imgui-rs/imgui-examples/examples/support/mod.rs

use imgui::{FontGlyphRange, FrameSize, ImFontConfig, ImGui, ImGuiMouseCursor, Ui};
use std::time::Instant;

#[derive(Copy, Clone, PartialEq, Debug, Default)]
struct MouseState {
    pos: (i32, i32),
    pressed: (bool, bool, bool),
    wheel: f32,
}

pub fn run<F: FnMut(&Ui) -> bool>(title: String, clear_color: [f32; 4], mut run_ui: F) {
    use glium::glutin;
    use glium::{Display, Surface};
    use imgui_glium_renderer::Renderer;

    let mut events_loop = glutin::EventsLoop::new();
    let context = glutin::ContextBuilder::new().with_vsync(true);
    let builder = glutin::WindowBuilder::new()
        .with_title(title)
        .with_dimensions(glutin::dpi::LogicalSize::new(1024f64, 768f64));
    let display = Display::new(builder, context, &events_loop).unwrap();
    let window = display.gl_window();

    let mut imgui = ImGui::init();
    imgui.set_ini_filename(None);

    let hidpi_factor = window.get_hidpi_factor();

    let font_oversample = hidpi_factor.ceil() as u32;
    let font_size = (13.0 * hidpi_factor) as f32;

    imgui.fonts().add_font_with_config(
        include_bytes!("../mplus-1p-regular.ttf"),
        ImFontConfig::new()
            .oversample_h(font_oversample)
            .oversample_v(font_oversample)
            .pixel_snap_h(true)
            .size_pixels(font_size)
            .rasterizer_multiply(1.75),
        &FontGlyphRange::japanese(),
    );

    imgui.fonts().add_default_font_with_config(
        ImFontConfig::new()
            .merge_mode(true)
            .oversample_h(font_oversample)
            .oversample_v(font_oversample)
            .pixel_snap_h(true)
            .size_pixels(font_size),
    );

    imgui.set_font_global_scale((1.0 / hidpi_factor) as f32);

    let mut renderer = Renderer::init(&mut imgui, &display).expect("Failed to initialize renderer");

    configure_keys(&mut imgui);

    let mut last_frame = Instant::now();
    let mut mouse_state = MouseState::default();
    let mut quit = false;

    loop {
        events_loop.poll_events(|event| {
            use glium::glutin::ElementState::Pressed;
            use glium::glutin::WindowEvent::*;
            use glium::glutin::{Event, MouseButton, MouseScrollDelta, TouchPhase};

            if let Event::WindowEvent { event, .. } = event {
                match event {
                    CloseRequested => quit = true,
                    KeyboardInput { input, .. } => {
                        use glium::glutin::VirtualKeyCode as Key;

                        let pressed = input.state == Pressed;
                        match input.virtual_keycode {
                            Some(Key::Tab) => imgui.set_key(0, pressed),
                            Some(Key::Left) => imgui.set_key(1, pressed),
                            Some(Key::Right) => imgui.set_key(2, pressed),
                            Some(Key::Up) => imgui.set_key(3, pressed),
                            Some(Key::Down) => imgui.set_key(4, pressed),
                            Some(Key::PageUp) => imgui.set_key(5, pressed),
                            Some(Key::PageDown) => imgui.set_key(6, pressed),
                            Some(Key::Home) => imgui.set_key(7, pressed),
                            Some(Key::End) => imgui.set_key(8, pressed),
                            Some(Key::Delete) => imgui.set_key(9, pressed),
                            Some(Key::Back) => imgui.set_key(10, pressed),
                            Some(Key::Return) => imgui.set_key(11, pressed),
                            Some(Key::Escape) => imgui.set_key(12, pressed),
                            Some(Key::A) => imgui.set_key(13, pressed),
                            Some(Key::C) => imgui.set_key(14, pressed),
                            Some(Key::V) => imgui.set_key(15, pressed),
                            Some(Key::X) => imgui.set_key(16, pressed),
                            Some(Key::Y) => imgui.set_key(17, pressed),
                            Some(Key::Z) => imgui.set_key(18, pressed),
                            Some(Key::LControl) | Some(Key::RControl) => {
                                imgui.set_key_ctrl(pressed)
                            }
                            Some(Key::LShift) | Some(Key::RShift) => imgui.set_key_shift(pressed),
                            Some(Key::LAlt) | Some(Key::RAlt) => imgui.set_key_alt(pressed),
                            Some(Key::LWin) | Some(Key::RWin) => imgui.set_key_super(pressed),
                            _ => {}
                        }
                    }
                    CursorMoved { position: pos, .. } => mouse_state.pos = pos.into(),
                    MouseInput { state, button, .. } => match button {
                        MouseButton::Left => mouse_state.pressed.0 = state == Pressed,
                        MouseButton::Right => mouse_state.pressed.1 = state == Pressed,
                        MouseButton::Middle => mouse_state.pressed.2 = state == Pressed,
                        _ => {}
                    },
                    MouseWheel {
                        delta: MouseScrollDelta::LineDelta(_, y),
                        phase: TouchPhase::Moved,
                        ..
                    } => mouse_state.wheel = y,
                    MouseWheel {
                        delta: MouseScrollDelta::PixelDelta(pos),
                        phase: TouchPhase::Moved,
                        ..
                    } => mouse_state.wheel = pos.y as f32,
                    ReceivedCharacter(c) => imgui.add_input_character(c),
                    _ => (),
                }
            }
        });

