qoi-img/src/lib.rs
2024-11-13 22:33:10 +01:00

829 lines
28 KiB
Rust

//! # qoi_img
//! `qoi_img` is a bad, from-scratch implementation of the decoder and encoder for the `.qoi` file format as described as on [qoiformat.org](https://qoiformat.org/qoi-specification.pdf).
//! This crate should not be published as better crates are available, e.g. [rapid-qoi](https://crates.io/crates/rapid-qoi).
#![allow(dead_code, unused_variables)]
pub mod qoi_img {
use std::fmt;
use std::io::prelude::*;
use std::fs::File;
use log::{debug,info, Level, Record, SetLoggerError, LevelFilter};
use array_init;
//Custom error for custom error handling
#[derive(Debug, Clone, PartialEq)]
pub enum ImgError {
DataError,
PixelNumberError,
DecodeError,
HeaderError,
}
//inherit from base Error
impl std::error::Error for ImgError {}
//Output for error handling
impl fmt::Display for ImgError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
ImgError::DataError => write!(f, "invalid number of bytes (must be devisible by 4)"),
ImgError::PixelNumberError => write!(f, "number of pixels does not match height and width params"),
ImgError::DecodeError => write!(f, "decoder failed to construct valid image"),
ImgError::HeaderError => write!(f, "not a valid QOI file header")
}
}
}
//boilerplate implementation of the log crate
struct SimpleLogger;
impl log::Log for SimpleLogger {
fn enabled(&self, metadata: &log::Metadata) -> bool {
metadata.level() <= Level::Debug
}
fn log(&self, record: &Record) {
if self.enabled(record.metadata()) {
eprintln!("{} - {}", record.level(), record.args());
}
}
fn flush(&self) {
}
}
//logging boilerplate
static LOGGER: SimpleLogger = SimpleLogger;
/// Initialises the logger provided by [log](https://crates.io/crates/log)
/// # Example
///
/// ```
/// # use std::error::Error;
/// # use crate::qoi_test::qoi_img::*;
/// # fn main() -> Result<(), Box<ImgError>> {
/// init().expect("Failed to initialize logger");
/// #
/// # Ok(())
/// #
/// # }
/// ```
///
/// If you want to pass the error on replace the `println!`:
///
/// ```
/// # use std::error::Error;
/// # use crate::qoi_test::qoi_img::*;
/// # fn main() -> Result<(), ImgError> {
/// match init() {
/// Ok(()) => (),
/// Err(e) => println!("Logger failed to initialize!")
/// }
/// #
/// # Ok(())
/// #
/// # }
/// ```
pub fn init() -> Result<(), SetLoggerError>{
log::set_logger(&LOGGER).map(|()| log::set_max_level(LevelFilter::Debug))
}
/// Custom image struct, which is used to store decoded data. Used by [encode_from_image] to encode the necessary data in bytes. Requires a Vector over [Pixel] values, `Vec<Pixel>`,
/// which can be generated by [`self::new`] if given byte data. Otherwise, [self.pixels] must be given filled vector.
/// `height` and `width` are given as u32 (note that qoi encoding does not guarantee functionality for images containing over 4000000 pixels.)
/// `channels` specifies the number of channels 3 (RGB) or 4 (RBGA).
/// `colorspace` specifies whether sRGB or all linear channels are used (0,1);
/// # Examples
/// Create a new image via constructor [`Image::new()`];
/// ```rust
/// # use std::error::Error;
/// # use crate::qoi_test::qoi_img::*;
/// # fn main() -> Result<(), Box<ImgError>> {
///
/// let pixels: Vec<u8> = vec![0;1024*1024*4];
/// let height: u32 = 1024;
/// let width: u32 = 1024;
/// let channels: u8 = 4;
/// let colorspace: u8 = 0;
/// let img: Image = Image::new(pixels, height, width, channels, colorspace)?;
/// #
/// # Ok(())
/// # }
/// ```
///
/// Alternatively, [`Image::from_pixels()`] can be used to create an image from pixel values.
