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

#include <qgsrasterlayer.h>

Inheritance diagram for QgsRasterLayer:

Classes
struct	LayerOptions
	Setting options for loading raster layers. More...

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 }
	Types of layers that can be added to a map. More...

enum	PropertyType { Style = 0, Metadata }
	Maplayer has a style and a metadata property. More...

Public Slots
void	showStatusMessage (const QString &message)

Public Slots inherited from QgsMapLayer
void	emitStyleChanged ()
	Triggers an emission of the styleChanged() signal. More...

virtual bool	setDependencies (const QSet< QgsMapLayerDependency > &layers)
	Sets the list of dependencies. More...

void	setMaximumScale (double scale)
	Sets the maximum map scale (i.e. More...

void	setMinimumScale (double scale)
	Sets the minimum map scale (i.e. More...

void	setRefreshOnNofifyMessage (const QString &message)
	Set the notification message that triggers repaine If refresh on notification is enabled, the notification will triggerRepaint only if the notification message is equal to. More...

void	setRefreshOnNotifyEnabled (bool enabled)
	Set whether provider notification is connected to triggerRepaint. More...

void	setScaleBasedVisibility (const bool enabled)
	Sets whether scale based visibility is enabled for the layer. More...

void	triggerRepaint (bool deferredUpdate=false)
	Will advise the map canvas (and any other interested party) that this layer requires to be repainted. More...

Public Member Functions
	QgsRasterLayer ()
	Constructor. Provider is not set. More...

	QgsRasterLayer (const QString &uri, const QString &baseName=QString(), const QString &providerKey="gdal", const QgsRasterLayer::LayerOptions &options=QgsRasterLayer::LayerOptions())
	This is the constructor for the RasterLayer class. More...

	~QgsRasterLayer () override

int	bandCount () const
	Get the number of bands in this layer. More...

QString	bandName (int bandNoInt) const
	Get the name of a band given its number. More...

QgsBrightnessContrastFilter *	brightnessFilter () const

QgsRasterLayer *	clone () const override
	Returns a new instance equivalent to this one. More...

QgsMapLayerRenderer *	createMapRenderer (QgsRenderContext &rendererContext) override
	Return new instance of QgsMapLayerRenderer that will be used for rendering of given context. More...

QgsRasterDataProvider *	dataProvider () override

const QgsRasterDataProvider *	dataProvider () const override
	Returns the data provider in a const-correct manner. More...

bool	defaultContrastEnhancementSettings (QgsContrastEnhancement::ContrastEnhancementAlgorithm &myAlgorithm, QgsRasterMinMaxOrigin::Limits &myLimits) const
	Return default contrast enhancemnt settings for that type of raster. More...

void	draw (QPainter theQPainter, QgsRasterViewPort myRasterViewPort, const QgsMapToPixel *qgsMapToPixel=nullptr)
	This is an overloaded version of the draw() function that is called by both draw() and thumbnailAsPixmap. More...

int	height () const
	Accessor that returns the height of the (unclipped) raster. More...

QString	htmlMetadata () const override
	Obtain a formatted HTML string containing assorted metadata for this layer. More...

QgsHueSaturationFilter *	hueSaturationFilter () const

bool	isSpatial () const override
	Returns true if the layer is considered a spatial layer, ie it has some form of geometry associated with it. More...

QgsLegendColorList	legendSymbologyItems () const
	Returns a list with classification items (Text and color) More...

QPixmap	paletteAsPixmap (int bandNumber=1)
	Get an 100x100 pixmap of the color palette. If the layer has no palette a white pixmap will be returned. More...

QgsRasterPipe *	pipe ()
	Get raster pipe. More...

QImage	previewAsImage (QSize size, const QColor &bgColor=Qt::white, QImage::Format format=QImage::Format_ARGB32_Premultiplied)
	Draws a preview of the rasterlayer into a QImage. More...

QString	providerType () const
	[ data provider interface ] Which provider is being used for this Raster Layer? More...

LayerType	rasterType ()
	Accessor for raster layer type (which is a read only property) More...

double	rasterUnitsPerPixelX () const
	Returns the number of raster units per each raster pixel in X axis. In a world file, this is normally the first row (without the sign) More...

double	rasterUnitsPerPixelY () const
	Returns the number of raster units per each raster pixel in Y axis. In a world file, this is normally the first row (without the sign) More...

void	refreshContrastEnhancement (const QgsRectangle &extent)
	Refresh contrast enhancement with new extent. More...

void	refreshRendererIfNeeded (QgsRasterRenderer *rasterRenderer, const QgsRectangle &extent)
	Refresh renderer with new extent, if needed. More...

void	reload () override
	Synchronises with changes in the datasource. More...

QgsRasterRenderer *	renderer () const

QgsRasterResampleFilter *	resampleFilter () const
	Set raster resample filter. Takes ownership of the resample filter object. More...

void	setContrastEnhancement (QgsContrastEnhancement::ContrastEnhancementAlgorithm algorithm, QgsRasterMinMaxOrigin::Limits limits=QgsRasterMinMaxOrigin::MinMax, const QgsRectangle &extent=QgsRectangle(), int sampleSize=QgsRasterLayer::SAMPLE_SIZE, bool generateLookupTableFlag=true)
	Set contrast enhancement algorithm. More...

void	setDataProvider (const QString &provider)
	[ data provider interface ] Set the data provider More...

void	setDefaultContrastEnhancement ()
	Set default contrast enhancement. More...

void	setLayerOrder (const QStringList &layers) override
	Reorders the previously selected sublayers of this layer from bottom to top. More...

void	setRenderer (QgsRasterRenderer *renderer)
	Set raster renderer. Takes ownership of the renderer object. More...

void	setSubLayerVisibility (const QString &name, bool vis) override
	Set the visibility of the given sublayer name. More...

