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Diffstat (limited to 'vendor/image/src/codecs/jpeg/encoder.rs')
| -rw-r--r-- | vendor/image/src/codecs/jpeg/encoder.rs | 1074 |
1 files changed, 1074 insertions, 0 deletions
diff --git a/vendor/image/src/codecs/jpeg/encoder.rs b/vendor/image/src/codecs/jpeg/encoder.rs new file mode 100644 index 0000000..edb2a05 --- /dev/null +++ b/vendor/image/src/codecs/jpeg/encoder.rs @@ -0,0 +1,1074 @@ +#![allow(clippy::too_many_arguments)] + +use std::borrow::Cow; +use std::convert::TryFrom; +use std::io::{self, Write}; + +use crate::error::{ + ImageError, ImageResult, ParameterError, ParameterErrorKind, UnsupportedError, + UnsupportedErrorKind, +}; +use crate::image::{ImageEncoder, ImageFormat}; +use crate::utils::clamp; +use crate::{ColorType, GenericImageView, ImageBuffer, Luma, LumaA, Pixel, Rgb, Rgba}; + +use super::entropy::build_huff_lut_const; +use super::transform; +use crate::traits::PixelWithColorType; + +// Markers +// Baseline DCT +static SOF0: u8 = 0xC0; +// Huffman Tables +static DHT: u8 = 0xC4; +// Start of Image (standalone) +static SOI: u8 = 0xD8; +// End of image (standalone) +static EOI: u8 = 0xD9; +// Start of Scan +static SOS: u8 = 0xDA; +// Quantization Tables +static DQT: u8 = 0xDB; +// Application segments start and end +static APP0: u8 = 0xE0; + +// section K.1 +// table K.1 +#[rustfmt::skip] +static STD_LUMA_QTABLE: [u8; 64] = [ + 16, 11, 10, 16, 24, 40, 51, 61, + 12, 12, 14, 19, 26, 58, 60, 55, + 14, 13, 16, 24, 40, 57, 69, 56, + 14, 17, 22, 29, 51, 87, 80, 62, + 18, 22, 37, 56, 68, 109, 103, 77, + 24, 35, 55, 64, 81, 104, 113, 92, + 49, 64, 78, 87, 103, 121, 120, 101, + 72, 92, 95, 98, 112, 100, 103, 99, +]; + +// table K.2 +#[rustfmt::skip] +static STD_CHROMA_QTABLE: [u8; 64] = [ + 17, 18, 24, 47, 99, 99, 99, 99, + 18, 21, 26, 66, 99, 99, 99, 99, + 24, 26, 56, 99, 99, 99, 99, 99, + 47, 66, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, +]; + +// section K.3 +// Code lengths and values for table K.3 +static STD_LUMA_DC_CODE_LENGTHS: [u8; 16] = [ + 0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, +]; + +static STD_LUMA_DC_VALUES: [u8; 12] = [ + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, +]; + +static STD_LUMA_DC_HUFF_LUT: [(u8, u16); 256] = + build_huff_lut_const(&STD_LUMA_DC_CODE_LENGTHS, &STD_LUMA_DC_VALUES); + +// Code lengths and values for table K.4 +static STD_CHROMA_DC_CODE_LENGTHS: [u8; 16] = [ + 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, +]; + +static STD_CHROMA_DC_VALUES: [u8; 12] = [ + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, +]; + +static STD_CHROMA_DC_HUFF_LUT: [(u8, u16); 256] = + build_huff_lut_const(&STD_CHROMA_DC_CODE_LENGTHS, &STD_CHROMA_DC_VALUES); + +// Code lengths and values for table k.5 +static STD_LUMA_AC_CODE_LENGTHS: [u8; 16] = [ + 0x00, 0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03, 0x05, 0x05, 0x04, 0x04, 0x00, 0x00, 0x01, 0x7D, +]; + +static STD_LUMA_AC_VALUES: [u8; 162] = [ + 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, + 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1, 0x08, 0x23, 0x42, 0xB1, 0xC1, 0x15, 0x52, 0xD1, 0xF0, + 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0A, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28, + 0x29, 0x2A, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, + 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, + 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, + 