#![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, accumulator: u32, nbits: u8, } impl BitWriter { 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 { // 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 { writer: BitWriter, components: Vec, 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 JpegEncoder { /// Create a new encoder that writes its output to ```w``` pub fn new(w: W) -> JpegEncoder { 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 { 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, _> = ImageBuffer::from_raw(width, height, image).unwrap(); self.encode_image(&image) } ColorType::La8 => { let image: ImageBuffer, _> = ImageBuffer::from_raw(width, height, image).unwrap(); self.encode_image(&image) } ColorType::Rgb8 => { let image: ImageBuffer, _> = ImageBuffer::from_raw(width, height, image).unwrap(); self.encode_image(&image) } ColorType::Rgba8 => { let image: ImageBuffer, _> = 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(&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(&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(&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 ImageEncoder for JpegEncoder { 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, 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, 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, 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, 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, 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(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(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( 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(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 { 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); }) } }