QStringList	subLayers () const override
	Returns the sublayers of this layer - Useful for providers that manage their own layers, such as WMS. More...

QDateTime	timestamp () const override
	Time stamp of data source in the moment when data/metadata were loaded by provider. More...

int	width () const
	Accessor that returns the width of the (unclipped) raster. More...

Public Member Functions inherited from QgsMapLayer
	QgsMapLayer (QgsMapLayer::LayerType type=VectorLayer, const QString &name=QString(), const QString &source=QString())
	Constructor for QgsMapLayer. More...

	QgsMapLayer (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied. More...

	~QgsMapLayer () override

QString	abstract () const
	Returns the abstract of the layer used by QGIS Server in GetCapabilities request. More...

QString	attribution () const
	Returns the attribution of the layer used by QGIS Server in GetCapabilities request. More...

QString	attributionUrl () const
	Returns the attribution URL of the layer used by QGIS Server in GetCapabilities request. More...

int	autoRefreshInterval () const
	Returns the auto refresh interval (in milliseconds). More...

QPainter::CompositionMode	blendMode () const
	Returns the current blending mode for a layer. More...

QgsCoordinateReferenceSystem	crs () const
	Returns the layer's spatial reference system. More...

QVariant	customProperty (const QString &value, const QVariant &defaultValue=QVariant()) const
	Read a custom property from layer. More...

QStringList	customPropertyKeys () const
	Returns list of all keys within custom properties. More...

QString	dataUrl () const
	Returns the DataUrl of the layer used by QGIS Server in GetCapabilities request. More...

QString	dataUrlFormat () const
	Returns the DataUrl format of the layer used by QGIS Server in GetCapabilities request. More...

virtual QSet< QgsMapLayerDependency >	dependencies () const
	Gets the list of dependencies. More...

virtual QgsError	error () const
	Get current status error. More...

void	exportNamedMetadata (QDomDocument &doc, QString &errorMsg) const
	Export the current metadata of this layer as named metadata in a QDomDocument. More...

virtual void	exportNamedStyle (QDomDocument &doc, QString &errorMsg) const
	Export the properties of this layer as named style in a QDomDocument. More...

virtual void	exportSldStyle (QDomDocument &doc, QString &errorMsg) const
	Export the properties of this layer as SLD style in a QDomDocument. More...

virtual QgsRectangle	extent () const
	Returns the extent of the layer. More...

bool	hasAutoRefreshEnabled () const
	Returns true if auto refresh is enabled for the layer. More...

bool	hasScaleBasedVisibility () const
	Returns whether scale based visibility is enabled for the layer. More...

QString	id () const
	Returns the layer's unique ID, which is used to access this layer from QgsProject. More...

bool	importNamedMetadata (QDomDocument &document, QString &errorMessage)
	Import the metadata of this layer from a QDomDocument. More...

virtual bool	importNamedStyle (QDomDocument &doc, QString &errorMsg)
	Import the properties of this layer from a QDomDocument. More...

virtual bool	isEditable () const
	Returns true if the layer can be edited. More...

bool	isInScaleRange (double scale) const
	Tests whether the layer should be visible at the specified scale. More...

bool	isRefreshOnNotifyEnabled () const
	Returns true if the refresh on provider nofification is enabled. More...

bool	isValid () const
	Return the status of the layer. More...

QString	keywordList () const
	Returns the keyword list of the layer used by QGIS Server in GetCapabilities request. More...

QgsMapLayerLegend *	legend () const
	Can be null. More...

QString	legendUrl () const
	Returns the URL for the layer's legend. More...

QString	legendUrlFormat () const
	Returns the format for a URL based layer legend. More...

QString	loadDefaultMetadata (bool &resultFlag)
	Retrieve the default metadata for this layer if one exists (either as a .qmd file on disk or as a record in the users metadata table in their personal qgis.db) More...

virtual QString	loadDefaultStyle (bool &resultFlag)
	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	loadNamedMetadata (const QString &uri, bool &resultFlag)
	Retrieve a named metadata for this layer if one exists (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db) More...

bool	loadNamedMetadataFromDatabase (const QString &db, const QString &uri, QString &qmd)
	Retrieve a named metadata for this layer from a sqlite database. More...

virtual QString	loadNamedStyle (const QString &uri, bool &resultFlag)
	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	loadNamedStyleFromDatabase (const QString &db, const QString &uri, QString &qml)
	Retrieve a named style for this layer from a sqlite database. More...

virtual QString	loadSldStyle (const QString &uri, bool &resultFlag)
	Attempts to style the layer using the formatting from an SLD type file. More...

double	maximumScale () const
	Returns the maximum map scale (i.e. More...

virtual const QgsLayerMetadata &	metadata () const
	Returns a reference to the layer's metadata store. More...

virtual QString	metadataUri () const
	Retrieve the metadata URI for this layer (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db) More...

