Class LcdFilter

Namespace

Egami.Drawing

Assembly

Egami.Drawing.dll

The five-tap filter LCD text spreads each subpixel's coverage with, across the subpixel and its two neighbours on each side. The weights add up to 256. A wider filter has softer colour fringes; a narrower one is sharper and more coloured.

public sealed class LcdFilter : IEquatable<LcdFilter>

Inheritance

object

LcdFilter

Implements

IEquatable<LcdFilter>

Inherited Members

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Examples

// GDI+ ClearType's look: its filter (an even spread over three subpixels), no smoothing along the stripes, and the text
// gamma that then matched GDI+'s weight for a white Trebuchet MS label at 16 pixels.
var gdiPlus = new CanvasOptions
{
    PixelGeometry = PixelGeometry.RgbHorizontal,
    LcdFilter = LcdFilter.Gdi,
    LcdSampling = LcdSampling.Gdi,
    TextGamma = 1.25f,
};
var label = new Font(face, 16) { Hinting = FontHinting.Light, Edging = FontEdging.Lcd, Subpixel = false };
using (RasterCanvas<Rgb8> canvas = button.CreateCanvas(gdiPlus))
{
    canvas.DrawText("Start the course", new Vector2(40, 26), label, Rgba8.White);
}

// Softer fringes: a balanced filter and half the colour of full ClearType.
var soft = new CanvasOptions { PixelGeometry = PixelGeometry.RgbHorizontal, LcdFilter = LcdFilter.Balanced, ClearTypeLevel = 0.5f };

// Or weights of your own, normalised to add up to 256.
var custom = new CanvasOptions { PixelGeometry = PixelGeometry.RgbHorizontal, LcdFilter = LcdFilter.Custom(1, 3, 4, 3, 1) };

Properties

Balanced

Gets a colour-balanced filter: 8, 77, 86, 77, 8, as FreeType's default LCD filter is described.

public static LcdFilter Balanced { get; }

Property Value

LcdFilter

Default

Gets Egami's filter since 2.7.2 and the default: 16, 64, 96, 64, 16 (1, 4, 6, 4, 1 over 16).

public static LcdFilter Default { get; }

Property Value

LcdFilter

Gdi

Gets the filter that matches GDI and GDI+ ClearType as measured in 2.7.5: each subpixel's coverage spread evenly over it and its two neighbours. It has the same weights as Light (0, 85, 86, 85, 0) and equals it; the two names say why the weights are chosen.

public static LcdFilter Gdi { get; }

Property Value

LcdFilter

Light

Gets a light three-tap filter: 0, 85, 86, 85, 0, a box over the subpixel and its two neighbours. Gdi has the same weights, and equals it.

public static LcdFilter Light { get; }

Property Value

LcdFilter

Name

Gets the preset's name, or Custom.

public string Name { get; }

Property Value

string

Weights

Gets the five weights from the farthest left neighbour to the farthest right; they add up to 256.

public IReadOnlyList<int> Weights { get; }

Property Value

IReadOnlyList<int>

Methods

Custom(float, float, float, float, float)

A filter of five weights, normalised to add up to 256 (largest remainders rounding up).

public static LcdFilter Custom(float outerLeft, float left, float center, float right, float outerRight)

Parameters

outerLeft float

The weight two subpixels to the left.

left float

The weight one subpixel to the left.

center float

The subpixel's own weight.

right float

The weight one subpixel to the right.

outerRight float

The weight two subpixels to the right.

Returns

LcdFilter

The filter.

Exceptions

ArgumentOutOfRangeException

A weight is negative or not finite, or they add up to 0.

Equals(LcdFilter?)

Indicates whether the current object is equal to another object of the same type.

public bool Equals(LcdFilter? other)

Parameters

other LcdFilter

An object to compare with this object.

Returns

bool

true if the current object is equal to the other parameter; otherwise, false.

Equals(object?)

Determines whether the specified object is equal to the current object.

public override bool Equals(object? obj)

Parameters

obj object

The object to compare with the current object.

Returns

bool

true if the specified object is equal to the current object; otherwise, false.

GetHashCode()

Serves as the default hash function.

public override int GetHashCode()

Returns

int

A hash code for the current object.

ToString()

Returns a string that represents the current object.

public override string ToString()

Returns

string

A string that represents the current object.