Preliminary implementation of CZ0 encoding

src/main.rs

@@ -1,73 +1,78 @@
-use sdl2::pixels::Color;
-use sdl2::rect::Point;
-//use sdl2::render::Canvas;
-//use sdl2::video::Window;
-use sdl2::event::Event;
-use sdl2::keyboard::Keycode;
-
 use image::{RgbaImage, ImageFormat, open};
 
 use std::io;
+use std::io::Write;
 use std::fs;
-use std::thread;
-use std::time::Duration;
+use std::fs::File;
 
-struct Header {
+#[derive(Copy, Clone)]
+struct HeaderCZ0 {
     magic: [u8; 3],     // The magic bytes, can be CZ0, (CZ1, CZ2?)
+    length: u8,
     res: (i16, i16),    // The width in the header
-    depth: i16,         // Bit depth
+    depth: u8,         // Bit depth
     crop: (i16, i16),   // Crop dimensions
     bounds: (i16, i16), // Bounding box dimensions
     offset: (i16, i16), // Offset coordinates
 }
 
-struct Image {
-    header: Header,
+struct CZ0File {
+    header: HeaderCZ0,
     bitmap: Vec<u8>,
 }
 
-// Converts 8 bit bytes to a 16 bit little endian word
-fn bytes_to_word(first:u8, second:u8) -> i16 {
+// Converts 8 bit bytes to a 16 bit little endian word or
+pub fn bytes_to_word(first:u8, second:u8) -> i16 {
     let final_value = ((second as i16) << 8) | (first as i16);
 
     return final_value;
 }
 
-fn extract_header(header_vec: &Vec<u8>) -> (Header, usize) {
+// Converts a 16 bit little endian word to 8 bit bytes
+pub fn word_to_bytes(word:i16) -> [u8; 2] {
+    let first: u8 = (word & 0xFF) as u8; // Extract the first byte
+    let second: u8 = ((word >> 8) & 0xFF) as u8; // Extract the second byte
+
+    return [first, second];
+}
+
+/// Extract all the header information from a CZ0 file
+fn extract_header_cz0(header_vec: &Vec<u8>) -> (HeaderCZ0, usize) {
     // Get the magic bytes
     let magic: [u8; 3] = header_vec[0..3].try_into().unwrap();
-    println!("Magic Bytes:   {:?}", magic);
+    println!("Magic Bytes  : {:?}", magic);
 
     // Get the length of the header
-    let header_length = header_vec[4];
-    println!("Header Length: {:?}", header_length);
+    let length = header_vec[4];
+    println!("Header Length: {:?}", length);
 
     // Convert the width and height to i16 values
     let width = bytes_to_word(header_vec[8], header_vec[9]);
     let height = bytes_to_word(header_vec[10], header_vec[11]);
-    println!("Resolution:    {}x{}", width, height);
+    println!("Resolution   : {}x{}", width, height);
 
     // Get the bit depth
-    let depth = bytes_to_word(header_vec[12], header_vec[13]);
-    println!("Bit Depth:     {} bits", depth);
+    let depth = header_vec[12];
+    println!("Bit Depth    : {} bits", depth);
 
     // Get the crop resolution
     let crop_width = bytes_to_word(header_vec[20], header_vec[21]);
     let crop_height = bytes_to_word(header_vec[22], header_vec[23]);
-    println!("Crop Coords:   {}x{}", crop_width, crop_height);
+    println!("Crop Coords  : {}x{}", crop_width, crop_height);
 
     // Get bounding box
     let bound_width = bytes_to_word(header_vec[24], header_vec[25]);
     let bound_height = bytes_to_word(header_vec[26], header_vec[27]);
-    println!("Bound Coords:  {}x{}", bound_width, bound_height);
+    println!("Bound Coords : {}x{}", bound_width, bound_height);
 
     // Get offset coordinates
     let offset_x = bytes_to_word(header_vec[28], header_vec[29]);
     let offset_y = bytes_to_word(header_vec[30], header_vec[31]);
     println!("Offset Coords: {}x{}", offset_x, offset_y);
 
-    let image_header = Header {
+    let image_header = HeaderCZ0 {
         magic,
+        length,
         res: (width, height),
         depth,
         crop: (crop_width, crop_height),
@@ -75,19 +80,24 @@ fn extract_header(header_vec: &Vec<u8>) -> (Header, usize) {
         offset: (offset_x, offset_y),
     };
 
-    return (image_header, header_length as usize);
+    return (image_header, length as usize);
 }
 
-// Provided a bitstream, extract the header information and
-// the rest of the metadata about a CZ file
-fn decode_cz(mut input:Vec<u8>) -> Image {
+/// Provided a bitstream, extract the header information and
+/// the rest of the metadata about a CZ0 file, returning a
+/// struct containing the header information and bitmap
+fn decode_cz0(input_filename:&str) -> CZ0File {
+    println!("Reading input file...");
+    let mut input = fs::read(input_filename).unwrap();
+
+    println!("Decoding input...");
 
     // TODO Research the header more!
-    let (header, header_length)= extract_header(&input);
+    let (header, header_length) = extract_header_cz0(&input);
     input.drain(..header_length);
 
-    // Construct the image struct
-    let final_image = Image {
+    // Construct the output CZ0 image
+    let final_image = CZ0File {
         header,
         bitmap: input,
     };
@@ -95,70 +105,81 @@ fn decode_cz(mut input:Vec<u8>) -> Image {
     return final_image;
 }
 