QString	metadataUrl () const
	Returns the metadata URL of the layer used by QGIS Server in GetCapabilities request. More...

QString	metadataUrlFormat () const
	Returns the metadata format of the layer used by QGIS Server in GetCapabilities request. More...

QString	metadataUrlType () const
	Returns the metadata type of the layer used by QGIS Server in GetCapabilities request. More...

double	minimumScale () const
	Returns the minimum map scale (i.e. More...

QString	name () const
	Returns the display name of the layer. More...

QgsMapLayer &	operator= (QgsMapLayer const &)=delete
	QgsMapLayer cannot be copied. More...

QString	publicSource () const
	Gets a version of the internal layer definition that has sensitive bits removed (for example, the password). More...

bool	readLayerXml (const QDomElement &layerElement, const QgsReadWriteContext &context)
	Sets state from Dom document. More...

bool	readOnly () const
	Returns if this layer is read only. More...

virtual bool	readSld (const QDomNode &node, QString &errorMessage)

QString	refreshOnNotifyMessage () const
	Returns the message that should be notified by the provider to triggerRepaint. More...

void	removeCustomProperty (const QString &key)
	Remove a custom property from layer. More...

QgsAbstract3DRenderer *	renderer3D () const
	Returns 3D renderer associated with the layer. More...

virtual void	resolveReferences (QgsProject *project)
	Resolve references to other layers (kept as layer IDs after reading XML) into layer objects. More...

virtual QString	saveDefaultMetadata (bool &resultFlag)
	Save the current metadata of this layer as the default metadata (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db) More...

virtual QString	saveDefaultStyle (bool &resultFlag)
	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...

QString	saveNamedMetadata (const QString &uri, bool &resultFlag)
	Save the current metadata of this layer as a named metadata (either as a .qmd file on disk or as a record in the users style table in their personal qgis.db) More...

virtual QString	saveNamedStyle (const QString &uri, bool &resultFlag)
	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 &uri, bool &resultFlag) const
	Saves the properties of this layer to an SLD format file. More...

void	setAbstract (const QString &abstract)
	Sets the abstract of the layer used by QGIS Server in GetCapabilities request. More...

void	setAttribution (const QString &attrib)
	Sets the attribution of the layer used by QGIS Server in GetCapabilities request. More...

void	setAttributionUrl (const QString &attribUrl)
	Sets the attribution URL of the layer used by QGIS Server in GetCapabilities request. More...

void	setAutoRefreshEnabled (bool enabled)
	Sets whether auto refresh is enabled for the layer. More...

void	setAutoRefreshInterval (int interval)
	Sets the auto refresh interval (in milliseconds) for the layer. More...

void	setBlendMode (QPainter::CompositionMode blendMode)
	Set the blending mode used for rendering a layer. More...

void	setCrs (const QgsCoordinateReferenceSystem &srs, bool emitSignal=true)
	Sets layer's spatial reference system. More...

void	setCustomProperties (const QgsObjectCustomProperties &properties)
	Set custom properties for layer. More...

void	setCustomProperty (const QString &key, const QVariant &value)
	Set a custom property for layer. More...

void	setDataUrl (const QString &dataUrl)
	Sets the DataUrl of the layer used by QGIS Server in GetCapabilities request. More...

void	setDataUrlFormat (const QString &dataUrlFormat)
	Sets the DataUrl format of the layer used by QGIS Server in GetCapabilities request. More...

void	setKeywordList (const QString &keywords)
	Sets the keyword list of the layer used by QGIS Server in GetCapabilities request. More...

void	setLegend (QgsMapLayerLegend *legend)
	Assign a legend controller to the map layer. More...

void	setLegendUrl (const QString &legendUrl)
	Sets the URL for the layer's legend. More...

void	setLegendUrlFormat (const QString &legendUrlFormat)
	Sets the format for a URL based layer legend. More...

virtual void	setMetadata (const QgsLayerMetadata &metadata)
	Sets the layer's metadata store. More...

void	setMetadataUrl (const QString &metaUrl)
	Sets the metadata URL of the layer used by QGIS Server in GetCapabilities request. More...

void	setMetadataUrlFormat (const QString &metaUrlFormat)
	Sets the metadata format of the layer used by QGIS Server in GetCapabilities request. More...

void	setMetadataUrlType (const QString &metaUrlType)
	Set the metadata type of the layer used by QGIS Server in GetCapabilities request MetadataUrlType indicates the standard to which the metadata complies. More...

void	setName (const QString &name)
	Set the display name of the layer. More...

void	setRenderer3D (QgsAbstract3DRenderer *renderer)
	Sets 3D renderer for the layer. More...

void	setShortName (const QString &shortName)
	Sets the short name of the layer used by QGIS Server to identify the layer. More...

void	setTitle (const QString &title)
	Sets the title of the layer used by QGIS Server in GetCapabilities request. More...

QString	shortName () const
	Returns the short name of the layer used by QGIS Server to identify the layer. More...

QString	source () const
	Returns the source for the layer. More...

QgsMapLayerStyleManager *	styleManager () const
	Get access to the layer's style manager. More...

virtual QString	styleURI () const
	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...

