cpp

@@ -0,0 +1,76 @@
+/***************************************************************************
+    qgsmapcanvasutils.cpp
+    -------------------
+    begin                : June 2020
+    copyright            : (C) 2020 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsmapcanvasutils.h"
+#include "qgsmapcanvas.h"
+#include "qgsvectorlayer.h"
+#include "qgsexpressioncontextutils.h"
+
+long QgsMapCanvasUtils::zoomToMatchingFeatures( QgsMapCanvas *canvas, QgsVectorLayer *layer, const QString &filter )
+{
+  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( layer ) );
+
+  QgsFeatureRequest request = QgsFeatureRequest().setFilterExpression( filter )
+                              .setExpressionContext( context )
+                              .setNoAttributes();
+
+  QgsFeatureIterator features = layer->getFeatures( request );
+
+  QgsRectangle bbox;
+  bbox.setMinimal();
+  QgsFeature feat;
+  int featureCount = 0;
+  while ( features.nextFeature( feat ) )
+  {
+    QgsGeometry geom = feat.geometry();
+    if ( geom.isNull() || geom.constGet()->isEmpty() )
+      continue;
+
+    QgsRectangle r = canvas->mapSettings().layerExtentToOutputExtent( layer, geom.boundingBox() );
+    bbox.combineExtentWith( r );
+    featureCount++;
+  }
+  features.close();
+
+  if ( featureCount > 0 )
+  {
+    canvas->zoomToFeatureExtent( bbox );
+  }
+  return featureCount;
+}
+
+long QgsMapCanvasUtils::flashMatchingFeatures( QgsMapCanvas *canvas, QgsVectorLayer *layer, const QString &filter )
+{
+  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( layer ) );
+
+  QgsFeatureRequest request = QgsFeatureRequest().setFilterExpression( filter )
+                              .setExpressionContext( context )
+                              .setNoAttributes();
+
+  QgsFeatureIterator features = layer->getFeatures( request );
+  QgsFeature feat;
+  QList< QgsGeometry > geoms;
+  while ( features.nextFeature( feat ) )
+  {
+    if ( feat.hasGeometry() )
+      geoms << feat.geometry();
+  }
+
+  if ( !geoms.empty() )
+  {
+    canvas->flashGeometries( geoms, layer->crs() );
+  }
+  return geoms.size();
+}

src/gui/qgsmapcanvasutils.h

@@ -0,0 +1,52 @@
+/***************************************************************************
+    qgsmapcanvasutils.h
+    -------------------
+    begin                : June 2020
+    copyright            : (C) 2020 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSMAPCANVASUTILS_H
+#define QGSMAPCANVASUTILS_H
+
+#include "qgis_gui.h"
+
+class QgsMapCanvas;
+class QgsVectorLayer;
+class QString;
+
+/**
+ * \ingroup gui
+ * \class QgsMapCanvasUtils
+ * Utility functions for working with QgsMapCanvas widgets.
+ * \since QGIS 3.14
+ */
+class GUI_EXPORT QgsMapCanvasUtils
+{
+
+  public:
+
+    /**
+     * Zooms a map \a canvas to features from the specified \a layer which match the given \a filter expression string.
+     *
+     * The total count of matching features will be returned.
+     */
+    static long zoomToMatchingFeatures( QgsMapCanvas *canvas, QgsVectorLayer *layer, const QString &filter );
+
+    /**
+     * Flashes features from the specified \a layer which match the given \a filter expression string with a map \a canvas.
+     *
+     * The total count of matching features will be returned.
+     */
+    static long flashMatchingFeatures( QgsMapCanvas *canvas, QgsVectorLayer *layer, const QString &filter );
+
+};
+
+#endif //QGSMAPCANVASUTILS_H