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, + 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5, + 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xE1, 0xE2, + 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, + 0xF9, 0xFA, +]; + +static STD_LUMA_AC_HUFF_LUT: [(u8, u16); 256] = + build_huff_lut_const(&STD_LUMA_AC_CODE_LENGTHS, &STD_LUMA_AC_VALUES); + +// Code lengths and values for table k.6 +static STD_CHROMA_AC_CODE_LENGTHS: [u8; 16] = [ + 0x00, 0x02, 0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07, 0x05, 0x04, 0x04, 0x00, 0x01, 0x02, 0x77, +]; +static STD_CHROMA_AC_VALUES: [u8; 162] = [ + 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, + 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xA1, 0xB1, 0xC1, 0x09, 0x23, 0x33, 0x52, 0xF0, + 0x15, 0x62, 0x72, 0xD1, 0x0A, 0x16, 0x24, 0x34, 0xE1, 0x25, 0xF1, 0x17, 0x18, 0x19, 0x1A, 0x26, + 0x27, 0x28, 0x29, 0x2A, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, + 0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, + 0x69, 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, + 0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, + 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, + 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, + 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, + 0xF9, 0xFA, +]; + +static STD_CHROMA_AC_HUFF_LUT: [(u8, u16); 256] = + build_huff_lut_const(&STD_CHROMA_AC_CODE_LENGTHS, &STD_CHROMA_AC_VALUES); + +static DCCLASS: u8 = 0; +static ACCLASS: u8 = 1; + +static LUMADESTINATION: u8 = 0; +static CHROMADESTINATION: u8 = 1; + +static LUMAID: u8 = 1; +static CHROMABLUEID: u8 = 2; +static CHROMAREDID: u8 = 3; + +/// The permutation of dct coefficients. +#[rustfmt::skip] +static UNZIGZAG: [u8; 64] = [ + 0, 1, 8, 16, 9, 2, 3, 10, + 17, 24, 32, 25, 18, 11, 4, 5, + 12, 19, 26, 33, 40, 48, 41, 34, + 27, 20, 13, 6, 7, 14, 21, 28, + 35, 42, 49, 56, 57, 50, 43, 36, + 29, 22, 15, 23, 30, 37, 44, 51, + 58, 59, 52, 45, 38, 31, 39, 46, + 53, 60, 61, 54, 47, 55, 62, 63, +]; + +/// A representation of a JPEG component +#[derive(Copy, Clone)] +struct Component { + /// The Component's identifier + id: u8, + + /// Horizontal sampling factor + h: u8, + + /// Vertical sampling factor + v: u8, + + /// The quantization table selector + tq: u8, + + /// Index to the Huffman DC Table + dc_table: u8, + + /// Index to the AC Huffman Table + ac_table: u8, + + /// The dc prediction of the component + _dc_pred: i32, +} + +pub(crate) struct BitWriter<W> { + w: W, + accumulator: u32, + nbits: u8, +} + +impl<W: Write> BitWriter<W> { + fn new(w: W) -> Self { + BitWriter { + w, + accumulator: 0, + nbits: 0, + } + } + + fn write_bits(&mut self, bits: u16, size: u8) -> io::Result<()> { + if size == 0 { + return Ok(()); + } + + self.nbits += size; + self.accumulator |= u32::from(bits) << (32 - self.nbits) as usize; + + while self.nbits >= 8 { + let byte = self.accumulator >> 24; + self.w.write_all(&[byte as u8])?; + + if byte == 0xFF { + self.w.write_all(&[0x00])?; + } + + self.nbits -= 8; + self.accumulator <<= 8; + } + + Ok(()) + } + + fn pad_byte(&mut self) -> io::Result<()> { + self.write_bits(0x7F, 7) + } + + fn huffman_encode(&mut self, val: u8, table: &[(u8, u16); 256]) -> io::Result<()> { + let (size, code) = table[val as usize]; + + if size > 16 { + panic!