QString	title () const
	Returns the title of the layer used by QGIS Server in GetCapabilities request. More...

QgsMapLayer::LayerType	type () const
	Returns the type of the layer. More...

QUndoStack *	undoStack ()
	Return pointer to layer's undo stack. More...

QUndoStack *	undoStackStyles ()
	Return pointer to layer's style undo stack. More...

bool	writeLayerXml (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context) const
	Stores state in Dom node. More...

Static Public Member Functions
static bool	isValidRasterFileName (const QString &fileNameQString, 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 &fileNameQString)

static QDateTime	lastModified (const QString &name)
	Return time stamp for given file name. More...

Static Public Member Functions inherited from QgsMapLayer
static QString	extensionPropertyType (PropertyType type)
	Returns the extension of a Property. More...

static QString	formatLayerName (const QString &name)
	A convenience function to capitalize and format a layer name. More...

Static Public Attributes
static const QgsContrastEnhancement::ContrastEnhancementAlgorithm	MULTIPLE_BAND_MULTI_BYTE_ENHANCEMENT_ALGORITHM = QgsContrastEnhancement::StretchToMinimumMaximum
	Default enhancement algorithm for multiple band raster of type different from Byte. More...

static const QgsRasterMinMaxOrigin::Limits	MULTIPLE_BAND_MULTI_BYTE_MIN_MAX_LIMITS = QgsRasterMinMaxOrigin::CumulativeCut
	Default enhancement limits for multiple band raster of type different from Byte. More...

static const QgsContrastEnhancement::ContrastEnhancementAlgorithm	MULTIPLE_BAND_SINGLE_BYTE_ENHANCEMENT_ALGORITHM = QgsContrastEnhancement::NoEnhancement
	Default enhancement algorithm for multiple band raster of type Byte. More...

static const QgsRasterMinMaxOrigin::Limits	MULTIPLE_BAND_SINGLE_BYTE_MIN_MAX_LIMITS = QgsRasterMinMaxOrigin::MinMax
	Default enhancement limits for multiple band raster of type Byte. More...

static const double	SAMPLE_SIZE = 250000
	Default sample size (number of pixels) for estimated statistics/histogram calculation. More...

static const QgsContrastEnhancement::ContrastEnhancementAlgorithm	SINGLE_BAND_ENHANCEMENT_ALGORITHM = QgsContrastEnhancement::StretchToMinimumMaximum
	Default enhancement algorithm for single band raster. More...

static const QgsRasterMinMaxOrigin::Limits	SINGLE_BAND_MIN_MAX_LIMITS = QgsRasterMinMaxOrigin::MinMax
	Default enhancement limits for single band raster. More...

Protected Member Functions
bool	readStyle (const QDomNode &node, QString &errorMessage, const QgsReadWriteContext &context) override
	Read the style information for the current layer from the Dom node supplied. More...

bool	readSymbology (const QDomNode &node, QString &errorMessage, const QgsReadWriteContext &context) override
	Read the symbology for the current layer from the Dom node supplied. More...

bool	readXml (const QDomNode &layer_node, const QgsReadWriteContext &context) override
	Reads layer specific state from project file Dom node. More...

bool	writeStyle (QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context) const override
	Write the style for the layer into the docment provided. More...

bool	writeSymbology (QDomNode &, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context) const override
	Write the symbology for the layer into the docment provided. More...

bool	writeXml (QDomNode &layer_node, QDomDocument &doc, const QgsReadWriteContext &context) const override
	Write layer specific state to project file Dom node. More...

Protected Member Functions inherited from QgsMapLayer
void	appendError (const QgsErrorMessage &error)
	Add error message. More...

void	clone (QgsMapLayer *layer) const
	Copies attributes like name, short name, ... More...

bool	hasDependencyCycle (const QSet< QgsMapLayerDependency > &layers) const
	Checks whether a new set of dependencies will introduce a cycle. More...

void	readCommonStyle (const QDomElement &layerElement, const QgsReadWriteContext &context)
	Read style data common to all layer types. More...

void	readCustomProperties (const QDomNode &layerNode, const QString &keyStartsWith=QString())
	Read custom properties from project file. More...

void	readStyleManager (const QDomNode &layerNode)
	Read style manager's configuration (if any). To be called by subclasses. More...

void	setError (const QgsError &error)
	Set error message. More...

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	writeCommonStyle (QDomElement &layerElement, QDomDocument &document, const QgsReadWriteContext &context) const
	Write style data common to all layer types. More...

void	writeCustomProperties (QDomNode &layerNode, QDomDocument &doc) const
	Write custom properties to project file. More...

void	writeStyleManager (QDomNode &layerNode, QDomDocument &doc) const
	Write style manager's configuration (if exists). To be called by subclasses. More...

