Create a QgsLayerStyleOverride and use it for the job renderer

qgis · Jun 11, 2018 · 5c267f2 · 5c267f2
1 parent 5ba1e91
commit 5c267f2
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Showing 4 changed files with 78 additions and 20 deletions.
diff --git a/python/core/auto_generated/qgsmaplayerstylemanager.sip.in b/python/core/auto_generated/qgsmaplayerstylemanager.sip.in
@@ -11,7 +11,6 @@
 
 
 
-
 class QgsMapLayerStyle
 {
 %Docstring
@@ -224,6 +223,35 @@ Emitted when the current style has been changed
 
 };
 
+
+class QgsLayerStyleOverride
+{
+%Docstring
+Restore overridden layer style on destruction.
+
+.. versionadded:: 3.2
+%End
+
+%TypeHeaderCode
+#include "qgsmaplayerstylemanager.h"
+%End
+  public:
+
+    QgsLayerStyleOverride( QgsMapLayer *layer );
+%Docstring
+Construct a style override object associated with a map layer.
+The overridden style will be restored upon object destruction.
+%End
+
+    ~QgsLayerStyleOverride();
+
+    void setOverrideStyle( const QString &style );
+%Docstring
+Temporarily apply a different style to the layer. The argument
+can be either a style name or a full QML style definition.
+%End
+
+};
 /************************************************************************
  * This file has been generated automatically from                      *
  *                                                                      *

diff --git a/src/core/qgsmaplayerstylemanager.cpp b/src/core/qgsmaplayerstylemanager.cpp
@@ -16,7 +16,6 @@
 #include "qgsmaplayerstylemanager.h"
 
 #include "qgslogger.h"
-#include "qgsmaplayer.h"
 
 #include <QDomElement>
 #include <QTextStream>

diff --git a/src/core/qgsmaplayerstylemanager.h b/src/core/qgsmaplayerstylemanager.h
@@ -16,16 +16,15 @@
 #ifndef QGSMAPLAYERSTYLEMANAGER_H
 #define QGSMAPLAYERSTYLEMANAGER_H
 
-
-class QgsMapLayer;
+#include "qgis_core.h"
+#include "qgis_sip.h"
+#include "qgsmaplayer.h"
 
 #include <QByteArray>
 #include <QMap>
 #include <QStringList>
 #include <QObject>
 
-#include "qgis_core.h"
-#include "qgis_sip.h"
 
 class QDomElement;
 
@@ -195,4 +194,47 @@ class CORE_EXPORT QgsMapLayerStyleManager : public QObject
     QString defaultStyleName() const;
 };
 
+
+/**
+ * \ingroup core
+ * Restore overridden layer style on destruction.
+ *
+ * \since QGIS 3.2
+ */
+class CORE_EXPORT QgsLayerStyleOverride
+{
+  public:
+
+    /**
+     * Construct a style override object associated with a map layer.
+     * The overridden style will be restored upon object destruction.
+     */
+    QgsLayerStyleOverride( QgsMapLayer *layer )
+      : mLayer( layer )
+    {
+    }
+
+    ~QgsLayerStyleOverride()
+    {
+      if ( mLayer && mStyleOverridden )
+        mLayer->styleManager()->restoreOverrideStyle();
+    }
+
+    /**
+     * Temporarily apply a different style to the layer. The argument
+     * can be either a style name or a full QML style definition.
+     */
+    void setOverrideStyle( const QString &style )
+    {
+      if ( mLayer && mStyleOverridden )
+        mLayer->styleManager()->restoreOverrideStyle();
+      mLayer->styleManager()->setOverrideStyle( style );
+      mStyleOverridden = true;
+    }
+
+  private:
+
+    QgsMapLayer *mLayer = nullptr;
+    bool mStyleOverridden = false;
+};
 #endif // QGSMAPLAYERSTYLEMANAGER_H
diff --git a/src/core/qgsmaprendererjob.cpp b/src/core/qgsmaprendererjob.cpp
@@ -216,8 +216,6 @@ bool QgsMapRendererJob::reprojectToLayerExtent( const QgsMapLayer *ml, const Qgs
   return split;
 }
 
-
-
 LayerRenderJobs QgsMapRendererJob::prepareJobs( QPainter *painter, QgsLabelingEngine *labelingEngine2 )
 {
   LayerRenderJobs layerJobs;
@@ -298,9 +296,9 @@ LayerRenderJobs QgsMapRendererJob::prepareJobs( QPainter *painter, QgsLabelingEn
     if ( mFeatureFilterProvider )
       job.context.setFeatureFilterProvider( mFeatureFilterProvider );
 
-    bool hasStyleOverride = mSettings.layerStyleOverrides().contains( ml->id() );
-    if ( hasStyleOverride )
-      ml->styleManager()->setOverrideStyle( mSettings.layerStyleOverrides().value( ml->id() ) );
+    QgsLayerStyleOverride styleOverride( ml );
+    if ( mSettings.layerStyleOverrides().contains( ml->id() ) )
+      styleOverride.setOverrideStyle( mSettings.layerStyleOverrides().value( ml->id() ) );
 
     job.blendMode = ml->blendMode();
     job.opacity = 1.0;
@@ -312,9 +310,6 @@ LayerRenderJobs QgsMapRendererJob::prepareJobs( QPainter *painter, QgsLabelingEn
     // if we can use the cache, let's do it and avoid rendering!
     if ( mCache && mCache->hasCacheImage( ml->id() ) )
     {
-      if ( hasStyleOverride )
-        ml->styleManager()->restoreOverrideStyle();
-
       job.cached = true;
       job.imageInitialized = true;
       job.img = new QImage( mCache->cacheImage( ml->id() ) );
@@ -335,9 +330,6 @@ LayerRenderJobs QgsMapRendererJob::prepareJobs( QPainter *painter, QgsLabelingEn
                                       mSettings.outputImageFormat() );
       if ( mypFlattenedImage->isNull() )
       {
-        if ( hasStyleOverride )
-          ml->styleManager()->restoreOverrideStyle();
-
         mErrors.append( Error( ml->id(), tr( "Insufficient memory for image %1x%2" ).arg( mSettings.outputSize().width() ).arg( mSettings.outputSize().height() ) ) );
         delete mypFlattenedImage;
         layerJobs.removeLast();
@@ -354,9 +346,6 @@ LayerRenderJobs QgsMapRendererJob::prepareJobs( QPainter *painter, QgsLabelingEn
     layerTime.start();
     job.renderer = ml->createMapRenderer( job.context );
     job.renderingTime = layerTime.elapsed(); // include job preparation time in layer rendering time
-
-    if ( hasStyleOverride )
-      ml->styleManager()->restoreOverrideStyle();
   } // while (li.hasPrevious())
 
   return layerJobs;