Work on modernizing atlas

python/core/core_auto.sip

@@ -161,6 +161,7 @@
 %Include composer/qgscomposermultiframecommand.sip
 %Include composer/qgscomposertexttable.sip
 %Include composer/qgspaperitem.sip
+%Include layout/qgsabstractlayoutiterator.sip
 %Include layout/qgslayoutaligner.sip
 %Include layout/qgslayoutexporter.sip
 %Include layout/qgslayoutgridsettings.sip

python/core/layout/qgsabstractlayoutiterator.sip

@@ -0,0 +1,103 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/layout/qgsabstractlayoutiterator.h                          *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+class QgsAbstractLayoutIterator
+{
+%Docstring
+*************************************************************************
+*
+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.                                   *
+*
+**************************************************************************
+%End
+
+%TypeHeaderCode
+#include "qgsabstractlayoutiterator.h"
+%End
+  public:
+
+    virtual ~QgsAbstractLayoutIterator();
+
+    virtual bool beginRender() = 0;
+%Docstring
+Called when rendering begins, before iteration commences. Returns true if successful, false if no iteration
+is available or required.
+
+.. seealso:: :py:func:`endRender()`
+%End
+
+    virtual bool endRender() = 0;
+%Docstring
+Ends the render, performing any required cleanup tasks.
+%End
+
+    virtual int count() const = 0;
+%Docstring
+Returns the number of features to iterate over.
+%End
+
+    virtual bool next() = 0;
+%Docstring
+Iterates to next feature, returning false if no more features exist to iterate over.
+
+.. seealso:: :py:func:`previous()`
+
+.. seealso:: :py:func:`last()`
+
+.. seealso:: :py:func:`first()`
+%End
+
+    virtual bool previous() = 0;
+%Docstring
+Iterates to the previous feature, returning false if no previous feature exists.
+
+.. seealso:: :py:func:`next()`
+
+.. seealso:: :py:func:`last()`
+
+.. seealso:: :py:func:`first()`
+%End
+
+    virtual bool last() = 0;
+%Docstring
+Seeks to the last feature, returning false if no feature was found.
+
+.. seealso:: :py:func:`next()`
+
+.. seealso:: :py:func:`previous()`
+
+.. seealso:: :py:func:`first()`
+%End
+
+    virtual bool first() = 0;
+%Docstring
+Seeks to the first feature, returning false if no feature was found.
+
+.. seealso:: :py:func:`next()`
+
+.. seealso:: :py:func:`previous()`
+
+.. seealso:: :py:func:`last()`
+%End
+};
+
+
+
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/layout/qgsabstractlayoutiterator.h                          *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/core/layout/qgslayoutatlas.sip

@@ -8,7 +8,7 @@
 
 
 
-class QgsLayoutAtlas : QObject, QgsLayoutSerializableObject
+class QgsLayoutAtlas : QObject, QgsAbstractLayoutIterator, QgsLayoutSerializableObject
 {
 %Docstring
 Class used to render an Atlas, iterating over geometry features.
@@ -245,8 +245,30 @@ will be set to the expression error.
 .. seealso:: :py:func:`setFilterFeatures()`
 %End
 
+    int updateFeatures();
+%Docstring
+Requeries the current atlas coverage layer and applies filtering and sorting. Returns
+number of matching features.
+%End
+
+    virtual bool beginRender();
+
+    virtual bool endRender();
+
+    virtual int count() const;
+
+
   public slots:
 
+    virtual bool next();
+
+    virtual bool previous();
+
+    virtual bool first();
+
+    virtual bool last();
+
+
   signals:
 
     void changed();
@@ -262,6 +284,26 @@ Emitted when atlas is enabled or disabled.
     void coverageLayerChanged( QgsVectorLayer *layer );
 %Docstring
 Emitted when the coverage layer for the atlas changes.
+%End
+
+    void messagePushed( const QString &message );
+%Docstring
+Is emitted when the atlas has an updated status bar ``message``.
+%End
+
+    void numberFeaturesChanged( int numFeatures );
+%Docstring
+Emitted when the number of features for the atlas changes.
+%End
+
+    void renderBegun();
+%Docstring
+Emitted when atlas rendering has begun.
+%End
+
+    void renderEnded();
+%Docstring
+Emitted when atlas rendering has ended.
 %End
 
 };

python/core/layout/qgslayoutcontext.sip

@@ -90,6 +90,8 @@ Sets the current ``feature`` for evaluating the layout. This feature may
 be used for altering an item's content and appearance for a report
 or atlas layout.
 
+Emits the changed() signal.
+
 .. seealso:: :py:func:`feature()`
 %End
 
@@ -113,6 +115,8 @@ Returns the vector layer associated with the layout's context.
 %Docstring
 Sets the vector ``layer`` associated with the layout's context.
 
+Emits the changed() signal.
+
 .. seealso:: :py:func:`layer()`
 %End
 
@@ -220,6 +224,12 @@ If ``layer`` is -1, all item layers should be rendered.
 Emitted whenever the context's ``flags`` change.
 
 .. seealso:: :py:func:`setFlags()`
+%End
+
+    void changed();
+%Docstring
+Emitted certain settings in the context is changed, e.g. by setting a new feature or vector layer
+for the context.
 %End
 
 };

src/core/CMakeLists.txt

@@ -1026,6 +1026,7 @@ SET(QGIS_CORE_HDRS
   composer/qgscomposertexttable.h
   composer/qgspaperitem.h
 
+  layout/qgsabstractlayoutiterator.h
   layout/qgslayoutaligner.h
   layout/qgslayoutexporter.h
   layout/qgslayoutgridsettings.h

src/core/layout/qgsabstractlayoutiterator.h

@@ -0,0 +1,82 @@
+/***************************************************************************
+                             qgsabstractlayoutiterator.h
+                             ---------------------------
+    begin                : December 2017
+    copyright            : (C) 2017 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 QGSABSTRACTLAYOUTITERATOR_H
+#define QGSABSTRACTLAYOUTITERATOR_H
+
+#include "qgis_core.h"
+
+
+class CORE_EXPORT QgsAbstractLayoutIterator
+{
+
+  public:
+
+    virtual ~QgsAbstractLayoutIterator() = default;
+
+    /**
+     * Called when rendering begins, before iteration commences. Returns true if successful, false if no iteration
+     * is available or required.
+     * \see endRender()
+    */
+    virtual bool beginRender() = 0;
+
+    /**
+     * Ends the render, performing any required cleanup tasks.
+     */
+    virtual bool endRender() = 0;
+
+    /**
+     * Returns the number of features to iterate over.
+     */
+    virtual int count() const = 0;
+
+    /**
+     * Iterates to next feature, returning false if no more features exist to iterate over.
+     * \see previous()
+     * \see last()
+     * \see first()
+     */
+    virtual bool next() = 0;
+
+    /**
+     * Iterates to the previous feature, returning false if no previous feature exists.
+     * \see next()
+     * \see last()
+     * \see first()
+     */
+    virtual bool previous() = 0;
+
+    /**
+     * Seeks to the last feature, returning false if no feature was found.
+     * \see next()
+     * \see previous()
+     * \see first()
+     */
+    virtual bool last() = 0;
+
+    /**
+     * Seeks to the first feature, returning false if no feature was found.
+     * \see next()
+     * \see previous()
+     * \see last()
+     */
+    virtual bool first() = 0;
+};
+
+#endif //QGSABSTRACTLAYOUTITERATOR_H
+
+
+