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|
pub use crate::Color;
use std::{
convert::{TryFrom, TryInto},
ops::Deref,
};
pub struct ColorTable {
table: Vec<Color>,
}
impl ColorTable {
pub fn new() -> Self {
Self { table: vec![] }
}
/// Returns the number of colors in the color table as used by the packed
/// fields in the Logical Screen Descriptor and Image Descriptor. You can
/// get the actual size with the [`len`](struct.ColorTable.html#method.len) method.
pub fn packed_len(&self) -> u8 {
((self.table.len() as f32).log2().ceil() - 1f32) as u8
}
/// Returns the number of items in the table
pub fn len(&self) -> usize {
self.table.len()
}
/// Pushes a color on to the end of the table
pub fn push(&mut self, color: Color) {
self.table.push(color);
}
}
impl Deref for ColorTable {
type Target = [Color];
fn deref(&self) -> &Self::Target {
&self.table
}
}
impl From<Vec<Color>> for ColorTable {
fn from(table: Vec<Color>) -> Self {
ColorTable { table }
}
}
impl From<&ColorTable> for Box<[u8]> {
fn from(table: &ColorTable) -> Self {
let mut vec = vec![];
for color in table.iter() {
vec.extend_from_slice(&[color.r, color.g, color.b]);
}
let packed_len = 2usize.pow(table.packed_len() as u32 + 1);
let padding = (packed_len as usize - table.len()) * 3;
if padding > 0 {
vec.extend_from_slice(&vec![0; padding]);
}
vec.into_boxed_slice()
}
}
//TODO: TryFrom Vec<u8> (must be multiple of 3 len) and From Vec<Color>
impl TryFrom<&[u8]> for ColorTable {
type Error = ();
fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
if value.len() % 3 != 0 {
return Err(());
} else {
Ok(Self {
table: value
.chunks(3)
.map(|slice| Color::from(TryInto::<[u8; 3]>::try_into(slice).unwrap()))
.collect::<Vec<Color>>(),
})
}
}
}
|
