QGIS API Documentation  2.5.0-Master
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QgsRasterLayer Class Reference

This class provides qgis with the ability to render raster datasets onto the mapcanvas. More...

#include <qgsrasterlayer.h>

Inheritance diagram for QgsRasterLayer:
Inheritance graph
[legend]

Public Types

enum  ColorShadingAlgorithm {
  UndefinedShader, PseudoColorShader, FreakOutShader, ColorRampShader,
  UserDefinedShader
}
 This enumerator describes the types of shading that can be used. More...
 
enum  LayerType { GrayOrUndefined, Palette, Multiband, ColorLayer }
 This enumerator describes the type of raster layer. More...
 
- Public Types inherited from QgsMapLayer
enum  LayerType { VectorLayer, RasterLayer, PluginLayer }
 Layers enum defining the types of layers that can be added to a map. More...
 

Public Slots

void showStatusMessage (const QString &theMessage)
 
Q_DECL_DEPRECATED void updateProgress (int, int)
 
void onProgress (int, double, QString)
 receive progress signal from provider More...
 
- Public Slots inherited from QgsMapLayer
virtual void invalidTransformInput ()
 Event handler for when a coordinate transform fails due to bad vertex error. More...
 
void setMinimumScale (float theMinScale)
 Accessor and mutator for the minimum scale denominator member. More...
 
float minimumScale () const
 
void setMaximumScale (float theMaxScale)
 Accessor and mutator for the maximum scale denominator member. More...
 
float maximumScale () const
 
void toggleScaleBasedVisibility (bool theVisibilityFlag)
 Accessor and mutator for the scale based visilibility flag. More...
 
bool hasScaleBasedVisibility () const
 
Q_DECL_DEPRECATED void clearCacheImage ()
 Clear cached image. More...
 
void triggerRepaint ()
 Will advice the map canvas (and any other interested party) that this layer requires to be repainted. More...
 

Signals

void progressUpdate (int theValue)
 Signal for notifying listeners of long running processes. More...
 
void dataChanged ()
 This is emitted whenever data or metadata (e.g. More...
 
- Signals inherited from QgsMapLayer
void drawingProgress (int theProgress, int theTotalSteps)
 
void statusChanged (QString theStatus)
 Emit a signal with status (e.g. More...
 
void layerNameChanged ()
 Emit a signal that the layer name has been changed. More...
 
void layerCrsChanged ()
 Emit a signal that layer's CRS has been reset added in 1.4. More...
 
void repaintRequested ()
 By emitting this signal the layer tells that either appearance or content have been changed and any view showing the rendered layer should refresh itself. More...
 
void screenUpdateRequested ()
 
void recalculateExtents ()
 This is used to send a request that any mapcanvas using this layer update its extents. More...
 
void dataChanged ()
 data of layer changed added in 1.5 More...
 
void blendModeChanged (const QPainter::CompositionMode &blendMode)
 Signal emitted when the blend mode is changed, through QgsMapLayer::setBlendMode() More...
 
void rendererChanged ()
 Signal emitted when renderer is changed. More...
 
void legendChanged ()
 Signal emitted when legend of the layer has changed. More...
 

Public Member Functions

 QgsRasterLayer ()
 Constructor. More...
 
 QgsRasterLayer (const QString &path, const QString &baseName=QString::null, bool loadDefaultStyleFlag=true)
 This is the constructor for the RasterLayer class. More...
 
 QgsRasterLayer (const QString &uri, const QString &baseName, const QString &providerKey, bool loadDefaultStyleFlag=true)
 [ data provider interface ] Constructor in provider mode More...
 
 ~QgsRasterLayer ()
 The destructor. More...
 
void setDataProvider (const QString &provider)
 [ data provider interface ] Set the data provider More...
 
LayerType rasterType ()
 Accessor for raster layer type (which is a read only property) More...
 
void setRenderer (QgsRasterRenderer *theRenderer)
 Set raster renderer. More...
 
QgsRasterRendererrenderer () const
 
QgsRasterResampleFilterresampleFilter () const
 Set raster resample filter. More...
 
QgsBrightnessContrastFilterbrightnessFilter () const
 
QgsHueSaturationFilterhueSaturationFilter () const
 
QgsRasterPipepipe ()
 Get raster pipe. More...
 
int width () const
 Accessor that returns the width of the (unclipped) raster. More...
 
int height () const
 Accessor that returns the height of the (unclipped) raster. More...
 
int bandCount () const
 Get the number of bands in this layer. More...
 
const QString bandName (int theBandNoInt)
 Get the name of a band given its number. More...
 
