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use crate::common::Color;
use super::OutVec;
use super::LZW;
pub struct ImageBuilder {
left_offset: u16,
top_offset: u16,
width: u16,
height: u16,
color_table: Option<Vec<Color>>,
indicies: Vec<u8>
}
impl ImageBuilder {
pub fn new(width: u16, height: u16) -> Self {
Self {
left_offset: 0,
top_offset: 0,
width,
height,
color_table: None,
indicies: vec![]
}
}
pub fn offsets(mut self, left_offset: u16, top_offset: u16) -> Self {
self.left_offset = left_offset;
self.top_offset = top_offset;
self
}
pub fn left_offset(mut self, offset: u16) -> Self {
self.left_offset = offset;
self
}
pub fn top_offset(mut self, offset: u16) -> Self {
self.top_offset = offset;
self
}
pub fn color_table(mut self, vec: Vec<Color>) -> Self {
if vec.len() == 0 || vec.len() > 256 {
//TODO: Throw error instead of panic
panic!("Color table has to be less than or 256 colors in size, and at least one");
}
self.color_table = Some(vec);
self
}
pub fn indicies(mut self, vec: Vec<u8>) -> Self {
self.indicies = vec;
self
}
//TODO: Make lzw_minimum_code_size optional. ONly needed with global color tables
pub fn write_to_vec(&self, lzw_minimum_code_size: u8) -> Vec<u8> {
let mut out = OutVec::new();
self.write_image_descriptor(&mut out)
.write_color_table(&mut out)
.write_image_data(&mut out, lzw_minimum_code_size);
out.vec()
}
fn write_image_descriptor(&self, out: &mut OutVec) -> &Self {
// Image seperator. At the start of every image descriptor
out.push_u8(0x2C)
.push_u16(self.left_offset)
.push_u16(self.top_offset)
.push_u16(self.width)
.push_u16(self.height);
// Taken from gifbuilder.rs
//TODO: deduplciate code
let mut packed: u8 = 0;
if let Some(ct) = &self.color_table {
packed |= 0b1000_0000; // Set the color table flag
let size = (ct.len() as f32).log2().ceil() - 1f32;
packed |= size as u8;
}
//TODO: Interlace and Sort flags in packed
out.push_u8(packed);
self
}
fn write_color_table(&self, out: &mut OutVec) -> &Self {
if let Some(ct) = &self.color_table {
out.push_colors(&ct);
}
self
}
fn write_image_data(&self, out: &mut OutVec, minimum_code_size: u8) -> &Self {
let mut mcs = minimum_code_size;
//TODO: Deduplicate color table size code
if let Some(ct) = &self.color_table {
mcs = ((ct.len() as f32).log2().ceil() - 1f32) as u8;
}
if mcs < 2 {
// Must always be true: 2 <= mcs <= 8
mcs = 2;
}
// First write out the MCS
out.push_u8(mcs);
let compressed = LZW::encode(mcs, &self.indicies);
for chunk in compressed.chunks(255) {
out.push_u8(chunk.len() as u8);
out.push_slice(chunk);
}
// Data block length 0 to indicate an end
out.push_u8(0x00);
self
}
}
#[cfg(test)]
mod imagebuilder_test {
use super::*;
#[test]
fn write_to_vec() {
let colortable = vec![
Color::new(0, 0, 0),
Color::new(128, 0, 255)
];
let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
let expected_out = vec![
0x2C, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x04, 0x00, 0b1000_0000, // Image Descriptor
0, 0, 0, 128, 0, 255, // Color Table
0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00 // Image Data
];
let actual_out = ImageBuilder::new(4, 4)
.color_table(colortable)
.indicies(indicies)
.write_to_vec(0);
assert_eq!(actual_out, expected_out);
}
#[test]
fn write_image_descriptor() {
let mut out = OutVec::new();
ImageBuilder::new(16, 16).offsets(1, 6).write_image_descriptor(&mut out);
assert_eq!(out.vec(), vec![0x2C, 0x01, 0x00, 0x06, 0x00, 0x10, 0x00, 0x10, 0x00, 0x00]);
let mut out = OutVec::new();
ImageBuilder::new(16, 16)
.offsets(1, 6)
.color_table(vec![Color::new(0, 0, 0)])
.write_image_descriptor(&mut out);
assert_eq!(out.vec(), vec![0x2C, 0x01, 0x00, 0x06, 0x00, 0x10, 0x00, 0x10, 0x00, 0b1000_0000]);
}
#[test]
fn write_color_table() {
let mut out = OutVec::new();
ImageBuilder::new(16, 16)
.color_table(vec![Color::new(1, 2, 3), Color::new(253, 254, 255)])
.write_color_table(&mut out);
assert_eq!(out.vec(), vec![0x01, 0x02, 0x03, 0xFD, 0xFE, 0xFF]);
}
#[test]
fn write_image_data() {
#[test]
fn encode() {
let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
let output = vec![0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00];
let mut out = OutVec::new();
ImageBuilder::new(16, 16)
.indicies(indicies)
.write_image_data(&mut out, 2);
assert_eq!(out.vec(), output);
}
}
}
|
