Raster data container. More...

#include <qgsrasterblock.h>

Public Member Functions
	QgsRasterBlock ()

	QgsRasterBlock (Qgis::DataType dataType, int width, int height)
	Constructor which allocates data block in memory.

virtual	~QgsRasterBlock ()

void	applyNoDataValues (const QgsRasterRangeList &rangeList)

void	applyScaleOffset (double scale, double offset)
	Apply band scale and offset to raster block values.

char *	bits ()
	Returns a pointer to block data.

char *	bits (int row, int column)
	Returns a pointer to block data.

char *	bits (qgssize index)
	Returns a pointer to block data.

const quint8 *	byteData () const
	Gives direct access to the raster block data.

QRgb	color (int row, int column) const
	Read a single color.

QRgb	color (qgssize index) const
	Read a single value.

QRgb *	colorData ()
	Gives direct read/write access to the raster RGB data.

bool	convert (Qgis::DataType destDataType)
	Convert data to different type.

QByteArray	data () const
	Gets access to raw data.

Qgis::DataType	dataType () const
	Returns data type.

int	dataTypeSize () const
	Data type size in bytes.

QgsError	error () const
	Returns the last error.

bool	hasNoData () const
	Returns `true` if the block may contain no data.

bool	hasNoDataValue () const
	`true` if the block has no data value.

int	height () const
	Returns the height (number of rows) of the raster block.

QImage	image () const
	Returns an image containing the block data, if the block's data type is color.

bool	isEmpty () const
	Returns `true` if block is empty, i.e.

bool	isNoData (int row, int column) const
	Checks if value at position is no data.

bool	isNoData (qgssize index) const
	Check if value at position is no data.

bool	isNoData (qgssize row, qgssize column) const
	Check if value at position is no data.

bool	isValid () const
	Returns `true` if the block is valid (correctly filled with data).

double	noDataValue () const
	Returns no data value.

bool	reset (Qgis::DataType dataType, int width, int height)
	Reset block.

void	resetNoDataValue ()
	Reset no data value: if there was a no data value previously set, it will be discarded.

bool	setColor (int row, int column, QRgb color)
	Set color on position.

bool	setColor (qgssize index, QRgb color)
	Set color on index (indexed line by line)

void	setData (const QByteArray &data, int offset=0)
	Rewrite raw pixel data.

void	setError (const QgsError &error)
	Sets the last error.

bool	setImage (const QImage *image)
	Sets the block data via an image.

void	setIsData (int row, int column)
	Remove no data flag on pixel.

void	setIsData (qgssize index)
	Remove no data flag on pixel.

bool	setIsNoData ()
	Set the whole block to no data.

bool	setIsNoData (int row, int column)
	Set no data on pixel.

bool	setIsNoData (qgssize index)
	Set no data on pixel.

bool	setIsNoDataExcept (QRect exceptRect)
	Set the whole block to no data except specified rectangle.

void	setNoDataValue (double noDataValue)
	Sets cell value that will be considered as "no data".

void	setValid (bool valid)
	Mark block as valid or invalid.

bool	setValue (int row, int column, double value)
	Set value on position.

bool	setValue (qgssize index, double value)
	Set value on index (indexed line by line)

QString	toString () const

double	value (int row, int column) const
	Read a single value if type of block is numeric.

double	value (qgssize index) const
	Reads a single value if type of block is numeric.

double	valueAndNoData (int row, int column, bool &isNoData) const
	Reads a single value from the pixel at row and column, if type of block is numeric.

double	valueAndNoData (qgssize index, bool &isNoData) const
	Reads a single value from the pixel at the specified data matrix index, if type of block is numeric.

int	width () const
	Returns the width (number of columns) of the raster block.