pub struct Image {
pixels: Vec<Pixel>,
height: u32,
width: u32,
channels: u8,
colorspace: u8,
}
impl Image {
//Image constructor, expects an array of u8 pixels values in order, left to right, top to bottom.
pub fn new(data: Vec<u8>, height: u32, width: u32, channels: u8, colorspace: u8,) -> Result<Image, ImgError> {
let pixels: Vec<Pixel> = match Image::pixels_from_bytes(data) {
Ok(out) => out,
Err(error) => return Err(error),
};
if pixels.len() == (height * width) as usize {
let out: Image = Image {
pixels,
height,
width,
channels,
colorspace,
};
Ok(out)
} else {
Err(ImgError::PixelNumberError)
}
}
pub fn from_pixels(pixels: Vec<Pixel>, height: u32, width: u32, channels: u8, colorspace: u8) -> Image {
let img = Image {
pixels,
height,
width,
channels,
colorspace
};
img
}
fn pixels_from_bytes(data: Vec<u8>) -> Result<Vec<Pixel>, ImgError> {
let mut pixels: Vec<Pixel> = Vec::with_capacity(data.len()/4);
if data.len() % 4 == 0 {
for i in 0..data.len()/4 {
pixels.push(Pixel {
r: data[i*4],
g: data[i*4+1],
b: data[i*4+2],
a: data[i*4+3],
});
}
Ok(pixels)
} else {
Err(ImgError::DataError)
}
}
}
#[derive(Clone,Copy,Debug, PartialEq)]
pub struct Pixel {
r: u8,
g: u8,
b: u8,
a: u8,
}
#[derive(Debug, PartialEq)]
pub enum ChunkType {
Run,
Index,
Luma,
Diff,
RGB,
RGBA
}
impl Pixel {
pub fn new(r: u8, g: u8, b: u8, a: u8) -> Pixel {
Pixel {
r,
g,
b,
a,
}
}
fn equals(&self, other: &Pixel) -> bool {
if (self.r == other.r) && (self.g == other.g) && (self.b == other.b) && (self.a == other.a) {
true
} else {
false
}
}
fn equals_rgb(&self, other: &Pixel) -> bool {
if (self.r == other.r) && (self.g == other.g) && (self.b == other.b) {
true
} else {
false
}
}
//self = curr pixel, other = prev pixel
pub fn determine_chunk(&self, other: &Pixel, buffer: &Vec<Pixel>) -> (ChunkType, Option<(u8,u8,u8)>){
if self.equals(&other) {
return (ChunkType::Run, None);
}
if self.equals(&buffer[color_hash(&self) as usize]) {
return (ChunkType::Index,Some((color_hash(&self), 0,0 )));
}
if self.a != other.a {
return (ChunkType::RGBA, None);
}
let diff_tuple: (i16,i16,i16) = self.diff(other);
let dr: i16 = diff_tuple.0;
let dg: i16 = diff_tuple.1;
let db: i16 = diff_tuple.2;
if (dr > -3 && dr < 2) && (dg > -3 && dg < 2) && (db > -3 && db < 2) {
let dr: u8 = (dr + DIFF_BIAS as i16) as u8;
let dg: u8 = (dg + DIFF_BIAS as i16) as u8;
let db: u8 = (db + DIFF_BIAS as i16) as u8;
return (ChunkType::Diff, Some((dr, dg, db)));
} else if (dg > -33 && dg < 32) && ((dr - dg) > -9) && ((dr - dg) < 8) && ((db - dg) > -9) && ((db - dg) < 8) {
let dg_out: u8 = (dg + LUMA_BIAS_G as i16) as u8;
