Start work on exporter for layouts

python/core/core_auto.sip

@@ -158,6 +158,7 @@
 %Include composer/qgscomposertexttable.sip
 %Include composer/qgspaperitem.sip
 %Include layout/qgslayoutaligner.sip
+%Include layout/qgslayoutexporter.sip
 %Include layout/qgslayoutgridsettings.sip
 %Include layout/qgslayoutmeasurement.sip
 %Include layout/qgslayoutmeasurementconverter.sip

python/core/layout/qgslayout.sip

@@ -62,6 +62,13 @@ class QgsLayout : QGraphicsScene, QgsExpressionContextGenerator, QgsLayoutUndoOb
  :rtype: QgsLayoutModel
 %End
 
+    QgsLayoutExporter &exporter();
+%Docstring
+ Returns the layout's exporter, which is used for rendering the layout and exporting
+ to various formats.
+ :rtype: QgsLayoutExporter
+%End
+
     QString name() const;
 %Docstring
  Returns the layout's name.

python/core/layout/qgslayoutexporter.sip

@@ -0,0 +1,57 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/layout/qgslayoutexporter.h                                  *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+class QgsLayoutExporter
+{
+%Docstring
+ Handles rendering and exports of layouts to various formats.
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgslayoutexporter.h"
+%End
+  public:
+
+    QgsLayoutExporter( QgsLayout *layout );
+%Docstring
+ Constructor for QgsLayoutExporter, for the specified ``layout``.
+%End
+
+    void renderPage( QPainter *painter, int page );
+%Docstring
+ Renders a full page to a destination ``painter``.
+
+ The ``page`` argument specifies the page number to render. Page numbers
+ are 0 based, such that the first page in a layout is page 0.
+
+.. seealso:: renderRect()
+%End
+
+    void renderRegion( QPainter *painter, const QRectF &region );
+%Docstring
+ Renders a ``region`` from the layout to a ``painter``. This method can be used
+ to render sections of pages rather than full pages.
+
+.. seealso:: renderPage()
+%End
+
+};
+
+
+
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/layout/qgslayoutexporter.h                                  *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/core/layout/qgslayoutitem.sip

@@ -589,14 +589,6 @@ class QgsLayoutItem : QgsLayoutObject, QGraphicsRectItem, QgsLayoutUndoObjectInt
  Draws the background for the item.
 %End
 
-    bool isPreviewRender( QPainter *painter ) const;
-%Docstring
- Returns true if the render to the specified ``painter`` is a preview render,
- i.e. is being rendered inside a QGraphicsView widget as opposed to a destination
- device (such as an image).
- :rtype: bool
-%End
-
     virtual void setFixedSize( const QgsLayoutSize &size );
 %Docstring
  Sets a fixed ``size`` for the layout item, which prevents it from being freely

python/core/layout/qgslayoututils.sip

@@ -72,6 +72,15 @@ class QgsLayoutUtils
  :rtype: float
 %End
 
+
+    static bool isPreviewRender( QPainter *painter );
+%Docstring
+ Returns true if the render to the specified ``painter`` is a preview render,
+ i.e. is being rendered inside a QGraphicsView widget as opposed to a destination
+ device (such as an image).
+ :rtype: bool
+%End
+
 };
 
 /************************************************************************

python/core/qgsmultirenderchecker.sip

@@ -152,6 +152,44 @@ class QgsCompositionChecker : QgsMultiRenderChecker
 
 };
 