Additional Inherited Members
Signals inherited from QgsMapLayer
void	autoRefreshIntervalChanged (int interval)
	Emitted when the auto refresh interval changes. More...

void	blendModeChanged (QPainter::CompositionMode blendMode)
	Signal emitted when the blend mode is changed, through QgsMapLayer::setBlendMode() More...

void	configChanged ()
	Emitted whenever the configuration is changed. More...

void	crsChanged ()
	Emit a signal that layer's CRS has been reset. More...

void	dataChanged ()
	Data of layer changed. More...

void	dependenciesChanged ()
	Emitted when dependencies are changed. More...

void	legendChanged ()
	Signal emitted when legend of the layer has changed. More...

void	metadataChanged ()
	Emitted when the layer's metadata is changed. More...

void	nameChanged ()
	Emitted when the name has been changed. More...

void	recalculateExtents () const
	This is used to send a request that any mapcanvas using this layer update its extents. More...

void	renderer3DChanged ()
	Signal emitted when 3D renderer associated with the layer has changed. More...

void	rendererChanged ()
	Signal emitted when renderer is changed. More...

void	repaintRequested (bool deferredUpdate=false)
	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	statusChanged (const QString &status)
	Emit a signal with status (e.g. to be caught by QgisApp and display a msg on status bar) More...

void	styleChanged ()
	Signal emitted whenever a change affects the layer's style. More...

void	willBeDeleted ()
	Emitted in the destructor when the layer is about to be deleted, but it is still in a perfectly valid state: the last chance for other pieces of code for some cleanup if they use the layer. More...

Protected Attributes inherited from QgsMapLayer
QString	mAbstract
	Description of the layer. More...

QString	mAttribution
	Attribution of the layer. More...

QString	mAttributionUrl

QString	mDataSource
	Data source description string, varies by layer type. More...

QString	mDataUrl
	DataUrl of the layer. More...

QString	mDataUrlFormat

QSet< QgsMapLayerDependency >	mDependencies
	List of layers that may modify this layer on modification. More...

QgsError	mError
	Error. More...

QgsRectangle	mExtent
	Extent of the layer. More...

bool	mIsRefreshOnNofifyEnabled = false

QString	mKeywordList

QString	mLayerName
	Name of the layer - used for display. More...

QString	mLegendUrl
	WMS legend. More...

QString	mLegendUrlFormat

QString	mMetadataUrl
	MetadataUrl of the layer. More...

QString	mMetadataUrlFormat

QString	mMetadataUrlType

QString	mRefreshOnNofifyMessage

QString	mShortName

QString	mTitle

bool	mValid = false
	Indicates if the layer is valid and can be drawn. More...

Properties inherited from QgsMapLayer
int	autoRefreshInterval

QgsLayerMetadata	metadata

QString	name

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 pseudo 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 initializes 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()) );

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.
}

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.

Definition at line 139 of file qgsrasterlayer.h.

Member Enumeration Documentation

◆ ColorShadingAlgorithm

enum QgsRasterLayer::ColorShadingAlgorithm

This enumerator describes the types of shading that can be used.

Enumerator
UndefinedShader
PseudoColorShader
FreakOutShader
ColorRampShader
UserDefinedShader

Definition at line 219 of file qgsrasterlayer.h.

◆ LayerType

enum QgsRasterLayer::LayerType

This enumerator describes the type of raster layer.

Enumerator
GrayOrUndefined
Palette
Multiband
ColorLayer

Definition at line 229 of file qgsrasterlayer.h.

Constructor & Destructor Documentation

◆ QgsRasterLayer() [1/2]

QgsRasterLayer::QgsRasterLayer ( )

Constructor. Provider is not set.

Definition at line 98 of file qgsrasterlayer.cpp.

◆ QgsRasterLayer() [2/2]

QgsRasterLayer::QgsRasterLayer	(	const QString &	uri,
		const QString &	baseName = `QString()`,
		const QString &	providerKey = `"gdal"`,
		const QgsRasterLayer::LayerOptions &	options = `QgsRasterLayer::LayerOptions()`
	)

explicit

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.

Definition at line 108 of file qgsrasterlayer.cpp.

◆ ~QgsRasterLayer()

QgsRasterLayer::~QgsRasterLayer ( )

override

Definition at line 139 of file qgsrasterlayer.cpp.

Member Function Documentation

◆ bandCount()

int QgsRasterLayer::bandCount ( ) const

Get the number of bands in this layer.

Definition at line 217 of file qgsrasterlayer.cpp.

◆ bandName()

QString QgsRasterLayer::bandName ( int bandNoInt ) const

Get the name of a band given its number.

Definition at line 223 of file qgsrasterlayer.cpp.

◆ brightnessFilter()

QgsBrightnessContrastFilter* QgsRasterLayer::brightnessFilter ( ) const

inline

Definition at line 262 of file qgsrasterlayer.h.

◆ clone()

QgsRasterLayer * QgsRasterLayer::clone ( ) const

overridevirtual

Returns a new instance equivalent to this one.

A new provider is created for the same data source and renderer is cloned too.

Returns: a new layer instance

Since: QGIS 3.0

Implements QgsMapLayer.

Definition at line 147 of file qgsrasterlayer.cpp.

◆ createMapRenderer()

QgsMapLayerRenderer * QgsRasterLayer::createMapRenderer ( QgsRenderContext & rendererContext )

overridevirtual

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

Since: QGIS 2.4

Implements QgsMapLayer.

Definition at line 257 of file qgsrasterlayer.cpp.

◆ dataProvider() [1/2]

QgsRasterDataProvider * QgsRasterLayer::dataProvider ( )

overridevirtual

Returns: 0 if not using the data provider model (i.e. directly using GDAL)

Reimplemented from QgsMapLayer.

