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b6b5afd885
The improvement allows immediate cancellation of raster rendering in progress. Until now, even when map rendering got cancelled (e.g. by zooming of panning canvas), the GUI got blocked while waiting for raster layers to finish their rendering (only vector layers have had support for cancellation). This should allow for much smoother user experience while browsing maps including rasters. The cancellation is supported currently by WMS/WMTS and WCS providers. GDAL provider may also get support thanks to improvements in GDAL 2. Funded by Land Information New Zealand.
328 lines
13 KiB
Plaintext
328 lines
13 KiB
Plaintext
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/**
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* \brief Handles asynchronous download of images
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*
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* \note added in 2.8
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*/
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class QgsImageFetcher : QObject
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{
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%TypeHeaderCode
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#include <qgsrasterdataprovider.h>
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%End
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public:
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/** Constructor */
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QgsImageFetcher( QObject* parent = 0 );
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/** Destructor */
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virtual ~QgsImageFetcher();
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/** Starts the image download
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* @note Make sure to connect to "finish" and "error" before starting */
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virtual void start() = 0;
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signals:
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/** Emitted when the download completes
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* @param legend The downloaded legend image */
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void finish( const QImage& legend );
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/** Emitted to report progress */
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void progress( qint64 received, qint64 total );
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/** Emitted when an error occurs */
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void error( const QString& msg );
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};
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/** \ingroup core
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* Base class for raster data providers.
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*/
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class QgsRasterDataProvider : QgsDataProvider, QgsRasterInterface
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{
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%TypeHeaderCode
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#include <qgsrasterdataprovider.h>
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#include <qgsrasterinterface.h>
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#include <qgsrasteridentifyresult.h>
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%End
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public:
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QgsRasterDataProvider();
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QgsRasterDataProvider( const QString & uri );
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virtual ~QgsRasterDataProvider();
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virtual QgsRasterInterface * clone() const = 0;
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/* It makes no sense to set input on provider */
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bool setInput( QgsRasterInterface* input );
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/** \brief Renders the layer as an image
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* \note When render caching (/qgis/enable_render_caching) is on the wms
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* provider doesn't wait for the reply of the getmap request or all
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* tiles replies and can return incomplete images.
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* Temporarily disable render caching if you require the complete
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* wms image in the first call.
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*/
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virtual QImage* draw( const QgsRectangle & viewExtent, int pixelWidth, int pixelHeight ) = 0;
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/** Get the extent of the data source.
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* @return QgsRectangle containing the extent of the layer
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*/
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virtual QgsRectangle extent() const = 0;
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/** Returns data type for the band specified by number */
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virtual Qgis::DataType dataType( int bandNo ) const = 0;
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/** Returns source data type for the band specified by number,
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* source data type may be shorter than dataType
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*/
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virtual Qgis::DataType sourceDataType( int bandNo ) const = 0;
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/** Returns data type for the band specified by number */
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virtual int colorInterpretation( int theBandNo ) const;
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QString colorName( int colorInterpretation ) const;
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/** Reload data (data could change) */
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virtual bool reload();
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virtual QString colorInterpretationName( int theBandNo ) const;
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/** Read band scale for raster value
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* @note added in 2.3
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*/
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virtual double bandScale( int bandNo ) const;
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/** Read band offset for raster value
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* @note added in 2.3
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*/
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virtual double bandOffset( int bandNo ) const;
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/** Get block size */
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virtual int xBlockSize() const;
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virtual int yBlockSize() const;
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/** Get raster size */
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virtual int xSize() const;
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virtual int ySize() const;
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/** Read block of data using given extent and size. */
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virtual QgsRasterBlock *block( int theBandNo, const QgsRectangle &theExtent, int theWidth, int theHeight, QgsRasterBlockFeedback* feedback = nullptr ) / Factory /;
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/** Return true if source band has no data value */
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virtual bool sourceHasNoDataValue( int bandNo ) const;
