iflLut(3) Image Format Library C++ Reference Manual iflLut(3)
NAME
iflLut - base class for defining look-up tables
INHERITS FROM
This is a base class with no inheritance.
HEADER FILE
#include <il/iflLut.h>
CLASS DESCRIPTION
iflLut is a base class used for accessing and manipulating look-up
tables. The class definition provides the necessary data structure for
defining and accessing the look-up table.
A look-up table is defined by the number of channels, the range of input
values it expects (the domain), the data type, and the actual look-up
table data. There is a table for each channel and the size and data type
of each table is the same. The look-up table data is stored in
iflSequential format. In other words, the table for each channel is
stored contiguously. The tables for each channel are packed together
into a single array.
Using iflLut
The iflLut object can either be used to allocate a look-up table whose
values are filled in by calls to the setVal() function, or it can be used
to wrap an object definition around an existing array of lut values.
Constructors are provided for both of these usages. When the iflLut
allocates the tables, it frees them when it is deleted. If the tables
are passed to the constructor, then the caller is responsible for the
management of the table memory. Once an iflLut is constructed, its table
can be completely replaced using the setData() function, or it can be
modified an entry at a time with setVal().
The values in the lut can be accesed by getting a pointer to the table
with getData(), getChan() or getOrigin(). The pointer returned must be
cast to match the internal type of the table as returned by
getDataType(). Alternatively, individual entries in the table can be
accesed using the getVal() function. While less efficient, this function
is easier to use since getVal() automatically converts to double so that
the data type of the table can be ignored. It also automatically deals
with and scaling necessary to deal with a domain that is not a one to one
mapping onto the number of entries in the look up tables.
The range of values contained in the tables can be interrogated by
getRange(). The range of values the lut expects as input can be accessed
with getDomain().
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iflLut(3) Image Format Library C++ Reference Manual iflLut(3)
CLASS MEMBER FUNCTION SUMMARY
Constructor
iflLut()
iflLut(int numChan, iflDataType dtype, double min, double max,
int length=0)
iflLut(void* table, int numChan, iflDataType dtype, double min,
double max, int length=0)
iflLut(const iflLut& other)
Basic attributes
int getNumChans()
iflDataType getDataType()
int getLength()
Entry access
double getVal(double domainIdx, int chan=0)
iflStatus setVal(double val, double domainIdx, int chan=0)
Direct table access
void* getOrigin(int chan)
void* getChan(int chan)
void* getData()
void setData(void* dataPnt)
Domain and range control
void getDomain(double& min, double& max)
double getDomainMin()
double getDomainMax()
double getDomainStep()
void getRange(double& min, double& max)
iflStatus setDomain(double min, double max)
Comparison
int isDiff(const iflLut& from)
Initialization
void operator=(const iflLut& from)
void init(void* table, int tabChannels, iflDataType tabType,
double min, double max, int length=0) protected
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iflLut(3) Image Format Library C++ Reference Manual iflLut(3)
FUNCTION DESCRIPTIONS
iflLut()
iflLut()
iflLut(const iflLut& other)
iflLut(int numChan, iflDataType dtype, double min, double max,
int length=0)
iflLut(void* table, int numChan, iflDataType dtype, double min,
double max, int length=0)
Constructors for the iflLut class. The number of tables or channels
in the lut is specified by numChan and the LUT data type is
specified by dtype. The domain of values the table handles is from
min to max. The length of each table is either max-min+1 if length
is 0, otherwise it is given by length. A constructor is also
provided that creates an iflLut whose look-up table data is pointed
to by table. Another constructor is provided that copies the tables
and attributes from the iflLut specified by other into this object
The default constructor generates an empty iflLut. This can be
useful in conjuction with the assigment operator.
getChan()
void* getChan(int chan)
Returns a pointer to the beginning of the table for channel number
chan.
getData()
void* getData()
Returns a pointer to the overall beginning of the tables for all
channels. If returns the same value as getChan(0).
getDataType()
iflDataType getDataType()
Returns the data type of the entries in the look-up table.
getDomain()
void getDomain(double& min, double& max)
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iflLut(3) Image Format Library C++ Reference Manual iflLut(3)
Returns the domain, in min and max, that the look-up table handles
as input.
getDomainMax()
double getDomainMax()
Returns the maximum value that the look-up table handles as input.
getDomainMin()
double getDomainMin()
Returns the minimum value that the look-up table handles as input.
getDomainStep()
double getDomainStep()
Returns the incremental step in the domain space between adjacent
entries in the look-up table.
getLength()
int getLength()
Returns the length of a table for an individual channel.
getNumChans()
int getNumChans()
Returns the number of channels in the look-up table.
getOrigin()
void* getOrigin(int chan)
Returns a pointer to the entry for value zero of the table for
channel number chan.
getRange()
void getRange(double& min, double& max)
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iflLut(3) Image Format Library C++ Reference Manual iflLut(3)
Returns the range of values that the look-up table contains in min
and max.
getVal()
double getVal(double domainIdx, int chan=0)
Returns the look-up table entry for channel, chan, and input value,
domainidx. The domain index is scaled as needed to map onto the
actual table entries when the table length does not map one to one
onto the domain.
init()
void init(void* table, int tabChannels, iflDataType tabType,
double min, double max, int length=0) protected
This method fully initializes this object with the specified
attributes, the interpreation of the parameters is the same as for
the constructors.
isDiff()
int isDiff(const iflLut& from)
The method returns TRUE if the the this lut is not identical, in
attributes and tables contents, to the lut specified by from; FALSE
is returned if the luts are the same.
operator=()
void operator=(const iflLut& from)
This function makes a copy of the look-up table (including all of
its tables) specified by from.
setData()
void setData(void* dataPnt)
This function replaces the array of all the tables in the lut with
the data pointed to be data. The array of data is not copied, nor
is it deallocated when the iflLut is deleted. The format of the
data must match the data type, length, and number of channels in the
iflLut. See the Class Description section for details on the layout
of the look-up table data.
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iflLut(3) Image Format Library C++ Reference Manual iflLut(3)
setDomain()
iflStatus setDomain(double min, double max)
Sets the range of values that this lut expects to min and max. If
max-min+1 exceeds the current length of the table, a status of
iflBADPARAMS is returned; iflOKAY is returned if the operation is
successful.
setVal()
iflStatus setVal(double val, double domainIdx, int chan=0)
This function sets the look-up table entry for channel, chan, and
input value, domainidx. The value given by val is converted to the
internal data type of the table. If the entry indicated is not
contained in the iflLut, a value of iflBADPARAMS is returned;
iflOKAY is returned if the operation is successful. The domain
index is scaled as needed to map onto the actual table entries when
the table length does not map one to one onto the domain.
SEE ALSO
iflColormap, iflSGIColormap
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