Static Public Member Functions
static QString	printValue (double value)
	Print double value with all necessary significant digits.

static QString	printValue (float value)
	Print float value with all necessary significant digits.

static double	readValue (void *data, Qgis::DataType type, qgssize index)

static QRect	subRect (const QgsRectangle &extent, int width, int height, const QgsRectangle &subExtent)
	For extent and width, height find rectangle covered by subextent.

static bool	typeIsColor (Qgis::DataType type)
	Returns `true` if data type is color.

static bool	typeIsNumeric (Qgis::DataType type)
	Returns `true` if data type is numeric.

static int	typeSize (Qgis::DataType dataType)
	Returns the size in bytes for the specified dataType.

static Qgis::DataType	typeWithNoDataValue (Qgis::DataType dataType, double *noDataValue)
	For given data type returns wider type and sets no data value.

static QByteArray	valueBytes (Qgis::DataType dataType, double value)
	Gets byte array representing a value.

static void	writeValue (void *data, Qgis::DataType type, qgssize index, double value)

Detailed Description

Raster data container.

Definition at line 36 of file qgsrasterblock.h.

Constructor & Destructor Documentation

◆ QgsRasterBlock() [1/2]

QgsRasterBlock::QgsRasterBlock ( )

Definition at line 30 of file qgsrasterblock.cpp.

◆ QgsRasterBlock() [2/2]

QgsRasterBlock::QgsRasterBlock	(	Qgis::DataType	dataType,
		int	width,
		int	height
	)

Constructor which allocates data block in memory.

Parameters

dataType	raster data type
width	width of data matrix
height	height of data matrix

Definition at line 35 of file qgsrasterblock.cpp.

◆ ~QgsRasterBlock()

QgsRasterBlock::~QgsRasterBlock ( )

virtual

Definition at line 44 of file qgsrasterblock.cpp.

Member Function Documentation

◆ applyNoDataValues()

void QgsRasterBlock::applyNoDataValues ( const QgsRasterRangeList & rangeList )

Definition at line 584 of file qgsrasterblock.cpp.

◆ applyScaleOffset()

void QgsRasterBlock::applyScaleOffset	(	double	scale,
		double	offset
	)

Apply band scale and offset to raster block values.

Definition at line 571 of file qgsrasterblock.cpp.

◆ bits() [1/3]

char * QgsRasterBlock::bits ( )

Returns a pointer to block data.

Note: not available in Python bindings

Definition at line 522 of file qgsrasterblock.cpp.

◆ bits() [2/3]

char * QgsRasterBlock::bits	(	int	row,
		int	column
	)

Returns a pointer to block data.

Parameters

row	row index
column	column index

Note: not available in Python bindings

Definition at line 517 of file qgsrasterblock.cpp.

◆ bits() [3/3]

char * QgsRasterBlock::bits ( qgssize index )

Returns a pointer to block data.

Parameters

index data matrix index (long type in Python)

Note: not available in Python bindings

Definition at line 497 of file qgsrasterblock.cpp.

◆ byteData()

const quint8 * QgsRasterBlock::byteData ( ) const

inline

Gives direct access to the raster block data.

The data type of the block must be Qgis::DataType::Byte otherwise it returns nullptr. Useful for most efficient read access.

Note: not available in Python bindings

Since: QGIS 3.4

Definition at line 247 of file qgsrasterblock.h.

◆ color() [1/2]

QRgb QgsRasterBlock::color	(	int	row,
		int	column
	)		const

inline

Read a single color.

Parameters

row	row index
column	column index

Returns: color

Definition at line 260 of file qgsrasterblock.h.

◆ color() [2/2]

QRgb QgsRasterBlock::color ( qgssize index ) const

inline

Read a single value.

Parameters

index data matrix index (long type in Python)

Returns: color

Definition at line 272 of file qgsrasterblock.h.

◆ colorData()

QRgb * QgsRasterBlock::colorData ( )

inline

Gives direct read/write access to the raster RGB data.

The data type of the block must be Qgis::DataType::ARGB32 or Qgis::DataType::ARGB32_Premultiplied otherwise it returns nullptr. Useful for most efficient read/write access to RGB blocks.

Note: not available in Python bindings

Since: QGIS 3.4

Definition at line 419 of file qgsrasterblock.h.

