Files
file	gin_imageeffects.h
	Image processing effects and filters.

Classes
struct	MipMapEnhance
	Post-processing of a MipMap's reduced levels, off by default. More...
class	MipMap
	An image with its halved levels down to 16 px, each halving a rounded 2x2 box average, so drawing it smaller picks the nearest larger level and stays sharp without aliasing. More...

Enumerations
enum class	ResizeAlgorirm { ResizeAlgorirm::avir , ResizeAlgorirm::lanczos }
	Image resize algorithms for high-quality scaling. More...
enum	BlendMode { Normal , Lighten , Darken , Multiply , Average , Add , Subtract , Difference , Negation , Screen , Exclusion , Overlay , SoftLight , HardLight , ColorDodge , ColorBurn , LinearDodge , LinearBurn , LinearLight , VividLight , PinLight , HardMix , Reflect , Glow , Phoenix }
	Blending modes for image compositing. More...

Functions
void	applyVignette (juce::Image &img, float amount, float radius, float falloff, juce::ThreadPool *threadPool=nullptr)
	Applies a vignette effect to an image.
void	applySepia (juce::Image &img, juce::ThreadPool *threadPool=nullptr)
	Applies a sepia tone effect to an image.
void	applyGreyScale (juce::Image &img, juce::ThreadPool *threadPool=nullptr)
	Converts an image to greyscale.
void	applySoften (juce::Image &img, juce::ThreadPool *threadPool=nullptr)
	Softens an image by reducing detail.
void	applySharpen (juce::Image &img, juce::ThreadPool *threadPool=nullptr)
	Sharpens an image by enhancing edges.
void	applyGamma (juce::Image &img, float gamma, juce::ThreadPool *threadPool=nullptr)
	Applies gamma correction to an image.
void	applyInvert (juce::Image &img, juce::ThreadPool *threadPool=nullptr)
	Inverts all colors in an image.
void	applyContrast (juce::Image &img, float contrast, juce::ThreadPool *threadPool=nullptr)
	Adjusts the contrast of an image.
void	applyBrightnessContrast (juce::Image &img, float brightness, float contrast, juce::ThreadPool *threadPool=nullptr)
	Adjusts brightness and contrast of an image.
void	applyHueSaturationLightness (juce::Image &img, float hue, float saturation, float lightness, juce::ThreadPool *threadPool=nullptr)
	Adjusts hue, saturation and lightness of an image.
void	applyStackBlur (juce::Image &img, int radius)
	Applies a fast, high-quality blur to an image.
juce::Image	applyResize (const juce::Image &img, int width, int height, ResizeAlgorirm resizeAlgorirm=ResizeAlgorirm::avir)
	Resizes an image to specific dimensions using high-quality algorithm.
juce::Image	applyResize (const juce::Image &img, float factor, ResizeAlgorirm resizeAlgorirm=ResizeAlgorirm::avir)
	Resizes an image by a scaling factor.
void	applyGradientMap (juce::Image &img, const juce::ColourGradient &gradient, juce::ThreadPool *threadPool=nullptr)
	Applies a gradient map to an image.
void	applyGradientMap (juce::Image &img, const juce::Colour c1, const juce::Colour c2, juce::ThreadPool *threadPool=nullptr)
	Applies a two-color gradient map to an image.
void	applyColour (juce::Image &img, juce::Colour c, juce::ThreadPool *threadPool=nullptr)
	Sets all pixels in an image to a solid color.
void	applyBlend (juce::Image &dst, const juce::Image &src, BlendMode mode, float alpha=1.0f, juce::Point< int > position={}, juce::ThreadPool *threadPool=nullptr)
	Blends two images using the specified blend mode.
void	applyBlend (juce::Image &dst, BlendMode mode, juce::Colour c, juce::ThreadPool *threadPool=nullptr)
	Blends a solid color onto an image using the specified blend mode.
uint8_t	channelBlendNormal (int A, int)
uint8_t	channelBlendLighten (int A, int B)
uint8_t	channelBlendDarken (int A, int B)
uint8_t	channelBlendMultiply (int A, int B)
uint8_t	channelBlendAverage (int A, int B)
uint8_t	channelBlendAdd (int A, int B)
uint8_t	channelBlendSubtract (int A, int B)
uint8_t	channelBlendDifference (int A, int B)
uint8_t	channelBlendNegation (int A, int B)
uint8_t	channelBlendScreen (int A, int B)
uint8_t	channelBlendExclusion (int A, int B)
uint8_t	channelBlendOverlay (int A, int B)
uint8_t	channelBlendSoftLight (int A, int B)
uint8_t	channelBlendHardLight (int A, int B)
uint8_t	channelBlendColorDodge (int A, int B)
uint8_t	channelBlendColorBurn (int A, int B)
uint8_t	channelBlendLinearDodge (int A, int B)
uint8_t	channelBlendLinearBurn (int A, int B)
uint8_t	channelBlendLinearLight (int A, int B)
uint8_t	channelBlendVividLight (int A, int B)
uint8_t	channelBlendPinLight (int A, int B)
uint8_t	channelBlendHardMix (int A, int B)
uint8_t	channelBlendReflect (int A, int B)
uint8_t	channelBlendGlow (int A, int B)
uint8_t	channelBlendPhoenix (int A, int B)
uint8_t	channelBlendAlpha (uint8_t A, uint8_t B, float O)
void	drawBlend (juce::Graphics &g, const MipMap &a, const MipMap &b, float progress, juce::Rectangle< float > rc, juce::RectanglePlacement placement=0)
	Draws a blend of two MipMaps in the same rectangle, each through MipMap::draw: a at full opacity, then b on top at progress.