QgsRasterDataProviderdataProvider ()
 Returns the data provider. More...
 
const QgsRasterDataProviderdataProvider () const
 Returns the data provider in a const-correct manner. More...
 
virtual void reload ()
 Synchronises with changes in the datasource. More...
 
virtual QgsMapLayerRenderercreateMapRenderer (QgsRenderContext &rendererContext)
 Return new instance of QgsMapLayerRenderer that will be used for rendering of given context. More...
 
bool draw (QgsRenderContext &rendererContext)
 This is called when the view on the raster layer needs to be redrawn. More...
 
void draw (QPainter *theQPainter, QgsRasterViewPort *myRasterViewPort, const QgsMapToPixel *theQgsMapToPixel=0)
 This is an overloaded version of the draw() function that is called by both draw() and thumbnailAsPixmap. More...
 
QgsLegendColorList legendSymbologyItems () const
 Returns a list with classification items (Text and color) More...
 
QString metadata ()
 Obtain GDAL Metadata for this layer. More...
 
QPixmap paletteAsPixmap (int theBandNumber=1)
 Get an 100x100 pixmap of the color palette. More...
 
QString providerType () const
 [ data provider interface ] Which provider is being used for this Raster Layer? More...
 
double rasterUnitsPerPixelX ()
 Returns the number of raster units per each raster pixel. More...
 
double rasterUnitsPerPixelY ()
 
void setContrastEnhancement (QgsContrastEnhancement::ContrastEnhancementAlgorithm theAlgorithm, QgsRaster::ContrastEnhancementLimits theLimits=QgsRaster::ContrastEnhancementMinMax, QgsRectangle theExtent=QgsRectangle(), int theSampleSize=SAMPLE_SIZE, bool theGenerateLookupTableFlag=true)
 Set contrast enhancement algorithm. More...
 
void setDefaultContrastEnhancement ()
 Set default contrast enhancement. More...
 
void setDrawingStyle (const QString &theDrawingStyleQString)
 Overloaded version of the above function for convenience when restoring from xml. More...
 
void showProgress (int theValue)
 [ data provider interface ] A wrapper function to emit a progress update signal More...
 
virtual QStringList subLayers () const
 Returns the sublayers of this layer - Useful for providers that manage their own layers, such as WMS. More...
 
Q_DECL_DEPRECATED QPixmap previewAsPixmap (QSize size, QColor bgColor=Qt::white)
 Draws a preview of the rasterlayer into a pixmap. More...
 
QImage previewAsImage (QSize size, QColor bgColor=Qt::white, QImage::Format format=QImage::Format_ARGB32_Premultiplied)
 Draws a preview of the rasterlayer into a QImage. More...
 
virtual void setLayerOrder (const QStringList &layers)
 Reorders the previously selected sublayers of this layer from bottom to top. More...
 
virtual void setSubLayerVisibility (QString name, bool vis)
 Set the visibility of the given sublayer name. More...
 
virtual QDateTime timestamp () const
 Time stamp of data source in the moment when data/metadata were loaded by provider. More...
 
- Public Member Functions inherited from QgsMapLayer
 QgsMapLayer (QgsMapLayer::LayerType type=VectorLayer, QString lyrname=QString::null, QString source=QString::null)
 Constructor. More...
 
virtual ~QgsMapLayer ()
 Destructor. More...
 
QgsMapLayer::LayerType type () const
 Get the type of the layer. More...
 
QString id () const
 Get this layer's unique ID, this ID is used to access this layer from map layer registry. More...
 
void setLayerName (const QString &name)
 Set the display name of the layer. More...
 
const QString & name () const
 Get the display name of the layer. More...
 
const QString & originalName () const
 Get the original name of the layer. More...
 
void setTitle (const QString &title)
 
const QString & title () const
 
void setAbstract (const QString &abstract)
 
const QString & abstract () const
 
void setKeywordList (const QString &keywords)
 
const QString & keywordList () const
 
void setDataUrl (const QString &dataUrl)
 
const QString & dataUrl () const
 
void setDataUrlFormat (const QString &dataUrlFormat)
 
const QString & dataUrlFormat () const
 
void setAttribution (const QString &attrib)
 
const QString & attribution () const
 
void setAttributionUrl (const QString &attribUrl)
 
const QString & attributionUrl () const
 
void setMetadataUrl (const QString &metaUrl)
 
const QString & metadataUrl () const
 
void setMetadataUrlType (const QString &metaUrlType)
 
const QString & metadataUrlType () const
 
void setMetadataUrlFormat (const QString &metaUrlFormat)
 
const QString & metadataUrlFormat () const
 
void setBlendMode (const QPainter::CompositionMode &blendMode)
 Write blend mode for layer. More...
 
