Port a bunch of low-level methods to layouts

Relating to expression contexts and variables
qgis · Jul 18, 2017 · dd37037 · dd37037
1 parent 15b65fa
commit dd37037
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Showing 13 changed files with 483 additions and 27 deletions.
diff --git a/python/core/layout/qgslayout.sip b/python/core/layout/qgslayout.sip
@@ -7,7 +7,7 @@
  ************************************************************************/
 
 
-class QgsLayout : QGraphicsScene
+class QgsLayout : QGraphicsScene, QgsExpressionContextGenerator
 {
 %Docstring
  Base class for layouts, which can contain items such as maps, labels, scalebars, etc.
@@ -24,7 +24,17 @@ class QgsLayout : QGraphicsScene
       ZMapTool,
     };
 
-    QgsLayout();
+    QgsLayout( QgsProject *project );
+%Docstring
+ Construct a new layout linked to the specified ``project``.
+%End
+
+    QgsProject *project() const;
+%Docstring
+ The project associated with the layout. Used to get access to layers, map themes,
+ relations and various other bits. It is never null.
+ :rtype: QgsProject
+%End
 
     QString name() const;
 %Docstring
@@ -117,6 +127,61 @@ class QgsLayout : QGraphicsScene
 %End
 
 
+    virtual QgsExpressionContext createExpressionContext() const;
+
+%Docstring
+ Creates an expression context relating to the layout's current state. The context includes
+ scopes for global, project, layout and layout context properties.
+ :rtype: QgsExpressionContext
+%End
+
+    void setCustomProperty( const QString &key, const QVariant &value );
+%Docstring
+ Set a custom property for the layout.
+ \param key property key. If a property with the same key already exists it will be overwritten.
+ \param value property value
+.. seealso:: customProperty()
+.. seealso:: removeCustomProperty()
+.. seealso:: customProperties()
+%End
+
+    QVariant customProperty( const QString &key, const QVariant &defaultValue = QVariant() ) const;
+%Docstring
+ Read a custom property from the layout.
+ \param key property key
+ \param defaultValue default value to return if property with matching key does not exist
+ :return: value of matching property
+.. seealso:: setCustomProperty()
+.. seealso:: removeCustomProperty()
+.. seealso:: customProperties()
+ :rtype: QVariant
+%End
+
+    void removeCustomProperty( const QString &key );
+%Docstring
+ Remove a custom property from the layout.
+ \param key property key
+.. seealso:: setCustomProperty()
+.. seealso:: customProperty()
+.. seealso:: customProperties()
+%End
+
+    QStringList customProperties() const;
+%Docstring
+ Return list of keys stored in custom properties for the layout.
+.. seealso:: setCustomProperty()
+.. seealso:: customProperty()
+.. seealso:: removeCustomProperty()
+ :rtype: list of str
+%End
+
+  signals:
+
+    void variablesChanged();
+%Docstring
+ Emitted whenever the expression variables stored in the layout have been changed.
+%End
+
 };
 
 

diff --git a/python/core/layout/qgslayoutobject.sip b/python/core/layout/qgslayoutobject.sip
@@ -9,7 +9,7 @@
 
 
 
-class QgsLayoutObject: QObject
+class QgsLayoutObject: QObject, QgsExpressionContextGenerator
 {
 %Docstring
  A base class for objects which belong to a layout.
@@ -151,6 +151,14 @@ class QgsLayoutObject: QObject
  :rtype: list of str
 %End
 
+    virtual QgsExpressionContext createExpressionContext() const;
+
+%Docstring
+ Creates an expression context relating to the objects' current state. The context includes
+ scopes for global, project and layout properties.
+ :rtype: QgsExpressionContext
+%End
+
   protected:
 