+class QgsLayoutChecker : QgsMultiRenderChecker
+{
+%Docstring
+ Renders a layout to an image and compares with an expected output
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgsmultirenderchecker.h"
+%End
+  public:
+
+    QgsLayoutChecker( const QString &testName, QgsLayout *layout );
+%Docstring
+ Constructor for QgsLayoutChecker.
+%End
+
+    void setSize( QSize size );
+%Docstring
+ Sets the output (reference) image ``size``.
+%End
+
+    bool runTest( QString &report, int page = 0, int pixelDiff = 0 );
+%Docstring
+ Runs a render check on the layout, adding results to the specified ``report``.
+
+ The maximum number of allowable pixels differing from the reference image is
+ specified via the ``pixelDiff`` argument.
+
+ The page number is specified via ``page``, where 0 corresponds to the first
+ page in the layout.
+
+ Returns false if the rendered layout differs from the expected reference image.
+ :rtype: bool
+%End
+
+};
+
 %End
 
 

src/core/CMakeLists.txt

@@ -363,6 +363,7 @@ SET(QGIS_CORE_SRCS
   layout/qgslayoutaligner.cpp
   layout/qgslayoutcontext.cpp
   layout/qgslayouteffect.cpp
+  layout/qgslayoutexporter.cpp
   layout/qgslayoutgridsettings.cpp
   layout/qgslayoutguidecollection.cpp
   layout/qgslayoutitem.cpp
@@ -975,6 +976,7 @@ SET(QGIS_CORE_HDRS
   composer/qgspaperitem.h
 
   layout/qgslayoutaligner.h
+  layout/qgslayoutexporter.h
   layout/qgslayoutgridsettings.h
   layout/qgslayoutitemundocommand.h
   layout/qgslayoutmeasurement.h

src/core/layout/qgslayout.cpp

@@ -31,6 +31,7 @@ QgsLayout::QgsLayout( QgsProject *project )
   , mGridSettings( this )
   , mPageCollection( new QgsLayoutPageCollection( this ) )
   , mUndoStack( new QgsLayoutUndoStack( this ) )
+  , mExporter( QgsLayoutExporter( this ) )
 {
   // just to make sure - this should be the default, but maybe it'll change in some future Qt version...
   setBackgroundBrush( Qt::NoBrush );
@@ -87,6 +88,11 @@ QgsLayoutModel *QgsLayout::itemsModel()
   return mItemsModel.get();
 }
 
+QgsLayoutExporter &QgsLayout::exporter()
+{
+  return mExporter;
+}
+
 QList<QgsLayoutItem *> QgsLayout::selectedLayoutItems( const bool includeLockedItems )
 {
   QList<QgsLayoutItem *> layoutItemList;

src/core/layout/qgslayout.h

@@ -25,6 +25,7 @@
 #include "qgslayoutgridsettings.h"
 #include "qgslayoutguidecollection.h"
 #include "qgslayoutundostack.h"
+#include "qgslayoutexporter.h"
 
 class QgsLayoutItemMap;
 class QgsLayoutModel;
@@ -83,6 +84,12 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene, public QgsExpressionContext
      */
     QgsLayoutModel *itemsModel();
 
+    /**
+     * Returns the layout's exporter, which is used for rendering the layout and exporting
+     * to various formats.
+     */
+    QgsLayoutExporter &exporter();
+
     /**
      * Returns the layout's name.
      * \see setName()
@@ -517,6 +524,7 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene, public QgsExpressionContext
 
     std::unique_ptr< QgsLayoutPageCollection > mPageCollection;
     std::unique_ptr< QgsLayoutUndoStack > mUndoStack;
+    QgsLayoutExporter mExporter;
 
     bool mBlockUndoCommands = false;
 