("bad huffman value"); + } + + self.write_bits(code, size) + } + + fn write_block( + &mut self, + block: &[i32; 64], + prevdc: i32, + dctable: &[(u8, u16); 256], + actable: &[(u8, u16); 256], + ) -> io::Result<i32> { + // Differential DC encoding + let dcval = block[0]; + let diff = dcval - prevdc; + let (size, value) = encode_coefficient(diff); + + self.huffman_encode(size, dctable)?; + self.write_bits(value, size)?; + + // Figure F.2 + let mut zero_run = 0; + + for &k in &UNZIGZAG[1..] { + if block[k as usize] == 0 { + zero_run += 1; + } else { + while zero_run > 15 { + self.huffman_encode(0xF0, actable)?; + zero_run -= 16; + } + + let (size, value) = encode_coefficient(block[k as usize]); + let symbol = (zero_run << 4) | size; + + self.huffman_encode(symbol, actable)?; + self.write_bits(value, size)?; + + zero_run = 0; + } + } + + if block[UNZIGZAG[63] as usize] == 0 { + self.huffman_encode(0x00, actable)?; + } + + Ok(dcval) + } + + fn write_marker(&mut self, marker: u8) -> io::Result<()> { + self.w.write_all(&[0xFF, marker]) + } + + fn write_segment(&mut self, marker: u8, data: &[u8]) -> io::Result<()> { + self.w.write_all(&[0xFF, marker])?; + self.w.write_all(&(data.len() as u16 + 2).to_be_bytes())?; + self.w.write_all(data) + } +} + +/// Represents a unit in which the density of an image is measured +#[derive(Clone, Copy, Debug, Eq, PartialEq)] +pub enum PixelDensityUnit { + /// Represents the absence of a unit, the values indicate only a + /// [pixel aspect ratio](https://en.wikipedia.org/wiki/Pixel_aspect_ratio) + PixelAspectRatio, + + /// Pixels per inch (2.54 cm) + Inches, + + /// Pixels per centimeter + Centimeters, +} + +/// Represents the pixel density of an image +/// +/// For example, a 300 DPI image is represented by: +/// +/// ```rust +/// use image::codecs::jpeg::*; +/// let hdpi = PixelDensity::dpi(300); +/// assert_eq!(hdpi, PixelDensity {density: (300,300), unit: PixelDensityUnit::Inches}) +/// ``` +#[derive(Clone, Copy, Debug, Eq, PartialEq)] +pub struct PixelDensity { + /// A couple of values for (Xdensity, Ydensity) + pub density: (u16, u16), + /// The unit in which the density is measured + pub unit: PixelDensityUnit, +} + +impl PixelDensity { + /// Creates the most common pixel density type: + /// the horizontal and the vertical density are equal, + /// and measured in pixels per inch. + pub fn dpi(density: u16) -> Self { + PixelDensity { + density: (density, density), + unit: PixelDensityUnit::Inches, + } + } +} + +impl Default for PixelDensity { + /// Returns a pixel density with a pixel aspect ratio of 1 + fn default() -> Self { + PixelDensity { + density: (1, 1), + unit: PixelDensityUnit::PixelAspectRatio, + } + } +} + +/// The representation of a JPEG encoder +pub struct JpegEncoder<W> { + writer: BitWriter<W>, + + components: Vec<Component>, + tables: Vec<[u8; 64]>, + + luma_dctable: Cow<'static, [(u8, u16); 256]>, + luma_actable: Cow<'static, [(u8, u16); 256]>, + chroma_dctable: Cow<'static, [(u8, u16); 256]>, + chroma_actable: Cow<'static, [(u8, u16); 256]>, + + pixel_density: PixelDensity, +} + +impl<W: Write> JpegEncoder<W> { + /// Create a new encoder that writes its output to ```w``` + pub fn new(w: W) -> JpegEncoder<W> { + JpegEncoder::new_with_quality(w, 75) + } + + /// Create a new encoder that writes its output to ```w```, and has + /// the quality parameter ```quality``` with a value in the range 1-100 + /// where 1 is the worst and 100 is the best. + pub fn new_with_quality(w: W, quality: u8) -> JpegEncoder<W> { + let components = vec![ + Component { + id: LUMAID, + h: 1, + v: 