let dr_dg: u8 = (dr - dg + LUMA_BIAS_RB as i16) as u8;
let db_dg: u8 = (db - dg + LUMA_BIAS_RB as i16) as u8;
return (ChunkType::Luma, Some((dg_out, dr_dg, db_dg)));
} else {
return (ChunkType::RGB, None);
}
}
pub fn diff(&self, other: &Pixel) -> (i16, i16, i16) {
let mut dr: i16;
let dr_inv: i16;
let mut dg: i16;
let dg_inv: i16;
let mut db: i16;
let db_inv: i16;
dr = self.r.wrapping_sub(other.r) as i16;
dr_inv = other.r.wrapping_sub(self.r) as i16;
if dr.abs() > dr_inv.abs() {
dr = dr_inv;
dr = -dr;
}
dg = self.g.wrapping_sub(other.g) as i16;
dg_inv = other.g.wrapping_sub(self.g) as i16;
if dg.abs() > dg_inv.abs() {
dg = dg_inv;
dg = -dg;
}
db = self.b.wrapping_sub(other.b) as i16;
db_inv = other.b.wrapping_sub(self.b) as i16;
if db.abs() > db_inv.abs() {
db = db_inv;
db = -db;
}
(dr, dg, db)
}
}
//Definition of header bytes
struct Header {
magic: [char; 4], //magic bytes "qoif"
width: u32, //image width in pixels (BE)
height: u32, //image height in pixels (BE)
channels: u8, // 3 = RGB, 4 = RBGA
colorspace: u8, // 0 = sRGB with linear alpha, 1 = all channels linear
}
impl Header {
fn convert_to_bytestream(&self) -> [u8;14] {
let mut out: [u8; 14] = [0;14];
//First, set magic bytes
out[0] = self.magic[0] as u8;
out[1] = self.magic[1] as u8;
out[2] = self.magic[2] as u8;
out[3] = self.magic[3] as u8;
//split width and height into 8-bit chunks
let width_bytes = self.width.to_be_bytes();
let height_bytes = self.height.to_be_bytes();
out[4] = width_bytes[0];
out[5] = width_bytes[1];
out[6] = width_bytes[2];
out[7] = width_bytes[3];
out[8] = height_bytes[0];
out[9] = height_bytes[1];
out[10] = height_bytes[2];
out[11] = height_bytes[3];
//Set information bits
out[12] = self.channels;
out[13] = self.colorspace;
out
}
}
//Definition of End of Stream bytes
#[derive(Debug)]
struct End {
bytes: [u8;8]
}
impl End {
fn new() -> End {
End {
bytes: [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01]
}
}
}
//chunks as defined in the QOI spec
const QOI_OP_RGB: u8 = 0b1111_1110;
const QOI_OP_RGBA: u8 = 0b1111_1111;
const QOI_OP_RUN: u8 = 0b1100_0000;
const QOI_OP_INDEX: u8 = 0b0000_0000;
const QOI_OP_DIFF: u8 = 0b0100_0000;
const QOI_OP_LUMA: u8 = 0b1000_0000;
//Biases as defined in the QOI spec
const RUN_BIAS: u8 = 1;
const DIFF_BIAS: u8 = 2;
const LUMA_BIAS_G: u8 = 32;
const LUMA_BIAS_RB: u8 = 8;
//hash function for assigning buffer indices to stored pixels
fn color_hash(pixel: &Pixel) -> u8 {
let store: u32 = pixel.r as u32 * 3 + pixel.g as u32 * 5 + pixel.b as u32 * 7 + pixel.a as u32 * 11;
(store % 64) as u8
}
pub fn encode_from_image(img: Image) -> Vec<u8> {
