fn vertical_par_sample(image: RgbaImage, new_height: u32, filter: &mut Filter) -> Rgba32FImage {
    let (width, height) = image.dimensions();

    let ratio = height as f32 / new_height as f32;
    let sratio = if ratio < 1.0 { 1.0 } else { ratio };
    let src_support = filter.support * sratio;

    let mut out = ImageBuffer::new(width, new_height);

    out.chunks_exact_mut(width as usize * 4)
        .enumerate()
        .par_bridge()
        .for_each(|(outy, outrow)| {
            // For an explanation of this algorithm, see the comments
            // in horizontal_sample.
            let inputy = (outy as f32 + 0.5) * ratio;

            let left = (inputy - src_support).floor() as i64;
            let left = clamp(left, 0, <i64 as From<_>>::from(height) - 1) as u32;

            let right = (inputy + src_support).ceil() as i64;
            let right = clamp(
                right,
                <i64 as From<_>>::from(left) + 1,
                <i64 as From<_>>::from(height),
            ) as u32;

            let inputy = inputy - 0.5;
            let mut ws = Vec::with_capacity((right - left) as usize);

            let mut sum = 0.0;
            for i in left..right {
                let w = (filter.kernel)((i as f32 - inputy) / sratio);
                ws.push(w);
                sum += w;
            }
            ws.iter_mut().for_each(|w| *w /= sum);

            outrow
                .chunks_exact_mut(4)
                .enumerate()
                .for_each(|(x, chunk)| {
                    let mut t = (0.0, 0.0, 0.0, 0.0);


                    for (i, w) in ws.iter().enumerate() {
                        let p = image.get_pixel(x as u32, left + i as u32);

                        #[allow(deprecated)]
                        let vec = p.channels4();

                        t.0 += SRGB_LUT[vec.0 as usize] * w;
                        t.1 += SRGB_LUT[vec.1 as usize] * w;
                        t.2 += SRGB_LUT[vec.2 as usize] * w;
                        t.3 += <f32 as NumCast>::from(vec.3).unwrap() * w;
                    }


                    chunk[0] = t.0;
                    chunk[1] = t.1;
                    chunk[2] = t.2;
                    chunk[3] = t.3;
                });
        });

    out
}
// Sample the columns of the supplied image using the provided filter.
// The width of the image remains unchanged.
// ```new_height``` is the desired height of the new image
// ```filter``` is the filter to use for sampling.
// The return value is not necessarily Rgba, the underlying order of channels in ```image``` is
// preserved.
Sample the columns of the supplied image using the provided filter.
The width of the image remains unchanged.
Sample the columns of the supplied image using the provided filter . The width of the image remains unchanged .
fn vertical_par_sample(image: RgbaImage, new_height: u32, filter: &mut Filter) -> Rgba32FImage {
    let (width, height) = image.dimensions();
    let ratio = height as f32 / new_height as f32;
    let sratio = if ratio < 1.0 { 1.0 } else { ratio };
    let src_support = filter.support * sratio;
    let mut out = ImageBuffer::new(width, new_height);
    out.chunks_exact_mut(width as usize * 4)
        .enumerate()
        .par_bridge()
        .for_each(|(outy, outrow)| {
            // For an explanation of this algorithm, see the comments
            // in horizontal_sample.
            let inputy = (outy as f32 + 0.5) * ratio;
            let left = (inputy - src_support).floor() as i64;
            let left = clamp(left, 0, <i64 as From<_>>::from(height) - 1) as u32;
            let right = (inputy + src_support).ceil() as i64;
            let right = clamp(
                right,
                <i64 as From<_>>::from(left) + 1,
                <i64 as From<_>>::from(height),
            ) as u32;
            let inputy = inputy - 0.5;
            let mut ws = Vec::with_capacity((right - left) as usize);
            let mut sum = 0.0;
            for i in left..right {
                let w = (filter.kernel)((i as f32 - inputy) / sratio);
                ws.push(w);
                sum += w;
            }
            ws.iter_mut().for_each(|w| *w /= sum);
            outrow
                .chunks_exact_mut(4)
                .enumerate()
                .for_each(|(x, chunk)| {
                    let mut t = (0.0, 0.0, 0.0, 0.0);
                    for (i, w) in ws.iter().enumerate() {
                        let p = image.get_pixel(x as u32, left + i as u32);
                        #[allow(deprecated)]
                        let vec = p.channels4();
                        t.0 += SRGB_LUT[vec.0 as usize] * w;
                        t.1 += SRGB_LUT[vec.1 as usize] * w;
                        t.2 += SRGB_LUT[vec.2 as usize] * w;
                        t.3 += <f32 as NumCast>::from(vec.3).unwrap() * w;
                    }
                    chunk[0] = t.0;
                    chunk[1] = t.1;
                    chunk[2] = t.2;
                    chunk[3] = t.3;
                });
        });
    out
}
fn vertical_par_sample ( image : RgbaImage , new_height : u32 , filter : & mut Filter ) -> Rgba32FImage { let ( width , height ) = image . dimensions ( ) ; let ratio = height as f32 / new_height as f32 ; let sratio = if ratio < 1.0 { 1.0 } else { ratio } ; let src_support = filter . support * sratio ; let mut out = ImageBuffer :: new ( width , new_height ) ; out . chunks_exact_mut ( width as usize * 4 ) . enumerate ( ) . par_bridge ( ) . for_each ( | ( outy , outrow ) | { // For an explanation of this algorithm, see the comments // in horizontal_sample. let inputy = ( outy as f32 + 0.5 ) * ratio ; let left = ( inputy - src_support ) . floor ( ) as i64 ; let left = clamp ( left , 0 , < i64 as From < _ > > :: from ( height ) - 1 ) as u32 ; let right = ( inputy + src_support ) . ceil ( ) as i64 ; let right = clamp ( right , < i64 as From < _ > > :: from ( left ) + 1 , < i64 as From < _ > > :: from ( height ) , ) as u32 ; let inputy = inputy - 0.5 ; let mut ws = Vec :: with_capacity ( ( right - left ) as usize ) ; let mut sum = 0.0 ; for i in left .. right { let w = ( filter . kernel ) ( ( i as f32 - inputy ) / sratio ) ; ws . push ( w ) ; sum += w ; } ws . iter_mut ( ) . for_each ( | w | * w /= sum ) ; outrow . chunks_exact_mut ( 4 ) . enumerate ( ) . for_each ( | ( x , chunk ) | { let mut t = ( 0.0 , 0.0 , 0.0 , 0.0 ) ; for ( i , w ) in ws . iter ( ) . enumerate ( ) { let p = image . get_pixel ( x as u32 , left + i as u32 ) ; # [ allow ( deprecated ) ] let vec = p . channels4 ( ) ; t . 0 += SRGB_LUT [ vec . 0 as usize ] * w ; t . 1 += SRGB_LUT [ vec . 1 as usize ] * w ; t . 2 += SRGB_LUT [ vec . 2 as usize ] * w ; t . 3 += < f32 as NumCast > :: from ( vec . 3 ) . unwrap ( ) * w ; } chunk [ 0 ] = t . 0 ; chunk [ 1 ] = t . 1 ; chunk [ 2 ] = t . 2 ; chunk [ 3 ] = t . 3 ; } ) ; } ) ; out }
Sample the columns of the supplied image using the provided filter.
Sample the columns of the supplied image using the provided filter .
image
RgbaImage
new_height
u32
filter
&mut Filter
image
RgbaImage
new_height
u32
filter
&mut Filter