1, + tq: LUMADESTINATION, + dc_table: LUMADESTINATION, + ac_table: LUMADESTINATION, + _dc_pred: 0, + }, + Component { + id: CHROMABLUEID, + h: 1, + v: 1, + tq: CHROMADESTINATION, + dc_table: CHROMADESTINATION, + ac_table: CHROMADESTINATION, + _dc_pred: 0, + }, + Component { + id: CHROMAREDID, + h: 1, + v: 1, + tq: CHROMADESTINATION, + dc_table: CHROMADESTINATION, + ac_table: CHROMADESTINATION, + _dc_pred: 0, + }, + ]; + + // Derive our quantization table scaling value using the libjpeg algorithm + let scale = u32::from(clamp(quality, 1, 100)); + let scale = if scale < 50 { + 5000 / scale + } else { + 200 - scale * 2 + }; + + let mut tables = vec![STD_LUMA_QTABLE, STD_CHROMA_QTABLE]; + tables.iter_mut().for_each(|t| { + t.iter_mut().for_each(|v| { + *v = clamp( + (u32::from(*v) * scale + 50) / 100, + 1, + u32::from(u8::max_value()), + ) as u8; + }) + }); + + JpegEncoder { + writer: BitWriter::new(w), + + components, + tables, + + luma_dctable: Cow::Borrowed(&STD_LUMA_DC_HUFF_LUT), + luma_actable: Cow::Borrowed(&STD_LUMA_AC_HUFF_LUT), + chroma_dctable: Cow::Borrowed(&STD_CHROMA_DC_HUFF_LUT), + chroma_actable: Cow::Borrowed(&STD_CHROMA_AC_HUFF_LUT), + + pixel_density: PixelDensity::default(), + } + } + + /// Set the pixel density of the images the encoder will encode. + /// If this method is not called, then a default pixel aspect ratio of 1x1 will be applied, + /// and no DPI information will be stored in the image. + pub fn set_pixel_density(&mut self, pixel_density: PixelDensity) { + self.pixel_density = pixel_density; + } + + /// Encodes the image stored in the raw byte buffer ```image``` + /// that has dimensions ```width``` and ```height``` + /// and ```ColorType``` ```c``` + /// + /// The Image in encoded with subsampling ratio 4:2:2 + pub fn encode( + &mut self, + image: &[u8], + width: u32, + height: u32, + color_type: ColorType, + ) -> ImageResult<()> { + match color_type { + ColorType::L8 => { + let image: ImageBuffer<Luma<_>, _> = + ImageBuffer::from_raw(width, height, image).unwrap(); + self.encode_image(&image) + } + ColorType::La8 => { + let image: ImageBuffer<LumaA<_>, _> = + ImageBuffer::from_raw(width, height, image).unwrap(); + self.encode_image(&image) + } + ColorType::Rgb8 => { + let image: ImageBuffer<Rgb<_>, _> = + ImageBuffer::from_raw(width, height, image).unwrap(); + self.encode_image(&image) + } + ColorType::Rgba8 => { + let image: ImageBuffer<Rgba<_>, _> = + ImageBuffer::from_raw(width, height, image).unwrap(); + self.encode_image(&image) + } + _ => Err(ImageError::Unsupported( + UnsupportedError::from_format_and_kind( + ImageFormat::Jpeg.into(), + UnsupportedErrorKind::Color(color_type.into()), + ), + )), + } + } + + /// Encodes the given image. + /// + /// As a special feature this does not require the whole image to be present in memory at the + /// same time such that it may be computed on the fly, which is why this method exists on this + /// encoder but not on others. Instead the encoder will iterate over 8-by-8 blocks of pixels at + /// a time, inspecting each pixel exactly once. You can rely on this behaviour when calling + /// this method. + /// + /// The Image in encoded with subsampling ratio 4:2:2 + pub fn encode_image<I: GenericImageView>(&mut self, image: &I) -> ImageResult<()> + where + I::Pixel: PixelWithColorType, + { + let n = I::Pixel::CHANNEL_COUNT; + let color_type = I::Pixel::COLOR_TYPE; + let num_components = if n == 1 || n == 2 { 1 } else { 3 }; + + self.writer.write_marker(SOI)?; + + let mut buf = Vec::new(); + + build_jfif_header(&mut buf, self.pixel_density); + self.writer.write_segment(APP0, &buf)?; + + build_frame_header( + &mut buf, + 8, + // TODO: not idiomatic yet. Should be an EncodingError and mention jpg. Further it + // should check dimensions prior to writing. + u16::try_from(image.width()).map_err(|_| { + ImageError::Parameter(ParameterError::from_kind( + ParameterErrorKind::DimensionMismatch, + )) + })?, + u16::try_from(image.height()).map_err(|_| { + ImageError::Parameter(ParameterError::from_kind( + ParameterErrorKind::DimensionMismatch, + )) + })?, + &self.components[..num_components], + ); + self.writer.write_segment(SOF0, &buf)?; + + assert_eq!(self.tables.len(), 2); + let numtables = if num_components == 1 { 1 } else { 2 }; + + for (i, table) in self.tables[..numtables].iter().enumerate() { + build_quantization_segment(&mut buf, 8, i as u8, table); + self.writer.write_segment(DQT, &buf)?; + } + + build_huffman_segment( + &mut buf, + DCCLASS, + LUMADESTINATION, + &STD_LUMA_DC_CODE_LENGTHS, + &STD_LUMA_DC_VALUES, + ); + self.writer.write_segment(DHT, &buf)?; + + build_huffman_segment( + &mut buf, + ACCLASS, + LUMADESTINATION, + &STD_LUMA_AC_CODE_LENGTHS, + &STD_LUMA_AC_VALUES, + ); + self.writer.write_segment(DHT, &buf)?; + + if num_components == 3 { + build_huffman_segment( + &mut buf, + DCCLASS, + CHROMADESTINATION, + &STD_CHROMA_DC_CODE_LENGTHS, + &STD_CHROMA_DC_VALUES, + ); + self.writer.write_segment(DHT, &buf)?; + + build_huffman_segment( + &mut buf, + ACCLASS, + CHROMADESTINATION, + &STD_CHROMA_AC_CODE_LENGTHS, + &STD_CHROMA_AC_VALUES, + ); + self.writer.write_segment(DHT, &buf)?; + } + + build_scan_header(&mut buf, &self.components[..num_components]); + self.writer.write_segment(SOS, &buf)?; + + if color_type.has_color() { + self.encode_rgb(image) + } else { + self.encode_gray(image) + }?; + + self.writer.pad_byte()?; + self.writer.write_marker(EOI)?; + Ok(()) + } + + fn encode_gray<I: GenericImageView>(&mut self, image: &I) -> io::Result<()> { + let mut yblock = [0u8; 64]; + let mut y_dcprev = 0; + let mut dct_yblock = [0i32; 64]; + + for y in (0..image.height()).step_by(8) { + for x in (0..image.width()).step_by(8) { + copy_blocks_gray(image, x, y, &mut yblock); + + // Level shift and fdct + // Coeffs are scaled by 8 + transform::fdct(&yblock, &mut dct_yblock); + + // Quantization + for (i, dct) in dct_yblock.iter_mut().enumerate() { + *dct = ((*dct / 8) as f32 / f32::from(self.tables[0][i])).round() as i32; + } + + let la = &*self.luma_actable; + let ld = &*self.luma_dctable; + + y_dcprev = self.writer.write_block(&dct_yblock, y_dcprev, ld, la)?; + } + } + + Ok(()) + } + + fn encode_rgb<I: GenericImageView>(&mut self, image: &I) -> io::Result<()> { + let mut y_dcprev = 0; + let mut cb_dcprev = 0; + let mut cr_dcprev = 0; + + let mut dct_yblock = [0i32; 64]; + let mut dct_cb_block = [0i32; 64]; + let mut dct_cr_block = [0i32; 64]; + + let mut yblock = [0u8; 64]; + let mut cb_block = [0u8; 64]; + let mut cr_block = [0u8; 64]; + + for y in (0..image.height()).step_by(8) { + for x in (0..image.width()).step_by(8) { + // RGB -> YCbCr + copy_blocks_ycbcr(image, x, y, &mut yblock, &mut cb_block, &mut cr_block); + + // Level shift and fdct + // Coeffs are scaled by 8 + transform::fdct(&yblock, &mut dct_yblock); + transform::fdct(&cb_block, &mut dct_cb_block); + transform::fdct(&cr_block, &mut