◆ convert()

bool QgsRasterBlock::convert ( Qgis::DataType destDataType )

Convert data to different type.

Parameters

destDataType dest data type

Returns: true on success

Definition at line 536 of file qgsrasterblock.cpp.

◆ data()

QByteArray QgsRasterBlock::data ( ) const

Gets access to raw data.

The returned QByteArray instance is not a copy of the data: it only refers to the array owned by the QgsRasterBlock, therefore it is only valid while the QgsRasterBlock object still exists. Writing to the returned QByteArray will not affect the original data: a deep copy of the data will be made and only the local copy will be modified.

Note: in Python the method returns ordinary bytes object as the

Definition at line 470 of file qgsrasterblock.cpp.

◆ dataType()

Qgis::DataType QgsRasterBlock::dataType ( ) const

inline

Returns data type.

Definition at line 135 of file qgsrasterblock.h.

◆ dataTypeSize()

int QgsRasterBlock::dataTypeSize ( ) const

inline

Data type size in bytes.

Definition at line 123 of file qgsrasterblock.h.

◆ error()

QgsError QgsRasterBlock::error ( ) const

inline

Returns the last error.

Definition at line 613 of file qgsrasterblock.h.

◆ hasNoData()

bool QgsRasterBlock::hasNoData ( ) const

inline

Returns true if the block may contain no data.

It does not guarantee that it really contains any no data. It can be used to speed up processing. Not the difference between this method and hasNoDataValue().

Returns: true if the block may contain no data

Definition at line 153 of file qgsrasterblock.h.

◆ hasNoDataValue()

bool QgsRasterBlock::hasNoDataValue ( ) const

inline

true if the block has no data value.

Returns: true if the block has no data value

See also: noDataValue(), setNoDataValue(), resetNoDataValue()

Definition at line 145 of file qgsrasterblock.h.

◆ height()

int QgsRasterBlock::height ( ) const

inline

Returns the height (number of rows) of the raster block.

See also: width

Definition at line 642 of file qgsrasterblock.h.

◆ image()

QImage QgsRasterBlock::image ( ) const

Returns an image containing the block data, if the block's data type is color.

Definition at line 603 of file qgsrasterblock.cpp.

◆ isEmpty()

bool QgsRasterBlock::isEmpty ( ) const

Returns true if block is empty, i.e.

its size is 0 (zero rows or cols). This method does not return true if size is not zero and all values are 'no data' (null).

Definition at line 130 of file qgsrasterblock.cpp.

◆ isNoData() [1/3]

bool QgsRasterBlock::isNoData	(	int	row,
		int	column
	)		const

inline

Checks if value at position is no data.

Parameters

row	row index
column	column index

Returns: true if value is no data

See also: valueAndNoData()

Definition at line 286 of file qgsrasterblock.h.

◆ isNoData() [2/3]

bool QgsRasterBlock::isNoData ( qgssize index ) const

inline

Check if value at position is no data.

Parameters

index data matrix index (long type in Python)

Returns: true if value is no data

See also: valueAndNoData()

Definition at line 309 of file qgsrasterblock.h.

◆ isNoData() [3/3]

bool QgsRasterBlock::isNoData	(	qgssize	row,
		qgssize	column
	)		const

inline

Check if value at position is no data.

Parameters

row	row index
column	column index

Returns: true if value is no data

See also: valueAndNoData()

Definition at line 298 of file qgsrasterblock.h.

◆ isValid()

bool QgsRasterBlock::isValid ( ) const

inline

Returns true if the block is valid (correctly filled with data).

An empty block may still be valid (if zero size block was requested). If the block is not valid, error may be retrieved by error() method.

Definition at line 68 of file qgsrasterblock.h.

◆ noDataValue()

double QgsRasterBlock::noDataValue ( ) const

inline

Returns no data value.

If the block does not have a no data value the returned value is undefined.

Returns: No data value

See also: hasNoDataValue(), setNoDataValue(), resetNoDataValue()

Definition at line 177 of file qgsrasterblock.h.