-/*
-fn encode_cz() -> Image {
-    let on_top = open("path/to/some.png").unwrap().into_rgb8();
+/// Provided an image, extract the bitstream and create the
+/// header information from a previous CZ0 file in order to
+/// replace it
+fn encode_cz0(original_file:CZ0File, in_name:&str, out_name:&str) -> io::Result<()> {
+    let input_image = open(in_name).unwrap().into_rgba8();
+    let (input_width, input_height) = input_image.dimensions();
 
-    // Construct the image struct
-    let final_image = Image {
-        header,
-        bitmap: input,
+    let width_diff = input_width as i16 - original_file.header.res.0;
+    let height_diff = input_height as i16 - original_file.header.res.1;
+
+    // Crop
+    let crop_width = input_width as i16;
+    let crop_height = input_height as i16;
+
+    // Offset
+    let offset_x = original_file.header.offset.0 + width_diff;
+    let offset_y = original_file.header.offset.1 + height_diff;
+
+    // Construct the header
+    let header = HeaderCZ0 {
+        magic: [67, 90, 48],
+        length: 36,
+        res: (input_width as i16, input_height as i16),
+        depth: 32,
+        crop: (crop_width, crop_height),
+        bounds: (original_file.header.bounds.0, original_file.header.bounds.1),
+        offset: (offset_x, offset_y),
     };
 
-    return Image;
-}*/
+    let bitmap = input_image.to_vec();
+    let mut file = File::create(out_name)?;
+
+    // Write magic and length
+    file.write_all(&header.magic)?;
+    file.write_all(&[0])?;
+    file.write_all(&[header.length])?;
+    file.write_all(&vec![0u8; 3])?;
+
+    // Write width and height
+    file.write_all(&word_to_bytes(header.res.0))?;
+    file.write_all(&word_to_bytes(header.res.1))?;
+
+    // Write bit depth
+    file.write_all(&[header.depth])?;
+    file.write_all(&vec![0u8; 7])?;
+
+    // Write crop width and height
+    file.write_all(&word_to_bytes(header.crop.0))?;
+    file.write_all(&word_to_bytes(header.crop.1))?;
+
+    // Write bound width and height
+    file.write_all(&word_to_bytes(header.bounds.0))?;
+    file.write_all(&word_to_bytes(header.bounds.1))?;
+
+    // Write offset width and height
+    file.write_all(&word_to_bytes(header.offset.0))?;
+    file.write_all(&word_to_bytes(header.offset.1))?;
+
+    // Write unknown padding bytes
+    file.write_all(&vec![0u8; 4])?;
+
+    // Write the actual image data
+    file.write_all(&bitmap)?;
+
+    return Ok(());
+}
 
 fn main() -> io::Result<()> {
-    let sdl_context = sdl2::init().unwrap();
-    let video_subsystem = sdl_context.video().unwrap();
+    let image = decode_cz0("775.cz0");
 
-    // Read all bytes of the CZ image to an array
-    println!("Reading image...");
-    let image_raw = fs::read("775.cz0")?;
-
-    let image = decode_cz(image_raw);
-
-    let width = image.header.res.0 as i32;
-    let height = image.header.res.1 as i32;
-
-    println!("{}", width*height);
-    println!("{}", image.bitmap.len() / 4);
-
-    // Build the window
-    let window = video_subsystem.window("SDL2 Rust", width as u32, height as u32)
-        .position_centered()
-        .build()
-        .unwrap();
-
-    let mut canvas = window.into_canvas().build().unwrap();
-    canvas.set_draw_color(Color::RGBA(255, 255, 255, 255));
-    canvas.clear();
-
-    thread::sleep(Duration::from_millis(40)); // Sleep to allow the window to display
-
-    // Draw the bitmap to the canvas
-    for (i, chunk) in image.bitmap.chunks(4).enumerate() {
-        let a = chunk[3] / 255;
-
-        // Get the pixel colors
-        let r = chunk[0] * a;
-        let g = chunk[1] * a;
-        let b = chunk[2] * a;
-        canvas.set_draw_color(Color::RGBA(r, g, b, a));
-
-        // Get the pixel location
-        let y = i as i32/width;
-        let x = i as i32%width;
-        canvas.draw_point(Point::new(x, y)).unwrap();
-    }
-
-    canvas.present(); // Display the image on the SDL2 canvas
-
-    // Create and save a PNG of the image data
+    /* Create and save a PNG of the image data
     // This errors if the image data is too short
     let tmp = match RgbaImage::from_raw(
-        width as u32,
-        height as u32,
+        image.header.res.0 as u32,
+        image.header.res.1 as u32,
         image.bitmap,
     ) {
         Some(img) => img,
@@ -175,25 +196,10 @@ fn main() -> io::Result<()> {
             eprintln!("ERROR SAVING IMAGE: {}", e);
             eprintln!("You probably have an image with the CZ0 offset bug!")
         }
-    }
+    }*/
 
-    // Wait for the user to press escape
-    let mut event_pump = sdl_context.event_pump().unwrap();
-    loop {
-        for event in event_pump.poll_iter() {
-            match event {
-                Event::Quit { .. } | Event::KeyDown {
-                    keycode: Some(Keycode::Escape),
-                    ..
-                } => {
-                    println!("Exiting");
-                    return Ok(());
-                }
+    encode_cz0(image, "melon_test.png", "test.cz0").unwrap();
+    decode_cz0("test.cz0");
 
-                _ => {
-                    continue;
-                }
-            }
-        }
-    }
+    return Ok(());
 }