Detailed Description

Enumeration Type Documentation

◆ ResizeAlgorirm

enum class ResizeAlgorirm

strong

Image resize algorithms for high-quality scaling.

Both algorithms provide superior quality compared to basic interpolation, using sinc function-based fractional delay filters.

See also: applyResize

Enumerator
avir	AVIR algorithm - high quality, balanced speed/quality.
lanczos	Lanczos algorithm - excellent quality, slightly slower.

◆ BlendMode

enum BlendMode

Blending modes for image compositing.

Defines how two images are combined when using applyBlend. Each mode produces different visual effects based on how source and destination pixel values interact.

Common modes:

Normal: Standard alpha compositing
Multiply: Darkens image, useful for shadows
Screen: Lightens image, useful for highlights
Overlay: Combines Multiply and Screen based on luminance
Add: Adds colors together, creates bright effects

See also: applyBlend

Enumerator
Normal	Standard alpha blending.
Lighten	Selects lighter of source and destination.
Darken	Selects darker of source and destination.
Multiply	Multiplies colors (darkens).
Average	Averages source and destination.
Add	Adds colors together (brightens).
Subtract	Subtracts source from destination.
Difference	Absolute difference between colors.
Negation	Inverted difference.
Screen	Inverse multiply (lightens).
Exclusion	Similar to Difference but lower contrast.
Overlay	Combines Multiply and Screen based on destination.
SoftLight	Subtle lighting effect.
HardLight	Strong lighting effect.
ColorDodge	Brightens based on source.
ColorBurn	Darkens based on source.
LinearDodge	Same as Add.
LinearBurn	Linear burn effect.
LinearLight	Combination of LinearDodge and LinearBurn.
VividLight	Combination of ColorDodge and ColorBurn.
PinLight	Replaces colors based on blend color.
HardMix	Posterizes to limited colors.
Reflect	Brightening reflect effect.
Glow	Inverse reflect.
Phoenix	Similar to glow with different formula.

Function Documentation

◆ applyVignette()

void applyVignette	(	juce::Image &	img,
		float	amount,
		float	radius,
		float	falloff,
		juce::ThreadPool *	threadPool = nullptr )

Applies a vignette effect to an image.

Darkens the edges of the image, creating a focus effect towards the center. Commonly used for artistic photography effects.

Parameters

img	The image to modify (modified in-place)
amount	Darkness amount [0, 1]. 0 = no darkening, 1 = black edges
radius	Vignette size [0, 1]. 1 = full image size, 0 = no vignette
falloff	Transition size [0, 1]. Controls softness of vignette edge
threadPool	Optional thread pool for parallel processing

◆ applySepia()

void applySepia	(	juce::Image &	img,
		juce::ThreadPool *	threadPool = nullptr )

Applies a sepia tone effect to an image.

Converts the image to warm brown tones, creating a vintage/aged photograph look.

Parameters

img	The image to modify (modified in-place)
threadPool	Optional thread pool for parallel processing

◆ applyGreyScale()

void applyGreyScale	(	juce::Image &	img,
		juce::ThreadPool *	threadPool = nullptr )

Converts an image to greyscale.

