[layouts] Add vector simplification method to QgsLayoutRendereContext

Allows specification of simplify method to use when rendering layouts
qgis · Aug 7, 2019 · daf3491 · daf3491
1 parent 615e245
commit daf3491
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diff --git a/python/core/auto_generated/layout/qgslayoutrendercontext.sip.in b/python/core/auto_generated/layout/qgslayoutrendercontext.sip.in
@@ -221,6 +221,45 @@ Sets the text render ``format``, which dictates how text is rendered (e.g. as pa
 .. seealso:: :py:func:`textRenderFormat`
 
 .. versionadded:: 3.4.3
+%End
+
+    void setSimplifyMethod( const QgsVectorSimplifyMethod &method );
+%Docstring
+Sets the simplification setting to use when rendering vector layers.
+
+If the simplify ``method`` is enabled, it apply to all vector layers rendered inside map items.
+
+This can be used to specify global simplification methods to apply during map exports,
+e.g. to allow vector layers to be simplified to an appropriate maximum level of detail
+during PDF exports (avoiding excessive PDF size due to huge numbers of vertices).
+
+The default is to use no simplification.
+
+.. note::
+
+   This simplification method is only used during non-preview renders.
+
+.. seealso:: :py:func:`simplifyMethod`
+
+
+.. versionadded:: 3.10
+%End
+
+    const QgsVectorSimplifyMethod &simplifyMethod() const;
+%Docstring
+Returns the simplification settings to use when rendering vector layers.
+
+If enabled, it will apply to all vector layers rendered for the map.
+
+The default is to use no simplification.
+
+.. note::
+
+   This simplification method is only used during non-preview renders.
+
+.. seealso:: :py:func:`setSimplifyMethod`
+
+.. versionadded:: 3.10
 %End
 
   signals:

diff --git a/src/core/layout/qgslayoutexporter.cpp b/src/core/layout/qgslayoutexporter.cpp
@@ -301,6 +301,7 @@ class LayoutContextSettingsRestorer
       , mPreviousFlags( layout->renderContext().flags() )
       , mPreviousTextFormat( layout->renderContext().textRenderFormat() )
       , mPreviousExportLayer( layout->renderContext().currentExportLayer() )
+      , mPreviousSimplifyMethod( layout->renderContext().simplifyMethod() )
     {
     }
 
@@ -310,6 +311,7 @@ class LayoutContextSettingsRestorer
       mLayout->renderContext().setFlags( mPreviousFlags );
       mLayout->renderContext().setTextRenderFormat( mPreviousTextFormat );
       mLayout->renderContext().setCurrentExportLayer( mPreviousExportLayer );
+      mLayout->renderContext().setSimplifyMethod( mPreviousSimplifyMethod );
     }
 
     LayoutContextSettingsRestorer( const LayoutContextSettingsRestorer &other ) = delete;
@@ -321,6 +323,8 @@ class LayoutContextSettingsRestorer
     QgsLayoutRenderContext::Flags mPreviousFlags = nullptr;
     QgsRenderContext::TextRenderFormat mPreviousTextFormat = QgsRenderContext::TextFormatAlwaysOutlines;
     int mPreviousExportLayer = 0;
+    QgsVectorSimplifyMethod mPreviousSimplifyMethod;
+
 };
 ///@endcond PRIVATE
 

diff --git a/src/core/layout/qgslayoutrendercontext.cpp b/src/core/layout/qgslayoutrendercontext.cpp
@@ -21,7 +21,9 @@ QgsLayoutRenderContext::QgsLayoutRenderContext( QgsLayout *layout )
   : QObject( layout )
   , mFlags( FlagAntialiasing | FlagUseAdvancedEffects )
   , mLayout( layout )
-{}
+{
+  mSimplifyMethod.setSimplifyHints( QgsVectorSimplifyMethod::NoSimplification );
+}
 
 void QgsLayoutRenderContext::setFlags( const QgsLayoutRenderContext::Flags flags )
 {

diff --git a/src/core/layout/qgslayoutrendercontext.h b/src/core/layout/qgslayoutrendercontext.h
@@ -223,6 +223,39 @@ class CORE_EXPORT QgsLayoutRenderContext : public QObject
       mTextRenderFormat = format;
     }
 
+    /**
+     * Sets the simplification setting to use when rendering vector layers.
+     *
+     * If the simplify \a method is enabled, it apply to all vector layers rendered inside map items.
+     *
+     * This can be used to specify global simplification methods to apply during map exports,
+     * e.g. to allow vector layers to be simplified to an appropriate maximum level of detail
+     * during PDF exports (avoiding excessive PDF size due to huge numbers of vertices).
+     *
+     * The default is to use no simplification.
+     *
+     * \note This simplification method is only used during non-preview renders.
+     *
+     * \see simplifyMethod()
+     *
+     * \since QGIS 3.10
+     */
+    void setSimplifyMethod( const QgsVectorSimplifyMethod &method ) { mSimplifyMethod = method; }
+
+    /**
+     * Returns the simplification settings to use when rendering vector layers.
+     *
+     * If enabled, it will apply to all vector layers rendered for the map.
+     *
+     * The default is to use no simplification.
+     *
+     * \note This simplification method is only used during non-preview renders.
+     *
+     * \see setSimplifyMethod()
+     * \since QGIS 3.10
+     */
+    const QgsVectorSimplifyMethod &simplifyMethod() const { return mSimplifyMethod; }
+
   signals:
 
     /**
@@ -255,6 +288,8 @@ class CORE_EXPORT QgsLayoutRenderContext : public QObject
 
     QgsRenderContext::TextRenderFormat mTextRenderFormat = QgsRenderContext::TextFormatAlwaysOutlines;
 
+    QgsVectorSimplifyMethod mSimplifyMethod;
+
     friend class QgsLayoutExporter;
     friend class TestQgsLayout;
     friend class LayoutContextPreviewSettingRestorer;

diff --git a/tests/src/core/testqgslayoutcontext.cpp b/tests/src/core/testqgslayoutcontext.cpp
@@ -48,6 +48,7 @@ class TestQgsLayoutContext: public QObject
     void exportLayer();
     void geometry();
     void scales();
+    void simplifyMethod();
 
   private:
     QString mReport;
@@ -273,5 +274,17 @@ void TestQgsLayoutContext::scales()
   QCOMPARE( context.predefinedScales(), QVector< qreal >() << 1 << 5 << 10 << 15 );
 }
 
+void TestQgsLayoutContext::simplifyMethod()
+{
+  QgsLayout l( QgsProject::instance() );
+  QgsLayoutRenderContext context( &l );
+  // must default to no simplification
+  QCOMPARE( context.simplifyMethod().simplifyHints(), QgsVectorSimplifyMethod::NoSimplification );
+  QgsVectorSimplifyMethod simplify;
+  simplify.setSimplifyHints( QgsVectorSimplifyMethod::GeometrySimplification );
+  context.setSimplifyMethod( simplify );
+  QCOMPARE( context.simplifyMethod().simplifyHints(), QgsVectorSimplifyMethod::GeometrySimplification );
+}
+
 QGSTEST_MAIN( TestQgsLayoutContext )
 #include "testqgslayoutcontext.moc"