fn unfilter(
    out: &mut [u8],
    inp: &[u8],
    w: u32,
    h: u32,
    bpp: u32,
) -> Result<(), Error> {
    use std::convert::TryInto;

    let mut prevline = None;

    /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
    let bytewidth = (bpp as usize + 7) / 8;
    let linebytes = (w as usize * bpp as usize + 7) / 8;
    let in_linebytes = 1 + linebytes; /*the extra filterbyte added to each row*/

    for (out_line, in_line) in out
        .chunks_mut(linebytes)
        .zip(inp.chunks(in_linebytes))
        .take(h as usize)
    {
        let filter_type = in_line[0];
        unfilter_scanline(
            out_line,
            &in_line[1..],
            prevline,
            bytewidth,
            filter_type,
            linebytes,
        )?;
        prevline = Some(out_line);
    }
    Ok(())
}
/*
For PNG filter method 0
this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times)
out must have enough bytes allocated already, in must have the scanlines + 1 filter_type byte per scanline
w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel
in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes)
*/
For PNG filter method 0
this function unfilters a single image
out must have enough bytes allocated already, in must have the scanlines + 1 filter_type byte per scanline
w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel
in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes)
For PNG filter method 0 this function unfilters a single image out must have enough bytes allocated already in must have the scanlines + 1 filter_type byte per scanline w and h are image dimensions or dimensions of reduced image bpp is bits per pixel in and out are allowed to be the same memory address ( but aren ' t the same size since in has the extra filter bytes )
fn unfilter(
    out: &mut [u8],
    inp: &[u8],
    w: u32,
    h: u32,
    bpp: u32,
) -> Result<(), Error> {
    use std::convert::TryInto;
    let mut prevline = None;
    /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
    let bytewidth = (bpp as usize + 7) / 8;
    let linebytes = (w as usize * bpp as usize + 7) / 8;
    let in_linebytes = 1 + linebytes; /*the extra filterbyte added to each row*/
    for (out_line, in_line) in out
        .chunks_mut(linebytes)
        .zip(inp.chunks(in_linebytes))
        .take(h as usize)
    {
        let filter_type = in_line[0];
        unfilter_scanline(
            out_line,
            &in_line[1..],
            prevline,
            bytewidth,
            filter_type,
            linebytes,
        )?;
        prevline = Some(out_line);
    }
    Ok(())
}
fn unfilter ( out : & mut [ u8 ] , inp : & [ u8 ] , w : u32 , h : u32 , bpp : u32 , ) -> Result < ( ) , Error > { use std :: convert :: TryInto ; let mut prevline = None ; /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/ let bytewidth = ( bpp as usize + 7 ) / 8 ; let linebytes = ( w as usize * bpp as usize + 7 ) / 8 ; let in_linebytes = 1 + linebytes ; /*the extra filterbyte added to each row*/ for ( out_line , in_line ) in out . chunks_mut ( linebytes ) . zip ( inp . chunks ( in_linebytes ) ) . take ( h as usize ) { let filter_type = in_line [ 0 ] ; unfilter_scanline ( out_line , & in_line [ 1 .. ] , prevline , bytewidth , filter_type , linebytes , ) ? ; prevline = Some ( out_line ) ; } Ok ( ( ) ) }
For PNG filter method 0
this function unfilters a single image (e.g.
For PNG filter method 0 this function unfilters a single image ( e . g .
out
&mut [u8]
inp
&[u8]
w
u32
h
u32
bpp
u32