Uses weighted RGB conversion with heavier weighting towards green channel, which better matches human luminance perception.

Parameters

img	The image to modify (modified in-place)
threadPool	Optional thread pool for parallel processing

◆ applySoften()

void applySoften	(	juce::Image &	img,
		juce::ThreadPool *	threadPool = nullptr )

Softens an image by reducing detail.

Applies a subtle blur to reduce image sharpness and detail.

Parameters

img	The image to modify (modified in-place)
threadPool	Optional thread pool for parallel processing

◆ applySharpen()

void applySharpen	(	juce::Image &	img,
		juce::ThreadPool *	threadPool = nullptr )

Sharpens an image by enhancing edges.

Increases image sharpness and edge definition using convolution.

Parameters

img	The image to modify (modified in-place)
threadPool	Optional thread pool for parallel processing

◆ applyGamma()

void applyGamma	(	juce::Image &	img,
		float	gamma,
		juce::ThreadPool *	threadPool = nullptr )

Applies gamma correction to an image.

Adjusts the brightness curve of the image non-linearly. Gamma < 1 brightens, gamma > 1 darkens.

Parameters

img	The image to modify (modified in-place)
gamma	Gamma value (typically 0.1 to 10.0, 1.0 = no change)
threadPool	Optional thread pool for parallel processing

◆ applyInvert()

void applyInvert	(	juce::Image &	img,
		juce::ThreadPool *	threadPool = nullptr )

Inverts all colors in an image.

Creates a negative/inverse effect by inverting RGB values.

Parameters

img	The image to modify (modified in-place)
threadPool	Optional thread pool for parallel processing

◆ applyContrast()

void applyContrast	(	juce::Image &	img,
		float	contrast,
		juce::ThreadPool *	threadPool = nullptr )

Adjusts the contrast of an image.

Modifies the difference between light and dark areas.

Parameters

img	The image to modify (modified in-place)
contrast	Contrast adjustment [-100, 100]. Negative = decrease, positive = increase
threadPool	Optional thread pool for parallel processing

◆ applyBrightnessContrast()

void applyBrightnessContrast	(	juce::Image &	img,
		float	brightness,
		float	contrast,
		juce::ThreadPool *	threadPool = nullptr )

Adjusts brightness and contrast of an image.

Combines brightness and contrast adjustments in a single pass.

Parameters

img	The image to modify (modified in-place)
brightness	Brightness adjustment [-100, 100]. Negative = darker, positive = brighter
contrast	Contrast adjustment [-100, 100]. Negative = decrease, positive = increase
threadPool	Optional thread pool for parallel processing

◆ applyHueSaturationLightness()

void applyHueSaturationLightness	(	juce::Image &	img,
		float	hue,
		float	saturation,
		float	lightness,
		juce::ThreadPool *	threadPool = nullptr )

Adjusts hue, saturation and lightness of an image.

Modifies color properties in HSL color space, allowing independent control of hue (color), saturation (intensity), and lightness (brightness).

Parameters

img	The image to modify (modified in-place)
hue	Hue shift [-180, 180] degrees. 0 = no change
saturation	Saturation adjustment [0, 200]. 100 = no change, 0 = greyscale
lightness	Lightness adjustment [-100, 100]. 0 = no change
threadPool	Optional thread pool for parallel processing

◆ applyStackBlur()

void applyStackBlur	(	juce::Image &	img,
		int	radius )

Applies a fast, high-quality blur to an image.

Uses stack blur algorithm - a compromise between Gaussian blur quality and box blur speed. Produces much better results than box blur while being ~7x faster than traditional Gaussian blur implementations.

Parameters

img	The image to modify (modified in-place)
radius	Blur radius [2, 254]. Larger values = more blur

◆ applyResize() [1/2]

juce::Image applyResize	(	const juce::Image &	img,
		int	width,
		int	height,
		ResizeAlgorirm	resizeAlgorirm = ResizeAlgorirm::avir )

Resizes an image to specific dimensions using high-quality algorithm.

Uses sinc function-based fractional delay filters for superior quality compared to basic bilinear/bicubic interpolation.

Parameters

img	The source image (not modified)
width	Target width in pixels
height	Target height in pixels
resizeAlgorirm	Algorithm to use (default: avir)

Returns: New resized image

References avir.