Definition at line 236 of file qgsrasterlayer.cpp.

◆ dataProvider() [2/2]

const QgsRasterDataProvider * QgsRasterLayer::dataProvider ( ) const

overridevirtual

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)

Reimplemented from QgsMapLayer.

Definition at line 244 of file qgsrasterlayer.cpp.

◆ defaultContrastEnhancementSettings()

bool QgsRasterLayer::defaultContrastEnhancementSettings	(	QgsContrastEnhancement::ContrastEnhancementAlgorithm &	myAlgorithm,
		QgsRasterMinMaxOrigin::Limits &	myLimits
	)		const

Return default contrast enhancemnt settings for that type of raster.

Note: not available in Python bindings

Definition at line 1120 of file qgsrasterlayer.cpp.

◆ draw()

void QgsRasterLayer::draw	(	QPainter *	theQPainter,
		QgsRasterViewPort *	myRasterViewPort,
		const QgsMapToPixel *	qgsMapToPixel = `nullptr`
	)

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

Definition at line 263 of file qgsrasterlayer.cpp.

◆ height()

int QgsRasterLayer::height ( ) const

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

Definition at line 1653 of file qgsrasterlayer.cpp.

◆ htmlMetadata()

QString QgsRasterLayer::htmlMetadata ( ) const

overridevirtual

Obtain a formatted HTML string containing assorted metadata for this layer.

Since: QGIS 3.0

Reimplemented from QgsMapLayer.

Definition at line 305 of file qgsrasterlayer.cpp.

◆ hueSaturationFilter()

QgsHueSaturationFilter* QgsRasterLayer::hueSaturationFilter ( ) const

inline

Definition at line 263 of file qgsrasterlayer.h.

◆ isSpatial()

bool QgsRasterLayer::isSpatial ( ) const

inlineoverridevirtual

Returns true if the layer is considered a spatial layer, ie it has some form of geometry associated with it.

Since: QGIS 2.16

Reimplemented from QgsMapLayer.

Definition at line 305 of file qgsrasterlayer.h.

◆ isValidRasterFileName() [1/2]

bool QgsRasterLayer::isValidRasterFileName	(	const QString &	fileNameQString,
		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.

Definition at line 171 of file qgsrasterlayer.cpp.

◆ isValidRasterFileName() [2/2]

bool QgsRasterLayer::isValidRasterFileName ( const QString & fileNameQString )

static

Definition at line 184 of file qgsrasterlayer.cpp.

◆ lastModified()

QDateTime QgsRasterLayer::lastModified ( const QString & name )

static

Return time stamp for given file name.

Definition at line 190 of file qgsrasterlayer.cpp.

◆ legendSymbologyItems()

QgsLegendColorList QgsRasterLayer::legendSymbologyItems ( ) const

Returns a list with classification items (Text and color)

Definition at line 294 of file qgsrasterlayer.cpp.

◆ paletteAsPixmap()

QPixmap QgsRasterLayer::paletteAsPixmap ( int bandNumber = 1 )

Get an 100x100 pixmap of the color palette. If the layer has no palette a white pixmap will be returned.

Parameters

bandNumber the number of the band to use for generating a pixmap of the associated palette

Returns: a 100x100 pixel QPixmap of the bands palette

Definition at line 490 of file qgsrasterlayer.cpp.

◆ pipe()

QgsRasterPipe* QgsRasterLayer::pipe ( )

inline

Get raster pipe.

Definition at line 266 of file qgsrasterlayer.h.

◆ previewAsImage()

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

Draws a preview of the rasterlayer into a QImage.

Since: QGIS 2.4

Definition at line 1248 of file qgsrasterlayer.cpp.

◆ providerType()

QString QgsRasterLayer::providerType ( ) const

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

Definition at line 544 of file qgsrasterlayer.cpp.

◆ rasterType()

LayerType QgsRasterLayer::rasterType ( )

inline

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

Definition at line 253 of file qgsrasterlayer.h.

◆ rasterUnitsPerPixelX()

double QgsRasterLayer::rasterUnitsPerPixelX ( ) const

Returns the number of raster units per each raster pixel in X axis. 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]

Definition at line 552 of file qgsrasterlayer.cpp.

◆ rasterUnitsPerPixelY()

double QgsRasterLayer::rasterUnitsPerPixelY ( ) const

Returns the number of raster units per each raster pixel in Y axis. In a world file, this is normally the first row (without the sign)

Definition at line 567 of file qgsrasterlayer.cpp.

◆ readStyle()

bool QgsRasterLayer::readStyle	(	const QDomNode &	node,
		QString &	errorMessage,
		const QgsReadWriteContext &	context
	)

overrideprotectedvirtual

Read the style information for the current layer from the Dom node supplied.

Reimplemented from QgsMapLayer.

Definition at line 1400 of file qgsrasterlayer.cpp.

◆ readSymbology()

bool QgsRasterLayer::readSymbology	(	const QDomNode &	node,
		QString &	errorMessage,
		const QgsReadWriteContext &	context
	)

overrideprotectedvirtual

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

Implements QgsMapLayer.

Definition at line 1308 of file qgsrasterlayer.cpp.