QPainter::CompositionMode blendMode () const
 Read blend mode for layer. More...
 
virtual void drawLabels (QgsRenderContext &rendererContext)
 Draw labels. More...
 
virtual QgsRectangle extent ()
 Return the extent of the layer. More...
 
bool isValid ()
 
QString publicSource () const
 
const QString & source () const
 Returns the source for the layer. More...
 
virtual bool isEditable () const
 True if the layer can be edited. More...
 
bool readLayerXML (const QDomElement &layerElement)
 sets state from Dom document More...
 
bool writeLayerXML (QDomElement &layerElement, QDomDocument &document)
 stores state in Dom node More...
 
void setCustomProperty (const QString &key, const QVariant &value)
 Set a custom property for layer. More...
 
QVariant customProperty (const QString &value, const QVariant &defaultValue=QVariant()) const
 Read a custom property from layer. More...
 
void removeCustomProperty (const QString &key)
 Remove a custom property from layer. More...
 
virtual Q_DECL_DEPRECATED QString lastErrorTitle ()
 
virtual Q_DECL_DEPRECATED QString lastError ()
 
virtual QgsError error () const
 Get current status error. More...
 
const
QgsCoordinateReferenceSystem
crs () const
 Returns layer's spatial reference system. More...
 
void setCrs (const QgsCoordinateReferenceSystem &srs, bool emitSignal=true)
 Sets layer's spatial reference system. More...
 
virtual QString styleURI ()
 Retrieve the style URI for this layer (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...
 
virtual QString loadDefaultStyle (bool &theResultFlag)
 Retrieve the default style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...
 
virtual QString loadNamedStyle (const QString &theURI, bool &theResultFlag)
 Retrieve a named style for this layer if one exists (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...
 
virtual bool loadNamedStyleFromDb (const QString &db, const QString &theURI, QString &qml)
 
virtual void exportNamedStyle (QDomDocument &doc, QString &errorMsg)
 Export the properties of this layer as named style in a QDomDocument. More...
 
virtual void exportSldStyle (QDomDocument &doc, QString &errorMsg)
 Export the properties of this layer as SLD style in a QDomDocument. More...
 
virtual QString saveDefaultStyle (bool &theResultFlag)
 Save the properties of this layer as the default style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...
 
virtual QString saveNamedStyle (const QString &theURI, bool &theResultFlag)
 Save the properties of this layer as a named style (either as a .qml file on disk or as a record in the users style table in their personal qgis.db) More...
 
virtual QString saveSldStyle (const QString &theURI, bool &theResultFlag)
 
virtual QString loadSldStyle (const QString &theURI, bool &theResultFlag)
 
virtual bool readSld (const QDomNode &node, QString &errorMessage)
 
QUndoStack * undoStack ()
 Return pointer to layer's undo stack. More...
 
void setLegendUrl (const QString &legendUrl)
 
const QString & legendUrl () const
 
void setLegendUrlFormat (const QString &legendUrlFormat)
 
const QString & legendUrlFormat () const
 
Q_DECL_DEPRECATED QImage * cacheImage ()
 
Q_DECL_DEPRECATED void setCacheImage (QImage *)
 
virtual Q_DECL_DEPRECATED void onCacheImageDelete ()
 
void setLegend (QgsMapLayerLegend *legend)
 Assign a legend controller to the map layer. More...
 
QgsMapLayerLegendlegend () const
 Can be null. More...
 

Static Public Member Functions

static bool isValidRasterFileName (const QString &theFileNameQString, QString &retError)
 This helper checks to see whether the file name appears to be a valid raster file name. More...
 
static bool isValidRasterFileName (const QString &theFileNameQString)
 
static QDateTime lastModified (const QString &name)
 Return time stamp for given file name. More...
 