let mut prev_pixel: Pixel = Pixel {r: 0u8, b: 0u8, g: 0u8, a: 255u8};
let mut prev_buffer: Vec<Pixel> = Vec::with_capacity(64);
for i in 0..64 {
let pix: Pixel = Pixel {r:0,g:0,b:0,a:0};
prev_buffer.push(pix);
}
let mut encoded_bytes: Vec<u8> = Vec::new();
let mut run: u8 = 0;
let head = Header {
magic: ['q', 'o', 'i', 'f'],
width: img.width,
height: img.height,
channels: img.channels,
colorspace: img.colorspace
};
let head_stream = head.convert_to_bytestream();
for i in head_stream {
encoded_bytes.push(i);
}
let mut counter: u32 = 0;
for pixel in img.pixels {
counter += 1;
let chunk: (ChunkType, Option<(u8,u8,u8)>) = pixel.determine_chunk(&prev_pixel, &prev_buffer);
if chunk == (ChunkType::Run, None) {
run += 1;
prev_pixel = pixel.clone();
continue;
}
if run > 0 {
if run > 62 {
while run > 0 {
if run/62 > 0 {
encoded_bytes.push(QOI_OP_RUN | (62-RUN_BIAS));
run -= 62;
} else if run%62 > 0 {
encoded_bytes.push(QOI_OP_RUN | (run-RUN_BIAS));
run = 0;
} else {
break;
}
}
} else {
encoded_bytes.push(QOI_OP_RUN | (run-RUN_BIAS));
run = 0;
}
}
match chunk {
(ChunkType::Index, Some((index, irr1, irr2))) => {
encoded_bytes.push(QOI_OP_INDEX | index);
prev_pixel = pixel;
},
(ChunkType::Diff, Some((dr, dg,db))) => {
let mut out: u8 = 0b0000_0000;
out = out | db;
out = out | (dg << 2);
out = out | (dr << 4);
encoded_bytes.push(QOI_OP_DIFF | out);
prev_pixel = pixel.clone();
prev_buffer[color_hash(&pixel) as usize] = pixel;
},
(ChunkType::Luma, Some((dg, dr_dg, db_dg))) => {
let mut out: [u8; 2] = [0b0000_0000;2];
out[0] |= dg;
out[0] |= QOI_OP_LUMA;
out[1] |= db_dg;
out[1] |= dr_dg << 4;
encoded_bytes.push(out[0]);
encoded_bytes.push(out[1]);
prev_pixel = pixel.clone();
prev_buffer[color_hash(&pixel) as usize] = pixel;
},
(ChunkType::RGB, None) => {
encoded_bytes.push(QOI_OP_RGB);
encoded_bytes.push(pixel.r);
encoded_bytes.push(pixel.g);
encoded_bytes.push(pixel.b);
prev_pixel = pixel.clone();
prev_buffer[color_hash(&pixel) as usize] = pixel;
},
(ChunkType::RGBA, None) => {
if (pixel.a as i16 - prev_pixel.a as i16) == 0i16 {
//this should never be reached, but it is
encoded_bytes.push(QOI_OP_RGB);
encoded_bytes.push(pixel.r);
encoded_bytes.push(pixel.g);
encoded_bytes.push(pixel.b);
prev_pixel = pixel.clone();
prev_buffer[color_hash(&pixel) as usize] = pixel;
} else {
encoded_bytes.push(QOI_OP_RGBA);
encoded_bytes.push(pixel.r);
encoded_bytes.push(pixel.g);
encoded_bytes.push(pixel.b);
encoded_bytes.push(pixel.a);
prev_pixel = pixel.clone();
prev_buffer[color_hash(&pixel) as usize] = pixel;
}
},
_ => panic!("Critical error at encoding stage: Illegal output from difference function.")
