use std::io::BufWriter;
use std::num::NonZeroU32;

use image::codecs::png::PngEncoder;
use image::io::Reader as ImageReader;
use image::{ColorType, ImageEncoder};

use fast_image_resize as fr;

fn main() {
    // Read source image from file
    let img = ImageReader::open("./data/nasa-4928x3279.png")
        .unwrap()
        .decode()
        .unwrap();
    let width = NonZeroU32::new(img.width()).unwrap();
    let height = NonZeroU32::new(img.height()).unwrap();
    let mut src_image = fr::Image::from_vec_u8(
        width,
        height,
        img.to_rgba8().into_raw(),
        fr::PixelType::U8x4,
    ).unwrap();

    // Multiple RGB channels of source image by alpha channel 
    // (not required for the Nearest algorithm)
    let alpha_mul_div = fr::MulDiv::default();
    alpha_mul_div
        .multiply_alpha_inplace(&mut src_image.view_mut())
        .unwrap();

    // Create container for data of destination image
    let dst_width = NonZeroU32::new(1024).unwrap();
    let dst_height = NonZeroU32::new(768).unwrap();
    let mut dst_image = fr::Image::new(
        dst_width,
        dst_height,
        src_image.pixel_type(),
    );

    // Get mutable view of destination image data
    let mut dst_view = dst_image.view_mut();

    // Create Resizer instance and resize source image
    // into buffer of destination image
    let mut resizer = fr::Resizer::new(
        fr::ResizeAlg::Convolution(fr::FilterType::Lanczos3),
    );
    resizer.resize(&src_image.view(), &mut dst_view).unwrap();

    // Divide RGB channels of destination image by alpha
    alpha_mul_div.divide_alpha_inplace(&mut dst_view).unwrap();

    // Write destination image as PNG-file
    let mut result_buf = BufWriter::new(Vec::new());
    PngEncoder::new(&mut result_buf)
        .write_image(
            dst_image.buffer(),
            dst_width.get(),
            dst_height.get(),
            ColorType::Rgba8,
        )
        .unwrap();
}

use std::num::NonZeroU32;

use image::codecs::png::PngEncoder;
use image::io::Reader as ImageReader;
use image::{ColorType, GenericImageView};

use fast_image_resize as fr;

fn resize_image_with_cropping(
    mut src_view: fr::DynamicImageView,
    dst_width: NonZeroU32,
    dst_height: NonZeroU32
) -> fr::Image {
    // Set cropping parameters
    src_view.set_crop_box_to_fit_dst_size(
        dst_width, 
        dst_height, 
        None,
    );

    // Create container for data of destination image
    let mut dst_image = fr::Image::new(
        dst_width,
        dst_height,
        src_view.pixel_type(),
    );
    // Get mutable view of destination image data
    let mut dst_view = dst_image.view_mut();

    // Create Resizer instance and resize source image
    // into buffer of destination image
    let mut resizer = fr::Resizer::new(
        fr::ResizeAlg::Convolution(fr::FilterType::Lanczos3)
    );
    resizer.resize(&src_view, &mut dst_view).unwrap();

    dst_image
}

fn main() {
    let img = ImageReader::open("./data/nasa-4928x3279.png")
        .unwrap()
        .decode()
        .unwrap();
    let width = NonZeroU32::new(img.width()).unwrap();
    let height = NonZeroU32::new(img.height()).unwrap();
    let src_image = fr::Image::from_vec_u8(
        width,
        height,
        img.to_rgba8().into_raw(),
        fr::PixelType::U8x4,
    ).unwrap();
    resize_image_with_cropping(
        src_image.view(),
        NonZeroU32::new(1024).unwrap(),
        NonZeroU32::new(768).unwrap(),
    );
}

use fast_image_resize as fr;

fn main() {
    let mut resizer = fr::Resizer::new(
        fr::ResizeAlg::Convolution(fr::FilterType::Lanczos3),
    );
    unsafe {
        resizer.set_cpu_extensions(fr::CpuExtensions::Sse4_1);
    }
}