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Diffstat (limited to 'vendor/gif/src/encoder.rs')
| -rw-r--r-- | vendor/gif/src/encoder.rs | 434 |
1 files changed, 0 insertions, 434 deletions
diff --git a/vendor/gif/src/encoder.rs b/vendor/gif/src/encoder.rs deleted file mode 100644 index 693a8cb..0000000 --- a/vendor/gif/src/encoder.rs +++ /dev/null @@ -1,434 +0,0 @@ -//! # Minimal gif encoder -use std::io; -use std::io::prelude::*; -use std::fmt; -use std::error; -use std::borrow::Cow; - -use weezl::{BitOrder, encode::Encoder as LzwEncoder}; - -use crate::traits::{WriteBytesExt}; -use crate::common::{AnyExtension, Block, DisposalMethod, Extension, Frame}; - -#[derive(Debug)] -enum FormatErrorKind { - /// The image has too many colors. - TooManyColors, - /// The image has no color palette which is required. - MissingColorPalette, -} - -/// The image has incorrect properties, making it impossible to encode as a gif. -#[derive(Debug)] -pub struct EncodingFormatError { - kind: FormatErrorKind -} - -impl error::Error for EncodingFormatError {} -impl fmt::Display for EncodingFormatError { - fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { - match self.kind { - FormatErrorKind::TooManyColors => write!(fmt, "the image has too many colors"), - FormatErrorKind::MissingColorPalette => write!(fmt, "the GIF format requires a color palette but none was given") - } - } -} - -impl From<FormatErrorKind> for EncodingFormatError { - fn from(kind: FormatErrorKind) -> Self { - EncodingFormatError { kind } - } -} - -#[derive(Debug)] -/// Encoding error. -pub enum EncodingError { - /// Returned if the to image is not encodable as a gif. - Format(EncodingFormatError), - /// Wraps `std::io::Error`. - Io(io::Error), -} - -impl fmt::Display for EncodingError { - fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { - match self { - EncodingError::Io(err) => err.fmt(fmt), - EncodingError::Format(err) => err.fmt(fmt), - } - } -} - -impl error::Error for EncodingError { - fn source(&self) -> Option<&(dyn error::Error + 'static)> { - match self { - EncodingError::Io(err) => Some(err), - EncodingError::Format(err) => Some(err), - } - } -} - -impl From<io::Error> for EncodingError { - fn from(err: io::Error) -> Self { - EncodingError::Io(err) - } -} - -impl From<EncodingFormatError> for EncodingError { - fn from(err: EncodingFormatError) -> Self { - EncodingError::Format(err) - } -} - -impl From<FormatErrorKind> for EncodingError { - fn from(kind: FormatErrorKind) -> Self { - EncodingError::Format(kind.into()) - } -} - - -/// Number of repetitions -#[derive(Copy, Clone, Debug)] -pub enum Repeat { - /// Finite number of repetitions - Finite(u16), - /// Infinite number of repetitions - Infinite -} - -/// Extension data. -pub enum ExtensionData { - /// Control extension. Use `ExtensionData::new_control_ext` to construct. - Control { - /// Flags. - flags: u8, - /// Frame delay. - delay: u16, - /// Transparent index. - trns: u8 - }, - /// Sets the number of repetitions - Repetitions(Repeat) -} - -impl ExtensionData { - /// Constructor for control extension data. - /// - /// `delay` is given in units of 10 ms. - pub fn new_control_ext(delay: u16, dispose: DisposalMethod, - needs_user_input: bool, trns: Option<u8>) -> ExtensionData { - let mut flags = 0; - let trns = match trns { - Some(trns) => { - flags |= 1; - trns as u8 - }, - None => 0 - }; - flags |= (needs_user_input as u8) << 1; - flags |= (dispose as u8) << 2; - ExtensionData::Control { - flags: flags, - delay: delay, - trns: trns - } - } -} - -impl<W: Write> Encoder<W> { - /// Creates a new encoder. - /// - /// `global_palette` gives the global color palette in the format `[r, g, b, ...]