◆ printValue() [1/2]

QString QgsRasterBlock::printValue ( double value )

static

Print double value with all necessary significant digits.

It is ensured that conversion back to double gives the same number.

Parameters

value the value to be printed

Returns: string representing the value

Definition at line 627 of file qgsrasterblock.cpp.

◆ printValue() [2/2]

QString QgsRasterBlock::printValue ( float value )

static

Print float value with all necessary significant digits.

It is ensured that conversion back to float gives the same number.

Parameters

value the value to be printed

Returns: string representing the value

Note: not available in Python bindings

Definition at line 666 of file qgsrasterblock.cpp.

◆ readValue()

double QgsRasterBlock::readValue	(	void *	data,
		Qgis::DataType	type,
		qgssize	index
	)

inlinestatic

Note: not available in Python bindings

Definition at line 732 of file qgsrasterblock.h.

◆ reset()

bool QgsRasterBlock::reset	(	Qgis::DataType	dataType,
		int	width,
		int	height
	)

Reset block.

Parameters

dataType	raster data type
width	width of data matrix
height	height of data matrix

Returns: true on success

Definition at line 52 of file qgsrasterblock.cpp.

◆ resetNoDataValue()

void QgsRasterBlock::resetNoDataValue ( )

Reset no data value: if there was a no data value previously set, it will be discarded.

See also: noDataValue(), hasNoDataValue(), setNoDataValue()

Definition at line 237 of file qgsrasterblock.cpp.

◆ setColor() [1/2]

bool QgsRasterBlock::setColor	(	int	row,
		int	column,
		QRgb	color
	)

inline

Set color on position.

Parameters

row	row index
column	column index
color	the color to be set, QRgb value

Returns: true on success

Definition at line 381 of file qgsrasterblock.h.

◆ setColor() [2/2]

bool QgsRasterBlock::setColor	(	qgssize	index,
		QRgb	color
	)

inline

Set color on index (indexed line by line)

Parameters

index	data matrix index (long type in Python)
color	the color to be set, QRgb value

Returns: true on success

Definition at line 392 of file qgsrasterblock.h.

◆ setData()

void QgsRasterBlock::setData	(	const QByteArray &	data,
		int	offset = `0`
	)

Rewrite raw pixel data.

If the data array is shorter than the internal array within the raster block object, pixels at the end will stay untouched. If the data array is longer than the internal array, only the initial data from the input array will be used. Optionally it is possible to set non-zero offset (in bytes) if the input data should overwrite data somewhere in the middle of the internal buffer.

Definition at line 480 of file qgsrasterblock.cpp.

◆ setError()

void QgsRasterBlock::setError ( const QgsError & error )

inline

Sets the last error.

Definition at line 616 of file qgsrasterblock.h.

◆ setImage()

bool QgsRasterBlock::setImage ( const QImage * image )

Sets the block data via an image.

Returns: true on success

Definition at line 612 of file qgsrasterblock.cpp.

◆ setIsData() [1/2]

void QgsRasterBlock::setIsData	(	int	row,
		int	column
	)

inline

Remove no data flag on pixel.

If the raster block does not have an explicit no data value set then an internal map of no data pixels is maintained for the block. In this case it is possible to reset a pixel to flag it as having valid data using this method. This method has no effect for raster blocks with an explicit no data value set.

Parameters

row	row index
column	column index

Definition at line 489 of file qgsrasterblock.h.

◆ setIsData() [2/2]

void QgsRasterBlock::setIsData ( qgssize index )

inline

Remove no data flag on pixel.

If the raster block does not have an explicit no data value set then an internal map of no data pixels is maintained for the block. In this case it is possible to reset a pixel to flag it as having valid data using this method. This method has no effect for raster blocks with an explicit no data value set.

Parameters

index data matrix index (long type in Python)

Definition at line 501 of file qgsrasterblock.h.

◆ setIsNoData() [1/3]

bool QgsRasterBlock::setIsNoData ( )

Set the whole block to no data.

