Isis 3.0
Home
Isis::Stretch Class Reference

Pixel value mapper. More...

#include <Stretch.h>

Public Member Functions

 Stretch ()
 Constructs a Stretch object with default mapping of special pixel values to themselves. More...
 
 ~Stretch ()
 Destroys the Stretch object. More...
 
void AddPair (const double input, const double output)
 Adds a stretch pair to the list of pairs. More...
 
void SetNull (const double value)
 Sets the mapping for NULL pixels. More...
 
void SetLis (const double value)
 Sets the mapping for LIS pixels. More...
 
void SetLrs (const double value)
 Sets the mapping for LRS pixels. More...
 
void SetHis (const double value)
 Sets the mapping for HIS pixels. More...
 
void SetHrs (const double value)
 Sets the mapping for HRS pixels. More...
 
void SetMinimum (const double value)
 
void SetMaximum (const double value)
 
void Load (Pvl &pvl, QString &grpName)
 Loads the stretch pairs from the pvl file into the Stretch object. More...
 
void Save (Pvl &pvl, QString &grpName)
 
void Load (QString &file, QString &grpName)
 Loads the stretch pairs from the pvl file into the Stretch object. More...
 
void Save (QString &file, QString &grpName)
 Saves the stretch pairs in the Stretch object into the given pvl file. More...
 
double Map (const double value) const
 Maps an input value to an output value based on the stretch pairs and/or special pixel mappings. More...
 
void Parse (const QString &pairs)
 Parses a string of the form "i1:o1 i2:o2...iN:oN" where each i:o represents an input:output pair. More...
 
void Parse (const QString &pairs, const Isis::Histogram *hist)
 Parses a string of the form "i1:o1 i2:o2...iN:oN" where each i:o represents an input:output pair where the input is a percentage. More...
 
QString Text () const
 Converts stretch pair to a string. More...
 
int Pairs () const
 Returns the number of stretch pairs. More...
 
double Input (const int index) const
 Returns the value of the input side of the stretch pair at the specified index. More...
 
double Output (const int index) const
 Returns the value of the output side of the stretch pair at the specified index. More...
 
void ClearPairs ()
 Clears the stretch pairs. More...
 
void CopyPairs (const Stretch &other)
 Copies the stretch pairs from another Stretch object, but maintains special pixel values. More...
 

Detailed Description

Pixel value mapper.

This class is used to stretch or remap pixel values. For example, it can be used to apply contrast stretches, color code stretches, or remap from a double range to 8-bit (0 to 255). The methodology used is straightforward. The program must set up a list of stretch pairs, input-to-output mappings, using the AddPair method. For example, (0,0) and (1,255) are two pairs which would cause an input of 0 to be mapped to 0, 0.5 would be mapped to 127.5 and 1 would be mapped to 255. More than two pairs can be used which generates piece-wise linear mappings. Special pixels are mapped to themselves unless overridden with methods such as SetNull. Input values outside the minimum and maximum input pair values are mapped to LRS and HRS respectively.

If you would like to see Stretch being used in implementation, see stretch.cpp

Author
2002-05-15 Jeff Anderson

Constructor & Destructor Documentation

Isis::Stretch::Stretch ( )

Constructs a Stretch object with default mapping of special pixel values to themselves.

References Isis::HIGH_INSTR_SAT8, Isis::HIGH_REPR_SAT8, Isis::LOW_INSTR_SAT8, Isis::LOW_REPR_SAT8, and Isis::NULL8.

Isis::Stretch::~Stretch ( )
inline

Destroys the Stretch object.

Member Function Documentation

void Isis::Stretch::AddPair ( const double  input,
const double  output 
)

Adds a stretch pair to the list of pairs.

Note that all input pairs must be in ascending order.

Parameters
inputInput value to map
outputOutput value when the input is mapped
Exceptions
Isis::IException::Programmer- input pairs must be in ascending order

References _FILEINFO_.

Referenced by Isis::IndependentCubeViewport::cubeDataChanged(), Isis::VisualDisplay::setPixelData(), Isis::LinearStretchType::setStretch(), Isis::BinaryStretchType::setStretch(), Isis::StretchTool::stretchBand(), and Isis::StretchTool::stretchBuffer().

void Isis::Stretch::ClearPairs ( )
inline
void Isis::Stretch::CopyPairs ( const Stretch other)
double Isis::Stretch::Input ( const int  index) const

Returns the value of the input side of the stretch pair at the specified index.

If the index number is out of bounds, then the method returns -1

Parameters
indexThe index number to retrieve the input stretch pair value from
Returns
double The input side of the stretch pair at the specified index

Referenced by Isis::BinaryStretchType::setStretch(), Isis::LinearStretchType::setStretch(), Isis::SawtoothStretchType::setStretch(), Isis::HistogramWidget::setStretch(), and Isis::StretchType::updateTable().

void Isis::Stretch::Load ( Isis::Pvl pvl,
QString &  grpName 
)

Loads the stretch pairs from the pvl file into the Stretch object.