dct_cr_block); + + // Quantization + for i in 0usize..64 { + dct_yblock[i] = + ((dct_yblock[i] / 8) as f32 / f32::from(self.tables[0][i])).round() as i32; + dct_cb_block[i] = ((dct_cb_block[i] / 8) as f32 / f32::from(self.tables[1][i])) + .round() as i32; + dct_cr_block[i] = ((dct_cr_block[i] / 8) as f32 / f32::from(self.tables[1][i])) + .round() as i32; + } + + let la = &*self.luma_actable; + let ld = &*self.luma_dctable; + let cd = &*self.chroma_dctable; + let ca = &*self.chroma_actable; + + y_dcprev = self.writer.write_block(&dct_yblock, y_dcprev, ld, la)?; + cb_dcprev = self.writer.write_block(&dct_cb_block, cb_dcprev, cd, ca)?; + cr_dcprev = self.writer.write_block(&dct_cr_block, cr_dcprev, cd, ca)?; + } + } + + Ok(()) + } +} + +impl<W: Write> ImageEncoder for JpegEncoder<W> { + fn write_image( + mut self, + buf: &[u8], + width: u32, + height: u32, + color_type: ColorType, + ) -> ImageResult<()> { + self.encode(buf, width, height, color_type) + } +} + +fn build_jfif_header(m: &mut Vec<u8>, density: PixelDensity) { + m.clear(); + m.extend_from_slice(b"JFIF"); + m.extend_from_slice(&[ + 0, + 0x01, + 0x02, + match density.unit { + PixelDensityUnit::PixelAspectRatio => 0x00, + PixelDensityUnit::Inches => 0x01, + PixelDensityUnit::Centimeters => 0x02, + }, + ]); + m.extend_from_slice(&density.density.0.to_be_bytes()); + m.extend_from_slice(&density.density.1.to_be_bytes()); + m.extend_from_slice(&[0, 0]); +} + +fn build_frame_header( + m: &mut Vec<u8>, + precision: u8, + width: u16, + height: u16, + components: &[Component], +) { + m.clear(); + + m.push(precision); + m.extend_from_slice(&height.to_be_bytes()); + m.extend_from_slice(&width.to_be_bytes()); + m.push(components.len() as u8); + + for &comp in components.iter() { + let hv = (comp.h << 4) | comp.v; + m.extend_from_slice(&[comp.id, hv, comp.tq]); + } +} + +fn build_scan_header(m: &mut Vec<u8>, components: &[Component]) { + m.clear(); + + m.push(components.len() as u8); + + for &comp in components.iter() { + let tables = (comp.dc_table << 4) | comp.ac_table; + m.extend_from_slice(&[comp.id, tables]); + } + + // spectral start and end, approx. high and low + m.extend_from_slice(&[0, 63, 0]); +} + +fn build_huffman_segment( + m: &mut Vec<u8>, + class: u8, + destination: u8, + numcodes: &[u8; 16], + values: &[u8], +) { + m.clear(); + + let tcth = (class << 4) | destination; + m.push(tcth); + + m.extend_from_slice(numcodes); + + let sum: usize = numcodes.iter().map(|&x| x as usize).sum(); + + assert_eq!(sum, values.len()); + + m.extend_from_slice(values); +} + +fn build_quantization_segment(m: &mut Vec<u8>, precision: u8, identifier: u8, qtable: &[u8; 64]) { + m.clear(); + + let p = if precision == 8 { 0 } else { 1 }; + + let pqtq = (p << 4) | identifier; + m.push(pqtq); + + for &i in &UNZIGZAG[..] { + m.push(qtable[i as usize]); + } +} + +fn encode_coefficient(coefficient: i32) -> (u8, u16) { + let mut magnitude = coefficient.unsigned_abs() as u16; + let mut num_bits = 0u8; + + while magnitude > 0 { + magnitude >>= 1; + num_bits += 1; + } + + let mask = (1 << num_bits as usize) - 1; + + let val = if coefficient < 0 { + (coefficient - 1) as u16 & mask + } else { + coefficient as u16 & mask + }; + + (num_bits, val) +} + +#[inline] +fn rgb_to_ycbcr<P: Pixel>(pixel: P) -> (u8, u8, u8) { + use crate::traits::Primitive; + use num_traits::cast::ToPrimitive; + + let [r, g, b] = pixel.to_rgb().0; + let max: f32 = P::Subpixel::DEFAULT_MAX_VALUE.to_f32().unwrap(); + let