OEColorGradientBase

class OEColorGradientBase

OEColorGradientBase is an abstract class used for interpolating between colors that are defined by using the OEColorStop class.

The following classes derive from this class:

• OEExponentColorGradient

• OEExponentialColorGradient

• OELinearColorGradient

• OELogarithmicColorGradient

Constructors

OEColorGradientBase()

Default constructor that creates an “empty” color gradient.

Note

An “empty” color gradient always returns the OEBlack color, when calling the OEColorGradientBase::GetColorAt, the OEColorGradientBase::GetMinColor or the OEColorGradientBase::GetMaxColor methods.

OEColorGradientBase(const OEColorStop &oneStop)

Creates an OEColorGradientBase object with one color stop. An OEColorGradientBase object that has only one color stop will always return that color when calling the OEColorGradientBase::GetColorAt method.

OEColorGradientBase(const OEColorStop &bgnStop, const OEColorStop &endStop)

Creates an OEColorGradientBase object with interpolation range between the two specified color stops.

OEColorGradientBase(const OEColorGradientBase &rhs)

Copy constructor.

operator=

OEColorGradientBase &operator=(const OEColorGradientBase &rhs)

Assignment operator.

AddStop

bool AddStop(const OEColorStop &stop)

Add a new color stop to the color gradient.

DeleteStop

bool DeleteStop(unsigned int stopidx)

Deletes the color stop at idx and returns true. If the color gradient only has one color stop or the idx is not between 0 and NumStops(), then OEColorGradientBase::DeleteStop throws a warning and returns false.

GetColorAt

OEColor GetColorAt(double value) const

Returns the interpolated color at value defined by the color stops in the color gradient. Returns OEColorGradientBase::GetMinColor if the value is less than OEColorGradientBase::GetMinValue. Returns OEColorGradientBase::GetMaxColor if the value is greater than OEColorGradientBase::GetMinValue.

GetMaxColor

const OEColor &GetMaxColor() const

Returns the color associated with the value returned by the OEColorGradientBase::GetMaxValue method.

GetMaxValue

double GetMaxValue() const

Returns the highest value stored in any of the color stops of the color gradient.

GetMinColor

const OEColor &GetMinColor() const

Returns the color associated with the value returned by the OEColorGradientBase::GetMinValue method.

GetMinValue

double GetMinValue() const

Returns the lowest value stored in any of the color stops of the color gradient.

GetStops

OEIterBase<OEColorStop> *GetStops() const

Returns an iterator over all color stops of the color gradient. The iterator is invariant to further modifications of the OEColorGradientBase object.

IsEmpty

bool IsEmpty() const

Returns true if no color stop has been added to the OEColorGradientBase object that has been created by the default constructor, otherwise it returns false.

NumStops

unsigned int NumStops() const

Returns the number of color stops of the color gradient.

TransformValue

double TransformValue(double value) const =0

This is a virtual const method that is implemented in the concrete color gradient derived classes. This method is called by OEColorGradientBase::GetColorAt method to transform a value before performing color interpolation.