}
}
if run > 0 {
if run > 62 {
while run > 0 {
if run/62 > 0 {
encoded_bytes.push(QOI_OP_RUN | (62-RUN_BIAS));
run -= 62;
} else if run%62 > 0 {
encoded_bytes.push(QOI_OP_RUN | (run-RUN_BIAS));
run = 0;
} else {
break;
}
}
} else {
encoded_bytes.push(QOI_OP_RUN | (run-RUN_BIAS));
}
}
let end_bytes = End::new();
for i in end_bytes.bytes {
encoded_bytes.push(i)
}
info!("Number of pixels processed: {}.", counter);
info!("Number of bytes in encoding: {:?}.", encoded_bytes.len()-22);
info!("Compression rate: {:.2}%.", (1.0-(encoded_bytes.len()-22) as f64/(counter*4)as f64)*100.0);
encoded_bytes
}
pub fn write_to_file(bytes: Vec<u8>, filename: &str) -> std::io::Result<()>{
let mut file_path: String = String::from(filename);
file_path.push_str(".qoi");
let mut buffer = File::create(file_path)?;
let mut pos = 0;
while pos < bytes.len() {
let bytes_written = buffer.write(&bytes[pos..])?;
pos += bytes_written;
}
Ok(())
}
fn read_header(bytes: &[u8]) -> Result<(u32,u32,u8,u8), ImgError> {
if bytes[0] == 'q' as u8 && bytes[1] == 'o' as u8 && bytes[2] == 'i' as u8 && bytes[3] == 'f' as u8 {
let mut width: u32 = 0b0000_0000_0000_0000_0000_0000_0000_0000;
let mut height: u32 = 0b0000_0000_0000_0000_0000_0000_0000_0000;
width |= ((bytes[4] as u32) << 24) as u32;
width |= ((bytes[5] as u32) << 16) as u32;
width |= ((bytes[6] as u32) << 8) as u32;
width |= (bytes[7]) as u32;
height |= ((bytes[8] as u32) << 24) as u32;
height |= ((bytes[9] as u32) << 16) as u32;
height |= ((bytes[10] as u32) << 8) as u32;
height |= (bytes[11]) as u32;
return Ok((width, height, bytes[12], bytes[13]));
} else {
return Err(ImgError::HeaderError);
}
}
fn read_tag(tag: u8) -> Result<ChunkType,ImgError> {
if tag == QOI_OP_RGB {
return Ok(ChunkType::RGB);
}
if tag == QOI_OP_RGBA {
return Ok(ChunkType::RGBA);
}
if (tag & 0b1100_0000) == QOI_OP_DIFF{
return Ok(ChunkType::Diff);
}
if (tag & 0b1100_0000) == QOI_OP_INDEX {
return Ok(ChunkType::Index);
}
if (tag & 0b1100_0000) == QOI_OP_LUMA {
return Ok(ChunkType::Luma);
}
if (tag & 0b1100_0000) == QOI_OP_RUN {
return Ok(ChunkType::Run);
}
return Err(ImgError::DecodeError);
}
fn dec_rgb(bytes: &[u8], alpha: u8) -> Pixel {
let pixel: Pixel = Pixel::new(bytes[1], bytes[2], bytes[3], alpha);
pixel
}
fn dec_rgba(bytes: &[u8]) -> Pixel {
let pixel: Pixel = Pixel::new(bytes[1], bytes[2], bytes[3], bytes[4]);
pixel
}
fn dec_diff(byte: u8, prev_pixel: &Pixel) -> Pixel {
let dr: u8;
let dg: u8;
let db: u8;
dr = (byte & 0b00110000) >> 4;
dg = (byte & 0b00001100) >> 2;
db = byte & 0b00000011;
let r: u8 = prev_pixel.r.wrapping_add(dr);
let g: u8 = prev_pixel.g.wrapping_add(dg);
let b: u8 = prev_pixel.b.wrapping_add(db);
let r: u8 = r.wrapping_sub(DIFF_BIAS);
let b: u8 = b.wrapping_sub(DIFF_BIAS);
let g: u8 = g.wrapping_sub(DIFF_BIAS);