`, - /// if no global palette shall be used an empty slice may be supplied. - pub fn new(w: W, width: u16, height: u16, global_palette: &[u8]) -> Result<Self, EncodingError> { - let buffer_size = (width as usize) * (height as usize); - Encoder { - w: Some(w), - global_palette: false, - width: width, - height: height, - buffer: Vec::with_capacity(buffer_size) - }.write_global_palette(global_palette) - } - - /// Write an extension block that signals a repeat behaviour. - pub fn set_repeat(&mut self, repeat: Repeat) -> Result<(), EncodingError> { - self.write_extension(ExtensionData::Repetitions(repeat)) - } - - /// Writes the global color palette. - pub fn write_global_palette(mut self, palette: &[u8]) -> Result<Self, EncodingError> { - self.global_palette = true; - let mut flags = 0; - flags |= 0b1000_0000; - let num_colors = palette.len() / 3; - if num_colors > 256 { - return Err(EncodingError::from(FormatErrorKind::TooManyColors)); - } - // Size of global color table. - flags |= flag_size(num_colors); - // Color resolution .. FIXME. This is mostly ignored (by ImageMagick at least) but hey, we - // should use some sensible value here or even allow configuring it? - flags |= flag_size(num_colors) << 4; // wtf flag - self.write_screen_desc(flags)?; - self.write_color_table(palette)?; - Ok(self) - } - - /// Writes a frame to the image. - /// - /// Note: This function also writes a control extension if necessary. - pub fn write_frame(&mut self, frame: &Frame) -> Result<(), EncodingError> { - self.write_frame_header(frame)?; - self.write_image_block(&frame.buffer) - } - - fn write_frame_header(&mut self, frame: &Frame) -> Result<(), EncodingError> { - // TODO commented off to pass test in lib.rs - //if frame.delay > 0 || frame.transparent.is_some() { - self.write_extension(ExtensionData::new_control_ext( - frame.delay, - frame.dispose, - frame.needs_user_input, - frame.transparent - - ))?; - //} - let writer = self.w.as_mut().unwrap(); - writer.write_le(Block::Image as u8)?; - writer.write_le(frame.left)?; - writer.write_le(frame.top)?; - writer.write_le(frame.width)?; - writer.write_le(frame.height)?; - let mut flags = 0; - if frame.interlaced { - flags |= 0b0100_0000; - } - match frame.palette { - Some(ref palette) => { - flags |= 0b1000_0000; - let num_colors = palette.len() / 3; - if num_colors > 256 { - return Err(EncodingError::from(FormatErrorKind::TooManyColors)); - } - flags |= flag_size(num_colors); - writer.write_le(flags)?; - self.write_color_table(palette) - }, - None => if !self.global_palette { - Err(EncodingError::from(FormatErrorKind::MissingColorPalette)) - } else { - writer.write_le(flags).map_err(Into::into) - } - } - } - - fn write_image_block(&mut self, data: &[u8]) -> Result<(), EncodingError> { - self.buffer.clear(); - lzw_encode(data, &mut self.buffer); - - let writer = self.w.as_mut().unwrap(); - Self::write_encoded_image_block(writer, &self.buffer) - } - - fn write_encoded_image_block(writer: &mut W, data_with_min_code_size: &[u8]) -> Result<(), EncodingError> { - let (&min_code_size, data) = data_with_min_code_size.split_first().unwrap_or((&2, &[])); - writer.write_le(min_code_size)?; - - // Write blocks. `chunks_exact` seems to be slightly faster - // than `chunks` according to both Rust docs and benchmark results. - let mut iter = data.chunks_exact(0xFF); - while let Some(full_block) = iter.next() { - writer.write_le(0xFFu8)?; - writer.write_all(full_block)?; - } - let last_block = iter.remainder(); - if !last_block.is_empty() { - writer.write_le(last_block.len() as u8)?; - writer.write_all(last_block)?; - } - writer.write_le(0u8).map_err(Into::into) - } - - fn write_color_table(&mut self, table: &[u8]) -> Result<(), EncodingError> { - let writer = self.w.as_mut().unwrap(); - let num_colors = table.len() / 3; - if num_colors > 256 { - return Err(EncodingError::from(FormatErrorKind::TooManyColors)); - } - let size = flag_size(num_colors); - writer.write_all(&table[..num_colors * 3])?; - // Waste some space as of gif spec - for _ in 0..((2 << size) - num_colors) { - writer.write_all(&[0, 0, 0])? - } - Ok(()) - } - - /// Writes an extension to the image. - /// - /// It is normally not necessary to call this method manually. - pub fn write_extension(&mut self, extension: ExtensionData) -> Result<(), EncodingError> { - use self::ExtensionData::*; - // 0 finite repetitions can only be achieved - // if the corresponting extension is not written - if let Repetitions(Repeat::Finite(0)) = extension { - return Ok(()) - } - let writer = self.w.as_mut().unwrap(); - writer.write_le(Block::Extension as u8)?; - match extension { - Control { flags, delay, trns } => { - writer.write_le(Extension::Control as u8)?; - writer.write_le(4u8)?; - writer.write_le(flags)?; - writer.write_le(delay)?; - writer.write_le(trns)?; - } - Repetitions(repeat) => { - writer.write_le(Extension::Application