- Static Public Member Functions inherited from QgsMapLayer
static QDomDocument asLayerDefinition (QList< QgsMapLayer * > layers)
 Returns the given layer as a layer definition document Layer definitions store the data source as well as styling and custom properties. More...
 
static QList< QgsMapLayer * > fromLayerDefinition (QDomDocument &document)
 Creates a new layer from a layer defininition document. More...
 
static QList< QgsMapLayer * > fromLayerDefinitionFile (const QString qlrfile)
 
static QString capitaliseLayerName (const QString &name)
 A convenience function to (un)capitalise the layer name. More...
 

Static Public Attributes

static const double CUMULATIVE_CUT_LOWER = 0.02
 Default cumulative cut lower limit. More...
 
static const double CUMULATIVE_CUT_UPPER = 0.98
 Default cumulative cut upper limit. More...
 
static const double SAMPLE_SIZE = 250000
 Default sample size (number of pixels) for estimated statistics/histogram calculation. More...
 

Protected Member Functions

bool readSymbology (const QDomNode &node, QString &errorMessage)
 Read the symbology for the current layer from the Dom node supplied. More...
 
bool readXml (const QDomNode &layer_node)
 Reads layer specific state from project file Dom node. More...
 
bool writeSymbology (QDomNode &, QDomDocument &doc, QString &errorMessage) const
 Write the symbology for the layer into the docment provided. More...
 
bool writeXml (QDomNode &layer_node, QDomDocument &doc)
 Write layer specific state to project file Dom node. More...
 
- Protected Member Functions inherited from QgsMapLayer
virtual void setExtent (const QgsRectangle &rect)
 Set the extent. More...
 
void setValid (bool valid)
 set whether layer is valid or not - should be used in constructor. More...
 
void readCustomProperties (const QDomNode &layerNode, const QString &keyStartsWith="")
 Read custom properties from project file. More...
 
void writeCustomProperties (QDomNode &layerNode, QDomDocument &doc) const
 Write custom properties to project file. More...
 
void connectNotify (const char *signal)
 debugging member - invoked when a connect() is made to this object More...
 
void appendError (const QgsErrorMessage &theMessage)
 Add error message. More...
 
void setError (const QgsError &theError)
 Set error message. More...
 

Additional Inherited Members

- Protected Attributes inherited from QgsMapLayer
QgsRectangle mExtent
 Extent of the layer. More...
 
bool mValid
 Indicates if the layer is valid and can be drawn. More...
 
QString mDataSource
 data source description string, varies by layer type More...
 
QString mLayerName
 Name of the layer - used for display. More...
 
QString mLayerOrigName
 Original name of the layer. More...
 
QString mTitle
 
QString mAbstract
 Description of the layer. More...
 
QString mKeywordList
 
QString mDataUrl
 DataUrl of the layer. More...
 
QString mDataUrlFormat
 
QString mAttribution
 Attribution of the layer. More...
 
QString mAttributionUrl
 
QString mMetadataUrl
 MetadataUrl of the layer. More...
 
QString mMetadataUrlType
 
QString mMetadataUrlFormat
 
QString mLegendUrl
 WMS legend. More...
 
QString mLegendUrlFormat
 
QgsError mError
 Error. More...
 

Detailed Description

This class provides qgis with the ability to render raster datasets onto the mapcanvas.

The qgsrasterlayer class makes use of gdal for data io, and thus supports any gdal supported format. The constructor attempts to infer what type of file (LayerType) is being opened - not in terms of the file format (tif, ascii grid etc.) but rather in terms of whether the image is a GRAYSCALE, PaletteD or Multiband,

Within the three allowable raster layer types, there are 8 permutations of how a layer can actually be rendered. These are defined in the DrawingStyle enum and consist of:

SingleBandGray -> a GRAYSCALE layer drawn as a range of gray colors (0-255) SingleBandPseudoColor -> a GRAYSCALE layer drawn using a pseudocolor algorithm PalettedSingleBandGray -> a PaletteD layer drawn in gray scale (using only one of the color components) PalettedSingleBandPseudoColor -> a PaletteD layer having only one of its color components rendered as psuedo color PalettedMultiBandColor -> a PaletteD image where the bands contains 24bit color info and 8 bits is pulled out per color MultiBandSingleBandGray -> a layer containing 2 or more bands, but using only one band to produce a grayscale image MultiBandSingleBandPseudoColor -> a layer containing 2 or more bands, but using only one band to produce a pseudocolor image MultiBandColor -> a layer containing 2 or more bands, mapped to the three RGBcolors. In the case of a multiband with only two bands, one band will have to be mapped to more than one color

Each of the above mentioned drawing styles is implemented in its own draw* function. Some of the drawing styles listed above require statistics about the layer such as the min / max / mean / stddev etc. statistics for a band can be gathered using the bandStatistics function. Note that statistics gathering is a slow process and every effort should be made to call this function as few times as possible. For this reason, qgsraster has a vector class member to store stats for each band. The constructor initialises this vector on startup, but only populates the band name and number fields.