let pixel: Pixel = Pixel::new(r,g,b, prev_pixel.a);
pixel
}
fn dec_luma(bytes: &[u8], prev_pixel: &Pixel) -> Pixel {
let dr: u8;
let dr_dg: u8;
let db_dg: u8;
let dg: u8;
let db: u8;
dg = bytes[0] & 0b00111111;
dr_dg = (bytes[1] & 0b11110000) >> 4;
db_dg = bytes[1] & 0b00001111;
dr = dr_dg + dg;
db = db_dg + dg;
let r: u8 = prev_pixel.r.wrapping_add(dr);
let g: u8 = prev_pixel.g.wrapping_add(dg);
let b: u8 = prev_pixel.b.wrapping_add(db);
let r: u8 = r.wrapping_sub(LUMA_BIAS_RB + LUMA_BIAS_G);
let g: u8 = g.wrapping_sub(LUMA_BIAS_G);
let b: u8 = b.wrapping_sub(LUMA_BIAS_RB + LUMA_BIAS_G);
let pixel: Pixel = Pixel::new(r, g, b, prev_pixel.a);
pixel
}
fn dec_run() {}
pub fn decode(mut bytes: Vec<u8>) -> Result<Image, ImgError> {
let width: u32;
let height: u32;
let channels: u8;
let colorspace: u8;
let mut prev_pixel: Pixel = Pixel {r: 0u8, g: 0u8, b: 0u8, a: 255u8};
let mut prev_buffer: [Pixel; 64] = array_init::array_init(|_| Pixel::new(0,0,0,0));
match read_header(&bytes[0..14]) {
Ok((w, h, ch, c))=> {
width = w;
height = h;
channels = ch;
colorspace = c;
},
Err(err) => {
return Err(err);
}
}
let mut pixels: Vec<Pixel> = Vec::with_capacity((width*height*4) as usize);
if bytes[bytes.len()-1] == 1 {
for i in 2..9 {
if bytes[bytes.len()-i] != 0 {
debug!("Ending bytes not present.");
return Err(ImgError::DecodeError);
}
}
for i in 0..8 {
bytes.pop();
}
} else {
debug!("Ending bytes not present.");
return Err(ImgError::DecodeError);
}
let mut i: usize = 14;
while i < bytes.len() {
match read_tag(bytes[i]) {
Ok(tag) => {
match tag {
ChunkType::RGB => {
let dec_pix: Pixel = dec_rgb(&bytes[i..i+4], prev_pixel.a);
prev_pixel = dec_pix.clone();
prev_buffer[color_hash(&dec_pix) as usize] = dec_pix.clone();
pixels.push(dec_pix);
i += 3;
},
ChunkType::RGBA => {
let dec_pix: Pixel = dec_rgba(&bytes[i..i+5]);
prev_pixel = dec_pix.clone();
prev_buffer[color_hash(&dec_pix) as usize] = dec_pix.clone();
pixels.push(dec_pix);
i += 4;
},
ChunkType::Diff => {
let dec_pix: Pixel = dec_diff(bytes[i], &prev_pixel);
prev_pixel = dec_pix.clone();
prev_buffer[color_hash(&dec_pix) as usize] = dec_pix.clone();
pixels.push(dec_pix);
},
ChunkType::Index => {
let dec_pix: Pixel = prev_buffer[bytes[i] as usize];
prev_pixel = dec_pix.clone();
prev_buffer[color_hash(&dec_pix) as usize] = dec_pix.clone();
pixels.push(dec_pix);
},
ChunkType::Luma => {
let dec_pix: Pixel = dec_luma(&bytes[i..i+2], &prev_pixel);
prev_pixel = dec_pix.clone();
prev_buffer[color_hash(&dec_pix) as usize] = dec_pix.clone();
pixels.push(dec_pix);
i += 1;
},
ChunkType::Run => {
let length: u8 = (bytes[i] & 0b00111111) + RUN_BIAS;
for j in 0..length {
pixels.push(prev_pixel.clone());
}
prev_buffer[color_hash(&prev_pixel) as usize] = prev_pixel.clone();
}
}
},
