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    moon_zeno

    A low level 2D rasterization library

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    0.1.4
    License
    Apache-2.0
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    #Milky2018/moon_zeno

    A low level 2D rasterization library with support for rendering paths of various styles into alpha or subpixel masks.

    #What You Get

    • SVG path parsing (String implements PathData)
    • Path evaluation: length, bounds, apply (fill/stroke + optional Transform)
    • Rendering: Mask (Format::Alpha / Format::Subpixel) and HitTest
    • Styles: Fill, Stroke, Style, Join, Cap
    • Traversal helpers: Vertices, Walk

    The intended public surface is defined by src/pkg.generated.mbti and is kept aligned with zeno-reference/src/lib.rs re-exports.

    #PathBuilder Notes

    Upstream zeno exposes rel_*, arc_to, and add_* as default methods on the PathBuilder trait. MoonBit traits don't support default method bodies, so this port keeps PathBuilder as a minimal sink interface and provides the defaults as public helper functions:

    • rel_move_to, rel_line_to, rel_quad_to, rel_curve_to, rel_arc_to
    • arc_to
    • add_rect, add_round_rect, add_ellipse, add_circle

    This means custom sinks only need to implement: current_point, move_to, line_to, quad_to, curve_to, close.

    #PathData Notes

    Besides String and Array[Command], this port also provides:

    • pub impl PathData for (Array[Point], Array[Verb])

    which matches upstream’s common point+verb representation.

    #Examples

    // SVG path data works directly because `String` implements `PathData`.
    let svg : String = "M0,0 L3,4 Z"
    let len = length(svg, None)

    // Point+verb lists also implement `PathData`.
    let data = (
      [@moon_zeno.Vector(1.0, 1.0), @moon_zeno.Vector(6.0, 1.0), @moon_zeno.Vector(3.5, 6.0)],
      [Verb::MoveTo, Verb::LineTo, Verb::LineTo, Verb::Close],
    )

    let (buf, placement) = @moon_zeno.Mask(data)
      .style(Style::Fill(Fill::NonZero))
      .size(8U, 8U)
      .render()

    // `Array[Command]` is both a `PathData` and a `PathBuilder` sink.
    let cmds : Array[Command] = []
    add_rect(cmds, @moon_zeno.Vector(1.0, 2.0), 3.0, 4.0)

    #Development

    • moon info && moon fmt
    • moon check
    • moon test

    PathBuilder

    source
    pub(open) trait PathBuilder {
      fn current_point(Self) -> Vector
      fn move_to(Self, Vector) -> Unit
      fn line_to(Self, Vector) -> Unit
      fn quad_to(Self, Vector, Vector) -> Unit
      fn curve_to(Self, Vector, Vector, Vector) -> Unit
      fn close(Self) -> Unit
    }

    Path builder sink interface.

    Ported from upstream zeno/src/path_builder.rs (Apache-2.0 OR MIT).

    PathData

    source
    pub(open) trait PathData {
      fn commands(Self) -> Iter[Command]
      fn copy_to(Self, &PathBuilder) -> Unit
    }

    Path data abstraction.

    Ported from upstream zeno/src/path_data.rs (Apache-2.0 OR MIT).
    impl PathData for String

    Angle

    source
    type Angle

    Represents an angle in radians (constructors provided for common units).

    Ported from upstream zeno/src/geometry.rs::Angle.

    Angle::from_degrees

    source
    fn Angle::from_degrees(degrees : Double) -> Angle

    Angle::from_gradians

    source
    fn Angle::from_gradians(gradians : Double) -> Angle

    Angle::from_radians

    source
    fn Angle::from_radians(radians : Double) -> Angle

    Angle::from_turns

    source
    fn Angle::from_turns(turns : Double) -> Angle

    Angle::to_degrees

    source
    fn Angle::to_degrees(self : Angle) -> Double

    Angle::to_radians

    source
    fn Angle::to_radians(self : Angle) -> Double

    Angle::zero

    source
    fn Angle::zero() -> Angle

    ArcSize

    source
    pub(all) enum ArcSize {
      Small
      Large
    }

    Arc size flag (SVG style).

    Ported from upstream zeno/src/path_builder.rs.

    ArcSweep

    source
    pub(all) enum ArcSweep {
      Positive
      Negative
    }

    Arc sweep flag (SVG style).