Note that where bands are of gdal 'undefined' type, their values may exceed the renderable range of 0-255. Because of this a linear scaling histogram enhanceContrast is applied to undefined layers to normalise the data into the 0-255 range.

A qgsrasterlayer band can be referred to either by name or by number (base=1). It should be noted that band names as stored in datafiles may not be unique, and so the rasterlayer class appends the band number in brackets behind each band name.

Sample usage of the QgsRasterLayer class:

QString myFileNameQString = "/path/to/file";
QFileInfo myFileInfo(myFileNameQString);
QString myBaseNameQString = myFileInfo.baseName();
QgsRasterLayer *myRasterLayer = new QgsRasterLayer(myFileNameQString, myBaseNameQString);

In order to automate redrawing of a raster layer, you should like it to a map canvas like this :

QObject::connect( myRasterLayer, SIGNAL(repaintRequested()), mapCanvas, SLOT(refresh()) );

A raster layer can also export its legend as a pixmap:

QPixmap myQPixmap = myRasterLayer->legendPixmap();

Once a layer has been created you can find out what type of layer it is (GrayOrUndefined, Palette or Multiband):

if (rasterLayer->rasterType()==QgsRasterLayer::Multiband)
{
//do something
}
else if (rasterLayer->rasterType()==QgsRasterLayer::Palette)
{
//do something
}
else // QgsRasterLayer::GrayOrUndefined
{
//do something.
}

You can combine layer type detection with the setDrawingStyle method to override the default drawing style assigned when a layer is loaded:

if (rasterLayer->rasterType()==QgsRasterLayer::Multiband)
{
myRasterLayer->setDrawingStyle(QgsRasterLayer::MultiBandSingleBandPseudoColor);
}
else if (rasterLayer->rasterType()==QgsRasterLayer::Palette)
{
myRasterLayer->setDrawingStyle(QgsRasterLayer::PalettedSingleBandPseudoColor);
}
else // QgsRasterLayer::GrayOrUndefined
{
myRasterLayer->setDrawingStyle(QgsRasterLayer::SingleBandPseudoColor);
}

Raster layers can also have an arbitrary level of transparency defined, and have their color palettes inverted using the setTransparency and setInvertHistogram methods.

Pseudocolor images can have their output adjusted to a given number of standard deviations using the setStandardDeviations method.

The final area of functionality you may be interested in is band mapping. Band mapping allows you to choose arbitrary band -> color mappings and is applicable only to Palette and Multiband rasters, There are four mappings that can be made: red, green, blue and gray. Mappings are non-exclusive. That is a given band can be assigned to no, some or all color mappings. The constructor sets sensible defaults for band mappings but these can be overridden at run time using the setRedBandName, setGreenBandName, setBlueBandName and setGrayBandName methods.

Constructor & Destructor Documentation

QgsRasterLayer::QgsRasterLayer ( )

Constructor.

Provider is not set.

QgsRasterLayer::QgsRasterLayer ( const QString &  path,
const QString &  baseName = QString::null,
bool  loadDefaultStyleFlag = true 
)

This is the constructor for the RasterLayer class.

The main tasks carried out by the constructor are:

-Load the rasters default style (.qml) file if it exists

-Populate the RasterStatsVector with initial values for each band.

-Calculate the layer extents

-Determine whether the layer is gray, paletted or multiband.

-Assign sensible defaults for the red, green, blue and gray bands.

QgsRasterLayer::QgsRasterLayer ( const QString &  uri,
const QString &  baseName,
const QString &  providerKey,
bool  loadDefaultStyleFlag = true 
)

[ data provider interface ] Constructor in provider mode

Todo:
Rename into a general constructor when the old raster interface is retired parameter dummy is just there to distinguish this function signature from the old non-provider one.
QgsRasterLayer::~QgsRasterLayer ( )

The destructor.

Member Function Documentation

int QgsRasterLayer::bandCount ( ) const

Get the number of bands in this layer.

const QString QgsRasterLayer::bandName ( int  theBandNoInt)

Get the name of a band given its number.