◆ applyResize() [2/2]

juce::Image applyResize	(	const juce::Image &	img,
		float	factor,
		ResizeAlgorirm	resizeAlgorirm = ResizeAlgorirm::avir )

Resizes an image by a scaling factor.

Convenience overload that scales proportionally by a factor.

Parameters

img	The source image (not modified)
factor	Scale factor (e.g., 0.5 = half size, 2.0 = double size)
resizeAlgorirm	Algorithm to use (default: avir)

Returns: New resized image

References avir.

◆ applyGradientMap() [1/2]

void applyGradientMap	(	juce::Image &	img,
		const juce::ColourGradient &	gradient,
		juce::ThreadPool *	threadPool = nullptr )

Applies a gradient map to an image.

Remaps the brightness of each pixel to a color from the gradient. Black pixels map to the start of the gradient, white pixels to the end, with smooth interpolation between.

Parameters

img	The image to modify (modified in-place)
gradient	The color gradient to map brightness values to
threadPool	Optional thread pool for parallel processing

◆ applyGradientMap() [2/2]

void applyGradientMap	(	juce::Image &	img,
		const juce::Colour	c1,
		const juce::Colour	c2,
		juce::ThreadPool *	threadPool = nullptr )

Applies a two-color gradient map to an image.

Convenience overload that creates a linear gradient between two colors.

Parameters

img	The image to modify (modified in-place)
c1	Color for black/dark pixels
c2	Color for white/bright pixels
threadPool	Optional thread pool for parallel processing

◆ applyColour()

void applyColour	(	juce::Image &	img,
		juce::Colour	c,
		juce::ThreadPool *	threadPool = nullptr )

Sets all pixels in an image to a solid color.

Fills the entire image with the specified color, preserving alpha if present.

Parameters

img	The image to modify (modified in-place)
c	The color to fill with
threadPool	Optional thread pool for parallel processing

◆ applyBlend() [1/2]

void applyBlend	(	juce::Image &	dst,
		const juce::Image &	src,
		BlendMode	mode,
		float	alpha = 1.0f,
		juce::Point< int >	position = {},
		juce::ThreadPool *	threadPool = nullptr )

Blends two images using the specified blend mode.

Composites a source image onto a destination image using various blending algorithms. The destination image is modified in-place.

Parameters

dst	Destination image (modified in-place)
src	Source image to blend on top
mode	Blending mode to use
alpha	Opacity of the blend [0, 1]. 0 = invisible, 1 = fully opaque
position	Position to place source image (default: 0,0)
threadPool	Optional thread pool for parallel processing

◆ applyBlend() [2/2]

void applyBlend	(	juce::Image &	dst,
		BlendMode	mode,
		juce::Colour	c,
		juce::ThreadPool *	threadPool = nullptr )

Blends a solid color onto an image using the specified blend mode.

Applies a blend mode with a solid color across the entire image.

Parameters

dst	Destination image (modified in-place)
mode	Blending mode to use
c	Color to blend with
threadPool	Optional thread pool for parallel processing

◆ channelBlendNormal()

uint8_t channelBlendNormal	(	int	A,
		int	)

◆ channelBlendLighten()

uint8_t channelBlendLighten	(	int	A,
		int	B )

Referenced by channelBlendPinLight().

◆ channelBlendDarken()

uint8_t channelBlendDarken	(	int	A,
		int	B )

Referenced by channelBlendPinLight().

◆ channelBlendMultiply()

uint8_t channelBlendMultiply	(	int	A,
		int	B )

◆ channelBlendAverage()

uint8_t channelBlendAverage	(	int	A,
		int	B )

◆ channelBlendAdd()

uint8_t channelBlendAdd	(	int	A,
		int	B )

Referenced by channelBlendLinearDodge().

◆ channelBlendSubtract()

uint8_t channelBlendSubtract	(	int	A,
		int	B )

Referenced by channelBlendLinearBurn().

◆ channelBlendDifference()

uint8_t channelBlendDifference	(	int	A,
		int	B )

◆ channelBlendNegation()

uint8_t channelBlendNegation	(	int	A,
		int	B )

◆ channelBlendScreen()

uint8_t channelBlendScreen	(	int	A,
		int	B )

◆ channelBlendExclusion()

uint8_t channelBlendExclusion	(	int	A,
		int	B )

◆ channelBlendOverlay()

uint8_t channelBlendOverlay	(	int	A,
		int	B )

Referenced by channelBlendHardLight().