r: f32 = r.to_f32().unwrap(); + let g: f32 = g.to_f32().unwrap(); + let b: f32 = b.to_f32().unwrap(); + + // Coefficients from JPEG File Interchange Format (Version 1.02), multiplied for 255 maximum. + let y = 76.245 / max * r + 149.685 / max * g + 29.07 / max * b; + let cb = -43.0185 / max * r - 84.4815 / max * g + 127.5 / max * b + 128.; + let cr = 127.5 / max * r - 106.7685 / max * g - 20.7315 / max * b + 128.; + + (y as u8, cb as u8, cr as u8) +} + +/// Returns the pixel at (x,y) if (x,y) is in the image, +/// otherwise the closest pixel in the image +#[inline] +fn pixel_at_or_near<I: GenericImageView>(source: &I, x: u32, y: u32) -> I::Pixel { + if source.in_bounds(x, y) { + source.get_pixel(x, y) + } else { + source.get_pixel(x.min(source.width() - 1), y.min(source.height() - 1)) + } +} + +fn copy_blocks_ycbcr<I: GenericImageView>( + source: &I, + x0: u32, + y0: u32, + yb: &mut [u8; 64], + cbb: &mut [u8; 64], + crb: &mut [u8; 64], +) { + for y in 0..8 { + for x in 0..8 { + let pixel = pixel_at_or_near(source, x + x0, y + y0); + let (yc, cb, cr) = rgb_to_ycbcr(pixel); + + yb[(y * 8 + x) as usize] = yc; + cbb[(y * 8 + x) as usize] = cb; + crb[(y * 8 + x) as usize] = cr; + } + } +} + +fn copy_blocks_gray<I: GenericImageView>(source: &I, x0: u32, y0: u32, gb: &mut [u8; 64]) { + use num_traits::cast::ToPrimitive; + for y in 0..8 { + for x in 0..8 { + let pixel = pixel_at_or_near(source, x0 + x, y0 + y); + let [luma] = pixel.to_luma().0; + gb[(y * 8 + x) as usize] = luma.to_u8().unwrap(); + } + } +} + +#[cfg(test)] +mod tests { + use std::io::Cursor; + + #[cfg(feature = "benchmarks")] + extern crate test; + #[cfg(feature = "benchmarks")] + use test::Bencher; + + use crate::color::ColorType; + use crate::error::ParameterErrorKind::DimensionMismatch; + use crate::image::ImageDecoder; + use crate::{ImageEncoder, ImageError}; + + use super::super::JpegDecoder; + use super::{ + build_frame_header, build_huffman_segment, build_jfif_header, build_quantization_segment, + build_scan_header, Component, JpegEncoder, PixelDensity, DCCLASS, LUMADESTINATION, + STD_LUMA_DC_CODE_LENGTHS, STD_LUMA_DC_VALUES, + }; + + fn decode(encoded: &[u8]) -> Vec<u8> { + let decoder = JpegDecoder::new(Cursor::new(encoded)).expect("Could not decode image"); + + let mut decoded = vec![0; decoder.total_bytes() as usize]; + decoder + .read_image(&mut decoded) + .expect("Could not decode image"); + decoded + } + + #[test] + fn roundtrip_sanity_check() { + // create a 1x1 8-bit image buffer containing a single red pixel + let img = [255u8, 0, 0]; + + // encode it into a memory buffer + let mut encoded_img = Vec::new(); + { + let encoder = JpegEncoder::new_with_quality(&mut encoded_img, 100); + encoder + .write_image(&img, 1, 1, ColorType::Rgb8) + .expect("Could not encode image"); + } + + // decode it from the memory buffer + { + let decoded = decode(&encoded_img); + // note that, even with the encode quality set to 100, we do not get the same image + // back. Therefore, we're going to assert that it's at least red-ish: + assert_eq!(3, decoded.len()); + assert!(decoded[0] > 0x80); + assert!(decoded[1] < 0x80); + assert!