Returns: true on success

Definition at line 243 of file qgsrasterblock.cpp.

◆ setIsNoData() [2/3]

bool QgsRasterBlock::setIsNoData	(	int	row,
		int	column
	)

inline

Set no data on pixel.

Parameters

row	row index
column	column index

Returns: true on success

Definition at line 432 of file qgsrasterblock.h.

◆ setIsNoData() [3/3]

bool QgsRasterBlock::setIsNoData ( qgssize index )

inline

Set no data on pixel.

Parameters

index data matrix index (long type in Python)

Returns: true on success

Definition at line 442 of file qgsrasterblock.h.

◆ setIsNoDataExcept()

bool QgsRasterBlock::setIsNoDataExcept ( QRect exceptRect )

Set the whole block to no data except specified rectangle.

Returns: true on success

Definition at line 305 of file qgsrasterblock.cpp.

◆ setNoDataValue()

void QgsRasterBlock::setNoDataValue ( double noDataValue )

Sets cell value that will be considered as "no data".

See also: noDataValue(), hasNoDataValue(), resetNoDataValue()

Definition at line 231 of file qgsrasterblock.cpp.

◆ setValid()

void QgsRasterBlock::setValid ( bool valid )

inline

Mark block as valid or invalid.

Definition at line 71 of file qgsrasterblock.h.

◆ setValue() [1/2]

bool QgsRasterBlock::setValue	(	int	row,
		int	column,
		double	value
	)

inline

Set value on position.

Parameters

row	row index
column	column index
value	the value to be set

Returns: true on success

Definition at line 347 of file qgsrasterblock.h.

◆ setValue() [2/2]

bool QgsRasterBlock::setValue	(	qgssize	index,
		double	value
	)

inline

Set value on index (indexed line by line)

Parameters

index	data matrix index (long type in Python)
value	the value to be set

Returns: true on success

Definition at line 358 of file qgsrasterblock.h.

◆ subRect()

QRect QgsRasterBlock::subRect	(	const QgsRectangle &	extent,
		int	width,
		int	height,
		const QgsRectangle &	subExtent
	)

static

For extent and width, height find rectangle covered by subextent.

The output rect has x oriented from left to right and y from top to bottom (upper-left to lower-right orientation).

Parameters

extent	extent, usually the larger
width	numbers of columns in theExtent
height	numbers of rows in theExtent
subExtent	extent, usually smaller than theExtent

Returns: the rectangle covered by sub extent

Definition at line 783 of file qgsrasterblock.cpp.

◆ toString()

QString QgsRasterBlock::toString ( ) const

Definition at line 777 of file qgsrasterblock.cpp.

◆ typeIsColor()

bool QgsRasterBlock::typeIsColor ( Qgis::DataType type )

static

Returns true if data type is color.

Definition at line 165 of file qgsrasterblock.cpp.

◆ typeIsNumeric()

bool QgsRasterBlock::typeIsNumeric ( Qgis::DataType type )

static

Returns true if data type is numeric.

Definition at line 139 of file qgsrasterblock.cpp.

◆ typeSize()

static int QgsRasterBlock::typeSize ( Qgis::DataType dataType )

inlinestatic

Returns the size in bytes for the specified dataType.

Definition at line 83 of file qgsrasterblock.h.

◆ typeWithNoDataValue()

Qgis::DataType QgsRasterBlock::typeWithNoDataValue	(	Qgis::DataType	dataType,
		double *	noDataValue
	)

static

For given data type returns wider type and sets no data value.

Definition at line 191 of file qgsrasterblock.cpp.

◆ value() [1/2]

double QgsRasterBlock::value	(	int	row,
		int	column
	)		const

inline

Read a single value if type of block is numeric.

If type is color, returned value is undefined.

Parameters

row	row index
column	column index

Returns: value

See also: valueAndNoData()

Definition at line 195 of file qgsrasterblock.h.

◆ value() [2/2]

double QgsRasterBlock::value ( qgssize index ) const

inline

Reads a single value if type of block is numeric.