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/** \brief Get source nodata value usage */
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virtual bool useSourceNoDataValue( int bandNo ) const;
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/** \brief Set source nodata value usage */
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virtual void setUseSourceNoDataValue( int bandNo, bool use );
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/** Value representing no data value. */
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virtual double sourceNoDataValue( int bandNo ) const;
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virtual void setUserNoDataValue( int bandNo, const QgsRasterRangeList& noData );
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/** Get list of user no data value ranges */
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virtual QgsRasterRangeList userNoDataValues( int bandNo ) const;
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virtual QList<QgsColorRampShader::ColorRampItem> colorTable( int bandNo ) const;
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/** \brief Returns the sublayers of this layer - useful for providers that manage
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* their own layers, such as WMS */
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virtual QStringList subLayers() const;
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/** \brief Returns whether the provider supplies a legend graphic */
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virtual bool supportsLegendGraphic() const;
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/** \brief Returns the legend rendered as pixmap
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*
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* useful for that layer that need to get legend layer remotely as WMS
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* \param scale Optional parameter that is the Scale of the layer
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* \param forceRefresh Optional bool parameter to force refresh getLegendGraphic call
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* \param visibleExtent Visible extent for providers supporting contextual legends, in layer CRS
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* \note visibleExtent parameter added in 2.8 (no available in python bindings)
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*/
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virtual QImage getLegendGraphic( double scale = 0, bool forceRefresh = false, const QgsRectangle * visibleExtent = 0 );
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/**
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* \brief Get an image downloader for the raster legend
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*
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* \param mapSettings map settings for legend providers supporting
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* contextual legends.
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*
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* \return a download handler or null if the provider does not support
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* legend at all. Ownership of the returned object is transferred
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* to caller.
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*
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* \note added in 2.8
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*
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*/
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virtual QgsImageFetcher* getLegendGraphicFetcher( const QgsMapSettings* mapSettings ) /Factory/;
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/** \brief Create pyramid overviews */
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virtual QString buildPyramids( const QList<QgsRasterPyramid> & thePyramidList,
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const QString & theResamplingMethod = "NEAREST",
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QgsRaster::RasterPyramidsFormat theFormat = QgsRaster::PyramidsGTiff,
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const QStringList & theConfigOptions = QStringList() );
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/** \brief Accessor for ths raster layers pyramid list.
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* @param overviewList used to construct the pyramid list (optional), when empty the list is defined by the provider.
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* A pyramid list defines the
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* POTENTIAL pyramids that can be in a raster. To know which of the pyramid layers
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* ACTUALLY exists you need to look at the existsFlag member in each struct stored in the
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* list.
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*/
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virtual QList<QgsRasterPyramid> buildPyramidList( QList<int> overviewList = QList<int>() );
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/** \brief Returns true if raster has at least one populated histogram. */
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bool hasPyramids();
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/**
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* Get metadata in a format suitable for feeding directly
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* into a subset of the GUI raster properties "Metadata" tab.
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*/
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virtual QString metadata() = 0;
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/** \brief Identify raster value(s) found on the point position. The context
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* parameters theExtent, theWidth and theHeight are important to identify
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* on the same zoom level as a displayed map and to do effective
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* caching (WCS). If context params are not specified the highest
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* resolution is used. capabilities() may be used to test if format
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* is supported by provider. Values are set to 'no data' or empty string
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* if point is outside data source extent.
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*
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* \note The arbitraryness of the returned document is enforced by WMS standards
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* up to at least v1.3.0
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* @param thePoint coordinates in data source CRS
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* @param theFormat result format
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* @param theExtent context extent
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* @param theWidth context width
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* @param theHeight context height
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* @param theDpi context dpi
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* @return QgsRaster::IdentifyFormatValue: map of values for each band, keys are band numbers
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* (from 1).
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* QgsRaster::IdentifyFormatFeature: map of QgsRasterFeatureList for each sublayer
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* (WMS) - TODO: it is not consistent with QgsRaster::IdentifyFormatValue.
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* QgsRaster::IdentifyFormatHtml: map of HTML strings for each sublayer (WMS).
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* Empty if failed or there are no results (TODO: better error reporting).
