Add signal which is emitted when a layout map's linked theme is changed

(cherry picked from commit 0930906)
qgis · Apr 6, 2020 · 8ad01a2 · 8ad01a2
1 parent deac6f5
commit 8ad01a2
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Showing 4 changed files with 120 additions and 2 deletions.
diff --git a/python/core/auto_generated/layout/qgslayoutitemmap.sip.in b/python/core/auto_generated/layout/qgslayoutitemmap.sip.in
@@ -296,13 +296,17 @@ Preset name that decides which layers and layer styles are used for map renderin
 used when followVisibilityPreset() returns ``True``.
 
 .. seealso:: :py:func:`setFollowVisibilityPresetName`
+
+.. seealso:: :py:func:`themeChanged`
 %End
 
     void setFollowVisibilityPresetName( const QString &name );
 %Docstring
 Sets preset name for map rendering. See followVisibilityPresetName() for more details.
 
 .. seealso:: :py:func:`followVisibilityPresetName`
+
+.. seealso:: :py:func:`themeChanged`
 %End
 
     virtual void moveContent( double dx, double dy );
@@ -680,6 +684,18 @@ Emitted when the map has been prepared for atlas rendering, just before actual r
 %Docstring
 Emitted when layer style overrides are changed... a means to let
 associated legend items know they should update
+%End
+
+    void themeChanged( const QString &theme );
+%Docstring
+Emitted when the map's associated ``theme`` is changed.
+
+.. note::
+
+   This signal is not emitted when the definition of the theme changes, only the map
+   is linked to a different theme then it previously was.
+
+.. versionadded:: 3.14
 %End
 
   public slots:

diff --git a/src/core/layout/qgslayoutitemmap.cpp b/src/core/layout/qgslayoutitemmap.cpp
@@ -309,6 +309,26 @@ void QgsLayoutItemMap::storeCurrentLayerStyles()
   }
 }
 
+void QgsLayoutItemMap::setFollowVisibilityPreset( bool follow )
+{
+  if ( mFollowVisibilityPreset == follow )
+    return;
+
+  mFollowVisibilityPreset = follow;
+  if ( !mFollowVisibilityPresetName.isEmpty() )
+    emit themeChanged( mFollowVisibilityPreset ? mFollowVisibilityPresetName : QString() );
+}
+
+void QgsLayoutItemMap::setFollowVisibilityPresetName( const QString &name )
+{
+  if ( name == mFollowVisibilityPresetName )
+    return;
+
+  mFollowVisibilityPresetName = name;
+  if ( mFollowVisibilityPreset )
+    emit themeChanged( mFollowVisibilityPresetName );
+}
+
 void QgsLayoutItemMap::moveContent( double dx, double dy )
 {
   mLastRenderedImageOffsetX -= dx;
@@ -1707,6 +1727,13 @@ void QgsLayoutItemMap::refreshDataDefinedProperty( const QgsLayoutObject::DataDe
   {
     refreshLabelMargin( false );
   }
+  if ( property == QgsLayoutObject::MapStylePreset || property == QgsLayoutObject::AllProperties )
+  {
+    const QString previousTheme = mLastEvaluatedThemeName.isEmpty() ? mFollowVisibilityPresetName : mLastEvaluatedThemeName;
+    mLastEvaluatedThemeName = mDataDefinedProperties.valueAsString( QgsLayoutObject::MapStylePreset, context, mFollowVisibilityPresetName );
+    if ( mLastEvaluatedThemeName != previousTheme )
+      emit themeChanged( mLastEvaluatedThemeName );
+  }
 
   //force redraw
   mCacheInvalidated = true;

diff --git a/src/core/layout/qgslayoutitemmap.h b/src/core/layout/qgslayoutitemmap.h
@@ -285,20 +285,24 @@ class CORE_EXPORT QgsLayoutItemMap : public QgsLayoutItem
     /**
      * Sets whether the map should follow a map theme. See followVisibilityPreset() for more details.
      */
-    void setFollowVisibilityPreset( bool follow ) { mFollowVisibilityPreset = follow; }
+    void setFollowVisibilityPreset( bool follow );
 
     /**
      * Preset name that decides which layers and layer styles are used for map rendering. It is only
      * used when followVisibilityPreset() returns TRUE.
      * \see setFollowVisibilityPresetName()
+     *
+     * \see themeChanged()
      */
     QString followVisibilityPresetName() const { return mFollowVisibilityPresetName; }
 
