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// Copyright 2025 Google LLC
// SPDX-License-Identifier: Apache-2.0
// 问题：实现一个 GUI API

// 问题：绘图 API 的最小有用行为是什么？
pub trait DrawApi {
    fn arc(&self, center: [f32; 2], radius: f32, start_angle: f32, end_angle: f32);
    fn line(&self, start: [f32; 2], end: [f32; 2]);
}

pub struct TextDraw;

impl DrawApi for TextDraw {
    fn arc(&self, center: [f32; 2], radius: f32, start_angle: f32, end_angle: f32) {
        println!("arc of radius ")
    }

    fn line(&self, start: [f32; 2], end: [f32; 2]) { /* ... */
    }
}

// 问题：对用户而言怎样的 API 更好？

pub trait Draw {
    fn draw<T: DrawApi>(&self, surface: &mut T);
}

pub struct Rect {
    start: [f32; 2],
    end: [f32; 2],
}

impl Draw for Rect {
    fn draw<T: DrawApi>(&self, surface: &mut T) {
        surface.line([self.start[0], self.start[1]], [self.end[0], self.start[1]]);
        surface.line([self.end[0], self.start[1]], [self.end[0], self.end[1]]);
        surface.line([self.end[0], self.end[1]], [self.start[0], self.end[1]]);
        surface.line([self.start[0], self.end[1]], [self.start[0], self.start[1]]);
    }
}