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*/
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//virtual QMap<int, QVariant> identify( const QgsPoint & thePoint, QgsRaster::IdentifyFormat theFormat, const QgsRectangle &theExtent = QgsRectangle(), int theWidth = 0, int theHeight = 0 );
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virtual QgsRasterIdentifyResult identify( const QgsPoint & thePoint, QgsRaster::IdentifyFormat theFormat, const QgsRectangle &theExtent = QgsRectangle(), int theWidth = 0, int theHeight = 0, int theDpi = 96 );
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/**
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* \brief Returns the caption error text for the last error in this provider
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*
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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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*
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*/
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virtual QString lastErrorTitle() = 0;
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/**
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* \brief Returns the verbose error text for the last error in this provider
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*
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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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*
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*/
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virtual QString lastError() = 0;
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/** Returns the format of the error text for the last error in this provider */
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virtual QString lastErrorFormat();
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/** Returns the dpi of the output device. */
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int dpi() const;
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/** Sets the output device resolution. */
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void setDpi( int dpi );
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/** Time stamp of data source in the moment when data/metadata were loaded by provider */
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virtual QDateTime timestamp() const;
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/** Current time stamp of data source */
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virtual QDateTime dataTimestamp() const;
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/** Writes into the provider datasource*/
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// TODO: add data type (may be defferent from band type)
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virtual bool write( void* data, int band, int width, int height, int xOffset, int yOffset );
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/** Creates a new dataset with mDataSourceURI */
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static QgsRasterDataProvider* create( const QString &providerKey,
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const QString &uri,
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const QString& format, int nBands,
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Qgis::DataType type,
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int width, int height, double* geoTransform,
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const QgsCoordinateReferenceSystem& crs,
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const QStringList& createOptions = QStringList() );
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/** Set no data value on created dataset
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* @param bandNo band number
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* @param noDataValue no data value
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*/
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virtual bool setNoDataValue( int bandNo, double noDataValue );
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/** Remove dataset*/
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virtual bool remove();
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/** Returns a list of pyramid resampling method name and label pairs
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* for given provider
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*/
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static QList<QPair<QString, QString> > pyramidResamplingMethods( const QString& providerKey );
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/** Validates creation options for a specific dataset and destination format.
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* @note used by GDAL provider only
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* @note see also validateCreationOptionsFormat() in gdal provider for validating options based on format only
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*/
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virtual QString validateCreationOptions( const QStringList& createOptions, const QString& format );
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/** Validates pyramid creation options for a specific dataset and destination format
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* @note used by GDAL provider only
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*/
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virtual QString validatePyramidsConfigOptions( QgsRaster::RasterPyramidsFormat pyramidsFormat,
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const QStringList & theConfigOptions, const QString & fileFormat );
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static QString identifyFormatName( QgsRaster::IdentifyFormat format );
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static QgsRaster::IdentifyFormat identifyFormatFromName( const QString& formatName );
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static QString identifyFormatLabel( QgsRaster::IdentifyFormat format );
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static Capability identifyFormatToCapability( QgsRaster::IdentifyFormat format );
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signals:
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/** Emit a signal to notify of the progress event.
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* Emitted theProgress is in percents (0.0-100.0) */
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void progress( int theType, double theProgress, const QString& theMessage );
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void progressUpdate( int theProgress );
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/** Emit a message to be displayed on status bar, usually used by network providers (WMS,WCS)
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* @note added in 2.14
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*/
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void statusChanged( const QString& ) const;
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protected:
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/** Read block of data
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* @note not available in python bindings
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*/
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virtual void readBlock( int bandNo, int xBlock, int yBlock, void *data );
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/** Read block of data using give extent and size
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* @note not available in python bindings
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*/
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//virtual void readBlock( int bandNo, QgsRectangle const & viewExtent, int width, int height, void *data, QgsRasterBlockFeedback* feedback = nullptr );
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/** Returns true if user no data contains value */
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bool userNoDataValuesContains( int bandNo, double value ) const;
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/** Copy member variables from other raster data provider. Useful for implementation of clone() method in subclasses */
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void copyBaseSettings( const QgsRasterDataProvider& other );
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//! @note not available in Python bindings
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//static QStringList cStringList2Q_( char ** stringList );
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static QString makeTableCell( const QString & value );
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static QString makeTableCells( const QStringList & values );
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/** Source no data value is available and is set to be used or internal no data
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* is available. Used internally only */
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//bool hasNoDataValue ( int theBandNo );
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};
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