blob: 8ed031906344f6e037e1c4491bf7b4909a9f94f3 (
plain)
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
|
use std::convert::TryFrom;
use super::{ColorTable, ImageDescriptor};
use crate::LZW;
pub struct IndexedImage {
pub image_descriptor: ImageDescriptor,
pub local_color_table: Option<ColorTable>,
pub indicies: Vec<u8>,
}
impl IndexedImage {
pub fn left(&self) -> u16 {
self.image_descriptor.left
}
pub fn top(&self) -> u16 {
self.image_descriptor.left
}
pub fn width(&self) -> u16 {
self.image_descriptor.width
}
pub fn height(&self) -> u16 {
self.image_descriptor.height
}
pub fn as_boxed_slice(&self, minimum_code_size: u8) -> Box<[u8]> {
let mut out = vec![];
let mut boxed: Box<[u8]> = (&self.image_descriptor).into();
out.extend_from_slice(&*boxed);
// Get the mcs while we write out the color table
let mut mcs = if let Some(lct) = &self.local_color_table {
boxed = lct.into();
out.extend_from_slice(&*boxed);
lct.packed_len()
} else {
minimum_code_size + 1
};
if mcs < 2 {
mcs = 2; // Must be true: 0 <= mcs <= 8
}
// First write out the MCS
out.push(mcs);
let compressed = LZW::encode(mcs, &self.indicies);
for chunk in compressed.chunks(255) {
out.push(chunk.len() as u8);
out.extend_from_slice(chunk);
}
// Data block length 0 to indicate an end
out.push(0x00);
out.into_boxed_slice()
}
}
pub struct CompressedImage {
pub image_descriptor: ImageDescriptor,
pub local_color_table: Option<ColorTable>,
pub lzw_minimum_code_size: u8,
pub blocks: Vec<Vec<u8>>,
}
|
