juce::ImageConvolutionKernel Class Reference

Detailed Description

Represents a filter kernel to use in convoluting an image.

See also

Image::applyConvolution

Public Member Functions
	ImageConvolutionKernel (int size)
	Creates an empty convolution kernel.
	~ImageConvolutionKernel ()
	Destructor.
void	clear ()
	Resets all values in the kernel to zero.
float	getKernelValue (int x, int y) const noexcept
	Returns one of the kernel values.
void	setKernelValue (int x, int y, float value) noexcept
	Sets the value of a specific cell in the kernel.
void	setOverallSum (float desiredTotalSum)
	Rescales all values in the kernel to make the total add up to a fixed value.
void	rescaleAllValues (float multiplier)
	Multiplies all values in the kernel by a value.
void	createGaussianBlur (float blurRadius)
	Initialises the kernel for a gaussian blur.
int	getKernelSize () const
	Returns the size of the kernel.
void	applyToImage (Image &destImage, const Image &sourceImage, const Rectangle< int > &destinationArea) const
	Applies the kernel to an image.

Constructors and Destructors

ImageConvolutionKernel()

juce::ImageConvolutionKernel::ImageConvolutionKernel

(

int

size

)

Creates an empty convolution kernel.

Parameters

size	the length of each dimension of the kernel, so e.g. if the size is 5, it will create a 5x5 kernel

Referenced by applyToImage().

~ImageConvolutionKernel()

juce::ImageConvolutionKernel::~ImageConvolutionKernel

(

)

Destructor.

Member Functions

clear()

void juce::ImageConvolutionKernel::clear

(

)

Resets all values in the kernel to zero.

getKernelValue()

float juce::ImageConvolutionKernel::getKernelValue ( int x, int y ) const

noexcept

Returns one of the kernel values.

References x, and y.

setKernelValue()

void juce::ImageConvolutionKernel::setKernelValue ( int x, int y, float value )

noexcept

Sets the value of a specific cell in the kernel.

The x and y parameters must be in the range 0 < x < getKernelSize().

See also

setOverallSum

References x, and y.

setOverallSum()

void juce::ImageConvolutionKernel::setOverallSum

(

float

desiredTotalSum

)

Rescales all values in the kernel to make the total add up to a fixed value.

This will multiply all values in the kernel by (desiredTotalSum / currentTotalSum).

rescaleAllValues()

void juce::ImageConvolutionKernel::rescaleAllValues

(

float

multiplier

)

Multiplies all values in the kernel by a value.

createGaussianBlur()

void juce::ImageConvolutionKernel::createGaussianBlur

(

float

blurRadius

)

Initialises the kernel for a gaussian blur.

Parameters

blurRadius

this may be larger or smaller than the kernel's actual size but this will obviously be wasteful or clip at the edges. Ideally the kernel should be just larger than (blurRadius * 2).

getKernelSize()

int juce::ImageConvolutionKernel::getKernelSize

(

)

const

Returns the size of the kernel.

E.g. if it's a 3x3 kernel, this returns 3.

applyToImage()

void juce::ImageConvolutionKernel::applyToImage	(	Image &	destImage,
		const Image &	sourceImage,
		const Rectangle< int > &	destinationArea ) const

Applies the kernel to an image.

Parameters

destImage	the image that will receive the resultant convoluted pixels.
sourceImage	the source image to read from - this can be the same image as the destination, but if different, it must be exactly the same size and format.
destinationArea	the region of the image to apply the filter to

References ImageConvolutionKernel().