 

diff --git a/python/core/qgsexpressioncontext.sip b/python/core/qgsexpressioncontext.sip
@@ -854,6 +854,37 @@ class QgsExpressionContextUtils
  \param variables new set of layer variables
 .. seealso:: setCompositionVariable()
 .. seealso:: compositionScope()
+%End
+
+    static QgsExpressionContextScope *layoutScope( const QgsLayout *layout ) /Factory/;
+%Docstring
+ Creates a new scope which contains variables and functions relating to a QgsLayout ``layout``.
+ For instance, number of pages and page sizes.
+.. versionadded:: 3.0
+ :rtype: QgsExpressionContextScope
+%End
+
+    static void setLayoutVariable( QgsLayout *layout, const QString &name, const QVariant &value );
+%Docstring
+ Sets a layout context variable. This variable will be contained within scopes retrieved via
+ layoutScope().
+ \param layout target layout
+ \param name variable name
+ \param value variable value
+.. seealso:: setLayoutVariables()
+.. seealso:: layoutScope()
+.. versionadded:: 3.0
+%End
+
+    static void setLayoutVariables( QgsLayout *layout, const QVariantMap &variables );
+%Docstring
+ Sets all layout context variables. Existing layout variables will be removed and replaced
+ with the variables specified.
+ \param layout target layout
+ \param variables new set of layer variables
+.. seealso:: setLayoutVariable()
+.. seealso:: layoutScope()
+.. versionadded:: 3.0
 %End
 
     static QgsExpressionContextScope *atlasScope( const QgsAtlasComposition *atlas ) /Factory/;

diff --git a/src/core/layout/qgslayout.cpp b/src/core/layout/qgslayout.cpp
@@ -16,10 +16,14 @@
 
 #include "qgslayout.h"
 
-QgsLayout::QgsLayout()
+QgsLayout::QgsLayout( QgsProject *project )
   : QGraphicsScene()
-{
+  , mProject( project )
+{}
 
+QgsProject *QgsLayout::project() const
+{
+  return mProject;
 }
 
 double QgsLayout::convertToLayoutUnits( const QgsLayoutMeasurement &measurement ) const
@@ -51,3 +55,41 @@ QgsLayoutPoint QgsLayout::convertFromLayoutUnits( const QPointF &point, const Qg
 {
   return mContext.measurementConverter().convert( QgsLayoutPoint( point.x(), point.y(), mUnits ), unit );
 }
+
+QgsExpressionContext QgsLayout::createExpressionContext() const
+{
+  QgsExpressionContext context = QgsExpressionContext();
+  context.appendScope( QgsExpressionContextUtils::globalScope() );
+  context.appendScope( QgsExpressionContextUtils::projectScope( mProject ) );
+  context.appendScope( QgsExpressionContextUtils::layoutScope( this ) );
+#if 0 //TODO
+  if ( mAtlasComposition.enabled() )
+  {
+    context.appendScope( QgsExpressionContextUtils::atlasScope( &mAtlasComposition ) );
+  }
+#endif
+  return context;
+}
+
+void QgsLayout::setCustomProperty( const QString &key, const QVariant &value )
+{
+  mCustomProperties.setValue( key, value );
+
+  if ( key.startsWith( QLatin1String( "variable" ) ) )
+    emit variablesChanged();
+}
+
+QVariant QgsLayout::customProperty( const QString &key, const QVariant &defaultValue ) const
+{
+  return mCustomProperties.value( key, defaultValue );
+}
+
+void QgsLayout::removeCustomProperty( const QString &key )
+{
+  mCustomProperties.remove( key );
+}
+
+QStringList QgsLayout::customProperties() const
+{
+  return mCustomProperties.keys();
+}
diff --git a/src/core/layout/qgslayout.h b/src/core/layout/qgslayout.h
@@ -19,14 +19,15 @@
 #include "qgis_core.h"
 #include <QGraphicsScene>
 #include "qgslayoutcontext.h"
+#include "qgsexpressioncontextgenerator.h"
 
 /**
  * \ingroup core
  * \class QgsLayout
  * \brief Base class for layouts, which can contain items such as maps, labels, scalebars, etc.
  * \since QGIS 3.0
  */
-class CORE_EXPORT QgsLayout : public QGraphicsScene
+class CORE_EXPORT QgsLayout : public QGraphicsScene, public QgsExpressionContextGenerator
 {
     Q_OBJECT
 