QgsBrightnessContrastFilter* QgsRasterLayer::brightnessFilter ( ) const
inline
QgsMapLayerRenderer * QgsRasterLayer::createMapRenderer ( QgsRenderContext rendererContext)
virtual

Return new instance of QgsMapLayerRenderer that will be used for rendering of given context.

Note
added in 2.4

Reimplemented from QgsMapLayer.

void QgsRasterLayer::dataChanged ( )
signal

This is emitted whenever data or metadata (e.g.

color table, extent) has changed

Note
added in 1.7
QgsRasterDataProvider * QgsRasterLayer::dataProvider ( )

Returns the data provider.

Returns
0 if not using the data provider model (i.e. directly using GDAL)
const QgsRasterDataProvider * QgsRasterLayer::dataProvider ( ) const

Returns the data provider in a const-correct manner.

Note
available in python bindings as constDataProvider()
Returns
0 if not using the data provider model (i.e. directly using GDAL)
bool QgsRasterLayer::draw ( QgsRenderContext rendererContext)
virtual

This is called when the view on the raster layer needs to be redrawn.

Reimplemented from QgsMapLayer.

void QgsRasterLayer::draw ( QPainter *  theQPainter,
QgsRasterViewPort myRasterViewPort,
const QgsMapToPixel theQgsMapToPixel = 0 
)

This is an overloaded version of the draw() function that is called by both draw() and thumbnailAsPixmap.

int QgsRasterLayer::height ( ) const

Accessor that returns the height of the (unclipped) raster.

QgsHueSaturationFilter* QgsRasterLayer::hueSaturationFilter ( ) const
inline
bool QgsRasterLayer::isValidRasterFileName ( const QString &  theFileNameQString,
QString &  retError 
)
static

This helper checks to see whether the file name appears to be a valid raster file name.

If the file name looks like it could be valid, but some sort of error occurs in processing the file, the error is returned in retError.

bool QgsRasterLayer::isValidRasterFileName ( const QString &  theFileNameQString)
static
QDateTime QgsRasterLayer::lastModified ( const QString &  name)
static

Return time stamp for given file name.

QgsLegendColorList QgsRasterLayer::legendSymbologyItems ( ) const

Returns a list with classification items (Text and color)

Note
this method was added in version 1.8
QString QgsRasterLayer::metadata ( )
virtual

Obtain GDAL Metadata for this layer.

Reimplemented from QgsMapLayer.

void QgsRasterLayer::onProgress ( int  theType,
double  theProgress,
QString  theMessage 
)
slot

receive progress signal from provider

QPixmap QgsRasterLayer::paletteAsPixmap ( int  theBandNumber = 1)

Get an 100x100 pixmap of the color palette.

If the layer has no palette a white pixmap will be returned

Parameters
theBandNumberthe number of the band to use for generating a pixmap of the associated palette
Returns
a 100x100 pixel QPixmap of the bands palette
QgsRasterPipe* QgsRasterLayer::pipe ( )
inline

Get raster pipe.

QImage QgsRasterLayer::previewAsImage ( QSize  size,
QColor  bgColor = Qt::white,
QImage::Format  format = QImage::Format_ARGB32_Premultiplied 
)

Draws a preview of the rasterlayer into a QImage.

Note
added in 2.4
QPixmap QgsRasterLayer::previewAsPixmap ( QSize  size,
QColor  bgColor = Qt::white 
)

Draws a preview of the rasterlayer into a pixmap.

Note
- use previewAsImage() for rendering with QGIS>=2.4
void QgsRasterLayer::progressUpdate ( int  theValue)
signal

Signal for notifying listeners of long running processes.

QString QgsRasterLayer::providerType ( ) const

[ data provider interface ] Which provider is being used for this Raster Layer?

Note
added in 2.0
LayerType QgsRasterLayer::rasterType ( )
inline

Accessor for raster layer type (which is a read only property)

double QgsRasterLayer::rasterUnitsPerPixelX ( )

Returns the number of raster units per each raster pixel.

In a world file, this is normally the first row (without the sign)

Returns
the horizontal units per pixel as reported in the GDAL geotramsform[1]
double QgsRasterLayer::rasterUnitsPerPixelY ( )
bool QgsRasterLayer::readSymbology ( const QDomNode &  node,
QString &  errorMessage 
)
protectedvirtual

Read the symbology for the current layer from the Dom node supplied.