    Ported from upstream zeno/src/path_builder.rs.

    Bounds

    source
    pub struct Bounds {
      min : Vector
      max : Vector
    }

    Bounds::Bounds

    source
    fn Bounds::Bounds(min : Vector, max : Vector) -> Bounds

    Bounds::add_point

    source
    fn Bounds::add_point(self : Bounds, p : Vector) -> Unit

    Bounds::contains

    source
    fn Bounds::contains(self : Bounds, p : Vector) -> Bool

    Bounds::default

    source
    fn Bounds::default() -> Bounds

    Bounds::from_points

    source
    fn Bounds::from_points(points : Array[Vector]) -> Bounds

    Bounds::height

    source
    fn Bounds::height(self : Bounds) -> Double

    Bounds::is_empty

    source
    fn Bounds::is_empty(self : Bounds) -> Bool

    Bounds::width

    source
    fn Bounds::width(self : Bounds) -> Double

    Cap

    source
    pub(all) enum Cap {
      Butt
      Square
      Round
    }

    Command

    source
    pub(all) enum Command {
      MoveTo(Vector)
      LineTo(Vector)
      QuadTo(Vector, Vector)
      CurveTo(Vector, Vector, Vector)
      Close
    }

    Path commands.

    Ported from upstream zeno/src/command.rs (Apache-2.0 OR MIT).

    Command::transform

    source
    fn Command::transform(self : Command, transform : Transform) -> Command

    Command::verb

    source
    fn Command::verb(self : Command) -> Verb

    Returns the associated verb for the command.

    Fill

    source
    pub(all) enum Fill {
      NonZero
      EvenOdd
    }

    Path styles.

    Ported from upstream zeno/src/style.rs (Apache-2.0 OR MIT).

    Format

    source
    pub(all) enum Format {
      Alpha
      Subpixel
      CustomSubpixel(Array[Double])
    }

    Mask generator (subset).

    Ported from upstream zeno/src/mask.rs (Apache-2.0 OR MIT).

    Format::buffer_size

    source
    fn Format::buffer_size(self : Format, width : UInt, height : UInt) -> Int

    Format::default

    source
    fn Format::default() -> Format

    Format::subpixel_bgra

    source
    fn Format::subpixel_bgra() -> Format

    HitTest

    source
    type HitTest

    Builder for configuring and executing a hit test.

    HitTest::HitTest

    source
    fn HitTest::HitTest(data : &PathData) -> HitTest

    HitTest::fill

    source
    fn HitTest::fill(self : HitTest, fill : Fill) -> HitTest

    HitTest::hit

    source
    fn HitTest::hit(self : HitTest, point : Vector) -> Bool

    HitTest::stroke

    source
    fn HitTest::stroke(self : HitTest, stroke : Stroke) -> HitTest

    HitTest::style

    source
    fn HitTest::style(self : HitTest, style : Style) -> HitTest

    HitTest::threshold

    source
    fn HitTest::threshold(self : HitTest, threshold : Int) -> HitTest

    HitTest::transform

    source
    fn HitTest::transform(self : HitTest, transform : Transform?) -> HitTest

    HitTest::with_scratch

    source
    fn HitTest::with_scratch(data : &PathData, scratch : 
    Ref    [Scratch]) -> HitTest

    Join

    source
    pub(all) enum Join {
      Bevel
      Miter
      Round
    }

    Mask

    source
    type Mask

    Builder for configuring and rendering a mask (alpha subset).

    Ported from upstream zeno/src/mask.rs (Apache-2.0 OR MIT).

    Mask::Mask

    source
    fn Mask::Mask(data : &PathData) -> Mask

    Mask::fill

    source
    fn Mask::fill(self : Mask, fill : Fill) -> Mask

    Convenience wrapper for .style(Style::Fill(fill)).

    Mask::format

    source
    fn Mask::format(self : Mask, format : Format) -> Mask

    Mask::inspect

    source
    fn Mask::inspect(self : Mask, f : (Format, UInt, UInt) -> Unit) -> Mask

    Mask::offset

    source
    fn Mask::offset(self : Mask, offset : Vector) -> Mask

    Mask::origin

    source
    fn Mask::origin(self : Mask, origin : Origin) -> Mask

    Mask::render

    source
    fn Mask::render(self : Mask) -> (Array[Byte], Placement)

    Renders the mask into a newly allocated buffer.

