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* \brief Base class for all map layer types.
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* This class is the base class for all map layer types (vector, raster).
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class QgsMapLayer : QObject
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#include <qgsmaplayer.h>
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%ConvertToSubClassCode
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if (sipCpp->inherits("QgsMapLayer"))
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sipClass = sipClass_QgsMapLayer;
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QgsMapLayer* layer = qobject_cast<QgsMapLayer*>(sipCpp);
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if (layer->type() == QgsMapLayer::VectorLayer)
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sipClass = sipClass_QgsVectorLayer;
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else if (layer->type() == QgsMapLayer::RasterLayer)
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sipClass = sipClass_QgsRasterLayer;
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/** Layers enum defining the types of layers that can be added to a map */
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* @param type Type of layer as defined in QgsMapLayer::LayerType enum
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* @param lyrname Display Name of the layer
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QgsMapLayer(QgsMapLayer::LayerType type = QgsMapLayer::VectorLayer, QString lyrname = QString::null, QString source = QString::null);
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virtual ~QgsMapLayer();
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/** Get the type of the layer
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* @return Integer matching a value in the QgsMapLayer::LayerType enum
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QgsMapLayer::LayerType type() const;
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/** Get this layer's unique ID, this ID is used to access this layer from map layer registry */
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QString getLayerID() const;
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/** Set the display name of the layer
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* @param name New name for the layer
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void setLayerName(const QString & name);
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/** Get the display name of the layer
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* @return the layer name
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const QString & name() const;
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/** Render the layer, to be overridden in child classes
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virtual bool draw(QgsRenderContext& rendererContext);
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* @TODO to be removed: used only in vector layers
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virtual void drawLabels(QgsRenderContext& rendererContext);
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/** Return the extent of the layer as a QRect */
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const QgsRectangle extent();
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/*! Return the status of the layer. An invalid layer is one which has a bad datasource
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* or other problem. Child classes set this flag when intialized
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* @return True if the layer is valid and can be accessed
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/*! Gets a version of the internal layer definition that has sensitive
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* bits removed (for example, the password). This function should
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* be used when displaying the source name for general viewing.
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QString publicSource() const;
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/** Returns the source for the layer */
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const QString & source() const;
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* Returns the sublayers of this layer
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* (Useful for providers that manage their own layers, such as WMS)
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virtual QStringList subLayers();
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* Reorders the *previously selected* sublayers of this layer from bottom to top
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* (Useful for providers that manage their own layers, such as WMS)
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virtual void setLayerOrder(QStringList layers);
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/** Set the visibility of the given sublayer name */
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virtual void setSubLayerVisibility(QString name, bool vis);
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/** True if the layer can be edited */
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virtual bool isEditable() const = 0;
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/** sets state from Dom document
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@param layer_node is Dom node corresponding to ``maplayer'' tag
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The Dom node corresponds to a Dom document project file XML element read
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This, in turn, calls readXml(), which is over-rideable by sub-classes so
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that they can read their own specific state from the given Dom node.
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Invoked by QgsProject::read().
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@returns true if successful
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bool readXML(QDomNode & layer_node);
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/** stores state in Dom node
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@param layer_node is Dom node corresponding to ``projectlayers'' tag
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The Dom node corresponds to a Dom document project file XML element to be
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written by QgsProject.
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This, in turn, calls writeXml(), which is over-rideable by sub-classes so
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that they can write their own specific state to the given Dom node.
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Invoked by QgsProject::write().
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@returns true if successful
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bool writeXML(QDomNode & layer_node, QDomDocument & document) const;
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/** Set a custom property for layer. Properties are stored in a map and saved in project file.
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* @note Added in v1.4 */
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void setCustomProperty( const QString& key, const QVariant& value );
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/** Read a custom property from layer. Properties are stored in a map and saved in project file.
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* @note Added in v1.4 */
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QVariant customProperty( const QString& value, const QVariant& defaultValue = QVariant() ) const;
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/** Remove a custom property from layer. Properties are stored in a map and saved in project file.
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* @note Added in v1.4 */
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void removeCustomProperty( const QString& key );
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/** Read the symbology for the current layer from the Dom node supplied.
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* @param QDomNode node that will contain the symbology definition for this layer.
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* @param errorMessage reference to string that will be updated with any error messages
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* @return true in case of success.
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virtual bool readSymbology(const QDomNode& node, QString& errorMessage) = 0;
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/** Write the symbology for the layer into the docment provided.
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* @param QDomNode the node that will have the style element added to it.
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* @param QDomDocument the document that will have the QDomNode added.
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* @param errorMessage reference to string that will be updated with any error messages
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* @return true in case of success.
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virtual bool writeSymbology(QDomNode&, QDomDocument& doc, QString& errorMessage) const = 0;
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/** Copies the symbology settings from another layer. Returns true in case of success */
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virtual bool copySymbologySettings(const QgsMapLayer& other) = 0;
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/** Returns true if this layer can be in the same symbology group with another layer */
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virtual bool hasCompatibleSymbology(const QgsMapLayer& other) const = 0;
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/** Accessor for transparency level. */
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unsigned int getTransparency();
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/** Mutator for transparency level. Should be between 0 and 255 */
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void setTransparency(unsigned int);
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* If an operation returns 0 (e.g. draw()), this function
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* returns the text of the error associated with the failure.