If type is color, returned value is undefined.

Parameters

index data matrix index (long type in Python)

Returns: value

See also: valueAndNoData()

Definition at line 813 of file qgsrasterblock.h.

◆ valueAndNoData() [1/2]

double QgsRasterBlock::valueAndNoData	(	int	row,
		int	column,
		bool &	isNoData
	)		const

inline

Reads a single value from the pixel at row and column, if type of block is numeric.

If type is color, returned value is undefined.

Additionally, the isNoData argument will be set to true if the pixel represents a nodata value. This method is more efficient then calling isNoData() and value() separately.

Note: Not available in Python bindings

See also: value(); isNoData()

Since: QGIS 3.6

Definition at line 212 of file qgsrasterblock.h.

◆ valueAndNoData() [2/2]

double QgsRasterBlock::valueAndNoData	(	qgssize	index,
		bool &	isNoData
	)		const

inline

Reads a single value from the pixel at the specified data matrix index, if type of block is numeric.

If type is color, returned value is undefined.

Additionally, the isNoData argument will be set to true if the pixel represents a nodata value. This method is more efficient then calling isNoData() and value() separately.

Note: Not available in Python bindings

See also: value(); isNoData()

Since: QGIS 3.6

Definition at line 823 of file qgsrasterblock.h.

◆ valueBytes()

QByteArray QgsRasterBlock::valueBytes	(	Qgis::DataType	dataType,
		double	value
	)

static

Gets byte array representing a value.

Parameters

dataType	data type
value	value

Returns: byte array representing the value

Definition at line 701 of file qgsrasterblock.cpp.

◆ width()

int QgsRasterBlock::width ( ) const

inline

Returns the width (number of columns) of the raster block.

See also: height

Definition at line 636 of file qgsrasterblock.h.

◆ writeValue()

void QgsRasterBlock::writeValue	(	void *	data,
		Qgis::DataType	type,
		qgssize	index,
		double	value
	)

inlinestatic

Note: not available in Python bindings

Definition at line 771 of file qgsrasterblock.h.

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

/build/qgis-3.36.0+99sid/src/core/raster/qgsrasterblock.h
/build/qgis-3.36.0+99sid/src/core/raster/qgsrasterblock.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ QgsRasterBlock() [1/2]

◆ QgsRasterBlock() [2/2]

◆ ~QgsRasterBlock()

Member Function Documentation

◆ applyNoDataValues()

◆ applyScaleOffset()

◆ bits() [1/3]

◆ bits() [2/3]

◆ bits() [3/3]

◆ byteData()

◆ color() [1/2]

◆ color() [2/2]

◆ colorData()

◆ convert()

◆ data()

◆ dataType()

◆ dataTypeSize()

◆ error()

◆ hasNoData()

◆ hasNoDataValue()

◆ height()

◆ image()

◆ isEmpty()

◆ isNoData() [1/3]

◆ isNoData() [2/3]

◆ isNoData() [3/3]

◆ isValid()

◆ noDataValue()

◆ printValue() [1/2]

◆ printValue() [2/2]

◆ readValue()

◆ reset()

◆ resetNoDataValue()

◆ setColor() [1/2]

◆ setColor() [2/2]

◆ setData()

◆ setError()

◆ setImage()

◆ setIsData() [1/2]

◆ setIsData() [2/2]

◆ setIsNoData() [1/3]

◆ setIsNoData() [2/3]

◆ setIsNoData() [3/3]

◆ setIsNoDataExcept()

◆ setNoDataValue()

◆ setValid()

◆ setValue() [1/2]

◆ setValue() [2/2]

◆ subRect()

◆ toString()

◆ typeIsColor()

◆ typeIsNumeric()

◆ typeSize()

◆ typeWithNoDataValue()

◆ value() [1/2]

◆ value() [2/2]

◆ valueAndNoData() [1/2]

◆ valueAndNoData() [2/2]

◆ valueBytes()

◆ width()

◆ writeValue()