    Mask::render_into

    source
    fn Mask::render_into(self : Mask, buffer : Array[Byte], pitch? : Int) -> Placement

    Renders the mask into a target buffer (tightly packed; alpha only for now).

    Mask::render_offset

    source
    fn Mask::render_offset(self : Mask, offset : Vector) -> Mask

    Mask::size

    source
    fn Mask::size(self : Mask, width : UInt, height : UInt) -> Mask

    Mask::stroke

    source
    fn Mask::stroke(self : Mask, stroke : Stroke) -> Mask

    Convenience wrapper for .style(Style::Stroke(stroke)).

    Mask::style

    source
    fn Mask::style(self : Mask, style : Style) -> Mask

    Mask::transform

    source
    fn Mask::transform(self : Mask, transform : Transform?) -> Mask

    Mask::with_scratch

    source
    fn Mask::with_scratch(data : &PathData, scratch : 
    Ref    [Scratch]) -> Mask

    Origin

    source
    pub(all) enum Origin {
      TopLeft
      BottomLeft
    }

    Bounds, origin and placement.

    Ported from upstream zeno/src/geometry.rs (Apache-2.0 OR MIT).

    Origin::default

    source
    fn Origin::default() -> Origin

    Placement

    source
    pub(all) struct Placement {
      left : Int
      top : Int
      width : UInt
      height : UInt
    }

    Placement::compute

    source
    fn Placement::compute(origin : Origin, offset : Vector, bounds : Bounds) -> (Vector, Placement)

    Scratch

    source
    type Scratch

    Context for reusing dynamic memory allocations.

    Ported from upstream zeno/src/scratch.rs (Apache-2.0 OR MIT).

    NOTE: This is currently a minimal subset: it only stores the heap raster storage used by the rasterizer.

    Scratch::Scratch

    source
    fn Scratch::Scratch() -> Scratch

    Scratch::apply

    source
    fn Scratch::apply(self : Scratch, data : &PathData, style : Style, transform : Transform?, sink : &PathBuilder) -> Fill

    Applies the style and transform to the path and emits the result to the sink.

    This is a thin wrapper that exists to mirror upstream Scratch::apply.

    Scratch::bounds

    source
    fn Scratch::bounds(self : Scratch, data : &PathData, style : Style, transform : Transform?) -> Bounds

    Computes the bounding box of the path.

    Mirrors upstream Scratch::bounds (fill-only accurate until we port stroke).

    Scratch::default

    source
    fn Scratch::default() -> Scratch

    Stroke

    source
    pub struct Stroke {
      width : Double
      join : Join
      miter_limit : Double
      start_cap : Cap
      end_cap : Cap
      dashes : Array[Double]
      offset : Double
      scale : Bool
    }

    Stroke::Stroke

    source
    fn Stroke::Stroke(width : Double) -> Stroke

    Stroke::cap

    source
    fn Stroke::cap(self : Stroke, cap : Cap) -> Stroke

    Stroke::caps

    source
    fn Stroke::caps(self : Stroke, start : Cap, end : Cap) -> Stroke

    Stroke::dash

    source
    fn Stroke::dash(self : Stroke, dashes : Array[Double], offset : Double) -> Stroke

    Stroke::default

    source
    fn Stroke::default() -> Stroke

    Stroke::join

    source
    fn Stroke::join(self : Stroke, join : Join) -> Stroke

    Stroke::miter_limit

    source
    fn Stroke::miter_limit(self : Stroke, limit : Double) -> Stroke

    Stroke::scale

    source
    fn Stroke::scale(self : Stroke, scale : Bool) -> Stroke

    Stroke::width

    source
    fn Stroke::width(self : Stroke, width : Double) -> Stroke

    Style

    source
    pub(all) enum Style {
      Fill(Fill)
      Stroke(Stroke)
    }

    Style::default

    source
    fn Style::default() -> Style

    Style::is_stroke

    source
    fn Style::is_stroke(self : Style) -> Bool

    Transform

    source
    pub struct Transform {
      xx : Double
      xy : Double
      yx : Double
      yy : Double
      x : Double
      y : Double
    }

    2D affine transform.

    Ported from upstream zeno/src/geometry.rs (Apache-2.0 OR MIT).

