Class LuminanceToAlphaEffect

Namespace

PaintDotNet.Direct2D1.Effects

Assembly

PaintDotNet.Windows.Core.dll

Use the luminance to alpha effect to set the alpha channel to the luminance of the image and sets the color channels to 0. You can use the output of this effect to make a semitransparent overlay based on the brightness of the input image. Or you can use it to make an image mask.
This effect sets the alpha channel of the output to the luminance of the input image using this color matrix:

                                 R'  G'  B'      A'
                              ┌                     ┐
                              │   0   0   0  0.2125 │  R
                              │   0   0   0  0.7154 │  G
[R' G' B' A'] = [R G B A 1] * │   0   0   0  0.0721 │  B
                              │   0   0   0       0 │  A
                              │   0   0   0       0 │  1
                              └                     ┘

This effect consumes and outputs premultiplied alpha images. The effect won't work on straight alpha images unless they are fully opaque.

This effect calculates the luminance for the image's color values, which is different than luma which is calculated by GrayscaleEffect. See Difference between Luma and Luminance for more information.

NOTE: Because images are stored in a gamma-compensated format, before you calculate the luminance for an image you should first perform inverse gamma correction to get the true color values for the image. Since images are normally stored at 2.2 gamma, you can use GammaTransferEffect with an exponent of (1/2.2) and then use the output of that effect.

For more information, see Luminance to alpha effect

public sealed class LuminanceToAlphaEffect : DeviceEffect<LuminanceToAlphaEffect.Props>, ISerializable, IDeviceEffect, IDeviceImage, IDirect2DResource, IFactoryProperty, IDeviceEffectProperties, IInternalImpl, IObjectRef, IIsDisposed, IDisposable

Inheritance

object

RefTrackedObject

DeviceEffect

DeviceEffect<LuminanceToAlphaEffect.Props>

LuminanceToAlphaEffect

Implements

ISerializable

IDeviceEffect

IDeviceImage

IDirect2DResource

IFactoryProperty

IDeviceEffectProperties

IInternalImpl

IObjectRef

IIsDisposed

IDisposable

Inherited Members

DeviceEffect<LuminanceToAlphaEffect.Props>.Properties

DeviceEffect.IsInputSet(int)

DeviceEffect.GetInput(int)

DeviceEffect.SetInput(int, IDeviceImage, bool)

DeviceEffect.TryGetSubProperties(int, out IDeviceEffectProperties)

DeviceEffect.TryGetPropertyName(int, out string)

DeviceEffect.TryGetPropertyIndex(string, out int)

DeviceEffect.TryGetPropertyType(int, out DeviceEffectPropertyType)

DeviceEffect.TryGetValueSize(int, out int)

DeviceEffect.GetValue(int, DeviceEffectPropertyType, Span<byte>)

DeviceEffect.GetValueByName(string, DeviceEffectPropertyType, Span<byte>)

DeviceEffect.GetValueRef(int, DeviceEffectPropertyType, Type)

DeviceEffect.GetValueRefByName(string, DeviceEffectPropertyType, Type)

DeviceEffect.GetValueSize(int)

DeviceEffect.SetValue(int, DeviceEffectPropertyType, ReadOnlySpan<byte>)

DeviceEffect.SetValueByName(string, DeviceEffectPropertyType, ReadOnlySpan<byte>)

DeviceEffect.SetValueRef(int, DeviceEffectPropertyType, IObjectRef)

DeviceEffect.SetValueRefByName(string, DeviceEffectPropertyType, IObjectRef)

DeviceEffect.InputCount

DeviceEffect.Factory

DeviceEffect.PropertyCount

RefTrackedObject.Dispose()

RefTrackedObject.TryCreateRef(Type, out IObjectRef)

RefTrackedObject.IsDisposed

object.GetType()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Extension Methods

DeviceEffectExtensions.Initialize<TEffect>(TEffect, Action<TEffect>)

DeviceEffectExtensions.InvalidateInputRectangle(IDeviceEffect, IDeviceContext, int, RectFloat)

DeviceImageExtensions.GetLocalBounds(IDeviceImage, IDeviceContext)

DeviceImageExtensions.GetWorldBounds(IDeviceImage, IDeviceContext)

Constructors

LuminanceToAlphaEffect(IDeviceEffectFactory)

LuminanceToAlphaEffect(IDeviceEffectFactory, IDeviceImage)