src/core/layout/qgslayoutexporter.cpp

@@ -0,0 +1,64 @@
+/***************************************************************************
+                              qgslayoutexporter.cpp
+                             -------------------
+    begin                : October 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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgslayoutexporter.h"
+#include "qgslayout.h"
+
+QgsLayoutExporter::QgsLayoutExporter( QgsLayout *layout )
+  : mLayout( layout )
+{
+
+}
+
+void QgsLayoutExporter::renderPage( QPainter *painter, int page )
+{
+  if ( !mLayout )
+    return;
+
+  if ( mLayout->pageCollection()->pageCount() <= page || page < 0 )
+  {
+    return;
+  }
+
+  QgsLayoutItemPage *pageItem = mLayout->pageCollection()->page( page );
+  if ( !pageItem )
+  {
+    return;
+  }
+
+  QRectF paperRect = QRectF( pageItem->pos().x(), pageItem->pos().y(), pageItem->rect().width(), pageItem->rect().height() );
+  renderRegion( painter, paperRect );
+}
+
+void QgsLayoutExporter::renderRegion( QPainter *painter, const QRectF &region )
+{
+  QPaintDevice *paintDevice = painter->device();
+  if ( !paintDevice || !mLayout )
+  {
+    return;
+  }
+
+#if 0 //TODO
+  setSnapLinesVisible( false );
+#endif
+
+  mLayout->render( painter, QRectF( 0, 0, paintDevice->width(), paintDevice->height() ), region );
+
+#if 0 // TODO
+  setSnapLinesVisible( true );
+#endif
+}
+

src/core/layout/qgslayoutexporter.h

@@ -0,0 +1,67 @@
+/***************************************************************************
+                              qgslayoutexporter.h
+                             -------------------
+    begin                : October 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 QGSLAYOUTEXPORTER_H
+#define QGSLAYOUTEXPORTER_H
+
+#include "qgis_core.h"
+#include <QPointer>
+
+class QgsLayout;
+class QPainter;
+
+/**
+ * \ingroup core
+ * \class QgsLayoutExporter
+ * \brief Handles rendering and exports of layouts to various formats.
+ * \since QGIS 3.0
+ */
+class CORE_EXPORT QgsLayoutExporter
+{
+
+  public:
+
+    /**
+     * Constructor for QgsLayoutExporter, for the specified \a layout.
+     */
+    QgsLayoutExporter( QgsLayout *layout );
+
+    /**
+     * Renders a full page to a destination \a painter.
+     *
+     * The \a page argument specifies the page number to render. Page numbers
+     * are 0 based, such that the first page in a layout is page 0.
+     *
+     * \see renderRect()
+     */
+    void renderPage( QPainter *painter, int page );
+
+    /**
+     * Renders a \a region from the layout to a \a painter. This method can be used
+     * to render sections of pages rather than full pages.
+     *
+     * \see renderPage()
+     */
+    void renderRegion( QPainter *painter, const QRectF &region );
+
+  private:
+
+    QPointer< QgsLayout > mLayout;
+};
+
+#endif //QGSLAYOUTEXPORTER_H
+
+
+

src/core/layout/qgslayoutitem.cpp

@@ -433,7 +433,7 @@ bool QgsLayoutItem::shouldBlockUndoCommands() const
 
 bool QgsLayoutItem::shouldDrawItem( QPainter *painter ) const
 {
-  if ( isPreviewRender( painter ) )
+  if ( QgsLayoutUtils::isPreviewRender( painter ) )
   {
     //preview mode so OK to draw item
     return true;
@@ -767,31 +767,6 @@ void QgsLayoutItem::drawBackground( QgsRenderContext &context )
   p->restore();
 }
 
-bool QgsLayoutItem::isPreviewRender( QPainter *painter ) const
-{
-  if ( !painter || !painter->device() )
-    return false;
-
-  // if rendering to a QGraphicsView, we are in preview mode
-  QPaintDevice *device = painter->device();
-  if ( dynamic_cast< QPixmap * >( device ) )
-    return true;
-
-  QObject *obj = dynamic_cast< QObject *>( device );
-  if ( !obj )
-    return false;
-
-  const QMetaObject *mo = obj->metaObject();
-  while ( mo )
-  {
-    if ( mo->className() == QStringLiteral( "QGraphicsView" ) )
-      return true;
-
-    mo = mo->superClass();
-  }
-  return false;
-}
-
 void QgsLayoutItem::setFixedSize( const QgsLayoutSize &size )
 {
   mFixedSize = size;