ValueFunctionConstant Class Reference

Provides an interface by which the caller can obtain the value of a given function at a given "position". More...

#include <valfunc.h>

Inheritance diagram for ValueFunctionConstant:

List of all members.

Public Member Functions
	ValueFunctionConstant (double Value=1.0)
	Constructor The Constant ValueFunction always returns the same value!
virtual double	GetValue (double Position)
	To read the value of this function at a given position.
virtual ValueFunction *	Clone (void)
	Clone operator. Creates an exact copy of this object.
virtual BOOL	IsDifferent (ValueFunction *pOther)
	Comparator. Determines if 2 different ValueFunction objects are considered different.
virtual CamelotFileRecord *	WriteFileRecord (INT32 RecordTag, INT32 ExtraBytes, BaseCamelotFilter *pFilter)
	Saves a ValueFunction object to a Xara file. This function will create a new variable-sized record with the given record tag, and will write out whatever data is needed to save this ValueFunction's state to the file.
virtual ValueFunctionID	GetUniqueID (void)
Protected Member Functions
virtual ValueFunction *	CreateAndReadFileRecord (CXaraFileRecord *pInputRecord)
	Loads a ValueFunction object from a record which was saved into a file using the WriteFileRecord call. This is called by the base class loader routine ReadFileRecord, which finds an appropriate instance of a derived class to call to load the data in question.
Protected Attributes
double	Value1
Private Member Functions
	CC_DECLARE_DYNAMIC (ValueFunctionConstant)

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Detailed Description

Provides an interface by which the caller can obtain the value of a given function at a given "position".

Author:

Jason_Williams (Xara Group Ltd) <camelotdev@xara.com>

Date:

30/12/96

This derived class simply returns a constant value

Definition at line 269 of file valfunc.h.

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Constructor & Destructor Documentation

ValueFunctionConstant::ValueFunctionConstant (  double  Value = 1.0  )

Constructor The Constant ValueFunction always returns the same value! Author: Jason_Williams (Xara Group Ltd) <camelotdev@xara.com> Date: 30/12/96 Parameters: Value  - The value to be used at all positions [INPUTS] Definition at line 468 of file valfunc.cpp. { Value1 = Value; }

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Member Function Documentation

ValueFunctionConstant::CC_DECLARE_DYNAMIC (  ValueFunctionConstant   )  [private]

ValueFunction * ValueFunctionConstant::Clone (  void   )  [virtual]

Clone operator. Creates an exact copy of this object. Author: Jason_Williams (Xara Group Ltd) <camelotdev@xara.com> Date: 8/1/97 Returns: NULL if it failed, else an exact copy of this object Implements ValueFunction. Definition at line 512 of file valfunc.cpp. { ValueFunction *pClone = new ValueFunctionConstant(Value1); return(pClone); }

ValueFunction * ValueFunctionConstant::CreateAndReadFileRecord (  CXaraFileRecord *  pInputRecord  )  [protected, virtual]

Loads a ValueFunction object from a record which was saved into a file using the WriteFileRecord call. This is called by the base class loader routine ReadFileRecord, which finds an appropriate instance of a derived class to call to load the data in question. Author: Jason_Williams (Xara Group Ltd) <camelotdev@xara.com> Date: 27/1/97 Parameters: pInputRecord  - The file record to read [INPUTS] Returns: NULL if it failed, else a pointer to new ValueFunction object representing whatever was saved in that record. This method creates a new instance of this particular ValueFunction class and then loads whatever information is necessary from the file to initialise itself properly. The record read-pointer is left pointing at the end of the ValueFunction-saved data so that the caller can continue reading their extra bytes of data after loading the ValueFunction. See also: ValueFunctionConstant::WriteFileRecord; ValueFunctionConstant::ReadFileRecord Implements ValueFunction. Definition at line 651 of file valfunc.cpp. { ERROR3IF(pInputRecord == NULL, "Illegal NULL param"); float ConstValue = (float)1.0; pInputRecord->ReadFLOAT(&ConstValue); return(new ValueFunctionConstant((double) ConstValue)); }

virtual ValueFunctionID ValueFunctionConstant::GetUniqueID (  void   )  [inline, virtual]

