Function sort_palette

src/quant.rs:331–362

(attr: &Attributes, palette: &mut PalF)

}

fn sort_palette(attr: &Attributes, palette: &mut PalF) {
    let last_index_transparent = attr.last_index_transparent;

    let mut tmp: ArrayVec<_, { MAX_COLORS }> = palette.iter_mut().map(|(c, p)| (*c, *p)).collect();
    tmp.sort_by_key(|(color, pop)| {
        let is_transparent = color.a <= MAX_TRANSP_A;
        (is_transparent == last_index_transparent, Reverse(OrdFloat::new(pop.popularity())))
    });
    palette.iter_mut().zip(tmp).for_each(|((dcol, dpop), (scol, spop))| {
        *dcol = scol;
        *dpop = spop;
    });

    if last_index_transparent {
        let alpha_index = palette.as_slice().iter().enumerate()
            .filter(|(_, c)| c.a <= MAX_TRANSP_A)
            .min_by_key(|(_, c)| OrdFloat::new(c.a))
            .map(|(i, _)| i);
        if let Some(alpha_index) = alpha_index {
            let last_index = palette.as_slice().len() - 1;
            palette.swap(last_index, alpha_index);
        }
    } else {
        let num_transparent = palette.as_slice().iter().enumerate()
            .filter(|(_, c)| c.a <= MAX_TRANSP_A)
            .map(|(i, _)| i + 1) // num entries, not index
            .max();
        if let Some(num_transparent) = num_transparent {
            attr.verbose_print(format!("  eliminated opaque tRNS-chunk entries...{} entr{} transparent", num_transparent, if num_transparent == 1 { "y" } else { "ies" }));
        }
    }
}

impl fmt::Debug for QuantizationResult {
    #[cold]