The pvl should look similar to this:

* Group = Pairs
* Input = (0,100,255)
* Output = (255,100,0)
* EndGroup
*
Parameters
pvl- The pvl containing the stretch pairs
grpName- The group name to get the input and output keywords from

References _FILEINFO_, Isis::PvlObject::findGroup(), Isis::PvlContainer::findKeyword(), Isis::PvlKeyword::size(), Isis::toDouble(), and Isis::PvlObject::Traverse.

void Isis::Stretch::Load ( QString &  file,
QString &  grpName 
)

Loads the stretch pairs from the pvl file into the Stretch object.

The file should look similar to this:

* Group = Pairs
* Input = (0,100,255)
* Output = (255,100,0)
* EndGroup
*
Parameters
file- The input file containing the stretch pairs
grpName- The group name to get the input and output keywords from
double Isis::Stretch::Map ( const double  value) const

Maps an input value to an output value based on the stretch pairs and/or special pixel mappings.

Parameters
valueValue to map
Returns
double The mapped output value is returned by this method

References Isis::IsHisPixel(), Isis::IsHrsPixel(), Isis::IsLisPixel(), Isis::IsNullPixel(), and Isis::IsValidPixel().

Referenced by Isis::VisualDisplay::paintPixmap().

double Isis::Stretch::Output ( const int  index) const

Returns the value of the output side of the stretch pair at the specified index.

If the index number is out of bounds, then the method returns -1.

Parameters
indexThe index number to retieve the output stretch pair value from
Returns
double The output side of the stretch pair at the specified index

Referenced by Isis::BinaryStretchType::setStretch(), Isis::SawtoothStretchType::setStretch(), Isis::HistogramWidget::setStretch(), and Isis::StretchType::updateTable().

void Isis::Stretch::Parse ( const QString &  pairs)

Parses a string of the form "i1:o1 i2:o2...iN:oN" where each i:o represents an input:output pair.

Therefore, the user can enter a string in this form and this method will parse the string and load the stretch pairs into the object via AddPairs.

Parameters
pairsA string containing stretch pairs for example "0:0 50:0 100:255 255:255"
Exceptions
Isis::IException::User- invalid stretch pair

References _FILEINFO_.

Referenced by Isis::CubeViewport::stretchBlue(), Isis::CubeViewport::stretchGray(), Isis::CubeViewport::stretchGreen(), and Isis::CubeViewport::stretchRed().

void Isis::Stretch::Parse ( const QString &  pairs,
const Isis::Histogram hist 
)

Parses a string of the form "i1:o1 i2:o2...iN:oN" where each i:o represents an input:output pair where the input is a percentage.

Using the Histogram an appropriate dn value will be calculated for each input percentage. Therefore, the user can enter a string in this form and this method will parse the string and load the stretch pairs into the object via AddPairs.

Parameters
pairsA string containing stretch pairs for example "0:0 50:0 100:255"
Exceptions
Isis::IException::User- invalid stretch pair

References _FILEINFO_, and Isis::Histogram::Percent().

void Isis::Stretch::Save ( Isis::Pvl pvl,
QString &  grpName 
)
void Isis::Stretch::Save ( QString &  file,
QString &  grpName 
)

Saves the stretch pairs in the Stretch object into the given pvl file.

Parameters
file- The file that the stretch pairs will be written to
grpName- The name of the group to create and put the stretch pairs into. The group will contain two keywords, Input, and Output.

References Isis::Pvl::write().

void Isis::Stretch::SetHis ( const double  value)
inline

Sets the mapping for HIS pixels.

If not called the HIS pixels will be mapped to HIS. Otherwise you can map HIS to any double value. For example, SetHis(255.0).

Parameters
valueValue to map input HIS

Referenced by Isis::CubeViewport::BandInfo::BandInfo(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

void Isis::Stretch::SetHrs ( const double  value)
inline

Sets the mapping for HRS pixels.

If not called the HRS pixels will be mapped to HRS. Otherwise you can map HRS to any double value. For example, SetHrs(255.0).

Parameters
valueValue to map input HRS

Referenced by Isis::CubeViewport::BandInfo::BandInfo(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

void Isis::Stretch::SetLis ( const double  value)
inline

Sets the mapping for LIS pixels.

If not called the LIS pixels will be mapped to LIS. Otherwise you can map LIS to any double value. For example, SetLis(0.0).

Parameters
valueValue to map input LIS

Referenced by Isis::CubeViewport::BandInfo::BandInfo(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

void Isis::Stretch::SetLrs ( const double  value)
inline

Sets the mapping for LRS pixels.

If not called the LRS pixels will be mapped to LRS. Otherwise you can map LRS to any double value. For example, SetLrs(0.0).

Parameters
valueValue to map input LRS

Referenced by Isis::CubeViewport::BandInfo::BandInfo(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

void Isis::Stretch::SetMaximum ( const double  value)
inline
void Isis::Stretch::SetMinimum ( const double  value)
inline
void Isis::Stretch::SetNull ( const double  value)
inline

Sets the mapping for NULL pixels.

If not called the NULL pixels will be mapped to NULL. Otherwise you can map NULLs to any double value. For example, SetNull(0.0).

Parameters
valueValue to map input NULLs

Referenced by Isis::CubeViewport::BandInfo::BandInfo(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

QString Isis::Stretch::Text ( ) const

Converts stretch pair to a string.

Returns
string The stretch pair as a string

References Isis::toString().

Referenced by Isis::BinaryStretchType::setStretch(), Isis::LinearStretchType::setStretch(), and Isis::ManualStretchType::setStretch().


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