@@ -38,7 +39,17 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene
       ZMapTool = 10000, //!< Z-Value for temporary map tool items
     };
 
-    QgsLayout();
+    /**
+     * Construct a new layout linked to the specified \a project.
+     */
+    QgsLayout( QgsProject *project );
+
+    /**
+     * The project associated with the layout. Used to get access to layers, map themes,
+     * relations and various other bits. It is never null.
+     *
+     */
+    QgsProject *project() const;
 
     /**
      * Returns the layout's name.
@@ -127,10 +138,65 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene
      */
     SIP_SKIP const QgsLayoutContext &context() const { return mContext; }
 
+    /**
+     * Creates an expression context relating to the layout's current state. The context includes
+     * scopes for global, project, layout and layout context properties.
+     */
+    QgsExpressionContext createExpressionContext() const override;
+
+    /**
+     * Set a custom property for the layout.
+     * \param key property key. If a property with the same key already exists it will be overwritten.
+     * \param value property value
+     * \see customProperty()
+     * \see removeCustomProperty()
+     * \see customProperties()
+     */
+    void setCustomProperty( const QString &key, const QVariant &value );
+
+    /**
+     * Read a custom property from the layout.
+     * \param key property key
+     * \param defaultValue default value to return if property with matching key does not exist
+     * \returns value of matching property
+     * \see setCustomProperty()
+     * \see removeCustomProperty()
+     * \see customProperties()
+     */
+    QVariant customProperty( const QString &key, const QVariant &defaultValue = QVariant() ) const;
+
+    /**
+     * Remove a custom property from the layout.
+     * \param key property key
+     * \see setCustomProperty()
+     * \see customProperty()
+     * \see customProperties()
+     */
+    void removeCustomProperty( const QString &key );
+
+    /**
+     * Return list of keys stored in custom properties for the layout.
+     * \see setCustomProperty()
+     * \see customProperty()
+     * \see removeCustomProperty()
+     */
+    QStringList customProperties() const;
+
+  signals:
+
+    /**
+     * Emitted whenever the expression variables stored in the layout have been changed.
+     */
+    void variablesChanged();
+
   private:
 
+    QgsProject *mProject = nullptr;
+
     QString mName;
 
+    QgsObjectCustomProperties mCustomProperties;
+
     QgsUnitTypes::LayoutUnit mUnits = QgsUnitTypes::LayoutMillimeters;
     QgsLayoutContext mContext;
 

diff --git a/src/core/layout/qgslayoutobject.cpp b/src/core/layout/qgslayoutobject.cpp
@@ -110,3 +110,15 @@ QStringList QgsLayoutObject::customProperties() const
 {
   return mCustomProperties.keys();
 }
+
+QgsExpressionContext QgsLayoutObject::createExpressionContext() const
+{
+  if ( mLayout )
+  {
+    return mLayout->createExpressionContext();
+  }
+  else
+  {
+    return QgsExpressionContext() << QgsExpressionContextUtils::globalScope();
+  }
+}
diff --git a/src/core/layout/qgslayoutobject.h b/src/core/layout/qgslayoutobject.h
@@ -21,6 +21,7 @@
 #include "qgis_sip.h"
 #include "qgspropertycollection.h"
 #include "qgsobjectcustomproperties.h"
+#include "qgsexpressioncontextgenerator.h"
 #include <QObject>
 #include <QDomNode>
 #include <QMap>
@@ -33,7 +34,7 @@ class QPainter;
  * A base class for objects which belong to a layout.
  * \since QGIS 3.0
  */
-class CORE_EXPORT QgsLayoutObject: public QObject
+class CORE_EXPORT QgsLayoutObject: public QObject, public QgsExpressionContextGenerator
 {
     Q_OBJECT
   public:
@@ -172,6 +173,12 @@ class CORE_EXPORT QgsLayoutObject: public QObject
      */
     QStringList customProperties() const;
 
+    /**
+     * Creates an expression context relating to the objects' current state. The context includes
+     * scopes for global, project and layout properties.
+     */
+    QgsExpressionContext createExpressionContext() const override;
+
   protected:
 
     QgsLayout *mLayout = nullptr;