Implements ValueFunction. Definition at line 282 of file valfunc.h. { return(ValueFunctionID_Constant); };

double ValueFunctionConstant::GetValue (  double  Position  )  [virtual]

To read the value of this function at a given position. Author: Jason_Williams (Xara Group Ltd) <camelotdev@xara.com> Date: 30/12/96 Parameters: Position  - A value between 0.0 and 1.0 [INPUTS] Returns: A constant value (Value, as given in the constructor) representing the value of the function at the given Position. Notes: Constant is a bit simple - it always returns the same value Implements ValueFunction. Definition at line 492 of file valfunc.cpp. { return(Value1); }

BOOL ValueFunctionConstant::IsDifferent (  ValueFunction *  pOther  )  [virtual]

Comparator. Determines if 2 different ValueFunction objects are considered different. Author: Jason_Williams (Xara Group Ltd) <camelotdev@xara.com> Date: 8/1/97 Parameters: pOther  - Another ValueFunction object to compare this one to [INPUTS] Returns: TRUE if the objects are considered different, FALSE if they are considered identical Notes: Calls the base class to see if they are different classes, and then compares identical classes by checking member vars Reimplemented from ValueFunction. Definition at line 541 of file valfunc.cpp. { if (ValueFunction::IsDifferent(pOther)) return(TRUE); // Both objects are instances of this class, so compare them more carefully return(Value1 != ((ValueFunctionConstant *)pOther)->Value1); }

CamelotFileRecord * ValueFunctionConstant::WriteFileRecord (  INT32  RecordTag, INT32  ExtraBytes, BaseCamelotFilter *  pFilter )  [virtual]

Saves a ValueFunction object to a Xara file. This function will create a new variable-sized record with the given record tag, and will write out whatever data is needed to save this ValueFunction's state to the file. Author: Jason_Williams (Xara Group Ltd) <camelotdev@xara.com> Date: 27/1/97 Parameters: RecordTag  - the tag to write this record under [INPUTS] ExtraBytes - The number of extra bytes of information the caller will write into the record after caling this function (Space for this many extra bytes will be reserved by this function when it creates the new file record) This may be 0 or more bytes. pFilter - The filter to write to Returns: NULL if it failed, else a pointer to a record which saves the state of this valueFunction object. Once the caller has written the record, they MUST DELETE it. "ExtraBytes" bytes will be added to the record size to reserve space at the end of the record for the caller to add their own data. This is to allow ValueFunctions to be saved embedded in other object's record structures (e.g. inside different types of attributes). All ValueFunction record data has 3 sections, whiich are recorded as follows: 1. ValueFunction header, identifying which type of VF is being saved INT32 ValueFunctionUniqueID (4 bytes) 2. Derived-class-data (0 or more bytes). This particular class adds: float ConstantValue (4 bytes) 3. Caller data. This is written by the caller to the returned record object. This data must be ExtraBytes (0 or more) bytes in length. See also: ValueFunctionConstant::CreateAndReadFileRecord Implements ValueFunction. Definition at line 594 of file valfunc.cpp. { ERROR3IF(pFilter == NULL, "Illegal NULL param"); ERROR3IF(ExtraBytes < 0, "Stupid ExtraBytes request in ValueFunction::WriteFileRecord"); // Calculate how many bytes of information this VF will write. We do not include // the header info written by the base class or the ExtraInfo desired by the caller - // the base class adds all that in for us. const INT32 MyRecordSize = 4; // Create an appropriate record, and write our data to it CamelotFileRecord *pRec = CreateAndWriteFileRecord(RecordTag, MyRecordSize, ExtraBytes, pFilter); if (pRec != NULL) { // Write out our ValueFunction's specific data. If it fails, then we'll return NULL if (!pRec->WriteFLOAT((float)Value1)) { delete pRec; pRec = NULL; } } return(pRec); }

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Member Data Documentation

double ValueFunctionConstant::Value1 [protected]

Definition at line 289 of file valfunc.h.

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

• Kernel/valfunc.h (r1785/r1282)
• Kernel/valfunc.cpp (r1785/r1517)

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