        let now = Instant::now();
        let delta = now - last_frame;
        let delta_s = delta.as_secs() as f32 + delta.subsec_nanos() as f32 / 1_000_000_000.0;
        last_frame = now;

        update_mouse(&mut imgui, &mut mouse_state);

        let mouse_cursor = imgui.mouse_cursor();
        if imgui.mouse_draw_cursor() || mouse_cursor == ImGuiMouseCursor::None {
            // Hide OS cursor
            window.hide_cursor(true);
        } else {
            // Set OS cursor
            window.hide_cursor(false);
            window.set_cursor(match mouse_cursor {
                ImGuiMouseCursor::None => unreachable!("mouse_cursor was None!"),
                ImGuiMouseCursor::Arrow => glutin::MouseCursor::Arrow,
                ImGuiMouseCursor::TextInput => glutin::MouseCursor::Text,
                ImGuiMouseCursor::Move => glutin::MouseCursor::Move,
                ImGuiMouseCursor::ResizeNS => glutin::MouseCursor::NsResize,
                ImGuiMouseCursor::ResizeEW => glutin::MouseCursor::EwResize,
                ImGuiMouseCursor::ResizeNESW => glutin::MouseCursor::NeswResize,
                ImGuiMouseCursor::ResizeNWSE => glutin::MouseCursor::NwseResize,
            });
        }

        let logical_size = window.get_inner_size().unwrap();

        let frame_size = FrameSize {
            logical_size: logical_size.into(),
            hidpi_factor: window.get_hidpi_factor(),
        };

        let ui = imgui.frame(frame_size, delta_s);
        if !run_ui(&ui) {
            break;
        }

        let mut target = display.draw();
        target.clear_color(
            clear_color[0],
            clear_color[1],
            clear_color[2],
            clear_color[3],
        );
        renderer.render(&mut target, ui).expect("Rendering failed");
        target.finish().unwrap();

        if quit {
            break;
        }
    }
}

fn configure_keys(imgui: &mut ImGui) {
    use imgui::ImGuiKey;

    imgui.set_imgui_key(ImGuiKey::Tab, 0);
    imgui.set_imgui_key(ImGuiKey::LeftArrow, 1);
    imgui.set_imgui_key(ImGuiKey::RightArrow, 2);
    imgui.set_imgui_key(ImGuiKey::UpArrow, 3);
    imgui.set_imgui_key(ImGuiKey::DownArrow, 4);
    imgui.set_imgui_key(ImGuiKey::PageUp, 5);
    imgui.set_imgui_key(ImGuiKey::PageDown, 6);
    imgui.set_imgui_key(ImGuiKey::Home, 7);
    imgui.set_imgui_key(ImGuiKey::End, 8);
    imgui.set_imgui_key(ImGuiKey::Delete, 9);
    imgui.set_imgui_key(ImGuiKey::Backspace, 10);
    imgui.set_imgui_key(ImGuiKey::Enter, 11);
    imgui.set_imgui_key(ImGuiKey::Escape, 12);
    imgui.set_imgui_key(ImGuiKey::A, 13);
    imgui.set_imgui_key(ImGuiKey::C, 14);
    imgui.set_imgui_key(ImGuiKey::V, 15);
    imgui.set_imgui_key(ImGuiKey::X, 16);
    imgui.set_imgui_key(ImGuiKey::Y, 17);
    imgui.set_imgui_key(ImGuiKey::Z, 18);
}

fn update_mouse(imgui: &mut ImGui, mouse_state: &mut MouseState) {
    imgui.set_mouse_pos(mouse_state.pos.0 as f32, mouse_state.pos.1 as f32);
    imgui.set_mouse_down([
        mouse_state.pressed.0,
        mouse_state.pressed.1,
        mouse_state.pressed.2,
        false,
        false,
    ]);
    imgui.set_mouse_wheel(mouse_state.wheel);
    mouse_state.wheel = 0.0;
}