(decoded[2] < 0x80); + } + } + + #[test] + fn grayscale_roundtrip_sanity_check() { + // create a 2x2 8-bit image buffer containing a white diagonal + let img = [255u8, 0, 0, 255]; + + // encode it into a memory buffer + let mut encoded_img = Vec::new(); + { + let encoder = JpegEncoder::new_with_quality(&mut encoded_img, 100); + encoder + .write_image(&img[..], 2, 2, ColorType::L8) + .expect("Could not encode image"); + } + + // decode it from the memory buffer + { + let decoded = decode(&encoded_img); + // note that, even with the encode quality set to 100, we do not get the same image + // back. Therefore, we're going to assert that the diagonal is at least white-ish: + assert_eq!(4, decoded.len()); + assert!(decoded[0] > 0x80); + assert!(decoded[1] < 0x80); + assert!(decoded[2] < 0x80); + assert!(decoded[3] > 0x80); + } + } + + #[test] + fn jfif_header_density_check() { + let mut buffer = Vec::new(); + build_jfif_header(&mut buffer, PixelDensity::dpi(300)); + assert_eq!( + buffer, + vec![ + b'J', + b'F', + b'I', + b'F', + 0, + 1, + 2, // JFIF version 1.2 + 1, // density is in dpi + 300u16.to_be_bytes()[0], + 300u16.to_be_bytes()[1], + 300u16.to_be_bytes()[0], + 300u16.to_be_bytes()[1], + 0, + 0, // No thumbnail + ] + ); + } + + #[test] + fn test_image_too_large() { + // JPEG cannot encode images larger than 65,535×65,535 + // create a 65,536×1 8-bit black image buffer + let img = [0; 65_536]; + // Try to encode an image that is too large + let mut encoded = Vec::new(); + let encoder = JpegEncoder::new_with_quality(&mut encoded, 100); + let result = encoder.write_image(&img, 65_536, 1, ColorType::L8); + match result { + Err(ImageError::Parameter(err)) => { + assert_eq!(err.kind(), DimensionMismatch) + } + other => { + assert!( + false, + "Encoding an image that is too large should return a DimensionError \ + it returned {:?} instead", + other + ) + } + } + } + + #[test] + fn test_build_jfif_header() { + let mut buf = vec![]; + let density = PixelDensity::dpi(100); + build_jfif_header(&mut buf, density); + assert_eq!( + buf, + [0x4A, 0x46, 0x49, 0x46, 0x00, 0x01, 0x02, 0x01, 0, 100, 0, 100, 0, 0] + ); + } + + #[test] + fn test_build_frame_header() { + let mut buf = vec![]; + let components = vec![ + Component { + id: 1, + h: 1, + v: 1, + tq: 5, + dc_table: 5, + ac_table: 5, + _dc_pred: 0, + }, + Component { + id: 2, + h: 1, + v: 1, + tq: 4, + dc_table: 4, + ac_table: 4, + _dc_pred: 0, + }, + ]; + build_frame_header(&mut buf, 5, 100, 150, &components); + assert_eq!( + buf, + [5, 0, 150, 0, 100, 2, 1, 1 << 4 | 1, 5, 2, 1 << 4 | 1, 4] + ); + } + + #[test] + fn test_build_scan_header() { + let mut buf = vec![]; + let components = vec![ + Component { + id: 1, + h: 1, + v: 1, + tq: 5, + dc_table: 5, + ac_table: 5, + _dc_pred: 0, + }, + Component { + id: 2, + h: 1, + v: 1, + tq: 4, + dc_table: 4, + ac_table: 4, + _dc_pred: 0, + }, + ]; + build_scan_header(&mut buf, &components); + assert_eq!(buf, [2, 1, 5 << 4 | 5, 2, 4 << 4 | 4, 0, 63, 0]); + } + + #[test] + fn test_build_huffman_segment() { + let mut buf = vec![]; + build_huffman_segment( + &mut buf, + DCCLASS, + LUMADESTINATION, + &STD_LUMA_DC_CODE_LENGTHS, + &STD_LUMA_DC_VALUES, + ); + assert_eq!( + buf, + vec![ + 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, + 10, 11 + ] + ); + } + + #[test] + fn test_build_quantization_segment() { + let mut buf = vec![]; + let qtable = [0u8; 64]; + build_quantization_segment(&mut buf, 8, 1, &qtable); + let mut expected = vec![]; + expected.push(0 << 4 | 1); + expected.extend_from_slice(&[0; 64]); + assert_eq!(buf, expected) + } + + #[cfg(feature = "benchmarks")] + #[bench] + fn bench_jpeg_encoder_new(b: &mut Bencher) { + b.iter(|| { + let mut y = vec![]; + let x = JpegEncoder::new(&mut y); + }) + } +} |