     /**
      * Sets preset name for map rendering. See followVisibilityPresetName() for more details.
      * \see followVisibilityPresetName()
+     *
+     * \see themeChanged()
     */
-    void setFollowVisibilityPresetName( const QString &name ) { mFollowVisibilityPresetName = name; }
+    void setFollowVisibilityPresetName( const QString &name );
 
     void moveContent( double dx, double dy ) override;
     void setMoveContentPreviewOffset( double dx, double dy ) override;
@@ -602,6 +606,16 @@ class CORE_EXPORT QgsLayoutItemMap : public QgsLayoutItem
      */
     void layerStyleOverridesChanged();
 
+    /**
+     * Emitted when the map's associated \a theme is changed.
+     *
+     * \note This signal is not emitted when the definition of the theme changes, only the map
+     * is linked to a different theme then it previously was.
+     *
+     * \since QGIS 3.14
+     */
+    void themeChanged( const QString &theme );
+
   public slots:
 
     void refresh() override;
@@ -716,6 +730,9 @@ class CORE_EXPORT QgsLayoutItemMap : public QgsLayoutItem
      *  is TRUE. May be overridden by data-defined expression. */
     QString mFollowVisibilityPresetName;
 
+    //! Name of the last data-defined evaluated theme name
+    QString mLastEvaluatedThemeName;
+
     /**
      * \brief Draw to paint device
      *  \param painter painter

diff --git a/tests/src/python/test_qgslayoutmap.py b/tests/src/python/test_qgslayoutmap.py
@@ -17,6 +17,7 @@
 from qgis.PyQt.QtCore import QFileInfo, QRectF, QDir
 from qgis.PyQt.QtXml import QDomDocument
 from qgis.PyQt.QtGui import QPainter, QColor
+from qgis.PyQt.QtTest import QSignalSpy
 
 from qgis.core import (QgsLayoutItemMap,
                        QgsRectangle,
@@ -398,6 +399,63 @@ def testBlockingItems(self):
         self.assertTrue(map_restore.isLabelBlockingItem(map2_restore))
         self.assertTrue(map_restore.isLabelBlockingItem(map3_restore))
 
+    def testTheme(self):
+        layout = QgsLayout(QgsProject.instance())
+        map = QgsLayoutItemMap(layout)
+        self.assertFalse(map.followVisibilityPreset())
+        self.assertFalse(map.followVisibilityPresetName())
+
+        spy = QSignalSpy(map.themeChanged)
+
+        map.setFollowVisibilityPresetName('theme')
+        self.assertFalse(map.followVisibilityPreset())
+        self.assertEqual(map.followVisibilityPresetName(), 'theme')
+        # should not be emitted - followVisibilityPreset is False
+        self.assertEqual(len(spy), 0)
+        map.setFollowVisibilityPresetName('theme2')
+        self.assertEqual(map.followVisibilityPresetName(), 'theme2')
+        self.assertEqual(len(spy), 0)
+
+        map.setFollowVisibilityPresetName('')
+        map.setFollowVisibilityPreset(True)
+        # should not be emitted - followVisibilityPresetName is empty
+        self.assertEqual(len(spy), 0)
+        self.assertFalse(map.followVisibilityPresetName())
+        self.assertTrue(map.followVisibilityPreset())
+
+        map.setFollowVisibilityPresetName('theme')
+        self.assertEqual(len(spy), 1)
+        self.assertEqual(spy[-1][0], 'theme')
+        map.setFollowVisibilityPresetName('theme')
+        self.assertEqual(len(spy), 1)
+        map.setFollowVisibilityPresetName('theme2')
+        self.assertEqual(len(spy), 2)
+        self.assertEqual(spy[-1][0], 'theme2')
+        map.setFollowVisibilityPreset(False)
+        self.assertEqual(len(spy), 3)
+        self.assertFalse(spy[-1][0])
+        map.setFollowVisibilityPreset(False)
+        self.assertEqual(len(spy), 3)
+        map.setFollowVisibilityPresetName('theme3')
+        self.assertEqual(len(spy), 3)
+        map.setFollowVisibilityPreset(True)
+        self.assertEqual(len(spy), 4)
+        self.assertEqual(spy[-1][0], 'theme3')
+        map.setFollowVisibilityPreset(True)
+        self.assertEqual(len(spy), 4)
+
+        # data defined theme
+        map.dataDefinedProperties().setProperty(QgsLayoutObject.MapStylePreset, QgsProperty.fromValue('theme4'))
+        map.refresh()
+        self.assertEqual(len(spy), 5)
+        self.assertEqual(spy[-1][0], 'theme4')
+        map.refresh()
+        self.assertEqual(len(spy), 5)
+        map.dataDefinedProperties().setProperty(QgsLayoutObject.MapStylePreset, QgsProperty.fromValue('theme6'))
+        map.refresh()
+        self.assertEqual(len(spy), 6)
+        self.assertEqual(spy[-1][0], 'theme6')
+
 
 if __name__ == '__main__':
     unittest.main()