You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: main.rs
    path of file: ./repos/iced/examples/screenshot/src
    
    the code of the file until where you have to start completion: use iced::alignment;
use iced::executor;
use iced::keyboard;
use iced::widget::{button, column, container, image, row, text, text_input};
use iced::window;
use iced::window::screenshot::{self, Screenshot};
use iced::{
    Alignment, Application, Command, ContentFit, Element, Length, Rectangle,
    Subscription, Theme,
};

use ::image as img;
use ::image::ColorType;

fn main() -> iced::Result {
    tracing_subscriber::fmt::init();

    Example::run(iced::Settings::default())
}

struct Example {
    screenshot: Option<Screenshot>,
    saved_png_path: Option<Result<String, PngError>>,
    png_saving: bool,
    crop_error: Option<screenshot::CropError>,
    x_input_value: Option<u32>,
    y_input_value: Option<u32>,
    width_input_value: Option<u32>,
    height_input_value: Option<u32>,
}

#[derive(Clone, Debug)]
enum Message {
    Crop,
    Screenshot,
    ScreenshotData(Screenshot),
    Png,
    PngSaved(Result<String, PngError>),
    XInputChanged(Option<u32>),
    YInputChanged(Option<u32>),
    WidthInputChanged(Option<u32>),
    HeightInputChanged(Option<u32>),
}

impl Application fo
    
    fn view(&self) -> Element<'_, Self::Message> {
        let image: Element<Message> = if let Some(screenshot) = &self.screenshot
        {
            image(image::Handle::from_pixels(
                screenshot.size.width,
                screenshot.size.height,
                screenshot.clone(),
            ))
            .content_fit(ContentFit::Contain)
            .width(Length::Fill)
            .height(Length::Fill)
            .into()
        } else {
            text("Press the button to take a screenshot!").into()
        };

        let image = container(image)
            .padding(10)
            .style(container::rounded_box)
            .width(Length::FillPortion(2))
            .height(Length::Fill)
            .center_x()
            .center_y();

        let crop_origin_controls = row![
            text("X:")
                .vertical_alignment(alignment::Vertical::Center)
                .width(30),
            numeric_input("0", self.x_input_value).map(Message::XInputChanged),
            text("Y:")
                .vertical_alignment(alignment::Vertical::Center)
                .width(30),
            numeric_input("0", self.y_input_value).map(Message::YInputChanged)
        ]
        .spacing(10)
        .align_items(Alignment::Center);

        let crop_dimension_controls = row![
            text("W:")
                .vertical_alignment(alignment::Vertical::Center)
                .width(30),
            numeric_input("0", self.width_input_value)
                .map(Message::WidthInputChanged),
            text("H:")
                .vertical_alignment(alignment::Vertical::Center)
                .width(30),
            numeric_input("0", self.height_input_value)
                .map(Message::HeightInputChanged)
        ]
        .spacing(10)
        .align_items(Alignment::Center);

        let crop_controls =
            column![crop_origin_controls, crop_dimension_controls]
                .push_maybe(
                    self.crop_error
                        .as_ref()
                        .map(|error| text(format!("Crop error! \n{error}"))),
                )
                .spacing(10)
                .align_items(Alignment::Center);

        let controls = {
            let save_result =
                self.saved_png_path.as_ref().map(
                    |png_result| match png_result {
                        Ok(path) => format!("Png saved as: {path:?}!"),
                        Err(PngError(error)) => {
                            format!("Png could not be saved due to:\n{}", error)
                        }
                    },
                );

            column![
                column![
                    button(centered_text("Screenshot!"))
                        .padding([10, 20, 10, 20])
                        .width(Length::Fill)
                        .on_press(Message::Screenshot),
                    if !self.png_saving {
                        button(centered_text("Save as png")).on_press_maybe(
                            self.screenshot.is_some().then(|| Message::Png),
                        )
                    } else {
                        button(centered_text("Saving..."))
                            .style(button::secondary)
                    }
                    .style(button::secondary)
                    .padding([10, 20, 10, 20])
                    .width(Length::Fill)
                ]
                .spacing(10),
                column![
                    crop_controls,
                    button(centered_text("Crop"))
                        .on_press(Message::Crop)
                        .style(button::danger)
                        .padding([10, 20, 10, 20])
                        .width(Length::Fill),
                ]
                .spacing(10)
                .align_items(Alignment::Center),
            ]
            .push_maybe(save_result.map(text))
            .spacing(40)
        };

        let side_content = container(controls)
            .align_x(alignment::Horizontal::Center)
            .width(Length::FillPortion(1))
            .height(Length::Fill)
            .center_y()
            .center_x();

        let content = row![side_content, image]
            .spacing(10)
            .width(Length::Fill)
            .height(Length::Fill)
            .align_items(Alignment::Center);

        container(content)
            .width(Length::Fill)
            .height(Length::Fill)
            .padding(10)
            .center_x()
            .center_y()
            .into()
    }