    Transform::Transform

    source
    fn Transform::Transform(xx : Double, xy : Double, yx : Double, yy : Double, x : Double, y : Double) -> Transform

    Transform::determinant

    source
    fn Transform::determinant(self : Transform) -> Double

    Transform::identity

    source
    fn Transform::identity() -> Transform

    Transform::invert

    source
    fn Transform::invert(self : Transform) -> Transform?

    Transform::pre_rotate

    source
    fn Transform::pre_rotate(self : Transform, angle : Angle) -> Transform

    Returns a new transform that represents a rotation followed by this transform.

    Transform::pre_scale

    source
    fn Transform::pre_scale(self : Transform, x : Double, y : Double) -> Transform

    Returns a new transform that represents a scale followed by this transform.

    Transform::pre_translate

    source
    fn Transform::pre_translate(self : Transform, x : Double, y : Double) -> Transform

    Returns a new transform that represents a translation followed by this transform.

    Transform::rotation

    source
    fn Transform::rotation(angle : Angle) -> Transform

    Transform::rotation_about

    source
    fn Transform::rotation_about(point : Vector, angle : Angle) -> Transform

    Transform::scale

    source
    fn Transform::scale(x : Double, y : Double) -> Transform

    Transform::skew

    source
    fn Transform::skew(x : Angle, y : Angle) -> Transform

    Transform::then

    source
    fn Transform::then(self : Transform, other : Transform) -> Transform

    Returns a new transform that represents the application of this transform followed by other.

    Transform::then_rotate

    source
    fn Transform::then_rotate(self : Transform, angle : Angle) -> Transform

    Returns a new transform that represents this transform followed by a rotation.

    Transform::then_scale

    source
    fn Transform::then_scale(self : Transform, x : Double, y : Double) -> Transform

    Returns a new transform that represents this transform followed by a scale.

    Transform::then_translate

    source
    fn Transform::then_translate(self : Transform, x : Double, y : Double) -> Transform

    Returns a new transform that represents this transform followed by a translation.

    Transform::transform_point

    source
    fn Transform::transform_point(self : Transform, point : Vector) -> Vector

    Transform::transform_vector

    source
    fn Transform::transform_vector(self : Transform, vector : Vector) -> Vector

    Transform::translate

    source
    fn Transform::translate(x : Double, y : Double) -> Transform

    Transform::translation

    source
    fn Transform::translation(x : Double, y : Double) -> Transform

    Vector

    source
    #alias(Point)
    pub struct Vector {
      x : Double
      y : Double
    }

    Two dimensional vector.
    impl Add for Vector
    impl Div for Vector
    impl Mul for Vector
    impl Neg for Vector
    impl Sub for Vector

    Vector::Vector

    source
    fn Vector::Vector(x : Double, y : Double) -> Vector

    Vector::add

    source
    fn Vector::add(self : Vector, other : Vector) -> Vector

    Vector::angle_to

    source
    fn Vector::angle_to(self : Vector, other : Vector) -> Angle

    Returns the angle to the specified vector.

    Vector::ceil

    source
    fn Vector::ceil(self : Vector) -> Vector

    Vector::cross

    source
    fn Vector::cross(self : Vector, other : Vector) -> Double

    Vector::distance_to

    source
    fn Vector::distance_to(self : Vector, other : Vector) -> Double

    Vector::div

    source
    fn Vector::div(self : Vector, rhs : Vector) -> Vector

    Vector::div_scalar

    source
    fn Vector::div_scalar(self : Vector, s : Double) -> Vector

    Vector::dot

    source
    fn Vector::dot(self : Vector, other : Vector) -> Double

    Vector::floor

    source
    fn Vector::floor(self : Vector) -> Vector

    Vector::length

    source
    fn Vector::length(self : Vector) -> Double

    Vector::length_squared

    source
    fn Vector::length_squared(self : Vector) -> Double

    Vector::mul

    source
    fn Vector::mul(self : Vector, rhs : Vector) -> Vector

    Vector::nearly_eq

    source
    fn Vector::nearly_eq(self : Vector, other : Vector) -> Bool

    Equivalent to upstream Vector::nearly_eq (uses f32 epsilon).