as u8)?; - writer.write_le(11u8)?; - writer.write_all(b"NETSCAPE2.0")?; - writer.write_le(3u8)?; - writer.write_le(1u8)?; - match repeat { - Repeat::Finite(no) => writer.write_le(no)?, - Repeat::Infinite => writer.write_le(0u16)?, - } - } - } - writer.write_le(0u8).map_err(Into::into) - } - - /// Writes a raw extension to the image. - /// - /// This method can be used to write an unsupported extension to the file. `func` is the extension - /// identifier (e.g. `Extension::Application as u8`). `data` are the extension payload blocks. If any - /// contained slice has a lenght > 255 it is automatically divided into sub-blocks. - pub fn write_raw_extension(&mut self, func: AnyExtension, data: &[&[u8]]) -> io::Result<()> { - let writer = self.w.as_mut().unwrap(); - writer.write_le(Block::Extension as u8)?; - writer.write_le(func.0)?; - for block in data { - for chunk in block.chunks(0xFF) { - writer.write_le(chunk.len() as u8)?; - writer.write_all(chunk)?; - } - } - writer.write_le(0u8) - } - - /// Writes a frame to the image, but expects `Frame.buffer` to contain LZW-encoded data - /// from [`Frame::make_lzw_pre_encoded`]. - /// - /// Note: This function also writes a control extension if necessary. - pub fn write_lzw_pre_encoded_frame(&mut self, frame: &Frame) -> Result<(), EncodingError> { - self.write_frame_header(frame)?; - let writer = self.w.as_mut().unwrap(); - Self::write_encoded_image_block(writer, &frame.buffer) - } - - /// Writes the logical screen desriptor - fn write_screen_desc(&mut self, flags: u8) -> io::Result<()> { - let writer = self.w.as_mut().unwrap(); - writer.write_all(b"GIF89a")?; - writer.write_le(self.width)?; - writer.write_le(self.height)?; - writer.write_le(flags)?; // packed field - writer.write_le(0u8)?; // bg index - writer.write_le(0u8) // aspect ratio - } - - /// Gets a reference to the writer instance used by this encoder. - pub fn get_ref(&self) -> &W { - self.w.as_ref().unwrap() - } - - /// Gets a mutable reference to the writer instance used by this encoder. - /// - /// It is inadvisable to directly write to the underlying writer. - pub fn get_mut(&mut self) -> &mut W { - self.w.as_mut().unwrap() - } - - /// Returns writer instance used by this encoder - pub fn into_inner(mut self) -> io::Result<W> { - self.write_trailer()?; - Ok(self.w.take().unwrap()) - } - - /// Write the final tailer. - fn write_trailer(&mut self) -> io::Result<()> { - self.w.as_mut().unwrap().write_le(Block::Trailer as u8) - } -} - -/// Encodes the data into the provided buffer. -/// -/// The first byte is the minimum code size, followed by LZW data. -fn lzw_encode(data: &[u8], buffer: &mut Vec<u8>) { - let min_code_size = match flag_size(1 + data.iter().copied().max().unwrap_or(0) as usize) + 1 { - 1 => 2, // As per gif spec: The minimal code size has to be >= 2 - n => n - }; - buffer.push(min_code_size); - let mut enc = LzwEncoder::new(BitOrder::Lsb, min_code_size); - let len = enc.into_vec(buffer).encode_all(data).consumed_out; - buffer.truncate(len+1); -} - -impl Frame<'_> { - /// Replace frame's buffer with a LZW-compressed one for use with [`Encoder::write_lzw_pre_encoded_frame`]. - /// - /// Frames can be compressed in any order, separately from the `Encoder`, which can be used to compress frames in parallel. - pub fn make_lzw_pre_encoded(&mut self) { - let mut buffer = Vec::with_capacity(self.buffer.len() / 2); - lzw_encode(&self.buffer, &mut buffer); - self.buffer = Cow::Owned(buffer); - } -} - -/// GIF encoder. -pub struct Encoder<W: Write> { - w: Option<W>, - global_palette: bool, - width: u16, - height: u16, - buffer: Vec<u8> -} - -impl<W: Write> Drop for Encoder<W> { - - #[cfg(feature = "raii_no_panic")] - fn drop(&mut self) { - if self.w.is_some() { - let _ = self.write_trailer(); - } - } - - #[cfg(not(feature = "raii_no_panic"))] - fn drop(&mut self) { - if self.w.is_some() { - self.write_trailer().unwrap(); - } - } -} - -// Color table size converted to flag bits -fn flag_size(size: usize) -> u8 { - match size { - 0 ..=2 => 0, - 3 ..=4 => 1, - 5 ..=8 => 2, - 9 ..=16 => 3, - 17 ..=32 => 4, - 33 ..=64 => 5, - 65 ..=128 => 6, - 129..=256 => 7, - _ => 7 - } -} - -#[test] -fn error_cast() { - let _ : Box<dyn error::Error> = EncodingError::from(FormatErrorKind::MissingColorPalette).into(); -} |