IlvHueRotateFilter Class Reference

Hue rotate filter. More...

#include <ilviews/bitmaps/filters/colmatrix.h>

Inheritance diagram for IlvHueRotateFilter:

List of all members.

Public Member Functions
	IlvHueRotateFilter (IlFloat angle=0.0)
	Constructor.
IlFloat	getAngle () const
	Returns the hue rotation angle.
void	setAngle (IlFloat angle)
	Sets the rotation angle for the hue.

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Detailed Description

Hue rotate filter.

Library: ilvbmpflt

This bitmap filter lets you rotate the hue value of the color components of an image. The hue rotate operation is equivalent to the following matrix operation:

 R' = a00  a01  a02   0   0    R
 G' = a10  a11  a12   0   0    G
 B' = a20  a21  a22   0   0    B
 A' =   0    0    0   1   0    A
 1  =   0    0    0   0   1    1
 

where the terms a00, a01, etc., are calculated as follows:

 | a00 a01 a02 |    [+0.213 +0.715 +0.072]
 | a10 a11 a12 | =  [+0.213 +0.715 +0.072] +
 | a20 a21 a22 |    [+0.213 +0.715 +0.072]

                         [+0.787 -0.715 -0.072]
           cos(angle) *  [-0.212 +0.285 -0.072] +
                         [-0.213 -0.715 +0.928]

                         [-0.213 -0.715+0.928]
           sin(angle) *  [+0.143 +0.140-0.283]
                         [-0.787 +0.715+0.072]
 

Thus, the upper left term of the hue matrix turns out to be: .213 + cos(hueRotate value)*.787 - sin(hueRotate value)*.213

The angle is given in degrees.

See also:

IlvRGBBitmapData, IlvBitmapFilter, IlvColorMatrixFilter, IlvLuminanceToAlphaFilter, IlvSaturationFilter

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Constructor & Destructor Documentation

IlvHueRotateFilter::IlvHueRotateFilter

(

IlFloat

angle = 0.0

)

Constructor.

Initializes a new instance of an IlvHueRotateFilter. The default angle is 0.

Parameters:

angle

The angle to rotate the hue.

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Member Function Documentation

IlFloat IlvHueRotateFilter::getAngle

(

)

const

Returns the hue rotation angle.

Returns:

The hue rotation angle.

void IlvHueRotateFilter::setAngle

(

IlFloat

angle

)

Sets the rotation angle for the hue.

Parameters:

angle

The angle to use.