◆ readXml()

bool QgsRasterLayer::readXml	(	const QDomNode &	layer_node,
		const QgsReadWriteContext &	context
	)

overrideprotectedvirtual

Reads layer specific state from project file Dom node.

Raster layer project file XML of form:

Note: Called by QgsMapLayer::readXml().

Reimplemented from QgsMapLayer.

Definition at line 1411 of file qgsrasterlayer.cpp.

◆ refreshContrastEnhancement()

void QgsRasterLayer::refreshContrastEnhancement ( const QgsRectangle & extent )

Refresh contrast enhancement with new extent.

Note: not available in Python bindings

Definition at line 982 of file qgsrasterlayer.cpp.

◆ refreshRendererIfNeeded()

void QgsRasterLayer::refreshRendererIfNeeded	(	QgsRasterRenderer *	rasterRenderer,
		const QgsRectangle &	extent
	)

Refresh renderer with new extent, if needed.

Note: not available in Python bindings

Definition at line 1023 of file qgsrasterlayer.cpp.

◆ reload()

void QgsRasterLayer::reload ( )

overridevirtual

Synchronises with changes in the datasource.

Reimplemented from QgsMapLayer.

Definition at line 249 of file qgsrasterlayer.cpp.

◆ renderer()

QgsRasterRenderer* QgsRasterLayer::renderer ( ) const

inline

Definition at line 257 of file qgsrasterlayer.h.

◆ resampleFilter()

QgsRasterResampleFilter* QgsRasterLayer::resampleFilter ( ) const

inline

Set raster resample filter. Takes ownership of the resample filter object.

Definition at line 260 of file qgsrasterlayer.h.

◆ setContrastEnhancement()

void QgsRasterLayer::setContrastEnhancement	(	QgsContrastEnhancement::ContrastEnhancementAlgorithm	algorithm,
		QgsRasterMinMaxOrigin::Limits	limits = `QgsRasterMinMaxOrigin::MinMax`,
		const QgsRectangle &	extent = `QgsRectangle()`,
		int	sampleSize = `QgsRasterLayer::SAMPLE_SIZE`,
		bool	generateLookupTableFlag = `true`
	)

Set contrast enhancement algorithm.

Parameters

algorithm	Contrast enhancement algorithm
limits	Limits
extent	Extent used to calculate limits, if empty, use full layer extent
sampleSize	Size of data sample to calculate limits, if 0, use full resolution
generateLookupTableFlag	Generate lookup table.

Definition at line 842 of file qgsrasterlayer.cpp.

◆ setDataProvider()

void QgsRasterLayer::setDataProvider ( const QString & provider )

[ data provider interface ] Set the data provider

Definition at line 589 of file qgsrasterlayer.cpp.

◆ setDefaultContrastEnhancement()

void QgsRasterLayer::setDefaultContrastEnhancement ( )

Set default contrast enhancement.

Definition at line 1180 of file qgsrasterlayer.cpp.

◆ setLayerOrder()

void QgsRasterLayer::setLayerOrder ( const QStringList & layers )

overridevirtual

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.

Definition at line 1191 of file qgsrasterlayer.cpp.

◆ setRenderer()

void QgsRasterLayer::setRenderer ( QgsRasterRenderer * renderer )

Set raster renderer. Takes ownership of the renderer object.

Definition at line 1219 of file qgsrasterlayer.cpp.

◆ setSubLayerVisibility()

void QgsRasterLayer::setSubLayerVisibility	(	const QString &	name,
		bool	vis
	)

overridevirtual

Set the visibility of the given sublayer name.

Reimplemented from QgsMapLayer.

Definition at line 1203 of file qgsrasterlayer.cpp.

◆ showStatusMessage

void QgsRasterLayer::showStatusMessage ( const QString & message )

slot

Definition at line 1232 of file qgsrasterlayer.cpp.

◆ subLayers()

QStringList QgsRasterLayer::subLayers ( ) const

overridevirtual

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

Reimplemented from QgsMapLayer.

Definition at line 1241 of file qgsrasterlayer.cpp.

◆ timestamp()

QDateTime QgsRasterLayer::timestamp ( ) const

overridevirtual

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

Reimplemented from QgsMapLayer.

Definition at line 1214 of file qgsrasterlayer.cpp.

◆ width()

int QgsRasterLayer::width ( ) const

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

Definition at line 1647 of file qgsrasterlayer.cpp.

◆ writeStyle()

bool QgsRasterLayer::writeStyle	(	QDomNode &	node,
		QDomDocument &	doc,
		QString &	errorMessage,
		const QgsReadWriteContext &	context
	)		const

overrideprotectedvirtual

Write the style for the layer into the docment provided.

Reimplemented from QgsMapLayer.

Definition at line 1581 of file qgsrasterlayer.cpp.

◆ writeSymbology()

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

overrideprotectedvirtual

Write the symbology for the layer into the docment provided.

Implements QgsMapLayer.

Definition at line 1552 of file qgsrasterlayer.cpp.

◆ writeXml()

bool QgsRasterLayer::writeXml	(	QDomNode &	layer_node,
		QDomDocument &	doc,
		const QgsReadWriteContext &	context
	)		const

overrideprotectedvirtual

Write layer specific state to project file Dom node.

Reimplemented from QgsMapLayer.

Definition at line 1591 of file qgsrasterlayer.cpp.

