Contrast

Contrast filter class

Example

const filter = new Contrast({
  contrast: 0.25
});
object.filters.push(filter);
object.applyFilters();

Extends

BaseFilter<"Contrast", ContrastOwnProps>

Constructors

new Contrast()

new Contrast(options?): Contrast

Constructor

Parameters

• options?: object & Partial<ContrastOwnProps> & Record<string, any> = {}

Options object

Properties

contrast

contrast: number

contrast value, range from -1 to 1.

Param

Default

Defined in

src/filters/Contrast.ts:29

defaults

static defaults: ContrastOwnProps = contrastDefaultValues

Overrides

BaseFilter.defaults

Defined in

src/filters/Contrast.ts:33

type

static type: string = 'Contrast'

The class type. Used to identify which class this is. This is used for serialization purposes and internally it can be used to identify classes. As a developer you could use instance of Class but to avoid importing all the code and blocking tree shaking we try to avoid doing that.

Overrides

BaseFilter.type

Defined in

src/filters/Contrast.ts:31

uniformLocations

static uniformLocations: string[]

Contains the uniform locations for the fragment shader. uStepW and uStepH are handled by the BaseFilter, each filter class needs to specify all the one that are needed

Overrides

BaseFilter.uniformLocations

Defined in

src/filters/Contrast.ts:35

Accessors

type

get type(): Name

Filter type

Default

Returns

Name

Inherited from

BaseFilter.type

Defined in

src/filters/BaseFilter.ts:30

Methods

_setupFrameBuffer()

_setupFrameBuffer(options): void

Parameters

• options: TWebGLPipelineState

Returns

void

Inherited from

BaseFilter._setupFrameBuffer

Defined in

src/filters/BaseFilter.ts:204

_swapTextures()

_swapTextures(options): void

Parameters

• options: TWebGLPipelineState

Returns

void

Inherited from

BaseFilter._swapTextures

Defined in

src/filters/BaseFilter.ts:231

applyTo()

applyTo(options): void

Apply this filter to the input image data provided.

Determines whether to use WebGL or Canvas2D based on the options.webgl flag.

Parameters

• options: TWebGLPipelineState | T2DPipelineState

Returns

void

Inherited from

BaseFilter.applyTo

Defined in

src/filters/BaseFilter.ts:264

applyTo2d()

applyTo2d(options): void

Apply the Contrast operation to a Uint8Array representing the pixels of an image.

Parameters

• options: T2DPipelineState

Returns

void

Overrides

BaseFilter.applyTo2d

Defined in

src/filters/Contrast.ts:51

applyToWebGL()

applyToWebGL(options): void

Apply this filter using webgl.

Parameters

• options: TWebGLPipelineState

Returns

void

Inherited from

BaseFilter.applyToWebGL

Defined in

src/filters/BaseFilter.ts:314

bindAdditionalTexture()

bindAdditionalTexture(gl, texture, textureUnit): void

Parameters

• gl: WebGLRenderingContext

• texture: WebGLTexture

• textureUnit: number

Returns

void

Inherited from

BaseFilter.bindAdditionalTexture

Defined in

src/filters/BaseFilter.ts:333

createHelpLayer()

createHelpLayer(options): void

If needed by a 2d filter, this functions can create an helper canvas to be used remember that options.targetCanvas is available for use till end of chain.

Parameters

• options: T2DPipelineState

Returns

void

Inherited from

BaseFilter.createHelpLayer

Defined in

src/filters/BaseFilter.ts:369

createProgram()

createProgram(gl, fragmentSource, vertexSource): object

Compile this filter’s shader program.

Parameters

• gl: WebGLRenderingContext

The GL canvas context to use for shader compilation.

• fragmentSource: string = ...

fragmentShader source for compilation

• vertexSource: string = ...

vertexShader source for compilation

Returns

object

attributeLocations

attributeLocations: TWebGLAttributeLocationMap

program

program: WebGLProgram

uniformLocations

uniformLocations: TWebGLUniformLocationMap

Inherited from

BaseFilter.createProgram

Defined in

src/filters/BaseFilter.ts:82

getAttributeLocations()

getAttributeLocations(gl, program): TWebGLAttributeLocationMap

Return a map of attribute names to WebGLAttributeLocation objects.

Parameters

• gl: WebGLRenderingContext

The canvas context used to compile the shader program.

• program: WebGLProgram

The shader program from which to take attribute locations.

Returns

TWebGLAttributeLocationMap

A map of attribute names to attribute locations.

Inherited from

BaseFilter.getAttributeLocations

Defined in

src/filters/BaseFilter.ts:152

getCacheKey()

getCacheKey(): string

Returns a string that represent the current selected shader code for the filter. Used to force recompilation when parameters change or to retrieve the shader from cache

Returns

string

Inherited from

BaseFilter.getCacheKey

Defined in

src/filters/BaseFilter.ts:283

getFragmentSource()

getFragmentSource(): string

Returns

string

Overrides

BaseFilter.getFragmentSource

Defined in

src/filters/Contrast.ts:37

getUniformLocations()

getUniformLocations(gl, program): TWebGLUniformLocationMap

Return a map of uniform names to WebGLUniformLocation objects.

Parameters

• gl: WebGLRenderingContext

The canvas context used to compile the shader program.

• program: WebGLProgram

The shader program from which to take uniform locations.

Returns

TWebGLUniformLocationMap

A map of uniform names to uniform locations.

Inherited from

BaseFilter.getUniformLocations

Defined in

src/filters/BaseFilter.ts:168

getVertexSource()

getVertexSource(): string

Returns

string

Inherited from

BaseFilter.getVertexSource

Defined in

src/filters/BaseFilter.ts:71

isNeutralState()

isNeutralState(): boolean

Generic isNeutral implementation for one parameter based filters. Used only in image applyFilters to discard filters that will not have an effect on the image Other filters may need their own version ( ColorMatrix, HueRotation, gamma, ComposedFilter )