1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
pub use crate::Color;
use crate::EncodingError;
use std::{
convert::{TryFrom, TryInto},
ops::Deref,
};
#[derive(Clone, Debug)]
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);
}
pub fn get(&self, index: u8) -> Option<Color> {
self.table.get(index as usize).map(|v| v.clone())
}
pub fn from_color(&self, color: Color) -> Option<u8> {
for (i, &c) in self.table.iter().enumerate() {
if c == color {
return Some(i as u8);
}
}
None
}
}
impl Deref for ColorTable {
type Target = [Color];
fn deref(&self) -> &Self::Target {
&self.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>>(),
})
}
}
}
impl TryFrom<Vec<Color>> for ColorTable {
type Error = EncodingError;
fn try_from(value: Vec<Color>) -> Result<Self, Self::Error> {
if value.len() > 256 {
Err(EncodingError::TooManyColors)
} else {
Ok(Self { table: value })
}
}
}
impl TryFrom<Vec<(u8, u8, u8)>> for ColorTable {
type Error = EncodingError;
fn try_from(value: Vec<(u8, u8, u8)>) -> Result<Self, Self::Error> {
if value.len() > 256 {
Err(EncodingError::TooManyColors)
} else {
Ok(Self {
table: value.into_iter().map(|c| c.into()).collect(),
})
}
}
}
|