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* Interactive users of this provider can then, for example,
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* call a QMessageBox to display the contents.
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virtual QString lastErrorTitle();
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* If an operation returns 0 (e.g. draw()), this function
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* returns the text of the error associated with the failure.
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* Interactive users of this provider can then, for example,
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* call a QMessageBox to display the contents.
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virtual QString lastError();
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/** Returns layer's spatial reference system
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@note This was introduced in QGIS 1.4
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const QgsCoordinateReferenceSystem& crs();
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/** Returns layer's spatial reference system
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@note This method is here for API compatibility
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and will be deprecited in 2.0
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const QgsCoordinateReferenceSystem& srs();
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/** Sets layer's spatial reference system
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@note emitSignal added in 1.4 */
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void setCrs( const QgsCoordinateReferenceSystem& srs, bool emitSignal = true );
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/** A convenience function to capitalise the layer name */
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static QString capitaliseLayerName(const QString name);
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/** Retrieve the default style for this layer if one
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* exists (either as a .qml file on disk or as a
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* record in the users style table in their personal qgis.db)
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* @param a reference to a flag that will be set to false if
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* we did not manage to load the default style.
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* @return a QString with any status messages
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* @see also loadNamedStyle ();
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virtual QString loadDefaultStyle( bool & theResultFlag );
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/** Retrieve a named style for this layer if one
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* exists (either as a .qml file on disk or as a
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* record in the users style table in their personal qgis.db)
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* @param QString theURI - the file name or other URI for the
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* style file. First an attempt will be made to see if this
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* is a file and load that, if that fails the qgis.db styles
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* table will be consulted to see if there is a style who's
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* key matches the URI.
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* @param a reference to a flag that will be set to false if
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* we did not manage to load the default style.
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* @return a QString with any status messages
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* @see also loadDefaultStyle ();
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virtual QString loadNamedStyle( const QString theURI, bool & theResultFlag );
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virtual bool loadNamedStyleFromDb( const QString db, const QString theURI, QString &qml );
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/** Save the properties of this layer as the default style
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* (either as a .qml file on disk or as a
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* record in the users style table in their personal qgis.db)
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* @param a reference to a flag that will be set to false if
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* we did not manage to save the default style.
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* @return a QString with any status messages
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* @see also loadNamedStyle () and saveNamedStyle()
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virtual QString saveDefaultStyle( bool & theResultFlag );
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/** Save the properties of this layer as a named style
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* (either as a .qml file on disk or as a
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* record in the users style table in their personal qgis.db)
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* @param QString theURI - the file name or other URI for the
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* style file. First an attempt will be made to see if this
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* is a file and save to that, if that fails the qgis.db styles
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* table will be used to create a style entry who's
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* key matches the URI.
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* @param a reference to a flag that will be set to false if
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* we did not manage to save the default style.
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* @return a QString with any status messages
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* @see also saveDefaultStyle ();
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virtual QString saveNamedStyle( const QString theURI, bool & theResultFlag );
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/** Return pointer to layer's undo stack */
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QUndoStack* undoStack();
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/** Get the QImage used for caching render operations
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* @note This method was added in QGIS 1.4 **/
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QImage *cacheImage();
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/** Set the QImage used for caching render operations
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* @note This method was added in QGIS 1.4 **/
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void setCacheImage( QImage * thepImage );
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/** Event handler for when a coordinate transform fails due to bad vertex error */
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virtual void invalidTransformInput();
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/** Accessor and mutator for the minimum scale member */
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void setMinimumScale(float theMinScale);
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float minimumScale();
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/** Accessor and mutator for the maximum scale member */
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void setMaximumScale(float theMaxScale);
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float maximumScale();
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/** Accessor and mutator for the scale based visilibility flag */
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void toggleScaleBasedVisibility( bool theVisibilityFlag);
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bool hasScaleBasedVisibility();
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/** Emit a signal to notify of a progress event */
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void setProgress(int theProgress, int theTotalSteps);
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/** Emit a signal with status (e.g. to be caught by QgiAapp and display a msg on status bar) */
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void setStatus(QString theStatusQString);
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/** Emit a signal that the layer name has been changed */
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void layerNameChanged();
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/** Emit a signal that layer's CRS has been reset
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void layerCrsChanged();
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/** This signal should be connected with the slot QgsMapCanvas::refresh()
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* @TODO: to be removed - GUI dependency
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void repaintRequested();
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/** This is used to send a request that any mapcanvas using this layer update its extents */
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void recalculateExtents();
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/** called by readXML(), used by children to read state specific to them from
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virtual bool readXml( QDomNode & layer_node );
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/** called by writeXML(), used by children to write state specific to them to
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virtual bool writeXml( QDomNode & layer_node, QDomDocument & document );
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/** debugging member - invoked when a connect() is made to this object */
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void connectNotify( const char * signal );
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/** private copy constructor - QgsMapLayer not copyable */
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QgsMapLayer( const QgsMapLayer & );
added
removed
python/core/qgsmaplayer.sip
