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moon_zeno

A low level 2D rasterization library

moon add Milky2018/moon_zeno@0.1.3
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0.1.3
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README

#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 = (
  [Point::new(1.0, 1.0), Point::new(6.0, 1.0), Point::new(3.5, 6.0)],
  [Verb::MoveTo, Verb::LineTo, Verb::LineTo, Verb::Close],
)

let (buf, placement) = Mask::new(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, Point::new(1.0, 2.0), 3.0, 4.0)

#Development

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

#
PathBuilder

source
pub(open) trait PathBuilder {
  current_point(Self) -> Vector
  move_to(Self, Vector) -> Unit
  line_to(Self, Vector) -> Unit
  quad_to(Self, Vector, Vector) -> Unit
  curve_to(Self, Vector, Vector, Vector) -> Unit
  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 {
  commands(Self) -> Iter[Command]
  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::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::new

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

#
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::fill

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

#
HitTest::hit

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

#
HitTest::new

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

#
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::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::new

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

#
Scratch::new

source
fn Scratch::new() -> 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::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::new

source
fn Stroke::new(width : 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::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::new

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

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

#
Vector::dot

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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::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::new

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

#
Vector::normalize

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

#
Vector::scale

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

source
fn Vertices::new(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::new

source
fn Walk::new(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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