    Vector::nearly_eq_by

    source
    fn Vector::nearly_eq_by(self : Vector, other : Vector, epsilon : Double) -> Bool

    Vector::neg

    source
    fn Vector::neg(self : Vector) -> Vector

    Vector::normalize

    source
    fn Vector::normalize(self : Vector) -> Vector

    Vector::scale

    source
    fn Vector::scale(self : Vector, s : Double) -> Vector

    Vector::sub

    source
    fn Vector::sub(self : Vector, rhs : Vector) -> Vector

    Vector::x

    source
    fn Vector::x(self : Vector) -> Double

    Vector::y

    source
    fn Vector::y(self : Vector) -> Double

    Vector::zero

    source
    fn Vector::zero() -> Vector

    Verb

    source
    pub(all) enum Verb {
      MoveTo
      LineTo
      QuadTo
      CurveTo
      Close
    }

    Minimal zeno port: path verbs.

    Ported from upstream zeno crate (Apache-2.0 OR MIT).

    Vertex

    source
    pub(all) enum Vertex {
      Start(Vector, Vector)
      Middle(Vector, Vector, Vector)
      End(Vector, Vector, Bool)
    }

    A vertex of a path.

    Vertices

    source
    type Vertices

    Iterator over the vertices of a path.

    Vertices::Vertices

    source
    fn Vertices::Vertices(data : &PathData) -> Vertices

    Vertices::next

    source
    fn Vertices::next(self : Vertices) -> Vertex?

    Vertices::with_transform

    source
    fn Vertices::with_transform(data : &PathData, transform : Transform) -> Vertices

    Walk

    source
    type Walk

    Iterator-like type that walks along a path by arbitrary steps.

    Walk::Walk

    source
    fn Walk::Walk(data : &PathData) -> Walk

    Walk::remaining

    source
    fn Walk::remaining(self : Walk) -> Double

    Walk::step

    source
    fn Walk::step(self : Walk, distance : Double) -> (Vector, Vector)?

    Steps by the specified distance.

    Walk::with_transform

    source
    fn Walk::with_transform(data : &PathData, transform : Transform) -> Walk

    add_circle

    source
    fn add_circle(sink : &PathBuilder, center : Vector, r : Double) -> Unit

    add_ellipse

    source
    fn add_ellipse(sink : &PathBuilder, center : Vector, rx : Double, ry : Double) -> Unit

    add_rect

    source
    fn add_rect(sink : &PathBuilder, xy : Vector, w : Double, h : Double) -> Unit

    add_round_rect

    source
    fn add_round_rect(sink : &PathBuilder, xy : Vector, w : Double, h : Double, rx0 : Double, ry0 : Double) -> Unit

    apply

    source
    fn apply(data : &PathData, style : Style, transform : Transform?, sink : &PathBuilder) -> Fill

    Applies the style and transform to the path and emits the result to the sink.

    arc_to

    source
    fn arc_to(sink : &PathBuilder, rx : Double, ry : Double, angle : Angle, size : ArcSize, sweep : ArcSweep, to : Vector) -> Unit

    bounds

    source
    fn bounds(data : &PathData, style : Style, transform : Transform?) -> Bounds

    Computes the bounding box of the path (style/transform aware; fill-only accurate for now).

    length

    source
    fn length(data : &PathData, transform : Transform?) -> Double

    Computes the total length of the path.

    Ported from upstream zeno/src/path_data.rs::length.

    rel_arc_to

    source
    fn rel_arc_to(sink : &PathBuilder, rx : Double, ry : Double, angle : Angle, size : ArcSize, sweep : ArcSweep, to : Vector) -> Unit

    rel_curve_to

    source
    fn rel_curve_to(sink : &PathBuilder, c1 : Vector, c2 : Vector, to : Vector) -> Unit

    rel_line_to

    source
    fn rel_line_to(sink : &PathBuilder, to : Vector) -> Unit

    rel_move_to

    source
    fn rel_move_to(sink : &PathBuilder, to : Vector) -> Unit

    Convenience operations built on top of the core PathBuilder methods.

    Upstream Rust exposes these as default trait methods on PathBuilder. MoonBit traits do not support default method bodies, so we provide them as free functions.

    rel_quad_to

    source
    fn rel_quad_to(sink : &PathBuilder, c : Vector, to : Vector) -> Unit

    validate_svg

    source
    fn validate_svg(svg : String) -> Result[Unit, Int]

    Validate an SVG path string and return the first invalid position.

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