Struct GlyphTransform

Namespace

Egami.Fonts

Assembly

Egami.Fonts.dll

A glyph's placement in a transformed GlyphRun: a rotation and uniform scale, then its origin, as Skia's RSXform. A point (x, y) of the glyph, y down, goes to (ScaleCos x - ScaleSin y + Tx, ScaleSin x + ScaleCos y + Ty).

public readonly record struct GlyphTransform : IEquatable<GlyphTransform>

Implements

IEquatable<GlyphTransform>

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

ValueType.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Examples

// A label along a curve: each glyph's midpoint on the path, turned to its direction, as SVG's textPath. The result is
// still a glyph run, so a PDF backend writes it as searchable text.
Path curve = new PathBuilder().MoveTo(20, 150).CubicTo(80, 20, 240, 20, 300, 150).ToPath();
var font = new Font(face, 18);
using (RasterCanvas<Rgba8> canvas = image.CreateCanvas())
{
    canvas.DrawTextOnPath("Text that follows the curve", curve, font, Rgba8.Black,
        new TextOnPathOptions { StartFraction = 0.5f, Anchor = TextAnchor.Center, BaselineShift = 4 });
}

// Or place glyphs yourself, each with its own turn and scale.
GlyphRun dial = GlyphRun.CreateTransformed(font, [face.GetGlyph('N'), face.GetGlyph('E')],
    [GlyphTransform.FromRotationScale(1, 0, new Vector2(150, 30)), GlyphTransform.FromRotationScale(1, 90, new Vector2(290, 90))]);

Constructors

GlyphTransform(float, float, float, float)

A glyph's placement in a transformed GlyphRun: a rotation and uniform scale, then its origin, as Skia's RSXform. A point (x, y) of the glyph, y down, goes to (ScaleCos x - ScaleSin y + Tx, ScaleSin x + ScaleCos y + Ty).

public GlyphTransform(float ScaleCos, float ScaleSin, float Tx, float Ty)

Parameters

ScaleCos float

The scale times the cosine of the turn; 1 for an upright glyph at the font's size.

ScaleSin float

The scale times the sine of the turn (clockwise on a y-down canvas); 0 for an upright glyph.

Tx float

The glyph origin's x, relative to the run's origin.

Ty float

The glyph origin's y, relative to the run's origin, y down.

Examples

// A label along a curve: each glyph's midpoint on the path, turned to its direction, as SVG's textPath. The result is
// still a glyph run, so a PDF backend writes it as searchable text.
Path curve = new PathBuilder().MoveTo(20, 150).CubicTo(80, 20, 240, 20, 300, 150).ToPath();
var font = new Font(face, 18);
using (RasterCanvas<Rgba8> canvas = image.CreateCanvas())
{
    canvas.DrawTextOnPath("Text that follows the curve", curve, font, Rgba8.Black,
        new TextOnPathOptions { StartFraction = 0.5f, Anchor = TextAnchor.Center, BaselineShift = 4 });
}

// Or place glyphs yourself, each with its own turn and scale.
GlyphRun dial = GlyphRun.CreateTransformed(font, [face.GetGlyph('N'), face.GetGlyph('E')],
    [GlyphTransform.FromRotationScale(1, 0, new Vector2(150, 30)), GlyphTransform.FromRotationScale(1, 90, new Vector2(290, 90))]);

Properties

IsTranslation

Gets whether the glyph is only moved, not turned or scaled.

public bool IsTranslation { get; }

Property Value

bool

ScaleCos

The scale times the cosine of the turn; 1 for an upright glyph at the font's size.

public float ScaleCos { get; init; }

Property Value

float

ScaleSin

The scale times the sine of the turn (clockwise on a y-down canvas); 0 for an upright glyph.

public float ScaleSin { get; init; }

Property Value

float

Tx

The glyph origin's x, relative to the run's origin.

public float Tx { get; init; }

Property Value

float

Ty

The glyph origin's y, relative to the run's origin, y down.

public float Ty { get; init; }

Property Value

float

Methods

FromRotationScale(float, float, Vector2)

Creates a placement that scales and turns a glyph about its origin and puts the origin at a position.

public static GlyphTransform FromRotationScale(float scale, float degrees, Vector2 origin)

Parameters

scale float

The scale; 1 for the font's size.

degrees float

The clockwise turn on a y-down canvas.

origin Vector2

Where the glyph's origin goes, relative to the run's origin.

Returns

GlyphTransform

The placement.

ToMatrix()

Returns the transform as a matrix from the glyph's y-down coordinates to the run's.

public Matrix3x2 ToMatrix()

Returns

Matrix3x2

The matrix.