Inherits from SPFragmentFilter : NSObject
Declared in SPColorMatrixFilter.h

Overview

The SPColorMatrixFilter class lets you apply a 4x5 matrix transformation on the RGBA color and alpha values of every pixel in the input image to produce a result with a new set of RGBA color and alpha values. It allows saturation changes, hue rotation, luminance to alpha, and various other effects.

The class contains several convenience methods for frequently used color adjustments. All those methods change the current matrix, which means you can easily combine them in one filter:

// create an inverted filter with 50% saturation and 180° hue rotation
SPColorMatrixFilter* filter = [[SPColorMatrixFilter alloc] init]
[filter invert];
[filter adjustSaturation:-0.5];
[filter adjustHue:1.0];

If you want to gradually animate one of the predefined color adjustments, either reset the matrix after each step, or use an identical adjustment value for each step; the changes will add up.

Tasks

Initialization

Methods

  • – invert

    Inverts the colors of the filtered objects.
  • – adjustSaturation:

    Changes the saturation. Typical values are in the range(-1, 1). Values above zero will raise, values below zero will reduce the saturation. ‘-1’ will produce a grayscale image.
  • – adjustContrast:

    Changes the contrast. Typical values are in the range(-1, 1). Values above zero will raise, values below zero will reduce the contrast.
  • – adjustBrightness:

    Changes the brightness. Typical values are in the range(-1, 1). Values above zero will make the image brighter, values below zero will make it darker.
  • – adjustHue:

    Changes the hue of the image. Typical values are in the range(-1, 1).

Matrix Manipulation

Properties

  •   colorMatrix

    The color matrix object used to apply the filter.

         property

Properties

colorMatrix

The color matrix object used to apply the filter.

@property (nonatomic, copy) SPColorMatrix *colorMatrix

Discussion

The color matrix object used to apply the filter.

Declared In

SPColorMatrixFilter.h

Class Methods

colorMatrixFilter

Factory method.

+ (instancetype)colorMatrixFilter

Discussion

Factory method.

Declared In

SPColorMatrixFilter.h

colorMatrixFilterWithMatrix:

Factory method.

+ (instancetype)colorMatrixFilterWithMatrix:(SPColorMatrix *)colorMatrix

Discussion

Factory method.

Declared In

SPColorMatrixFilter.h

Instance Methods

adjustBrightness:

Changes the brightness. Typical values are in the range(-1, 1). Values above zero will make the image brighter, values below zero will make it darker.

- (void)adjustBrightness:(float)brightness

Discussion

Changes the brightness. Typical values are in the range(-1, 1). Values above zero will make the image brighter, values below zero will make it darker.

Declared In

SPColorMatrixFilter.h

adjustContrast:

Changes the contrast. Typical values are in the range(-1, 1). Values above zero will raise, values below zero will reduce the contrast.

- (void)adjustContrast:(float)contrast

Discussion

Changes the contrast. Typical values are in the range(-1, 1). Values above zero will raise, values below zero will reduce the contrast.

Declared In

SPColorMatrixFilter.h

adjustHue:

Changes the hue of the image. Typical values are in the range(-1, 1).

- (void)adjustHue:(float)hue

Discussion

Changes the hue of the image. Typical values are in the range(-1, 1).

Declared In

SPColorMatrixFilter.h

adjustSaturation:

Changes the saturation. Typical values are in the range(-1, 1). Values above zero will raise, values below zero will reduce the saturation. ‘-1’ will produce a grayscale image.

- (void)adjustSaturation:(float)saturation

Discussion

Changes the saturation. Typical values are in the range(-1, 1). Values above zero will raise, values below zero will reduce the saturation. ‘-1’ will produce a grayscale image.

Declared In

SPColorMatrixFilter.h

concatColorMatrix:

Concatenates the current matrix with another one.

- (void)concatColorMatrix:(SPColorMatrix *)colorMatrix

Discussion

Concatenates the current matrix with another one.

Declared In

SPColorMatrixFilter.h

init

Initialize a color matrix filter with an identity color matrix.

- (instancetype)init

Discussion

Initialize a color matrix filter with an identity color matrix.

Declared In

SPColorMatrixFilter.h

initWithMatrix:

Initialize a color matrix filter with a color matrix. Designated initializer.

- (instancetype)initWithMatrix:(SPColorMatrix *)colorMatrix

Discussion

Initialize a color matrix filter with a color matrix. Designated initializer.

Declared In

SPColorMatrixFilter.h

invert

Inverts the colors of the filtered objects.

- (void)invert

Discussion

Inverts the colors of the filtered objects.

Declared In

SPColorMatrixFilter.h

reset

Changes the filter matrix back to the identity matrix.

- (void)reset

Discussion

Changes the filter matrix back to the identity matrix.

Declared In

SPColorMatrixFilter.h