Detailed Description

Functions for applying gamma adjustments to LED data.

Gamma correction tries to compensate for the non-linear manner in which humans perceive light and color. Gamma correction is applied using the following expression:

output = pow(input / 255.0, gamma) * 255.0;

Larger gamma values result in darker images that have more contrast. Lower gamma values result in lighter images with less contrast.

These functions apply either:

a single gamma adjustment to a single scalar value
a single gamma adjustment to each channel of a CRGB color, or
different gamma adjustments for each channel of a CRGB color

Note that the gamma is specified as a traditional floating point value, e.g., "2.5", and as such these functions should not be called in your innermost pixel loops, or in animations that are extremely low on program storage space. Nevertheless, if you need these functions, here they are.

Furthermore, bear in mind that CRGB LEDs have only eight bits per channel of color resolution, and that very small, subtle shadings may not be visible.

See also: Dimming and Brightening Functions; https://en.wikipedia.org/wiki/Gamma_correction

Functions
uint8_t	applyGamma_video (uint8_t brightness, float gamma)
	Applies a gamma adjustment to a color channel.

CRGB	applyGamma_video (const CRGB &orig, float gamma)
	Applies a gamma adjustment to a color.

CRGB	applyGamma_video (const CRGB &orig, float gammaR, float gammaG, float gammaB)
	Applies a gamma adjustment to a color.

CRGB &	napplyGamma_video (CRGB &rgb, float gamma)
	Destructively applies a gamma adjustment to a color.

CRGB &	napplyGamma_video (CRGB &rgb, float gammaR, float gammaG, float gammaB)
	Destructively applies a gamma adjustment to a color.

void	napplyGamma_video (CRGB *rgbarray, uint16_t count, float gamma)
	Destructively applies a gamma adjustment to a color array.

void	napplyGamma_video (CRGB *rgbarray, uint16_t count, float gammaR, float gammaG, float gammaB)
	Destructively applies a gamma adjustment to a color array.

Function Documentation

◆ applyGamma_video() [1/3]

CRGB applyGamma_video	(	const CRGB &	orig,
		float	gamma )

Applies a gamma adjustment to a color.

Parameters

orig	the color to apply an adjustment to
gamma	the gamma value to apply

Returns: copy of the CRGB object with gamma adjustment applied

Definition at line 1374 of file colorutils.cpp.

◆ applyGamma_video() [2/3]

CRGB applyGamma_video	(	const CRGB &	orig,
		float	gammaR,
		float	gammaG,
		float	gammaB )

Applies a gamma adjustment to a color.

Parameters

orig	the color to apply an adjustment to
gammaR	the gamma value to apply to the CRGB::red channel
gammaG	the gamma value to apply to the CRGB::green channel
gammaB	the gamma value to apply to the CRGB::blue channel

Returns: copy of the CRGB object with gamma adjustment applied

Definition at line 1383 of file colorutils.cpp.

◆ applyGamma_video() [3/3]

uint8_t applyGamma_video	(	uint8_t	brightness,
		float	gamma )

Applies a gamma adjustment to a color channel.

Parameters

brightness	the value of the color data
gamma	the gamma value to apply

Returns: the color data, adjusted for gamma

Definition at line 1361 of file colorutils.cpp.

◆ napplyGamma_video() [1/4]

CRGB & napplyGamma_video	(	CRGB &	rgb,
		float	gamma )

Destructively applies a gamma adjustment to a color.

Parameters

rgb	the color to apply an adjustment to (modified in place)
gamma	the gamma value to apply

Definition at line 1392 of file colorutils.cpp.

◆ napplyGamma_video() [2/4]

CRGB & napplyGamma_video	(	CRGB &	rgb,
		float	gammaR,
		float	gammaG,
		float	gammaB )

Destructively applies a gamma adjustment to a color.

Parameters

rgb	the color to apply an adjustment to (modified in place)
gammaR	the gamma value to apply to the CRGB::red channel
gammaG	the gamma value to apply to the CRGB::green channel
gammaB	the gamma value to apply to the CRGB::blue channel

Definition at line 1398 of file colorutils.cpp.

◆ napplyGamma_video() [3/4]

void napplyGamma_video	(	CRGB *	rgbarray,
		uint16_t	count,
		float	gamma )

Destructively applies a gamma adjustment to a color array.

Parameters

rgbarray	pointer to an LED array to apply an adjustment to (modified in place)
count	the number of LEDs to modify
gamma	the gamma value to apply

Definition at line 1404 of file colorutils.cpp.

◆ napplyGamma_video() [4/4]

void napplyGamma_video	(	CRGB *	rgbarray,
		uint16_t	count,
		float	gammaR,
		float	gammaG,
		float	gammaB )

Destructively applies a gamma adjustment to a color array.

Parameters

rgbarray	pointer to an LED array to apply an adjustment to (modified in place)
count	the number of LEDs to modify
gammaR	the gamma value to apply to the CRGB::red channel
gammaG	the gamma value to apply to the CRGB::green channel
gammaB	the gamma value to apply to the CRGB::blue channel

Definition at line 1411 of file colorutils.cpp.