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QgsRasterBlock Class Reference

Raster data container. More...

#include <qgsrasterblock.h>

Public Member Functions

 QgsRasterBlock ()
 
 QgsRasterBlock (QGis::DataType theDataType, int theWidth, int theHeight)
 Constructor which allocates data block in memory. More...
 
 QgsRasterBlock (QGis::DataType theDataType, int theWidth, int theHeight, double theNoDataValue)
 Constructor which allocates data block in memory. More...
 
virtual ~QgsRasterBlock ()
 
bool reset (QGis::DataType theDataType, int theWidth, int theHeight)
 Reset block. More...
 
bool reset (QGis::DataType theDataType, int theWidth, int theHeight, double theNoDataValue)
 Reset block. More...
 
bool isValid () const
 Returns true if the block is valid (correctly filled with data). More...
 
void setValid (bool valid)
 Mark block as valid or invalid. More...
 
bool isEmpty () const
 Returns true if block is empty, i.e. More...
 
int dataTypeSize () const
 
QGis::DataType dataType () const
 Returns data type. More...
 
bool hasNoDataValue () const
 True if the block has no data value. More...
 
bool hasNoData () const
 Returns true if the block may contain no data. More...
 
double noDataValue () const
 Return no data value. More...
 
double value (int row, int column) const
 Read a single value if type of block is numeric. More...
 
double value (qgssize index) const
 Read a single value if type of block is numeric. More...
 
QRgb color (int row, int column) const
 Read a single color. More...
 
QRgb color (qgssize index) const
 Read a single value. More...
 
bool isNoData (int row, int column)
 Check if value at position is no data. More...
 
bool isNoData (qgssize index)
 Check if value at position is no data. More...
 
bool setValue (int row, int column, double value)
 Set value on position. More...
 
bool setValue (qgssize index, double value)
 Set value on index (indexed line by line) More...
 
bool setColor (int row, int column, QRgb color)
 Set color on position. More...
 
bool setColor (qgssize index, QRgb color)
 Set color on index (indexed line by line) More...
 
bool setIsNoData (int row, int column)
 Set no data on pixel. More...
 
bool setIsNoData (qgssize index)
 Set no data on pixel. More...
 
bool setIsNoData ()
 Set the whole block to no data. More...
 
bool setIsNoDataExcept (const QRect &theExceptRect)
 Set the whole block to no data except specified rectangle. More...
 
char * bits (int row, int column)
 Get pointer to data. More...
 
char * bits (qgssize index)
 Get pointer to data. More...
 
char * bits ()
 Get pointer to data. More...
 
bool convert (QGis::DataType destDataType)
 Convert data to different type. More...
 
QImage image () const
 Get image if type is color. More...
 
bool setImage (const QImage *image)
 set image. More...
 
void applyNoDataValues (const QgsRasterRangeList &rangeList)
 
void applyScaleOffset (double scale, double offset)
 apply band scale and offset to raster block values @note added in 2.3 More...
 
QgsError error () const
 Get error. More...
 
void setError (const QgsError &theError)
 Set error. More...
 

Static Public Member Functions

static int typeSize (int dataType)
 
static bool typeIsNumeric (QGis::DataType type)
 Returns true if data type is numeric. More...
 
static bool typeIsColor (QGis::DataType type)
 Returns true if data type is color. More...
 
static QGis::DataType typeWithNoDataValue (QGis::DataType dataType, double *noDataValue)
 For given data type returns wider type and sets no data value. More...
 
static QByteArray valueBytes (QGis::DataType theDataType, double theValue)
 Get byte array representing a value. More...
 
static QString printValue (double value)
 Print double value with all necessary significant digits. More...
 
static double readValue (void *data, QGis::DataType type, qgssize index)
 
static void writeValue (void *data, QGis::DataType type, qgssize index, double value)
 
static QRect subRect (const QgsRectangle &theExtent, int theWidth, int theHeight, const QgsRectangle &theSubExtent)
 For theExtent and theWidht, theHeight find rectangle covered by subextent. More...
 

Detailed Description

Raster data container.

Constructor & Destructor Documentation

QgsRasterBlock::QgsRasterBlock ( )
QgsRasterBlock::QgsRasterBlock ( QGis::DataType  theDataType,
int  theWidth,
int  theHeight 
)

Constructor which allocates data block in memory.

Parameters
theDataTyperaster data type
theWidthwidth of data matrix
theHeightheight of data matrix
Note
not available in python bindings (use variant with theNoDataValue)
QgsRasterBlock::QgsRasterBlock ( QGis::DataType  theDataType,
int  theWidth,
int  theHeight,
double  theNoDataValue 
)

Constructor which allocates data block in memory.

Parameters
theDataTyperaster data type
theWidthwidth of data matrix
theHeightheight of data matrix
theNoDataValuethe value representing no data (NULL)
QgsRasterBlock::~QgsRasterBlock ( )
virtual

Member Function Documentation

void QgsRasterBlock::applyNoDataValues ( const QgsRasterRangeList rangeList)
void QgsRasterBlock::applyScaleOffset ( double  scale,
double  offset 
)

apply band scale and offset to raster block values @note added in 2.3

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

Get pointer to data.

Parameters
rowrow index
columncolumn index
Returns
pointer to data
Note
not available in python bindings
char * QgsRasterBlock::bits ( qgssize  index)

Get pointer to data.

Parameters
indexdata matrix index (long type in Python)
Returns
pointer to data
Note
not available in python bindings
char * QgsRasterBlock::bits ( )

Get pointer to data.

