75 lines
2.5 KiB
Rust
75 lines
2.5 KiB
Rust
use std::io::Write;
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use crate::{
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PngResult,
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error::PngError,
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headers::{read_be_u16, read_be_u32},
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};
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#[derive(Debug, Clone)]
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/// Animated PNG frame
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pub struct Frame {
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/// Width of the frame
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pub width: u32,
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/// Height of the frame
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pub height: u32,
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/// X offset of the frame
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pub x_offset: u32,
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/// Y offset of the frame
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pub y_offset: u32,
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/// Frame delay numerator
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pub delay_num: u16,
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/// Frame delay denominator
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pub delay_den: u16,
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/// Frame disposal operation
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pub dispose_op: u8,
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/// Frame blend operation
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pub blend_op: u8,
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/// Frame data, from fdAT chunks
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pub data: Vec<u8>,
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}
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impl Frame {
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/// Construct a new Frame from the data in a fcTL chunk
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pub fn from_fctl_data(byte_data: &[u8]) -> PngResult<Self> {
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if byte_data.len() < 26 {
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return Err(PngError::TruncatedData);
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}
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Ok(Self {
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width: read_be_u32(&byte_data[4..8]),
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height: read_be_u32(&byte_data[8..12]),
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x_offset: read_be_u32(&byte_data[12..16]),
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y_offset: read_be_u32(&byte_data[16..20]),
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delay_num: read_be_u16(&byte_data[20..22]),
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delay_den: read_be_u16(&byte_data[22..24]),
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dispose_op: byte_data[24],
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blend_op: byte_data[25],
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data: vec![],
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})
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}
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/// Construct the data for a fcTL chunk using the given sequence number
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#[must_use]
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pub fn fctl_data(&self, sequence_number: u32) -> Vec<u8> {
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let mut byte_data = Vec::with_capacity(26);
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byte_data.write_all(&sequence_number.to_be_bytes()).unwrap();
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byte_data.write_all(&self.width.to_be_bytes()).unwrap();
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byte_data.write_all(&self.height.to_be_bytes()).unwrap();
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byte_data.write_all(&self.x_offset.to_be_bytes()).unwrap();
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byte_data.write_all(&self.y_offset.to_be_bytes()).unwrap();
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byte_data.write_all(&self.delay_num.to_be_bytes()).unwrap();
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byte_data.write_all(&self.delay_den.to_be_bytes()).unwrap();
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byte_data.push(self.dispose_op);
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byte_data.push(self.blend_op);
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byte_data
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}
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/// Construct the data for a fdAT chunk using the given sequence number
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#[must_use]
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pub fn fdat_data(&self, sequence_number: u32) -> Vec<u8> {
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let mut byte_data = Vec::with_capacity(4 + self.data.len());
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byte_data.write_all(&sequence_number.to_be_bytes()).unwrap();
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byte_data.write_all(&self.data).unwrap();
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byte_data
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}
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}
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