Err(err) => return Err(err),
}
i += 1;
}
if pixels.len() as u32 != height*width {
debug!("h*w: {}", height*width);
debug!("n pixels: {}", pixels.len());
return Err(ImgError::DecodeError);
}
let img = Image::from_pixels(pixels, height, width, channels, colorspace);
Ok(img)
}
#[cfg(test)]
mod tests {
use super::*;
use std::io;
use std::io::{Read, BufReader};
use std::fs::File;
#[test]
fn diff_test() {
init().expect("Logger initialisation failed!");
let pix1: Pixel = Pixel::new( 0, 0, 0,255);
let pix2: Pixel = Pixel::new(255,255,255,255);
let pix3: Pixel = Pixel::new(155,155,155,255);
let pix4: Pixel = Pixel::new(160,160,160,255);
assert_eq!(pix1.diff(&pix2), ( 1, 1, 1));
assert_eq!(pix2.diff(&pix1), (-1,-1,-1));
assert_eq!(pix4.diff(&pix3), ( 5, 5, 5));
assert_eq!(pix3.diff(&pix4), (-5,-5,-5));
}
#[test]
fn encode_test() -> io::Result<()> {
let f: File = File::open("test.qoi")?;
let mut reader = BufReader::new(f);
let mut bytes: Vec<u8> = Vec::new();
reader.read_to_end(&mut bytes)?;
let out_img: super::Image;
match super::decode(bytes) {
Ok(img) => out_img = img,
Err(err) => panic!("wallah geht nicht :/ {:?}", err)
}
write_to_file(encode_from_image(out_img), "test_dec").expect("wallahi!");
Ok(())
}
#[test]
fn decode_test() -> io::Result<()> {
let f: File = File::open("testcard_rgba.qoi")?;
let mut reader = BufReader::new(f);
let mut bytes: Vec<u8> = Vec::new();
reader.read_to_end(&mut bytes)?;
let out_img: super::Image;
match super::decode(bytes) {
Ok(img) => out_img = img,
Err(err) => panic!("Ja bruder war nicht so erfolgreich ahahahahahha {:?}", err)
}
write_to_file(encode_from_image(out_img), "testcard_new").expect("Boowomb!");
Ok(())
}
#[test]
fn tag_test() {
//init().expect("Logger initialisation failed!");
let test_rgb: u8 = 0b1111_1110;
let test_rgba: u8 = 0b1111_1111;
let test_luma: u8 = 0b1011_1010;
let test_run: u8 = 0b1110_1101;
let test_diff: u8 = 0b0110_1010;
let test_index: u8 = 0b0010_1010;
assert_eq!(Ok(ChunkType::RGB), super::read_tag(test_rgb));
assert_eq!(Ok(ChunkType::RGBA), super::read_tag(test_rgba));
assert_eq!(Ok(ChunkType::Luma), super::read_tag(test_luma));
assert_eq!(Ok(ChunkType::Diff), super::read_tag(test_diff));
assert_eq!(Ok(ChunkType::Index), super::read_tag(test_index));
assert_eq!(Ok(ChunkType::Run), super::read_tag(test_run));
}
#[test]
fn sub_decoders_test() {
//init().expect("Logger initialisation failed!");
let pix: Pixel = Pixel { r: 255, g: 255, b: 255, a: 255 };
let prev: Pixel = Pixel { r: 1, g: 1, b: 1, a: 255 };
let byte: u8 = 0b01000000;
assert_eq!(pix,dec_diff(byte, &prev));
let pix: Pixel = Pixel { r: 17, g: 22, b: 28, a: 100 };
let prev: Pixel = Pixel { r: 10, g: 10, b: 10, a: 100 };
let byte: [u8;2] = [ 0b10101100, 0b00111110 ];
assert_eq!(pix, dec_luma(&byte[0..2], &prev));
}
}
}