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Implement alpha and luminosity palette sorting

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This commit is contained in:
Felix Hanau 2019-07-18 17:54:31 +01:00
parent 9408a50b1b
commit b302ae4246
1 changed files with 18 additions and 3 deletions
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21
src/reduction/mod.rs
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@ -61,9 +61,24 @@ pub fn reduced_palette(png: &PngImage) -> Option<PngImage> {
}
}
let mut used_enumerated : Vec<(usize, &bool)>= used.iter().enumerate().collect();
used_enumerated.sort_by(|a, b| {
//Sort by ascending alpha and descending luma.
let color_val = |palette : &Vec<rgb::RGBA<u8>>, i| {
let color = palette.get(i).cloned()
.unwrap_or_else(|| RGBA8::new(0, 0, 0, 255));
let mut result = (color.a as i32) << 18;
result -= (color.r as i32) * 299;
result -= (color.g as i32) * 587;
result -= (color.b as i32) * 114;
result
};
color_val(palette, a.0).cmp(&color_val(palette, b.0))
});
let mut next_index = 0u16;
let mut seen = HashMap::with_capacity(palette.len());
for (i, (used, palette_map)) in used.iter().cloned().zip(palette_map.iter_mut()).enumerate()
for (i, used) in used_enumerated.iter().cloned()
{
if !used {
continue;
@ -75,12 +90,12 @@ pub fn reduced_palette(png: &PngImage) -> Option<PngImage> {
.unwrap_or_else(|| RGBA8::new(0, 0, 0, 255));
match seen.entry(color) {
Vacant(new) => {
*palette_map = Some(next_index as u8);
palette_map[i] = Some(next_index as u8);
new.insert(next_index as u8);
next_index += 1;
}
Occupied(remap_to) => {
*palette_map = Some(*remap_to.get());
palette_map[i] = Some(*remap_to.get())
}
}
}