rectangle.rs

use raw_window_handle::{HasDisplayHandle, HasWindowHandle};
use softbuffer::Buffer;
use std::num::NonZeroU32;
use winit::event::{ElementState, Event, KeyEvent, WindowEvent};
use winit::event_loop::{ControlFlow, EventLoop};
use winit::keyboard::{Key, NamedKey};

#[path = "utils/winit_app.rs"]
mod winit_app;

fn redraw(buffer: &mut Buffer<'_, impl HasDisplayHandle, impl HasWindowHandle>, flag: bool) {
    let width = buffer.width();
    let height = buffer.height();
    for y in 0..height {
        for x in 0..width {
            let value = if flag && x >= 100 && x < width - 100 && y >= 100 && y < height - 100 {
                0x00ffffff
            } else {
                let red = (x & 0xff) ^ (y & 0xff);
                let green = (x & 0x7f) ^ (y & 0x7f);
                let blue = (x & 0x3f) ^ (y & 0x3f);
                (blue | (green << 8) | (red << 16)) as u32
            };
            buffer[y * width + x] = value;
        }
    }
}

fn main() {
    let event_loop = EventLoop::new().unwrap();

    let app = winit_app::WinitAppBuilder::with_init(
        |elwt| {
            let window = winit_app::make_window(elwt, |w| {
                w.with_title("Press space to show/hide a rectangle")
            });

            let context = softbuffer::Context::new(window.clone()).unwrap();

            let flag = false;

            (window, context, flag)
        },
        |_elwt, (window, context, _flag)| {
            softbuffer::Surface::new(context, window.clone()).unwrap()
        },
    )
    .with_event_handler(|state, surface, event, elwt| {
        let (window, _context, flag) = state;

        elwt.set_control_flow(ControlFlow::Wait);

        match event {
            Event::WindowEvent {
                window_id,
                event: WindowEvent::Resized(size),
            } if window_id == window.id() => {
                let Some(surface) = surface else {
                    eprintln!("Resized fired before Resumed or after Suspended");
                    return;
                };

                if let (Some(width), Some(height)) =
                    (NonZeroU32::new(size.width), NonZeroU32::new(size.height))
                {
                    // Resize surface
                    surface.resize(width, height).unwrap();
                }
            }
            Event::WindowEvent {
                window_id,
                event: WindowEvent::RedrawRequested,
            } if window_id == window.id() => {
                let Some(surface) = surface else {
                    eprintln!("RedrawRequested fired before Resumed or after Suspended");
                    return;
                };
                // Draw something in the window
                let mut buffer = surface.buffer_mut().unwrap();
                redraw(&mut buffer, *flag);
                buffer.present().unwrap();
            }

            Event::WindowEvent {
                event:
                    WindowEvent::CloseRequested
                    | WindowEvent::KeyboardInput {
                        event:
                            KeyEvent {
                                logical_key: Key::Named(NamedKey::Escape),
                                ..
                            },
                        ..
                    },
                window_id,
            } if window_id == window.id() => {
                elwt.exit();
            }

            Event::WindowEvent {
                event:
                    WindowEvent::KeyboardInput {
                        event:
                            KeyEvent {
                                state: ElementState::Pressed,
                                logical_key: Key::Named(NamedKey::Space),
                                ..
                            },
                        ..
                    },
                window_id,
            } if window_id == window.id() => {
                // Flip the rectangle flag and request a redraw to show the changed image
                *flag = !*flag;
                window.request_redraw();
            }

            _ => {}
        }
    });

    winit_app::run_app(event_loop, app);
}