◆ channelBlendSoftLight()

uint8_t channelBlendSoftLight	(	int	A,
		int	B )

◆ channelBlendHardLight()

uint8_t channelBlendHardLight	(	int	A,
		int	B )

References channelBlendOverlay().

◆ channelBlendColorDodge()

uint8_t channelBlendColorDodge	(	int	A,
		int	B )

Referenced by channelBlendVividLight().

◆ channelBlendColorBurn()

uint8_t channelBlendColorBurn	(	int	A,
		int	B )

Referenced by channelBlendVividLight().

◆ channelBlendLinearDodge()

uint8_t channelBlendLinearDodge	(	int	A,
		int	B )

References channelBlendAdd().

Referenced by channelBlendLinearLight().

◆ channelBlendLinearBurn()

uint8_t channelBlendLinearBurn	(	int	A,
		int	B )

References channelBlendSubtract().

Referenced by channelBlendLinearLight().

◆ channelBlendLinearLight()

uint8_t channelBlendLinearLight	(	int	A,
		int	B )

References channelBlendLinearBurn(), and channelBlendLinearDodge().

◆ channelBlendVividLight()

uint8_t channelBlendVividLight	(	int	A,
		int	B )

References channelBlendColorBurn(), and channelBlendColorDodge().

Referenced by channelBlendHardMix().

◆ channelBlendPinLight()

uint8_t channelBlendPinLight	(	int	A,
		int	B )

References channelBlendDarken(), and channelBlendLighten().

◆ channelBlendHardMix()

uint8_t channelBlendHardMix	(	int	A,
		int	B )

References channelBlendVividLight().

◆ channelBlendReflect()

uint8_t channelBlendReflect	(	int	A,
		int	B )

Referenced by channelBlendGlow().

◆ channelBlendGlow()

uint8_t channelBlendGlow	(	int	A,
		int	B )

References channelBlendReflect().

◆ channelBlendPhoenix()

uint8_t channelBlendPhoenix	(	int	A,
		int	B )

◆ channelBlendAlpha()

uint8_t channelBlendAlpha	(	uint8_t	A,
		uint8_t	B,
		float	O )

◆ drawBlend()

void drawBlend	(	juce::Graphics &	g,
		const MipMap &	a,
		const MipMap &	b,
		float	progress,
		juce::Rectangle< float >	rc,
		juce::RectanglePlacement	placement = 0 )

Draws a blend of two MipMaps in the same rectangle, each through MipMap::draw: a at full opacity, then b on top at progress.

0 draws only a, 1 only b. An empty side is skipped.

Files

Classes

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ ResizeAlgorirm

◆ BlendMode

Function Documentation

◆ applyVignette()

◆ applySepia()

◆ applyGreyScale()

◆ applySoften()

◆ applySharpen()

◆ applyGamma()

◆ applyInvert()

◆ applyContrast()

◆ applyBrightnessContrast()

◆ applyHueSaturationLightness()

◆ applyStackBlur()

◆ applyResize() [1/2]

◆ applyResize() [2/2]

◆ applyGradientMap() [1/2]

◆ applyGradientMap() [2/2]

◆ applyColour()

◆ applyBlend() [1/2]

◆ applyBlend() [2/2]

◆ channelBlendNormal()

◆ channelBlendLighten()

◆ channelBlendDarken()

◆ channelBlendMultiply()

◆ channelBlendAverage()

◆ channelBlendAdd()

◆ channelBlendSubtract()

◆ channelBlendDifference()

◆ channelBlendNegation()

◆ channelBlendScreen()

◆ channelBlendExclusion()

◆ channelBlendOverlay()

◆ channelBlendSoftLight()

◆ channelBlendHardLight()

◆ channelBlendColorDodge()

◆ channelBlendColorBurn()

◆ channelBlendLinearDodge()

◆ channelBlendLinearBurn()

◆ channelBlendLinearLight()

◆ channelBlendVividLight()

◆ channelBlendPinLight()

◆ channelBlendHardMix()

◆ channelBlendReflect()

◆ channelBlendGlow()

◆ channelBlendPhoenix()

◆ channelBlendAlpha()

◆ drawBlend()