Member Data Documentation

◆ MULTIPLE_BAND_MULTI_BYTE_ENHANCEMENT_ALGORITHM

const QgsContrastEnhancement::ContrastEnhancementAlgorithm QgsRasterLayer::MULTIPLE_BAND_MULTI_BYTE_ENHANCEMENT_ALGORITHM = QgsContrastEnhancement::StretchToMinimumMaximum

static

Default enhancement algorithm for multiple band raster of type different from Byte.

Definition at line 154 of file qgsrasterlayer.h.

◆ MULTIPLE_BAND_MULTI_BYTE_MIN_MAX_LIMITS

const QgsRasterMinMaxOrigin::Limits QgsRasterLayer::MULTIPLE_BAND_MULTI_BYTE_MIN_MAX_LIMITS = QgsRasterMinMaxOrigin::CumulativeCut

static

Default enhancement limits for multiple band raster of type different from Byte.

Definition at line 163 of file qgsrasterlayer.h.

◆ MULTIPLE_BAND_SINGLE_BYTE_ENHANCEMENT_ALGORITHM

const QgsContrastEnhancement::ContrastEnhancementAlgorithm QgsRasterLayer::MULTIPLE_BAND_SINGLE_BYTE_ENHANCEMENT_ALGORITHM = QgsContrastEnhancement::NoEnhancement

static

Default enhancement algorithm for multiple band raster of type Byte.

Definition at line 151 of file qgsrasterlayer.h.

◆ MULTIPLE_BAND_SINGLE_BYTE_MIN_MAX_LIMITS

const QgsRasterMinMaxOrigin::Limits QgsRasterLayer::MULTIPLE_BAND_SINGLE_BYTE_MIN_MAX_LIMITS = QgsRasterMinMaxOrigin::MinMax

static

Default enhancement limits for multiple band raster of type Byte.

Definition at line 160 of file qgsrasterlayer.h.

◆ SAMPLE_SIZE

const double QgsRasterLayer::SAMPLE_SIZE = 250000

static

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

Definition at line 145 of file qgsrasterlayer.h.

◆ SINGLE_BAND_ENHANCEMENT_ALGORITHM

const QgsContrastEnhancement::ContrastEnhancementAlgorithm QgsRasterLayer::SINGLE_BAND_ENHANCEMENT_ALGORITHM = QgsContrastEnhancement::StretchToMinimumMaximum

static

Default enhancement algorithm for single band raster.

Definition at line 148 of file qgsrasterlayer.h.

◆ SINGLE_BAND_MIN_MAX_LIMITS

const QgsRasterMinMaxOrigin::Limits QgsRasterLayer::SINGLE_BAND_MIN_MAX_LIMITS = QgsRasterMinMaxOrigin::MinMax

static

Default enhancement limits for single band raster.

Definition at line 157 of file qgsrasterlayer.h.

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

/tmp/buildd/qgis-3.0.2+14stretch/src/core/raster/qgsrasterlayer.h
/tmp/buildd/qgis-3.0.2+14stretch/src/core/raster/qgsrasterlayer.cpp

Classes

Public Types

Public Slots

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ ColorShadingAlgorithm

◆ LayerType

Constructor & Destructor Documentation

◆ QgsRasterLayer() [1/2]

◆ QgsRasterLayer() [2/2]

◆ ~QgsRasterLayer()

Member Function Documentation

◆ bandCount()

◆ bandName()

◆ brightnessFilter()

◆ clone()

◆ createMapRenderer()

◆ dataProvider() [1/2]

◆ dataProvider() [2/2]

◆ defaultContrastEnhancementSettings()

◆ draw()

◆ height()

◆ htmlMetadata()

◆ hueSaturationFilter()

◆ isSpatial()

◆ isValidRasterFileName() [1/2]

◆ isValidRasterFileName() [2/2]

◆ lastModified()

◆ legendSymbologyItems()

◆ paletteAsPixmap()

◆ pipe()

◆ previewAsImage()

◆ providerType()

◆ rasterType()

◆ rasterUnitsPerPixelX()

◆ rasterUnitsPerPixelY()

◆ readStyle()

◆ readSymbology()

◆ readXml()

◆ refreshContrastEnhancement()

◆ refreshRendererIfNeeded()

◆ reload()

◆ renderer()

◆ resampleFilter()

◆ setContrastEnhancement()

◆ setDataProvider()

◆ setDefaultContrastEnhancement()

◆ setLayerOrder()

◆ setRenderer()

◆ setSubLayerVisibility()

◆ showStatusMessage

◆ subLayers()

◆ timestamp()

◆ width()

◆ writeStyle()

◆ writeSymbology()

◆ writeXml()

Member Data Documentation

◆ MULTIPLE_BAND_MULTI_BYTE_ENHANCEMENT_ALGORITHM

◆ MULTIPLE_BAND_MULTI_BYTE_MIN_MAX_LIMITS

◆ MULTIPLE_BAND_SINGLE_BYTE_ENHANCEMENT_ALGORITHM

◆ MULTIPLE_BAND_SINGLE_BYTE_MIN_MAX_LIMITS

◆ SAMPLE_SIZE

◆ SINGLE_BAND_ENHANCEMENT_ALGORITHM

◆ SINGLE_BAND_MIN_MAX_LIMITS