Isis 3 Programmer Reference
Isis::Stretch Class Reference

Pixel value mapper. More...

#include <Stretch.h>

Collaboration diagram for Isis::Stretch:
Collaboration graph

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...
 

Private Member Functions

std::pair< double, double > NextPair (QString &pairs)
 Given a string containing stretch pairs for example "0:0 50:0 100:255 255:255" evaluate the first pair and return a pair of doubles where first is the first input and second is the first output. More...
 

Private Attributes

std::vector< double > p_input
 Array for input side of stretch pairs. More...
 
std::vector< double > p_output
 Array for output side of stretch pairs. More...
 
int p_pairs
 Number of stretch pairs. More...
 
double p_null
 Mapping of input NULL values go to this value (default NULL) More...
 
double p_lis
 Mapping of input LIS values go to this value (default LIS) More...
 
double p_lrs
 Mapping of input LRS values go to this value (default LRS) More...
 
double p_his
 Mapping of input HIS values go to this value (default HIS) More...
 
double p_hrs
 Mapping of input HRS values go to this value (default HRS) More...
 
double p_minimum
 By default this value is set to p_lrs. More...
 
double p_maximum
 By default this value is set to p_hrs. 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
History:

2002-09-17 Jeff Anderson - Added Parse method

2003-05-16 Stuart Sides - Modified schema from astrogeology... isis.astrogeology...

2005-02-16 Elizabeth Ribelin - Modified file to support Doxygen documentation

2005-03-11 Elizabeth Ribelin - Modified unitTest to test all methods in the class

2006-05-25 Jacob Danton - Fixed typo in documentation

2007-03-02 Elizabeth Miller - Added Load and Save methods

2008-11-12 Steven Lambright - Changed search algorithm into a binary search replacing a linear search.

2009-04-30 Eric Hyer - Modified parse method. New private method NextPair() now handles low level details of parsing. Created second Parse method for handling pairs where the input side is a perentage. Fixed Input and Output getters to check both sides of boundry condition for valid data

Definition at line 72 of file Stretch.h.

Constructor & Destructor Documentation

◆ Stretch()

Isis::Stretch::Stretch ( )

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

Definition at line 41 of file Stretch.cpp.

◆ ~Stretch()

Isis::Stretch::~Stretch ( )
inline

Destroys the Stretch object.

Definition at line 97 of file Stretch.h.

Member Function Documentation

◆ AddPair()

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

◆ ClearPairs()

◆ CopyPairs()

◆ Input()

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

Definition at line 302 of file Stretch.cpp.

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

◆ Load() [1/2]

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

Definition at line 357 of file Stretch.cpp.

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

◆ Load() [2/2]

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

Definition at line 338 of file Stretch.cpp.

◆ Map()

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

Definition at line 84 of file Stretch.cpp.

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

Referenced by Isis::MosaicSceneItem::drawImage(), Isis::ChipViewport::paintImage(), Isis::VisualDisplay::paintPixmap(), and Isis::CubeViewport::paintPixmap().

◆ NextPair()

std::pair< double, double > Isis::Stretch::NextPair ( QString &  pairs)
private

Given a string containing stretch pairs for example "0:0 50:0 100:255 255:255" evaluate the first pair and return a pair of doubles where first is the first input and second is the first output.

Parameters
pairsA string containing stretch pairs for example "0:0 50:0 100:255 255:255"
Exceptions
Isis::IException::User- invalid stretch pair
Returns
std::pair of doubles where first is the first input and second is the first output

Definition at line 160 of file Stretch.cpp.

References Isis::Null, and Isis::toDouble().

◆ Output()

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

Definition at line 317 of file Stretch.cpp.

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

◆ Pairs()

◆ Parse() [1/2]

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

Definition at line 196 of file Stretch.cpp.

References _FILEINFO_.

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

◆ Parse() [2/2]

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

Definition at line 233 of file Stretch.cpp.

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

◆ Save()

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.

Definition at line 382 of file Stretch.cpp.

References Isis::Pvl::write().

◆ SetHis()

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

Definition at line 141 of file Stretch.h.

References p_his.

Referenced by Isis::SpecialPixelTool::apply(), Isis::MosaicSceneItem::getStretch(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

◆ SetHrs()

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

Definition at line 152 of file Stretch.h.

References p_hrs.

Referenced by Isis::SpecialPixelTool::apply(), Isis::MosaicSceneItem::getStretch(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

◆ SetLis()

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

Definition at line 119 of file Stretch.h.

References p_lis.

Referenced by Isis::SpecialPixelTool::apply(), Isis::MosaicSceneItem::getStretch(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

◆ SetLrs()

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

Definition at line 130 of file Stretch.h.

References p_lrs.

Referenced by Isis::SpecialPixelTool::apply(), Isis::MosaicSceneItem::getStretch(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

◆ SetNull()

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

Definition at line 108 of file Stretch.h.

References p_null.

Referenced by Isis::SpecialPixelTool::apply(), Isis::MosaicSceneItem::getStretch(), Isis::QStretch::QStretch(), and Isis::VisualDisplay::VisualDisplay().

◆ Text()

Member Data Documentation

◆ p_his

double Isis::Stretch::p_his
private

Mapping of input HIS values go to this value (default HIS)

Definition at line 84 of file Stretch.h.

Referenced by SetHis().

◆ p_hrs

double Isis::Stretch::p_hrs
private

Mapping of input HRS values go to this value (default HRS)

Definition at line 86 of file Stretch.h.

Referenced by SetHrs().

◆ p_input

std::vector<double> Isis::Stretch::p_input
private

Array for input side of stretch pairs.

Definition at line 74 of file Stretch.h.

Referenced by ClearPairs(), and CopyPairs().

◆ p_lis

double Isis::Stretch::p_lis
private

Mapping of input LIS values go to this value (default LIS)

Definition at line 80 of file Stretch.h.

Referenced by SetLis().

◆ p_lrs

double Isis::Stretch::p_lrs
private

Mapping of input LRS values go to this value (default LRS)

Definition at line 82 of file Stretch.h.

Referenced by SetLrs().

◆ p_maximum

double Isis::Stretch::p_maximum
private

By default this value is set to p_hrs.

Definition at line 89 of file Stretch.h.

◆ p_minimum

double Isis::Stretch::p_minimum
private

By default this value is set to p_lrs.

Definition at line 88 of file Stretch.h.

◆ p_null

double Isis::Stretch::p_null
private

Mapping of input NULL values go to this value (default NULL)

Definition at line 78 of file Stretch.h.

Referenced by SetNull().

◆ p_output

std::vector<double> Isis::Stretch::p_output
private

Array for output side of stretch pairs.

Definition at line 75 of file Stretch.h.

Referenced by ClearPairs(), and CopyPairs().

◆ p_pairs

int Isis::Stretch::p_pairs
private

Number of stretch pairs.

Definition at line 76 of file Stretch.h.

Referenced by ClearPairs(), CopyPairs(), and Pairs().


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