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use std::borrow::Borrow;
use bitvec::{prelude::*, vec::BitVec};
use byteorder::{LittleEndian, WriteBytesExt};
use crate::{
error::{OBIError, OBIResult},
rle::RLE,
CompressionType, Image,
};
pub fn encode_image<I>(obi_image: I) -> OBIResult<Vec<u8>>
where
I: Borrow<Image>,
{
let obi_image = obi_image.borrow();
let mut obi_data = Vec::with_capacity(obi_image.file_header.file_size as usize);
// file header
let file_header = &obi_image.file_header;
obi_data
.write_u16::<LittleEndian>(file_header.version)
.map_err(|_| OBIError::Encode)?;
obi_data
.write_u32::<LittleEndian>(file_header.file_size)
.map_err(|_| OBIError::Encode)?;
obi_data
.write_u32::<LittleEndian>(file_header.data_offset)
.map_err(|_| OBIError::Encode)?;
// image info header
let image_info_header = &obi_image.image_info_header;
obi_data
.write_u32::<LittleEndian>(image_info_header.width)
.map_err(|_| OBIError::Encode)?;
obi_data
.write_u32::<LittleEndian>(image_info_header.height)
.map_err(|_| OBIError::Encode)?;
obi_data
.write_u32::<LittleEndian>(image_info_header.compression_type)
.map_err(|_| OBIError::Encode)?;
obi_data
.write_u32::<LittleEndian>(image_info_header.post_compression_size)
.map_err(|_| OBIError::Encode)?;
let write_pixel_data = |pixels: &Vec<bool>, obi_data: &mut Vec<u8>| -> OBIResult<()> {
for byte in pixels.chunks(8) {
let mut bv = BitVec::<u8>::new();
for &b in byte {
bv.push(b)
}
obi_data
.write_u8(bv.load::<u8>())
.map_err(|_| OBIError::Encode)?;
}
Ok(())
};
// pixmap data
let pixmap = &obi_image.data;
match CompressionType::from_u32(obi_image.image_info_header.compression_type) {
CompressionType::RLE => {
let (data_points, lengths): (Vec<_>, Vec<_>) = pixmap.compress().into_iter().unzip();
for l in lengths {
obi_data
.write_u32::<LittleEndian>(l as u32)
.map_err(|_| OBIError::Encode)?;
}
// end length sequence with zero
obi_data
.write_u32::<LittleEndian>(0)
.map_err(|_| OBIError::Encode)?;
// begin data point sequence
write_pixel_data(&data_points, &mut obi_data)?;
}
_ => write_pixel_data(pixmap, &mut obi_data)?,
};
Ok(obi_data)
}
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