Method optionally_generate_dither_map

src/quant.rs:119–131

(use_dither_map: DitherMapMode, image: &mut Image<'_>, uses_background: bool, output_pixels: &mut RowBitmapMut<'_, MaybeUninit<PalIndexRemap>>, palette: &mut PalF)

    }

    fn optionally_generate_dither_map(use_dither_map: DitherMapMode, image: &mut Image<'_>, uses_background: bool, output_pixels: &mut RowBitmapMut<'_, MaybeUninit<PalIndexRemap>>, palette: &mut PalF) -> Result<Option<f64>, Error> {
        let is_image_huge = (image.px.width * image.px.height) > 2000 * 2000;
        let allow_dither_map = use_dither_map == DitherMapMode::Always || (!is_image_huge && use_dither_map != DitherMapMode::None);
        let generate_dither_map = allow_dither_map && image.dither_map.is_none();
        if !generate_dither_map {
            return Ok(None);
        }

        // If dithering (with dither map) is required, this image is used to find areas that require dithering
        let (palette_error, row_pointers_remapped) = remap_to_palette(&mut image.px, None, image.importance_map.as_deref(), output_pixels, palette)?;
        image.update_dither_map(&row_pointers_remapped, &*palette, uses_background)?;
        Ok(Some(palette_error))
    }

    /// Set to 1.0 to get nice smooth image
    pub fn set_dithering_level(&mut self, value: f32) -> Result<(), Error> {