piet-scene/src/scene/style.rs

// Copyright 2022 The piet-gpu authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Also licensed under MIT license, at your choice.

use core::borrow::Borrow;

/// Describes the winding rule that determines the interior portion of a path.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Fill {
    NonZero,
    EvenOdd,
}

/// Defines the connection between two segments of a stroke.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Join {
    /// A straight line connecting the segments.
    Bevel,
    /// The segments are extended to their natural intersection point.
    Miter,
    /// An arc between the segments.
    Round,
}

/// Defines the shape to be drawn at the ends of a stroke.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Cap {
    /// Flat cap.
    Butt,
    /// Square cap with dimensions equal to half the stroke width.
    Square,
    /// Rounded cap with radius equal to half the stroke width.
    Round,
}

/// Describes the visual style of a stroke.
#[derive(Copy, Clone, Debug)]
pub struct Stroke<D>
where
    D: Borrow<[f32]>,
{
    /// Width of the stroke.
    pub width: f32,
    /// Style for connecting segments of the stroke.
    pub join: Join,
    /// Limit for miter joins.
    pub miter_limit: f32,
    /// Style for capping the beginning of an open subpath.
    pub start_cap: Cap,
    /// Style for capping the end of an open subpath.
    pub end_cap: Cap,
    /// Lengths of dashes in alternating on/off order.
    pub dash_pattern: D,
    /// Offset of the first dash.
    pub dash_offset: f32,
    /// True if the stroke width should be affected by the scale of a
    /// transform.
    pub scale: bool,
}