Implements QgsMapLayer.

bool QgsRasterLayer::readXml ( const QDomNode &  layer_node)
protectedvirtual

Reads layer specific state from project file Dom node.

Raster layer project file XML of form:

Note
Called by QgsMapLayer::readXML().
Note
Make sure to read the file first so stats etc are initialised properly!

Reimplemented from QgsMapLayer.

void QgsRasterLayer::reload ( )
virtual

Synchronises with changes in the datasource.

Note
added in version 1.6

Reimplemented from QgsMapLayer.

QgsRasterRenderer* QgsRasterLayer::renderer ( ) const
inline
QgsRasterResampleFilter* QgsRasterLayer::resampleFilter ( ) const
inline

Set raster resample filter.

Takes ownership of the resample filter object

void QgsRasterLayer::setContrastEnhancement ( QgsContrastEnhancement::ContrastEnhancementAlgorithm  theAlgorithm,
QgsRaster::ContrastEnhancementLimits  theLimits = QgsRaster::ContrastEnhancementMinMax,
QgsRectangle  theExtent = QgsRectangle(),
int  theSampleSize = SAMPLE_SIZE,
bool  theGenerateLookupTableFlag = true 
)

Set contrast enhancement algorithm.

Parameters
theAlgorithmContrast enhancement algorithm
theLimitsLimits
theExtentExtent used to calculate limits, if empty, use full layer extent
theSampleSizeSize of data sample to calculate limits, if 0, use full resolution
theGenerateLookupTableFlagGenerate llokup table.
void QgsRasterLayer::setDataProvider ( const QString &  provider)

[ data provider interface ] Set the data provider

void QgsRasterLayer::setDefaultContrastEnhancement ( )

Set default contrast enhancement.

void QgsRasterLayer::setDrawingStyle ( const QString &  theDrawingStyleQString)

Overloaded version of the above function for convenience when restoring from xml.

Implemented mainly for serialisation / deserialisation of settings to xml.

Note
May be deprecated in the future! Use setDrawingStyle( DrawingStyle ) instead.
void QgsRasterLayer::setLayerOrder ( const QStringList &  layers)
virtual

Reorders the previously selected sublayers of this layer from bottom to top.

(Useful for providers that manage their own layers, such as WMS)

Reimplemented from QgsMapLayer.

void QgsRasterLayer::setRenderer ( QgsRasterRenderer theRenderer)

Set raster renderer.

Takes ownership of the renderer object

void QgsRasterLayer::setSubLayerVisibility ( QString  name,
bool  vis 
)
virtual

Set the visibility of the given sublayer name.

Reimplemented from QgsMapLayer.

void QgsRasterLayer::showProgress ( int  theValue)

[ data provider interface ] A wrapper function to emit a progress update signal

void QgsRasterLayer::showStatusMessage ( const QString &  theMessage)
slot
QStringList QgsRasterLayer::subLayers ( ) const
virtual

Returns the sublayers of this layer - Useful for providers that manage their own layers, such as WMS.

Reimplemented from QgsMapLayer.

virtual QDateTime QgsRasterLayer::timestamp ( ) const
inlinevirtual

Time stamp of data source in the moment when data/metadata were loaded by provider.

Reimplemented from QgsMapLayer.

void QgsRasterLayer::updateProgress ( int  theProgress,
int  theMax 
)
slot
Deprecated:
in 2.4 - does nothing
int QgsRasterLayer::width ( ) const

Accessor that returns the width of the (unclipped) raster.

bool QgsRasterLayer::writeSymbology ( QDomNode &  layer_node,
QDomDocument &  doc,
QString &  errorMessage 
) const
protectedvirtual

Write the symbology for the layer into the docment provided.

Implements QgsMapLayer.

bool QgsRasterLayer::writeXml ( QDomNode &  layer_node,
QDomDocument &  doc 
)
protectedvirtual

Write layer specific state to project file Dom node.

Reimplemented from QgsMapLayer.

Member Data Documentation

const double QgsRasterLayer::CUMULATIVE_CUT_LOWER = 0.02
static

Default cumulative cut lower limit.

const double QgsRasterLayer::CUMULATIVE_CUT_UPPER = 0.98
static

Default cumulative cut upper limit.

const double QgsRasterLayer::SAMPLE_SIZE = 250000
static

Default sample size (number of pixels) for estimated statistics/histogram calculation.


The documentation for this class was generated from the following files: