sugarloaf 0.4.6

Sugarloaf is Rio rendering engine, designed to be multiplatform. It is based on WebGPU, Rust library for Desktops and WebAssembly for Web (JavaScript). This project is created and maintained for Rio terminal purposes but feel free to use it.
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// Copyright (c) 2023-present, Raphael Amorim.
//
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.

//! Powerline + Powerline Extra Symbols (geometric subset):
//! U+E0B0..=U+E0BF, U+E0D2, U+E0D4.
//!
//! We render the geometric glyphs (filled triangles, chevrons, rounded
//! caps, diagonals, trapezoid dividers) and leave the stylized ones
//! (flames, ice, etc.) to the font.

use super::box_drawing;
use super::canvas::Canvas;
use std::f32::consts::SQRT_2;
use tiny_skia::PathBuilder;

pub fn draw(cp: u32, canvas: &mut Canvas) -> bool {
    let w = canvas.width() as f32;
    let h = canvas.height() as f32;
    match cp {
        // Filled separator triangles.
        0xE0B0 => canvas.triangle(0.0, 0.0, w, h / 2.0, 0.0, h),
        0xE0B2 => canvas.triangle(w, 0.0, 0.0, h / 2.0, w, h),
        // Chevron (hollow) separators.
        0xE0B1 => chevron(canvas),
        0xE0B3 => {
            chevron(canvas);
            canvas.flip_horizontal();
        }
        // Rounded caps.
        0xE0B4 => rounded_cap_filled(canvas),
        0xE0B5 => rounded_cap_stroke(canvas),
        0xE0B6 => {
            rounded_cap_filled(canvas);
            canvas.flip_horizontal();
        }
        0xE0B7 => {
            rounded_cap_stroke(canvas);
            canvas.flip_horizontal();
        }
        // Half-cell slant triangles + their hollow diagonals.
        0xE0B8 => canvas.triangle(0.0, 0.0, w, h, 0.0, h),
        0xE0B9 => box_drawing::diagonal_ul_lr(canvas),
        0xE0BA => canvas.triangle(w, 0.0, w, h, 0.0, h),
        0xE0BB => box_drawing::diagonal_ur_ll(canvas),
        0xE0BC => canvas.triangle(0.0, 0.0, w, 0.0, 0.0, h),
        0xE0BD => box_drawing::diagonal_ur_ll(canvas),
        0xE0BE => canvas.triangle(0.0, 0.0, w, 0.0, w, h),
        0xE0BF => box_drawing::diagonal_ul_lr(canvas),
        // Trapezoid dividers.
        0xE0D2 => trapezoids(canvas),
        0xE0D4 => {
            trapezoids(canvas);
            canvas.flip_horizontal();
        }
        _ => return false,
    }
    true
}

fn chevron(canvas: &mut Canvas) {
    let w = canvas.width() as f32;
    let h = canvas.height() as f32;
    let thick = box_drawing::box_thickness(canvas.height()) as f32;
    let mut pb = PathBuilder::new();
    pb.move_to(0.0, 0.0);
    pb.line_to(w, h / 2.0);
    pb.line_to(0.0, h);
    if let Some(path) = pb.finish() {
        canvas.stroke(&path, thick);
    }
}

/// Cubic control-point coefficient for approximating a circular quarter arc.
const ARC_C: f32 = (SQRT_2 - 1.0) * 4.0 / 3.0;

fn rounded_cap_path(canvas: &Canvas, close: bool) -> Option<tiny_skia::Path> {
    let w = canvas.width() as f32;
    let h = canvas.height() as f32;
    let r = w.min(h / 2.0);
    let mut pb = PathBuilder::new();
    pb.move_to(0.0, 0.0);
    pb.cubic_to(r * ARC_C, 0.0, r, r - r * ARC_C, r, r);
    pb.line_to(r, h - r);
    pb.cubic_to(r, h - r + r * ARC_C, r * ARC_C, h, 0.0, h);
    if close {
        pb.close();
    }
    pb.finish()
}

fn rounded_cap_filled(canvas: &mut Canvas) {
    if let Some(path) = rounded_cap_path(canvas, true) {
        canvas.fill_path(&path);
    }
}

fn rounded_cap_stroke(canvas: &mut Canvas) {
    let thick = box_drawing::box_thickness(canvas.height()) as f32;
    if let Some(path) = rounded_cap_path(canvas, false) {
        canvas.stroke(&path, thick);
    }
}

fn trapezoids(canvas: &mut Canvas) {
    let w = canvas.width() as f32;
    let h = canvas.height() as f32;
    let t = box_drawing::box_thickness(canvas.height()) as f32;

    // Top piece.
    let mut pb = PathBuilder::new();
    pb.move_to(0.0, 0.0);
    pb.line_to(w, 0.0);
    pb.line_to(w / 2.0, h / 2.0 - t / 2.0);
    pb.line_to(0.0, h / 2.0 - t / 2.0);
    pb.close();
    if let Some(path) = pb.finish() {
        canvas.fill_path(&path);
    }

    // Bottom piece.
    let mut pb = PathBuilder::new();
    pb.move_to(0.0, h);
    pb.line_to(w, h);
    pb.line_to(w / 2.0, h / 2.0 + t / 2.0);
    pb.line_to(0.0, h / 2.0 + t / 2.0);
    pb.close();
    if let Some(path) = pb.finish() {
        canvas.fill_path(&path);
    }
}