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use std::convert::TryInto;
pub struct ImageDescriptor {
// Image Seperator 0x2C is the first byte //
pub left: u16,
pub top: u16,
pub width: u16,
pub height: u16,
pub packed: u8,
}
impl ImageDescriptor {
pub fn set_color_table_present(&mut self, is_present: bool) {
if is_present {
self.packed |= 0b1000_0000;
} else {
self.packed &= 0b0111_1111;
}
}
pub fn set_color_table_size(&mut self, size: u8) {
// GCT size is calulated by raising two to this number plus one,
// so we have to work backwards.
let size = (size as f32).log2().ceil() - 1f32;
self.packed |= size as u8;
}
//TODO: Setter for sort flag in packed field
//TODO: Setter for interlace flag in packed field
pub fn color_table_present(&self) -> bool {
self.packed & 0b1000_0000 != 0
}
pub fn color_table_size(&self) -> usize {
crate::packed_to_color_table_length(self.packed & 0b0000_0111)
}
}
impl From<&ImageDescriptor> for Box<[u8]> {
fn from(desc: &ImageDescriptor) -> Self {
let mut vec = vec![];
vec.push(0x2C); // Image Seperator
vec.extend_from_slice(&desc.left.to_le_bytes());
vec.extend_from_slice(&desc.top.to_le_bytes());
vec.extend_from_slice(&desc.width.to_le_bytes());
vec.extend_from_slice(&desc.height.to_le_bytes());
vec.push(desc.packed);
vec.into_boxed_slice()
}
}
impl From<[u8; 9]> for ImageDescriptor {
fn from(arr: [u8; 9]) -> Self {
let left = u16::from_le_bytes(arr[0..2].try_into().unwrap());
let top = u16::from_le_bytes(arr[2..4].try_into().unwrap());
let width = u16::from_le_bytes(arr[4..6].try_into().unwrap());
let height = u16::from_le_bytes(arr[6..8].try_into().unwrap());
let packed = arr[8];
Self {
left,
top,
width,
height,
packed,
}
}
}
//TODO: Impl to allow changing the packed field easier
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