Returns
pointer to data
Note
not available in python bindings
QRgb QgsRasterBlock::color ( int  row,
int  column 
) const

Read a single color.

Parameters
rowrow index
columncolumn index
Returns
color
QRgb QgsRasterBlock::color ( qgssize  index) const

Read a single value.

Parameters
indexdata matrix index (long type in Python)
Returns
color
bool QgsRasterBlock::convert ( QGis::DataType  destDataType)

Convert data to different type.

Parameters
destDataTypedest data type
Returns
true on success
QGis::DataType QgsRasterBlock::dataType ( ) const
inline

Returns data type.

int QgsRasterBlock::dataTypeSize ( ) const
inline
QgsError QgsRasterBlock::error ( ) const
inline

Get error.

bool QgsRasterBlock::hasNoData ( ) const

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
bool QgsRasterBlock::hasNoDataValue ( ) const
inline

True if the block has no data value.

Returns
true if the block has no data value
QImage QgsRasterBlock::image ( ) const

Get image if type is color.

Returns
image
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).

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

Check if value at position is no data.

Parameters
rowrow index
columncolumn index
Returns
true if value is no data
bool QgsRasterBlock::isNoData ( qgssize  index)

Check if value at position is no data.

Parameters
indexdata matrix index (long type in Python)
Returns
true if value is no data
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.

double QgsRasterBlock::noDataValue ( ) const
inline

Return no data value.

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

Returns
No data value
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
valuethe value to be printed
Returns
string representing the value
double QgsRasterBlock::readValue ( void *  data,
QGis::DataType  type,
qgssize  index 
)
inlinestatic
bool QgsRasterBlock::reset ( QGis::DataType  theDataType,
int  theWidth,
int  theHeight 
)

Reset block.

Parameters
theDataTyperaster data type
theWidthwidth of data matrix
theHeightheight of data matrix
Returns
true on success
Note
not available in python bindings (use variant with theNoDataValue)
bool QgsRasterBlock::reset ( QGis::DataType  theDataType,
int  theWidth,
int  theHeight,
double  theNoDataValue 
)

Reset block.

Parameters
theDataTyperaster data type
theWidthwidth of data matrix
theHeightheight of data matrix
theNoDataValuethe value representing no data (NULL)
Returns
true on success
bool QgsRasterBlock::setColor ( int  row,
int  column,
QRgb  color 
)

Set color on position.

Parameters
rowrow index
columncolumn index
colorthe color to be set, QRgb value
Returns
true on success
bool QgsRasterBlock::setColor ( qgssize  index,
QRgb  color 
)

Set color on index (indexed line by line)

Parameters
indexdata matrix index (long type in Python)
colorthe color to be set, QRgb value
Returns
true on success
void QgsRasterBlock::setError ( const QgsError theError)
inline

Set error.

bool QgsRasterBlock::setImage ( const QImage *  image)

set image.

Parameters
imageimage
Returns
true on success
bool QgsRasterBlock::setIsNoData ( int  row,
int  column 
)

Set no data on pixel.

Parameters
rowrow index
columncolumn index
Returns
true on success
bool QgsRasterBlock::setIsNoData ( qgssize  index)

Set no data on pixel.

Parameters
indexdata matrix index (long type in Python)
Returns
true on success
bool QgsRasterBlock::setIsNoData ( )

Set the whole block to no data.

Returns
true on success
bool QgsRasterBlock::setIsNoDataExcept ( const QRect &  theExceptRect)

Set the whole block to no data except specified rectangle.

Returns
true on success
void QgsRasterBlock::setValid ( bool  valid)
inline

Mark block as valid or invalid.

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

Set value on position.

Parameters
rowrow index
columncolumn index
valuethe value to be set
Returns
true on success
bool QgsRasterBlock::setValue ( qgssize  index,
double  value 
)

Set value on index (indexed line by line)

Parameters
indexdata matrix index (long type in Python)
valuethe value to be set
Returns
true on success
QRect QgsRasterBlock::subRect ( const QgsRectangle theExtent,
int  theWidth,
int  theHeight,
const QgsRectangle theSubExtent 
)
static

For theExtent and theWidht, theHeight 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
theExtentextent, usually the larger
theWidthnumbers of columns in theExtent
theHeightnumbers of rows in theExtent
theSubExtentextent, usually smaller than theExtent
Returns
the rectangle covered by sub extent
bool QgsRasterBlock::typeIsColor ( QGis::DataType  type)
static

Returns true if data type is color.

bool QgsRasterBlock::typeIsNumeric ( QGis::DataType  type)
static

Returns true if data type is numeric.

static int QgsRasterBlock::typeSize ( int  dataType)
inlinestatic
QGis::DataType QgsRasterBlock::typeWithNoDataValue ( QGis::DataType  dataType,
double *  noDataValue 
)
static

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

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

Read a single value if type of block is numeric.

If type is color, returned value is undefined.

Parameters
rowrow index
columncolumn index
Returns
value
double QgsRasterBlock::value ( qgssize  index) const
inline

Read a single value if type of block is numeric.

If type is color, returned value is undefined.

Parameters
indexdata matrix index (long type in Python)
Returns
value
QByteArray QgsRasterBlock::valueBytes ( QGis::DataType  theDataType,
double  theValue 
)
static

Get byte array representing a value.

Parameters
theDataTypedata type
theValuevalue
Returns
byte array representing the value
void QgsRasterBlock::writeValue ( void *  data,
QGis::DataType  type,
qgssize  index,
double  value 
)
inlinestatic

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