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| 1 | +use image::{ |
| 2 | + imageops::{colorops, FilterType}, |
| 3 | + math::nq::NeuQuant, |
| 4 | + DynamicImage, GenericImageView, ImageBuffer, Pixel, Rgb, |
| 5 | +}; |
| 6 | +use libc::{ |
| 7 | + c_void, ioctl, poll, pollfd, read, tcgetattr, tcsetattr, termios, winsize, ECHO, ICANON, |
| 8 | + POLLIN, STDIN_FILENO, STDOUT_FILENO, TCSANOW, TIOCGWINSZ, |
| 9 | +}; |
| 10 | +use std::time::Instant; |
| 11 | + |
| 12 | +pub struct SixelBackend {} |
| 13 | + |
| 14 | +impl SixelBackend { |
| 15 | + pub fn new() -> Self { |
| 16 | + Self {} |
| 17 | + } |
| 18 | + |
| 19 | + pub fn supported() -> bool { |
| 20 | + // save terminal attributes and disable canonical input processing mode |
| 21 | + let old_attributes = unsafe { |
| 22 | + let mut old_attributes: termios = std::mem::zeroed(); |
| 23 | + tcgetattr(STDIN_FILENO, &mut old_attributes); |
| 24 | + |
| 25 | + let mut new_attributes = old_attributes; |
| 26 | + new_attributes.c_lflag &= !ICANON; |
| 27 | + new_attributes.c_lflag &= !ECHO; |
| 28 | + tcsetattr(STDIN_FILENO, TCSANOW, &new_attributes); |
| 29 | + old_attributes |
| 30 | + }; |
| 31 | + |
| 32 | + // ask for the primary device attribute string |
| 33 | + println!("\x1B[c"); |
| 34 | + |
| 35 | + let start_time = Instant::now(); |
| 36 | + let mut stdin_pollfd = pollfd { |
| 37 | + fd: STDIN_FILENO, |
| 38 | + events: POLLIN, |
| 39 | + revents: 0, |
| 40 | + }; |
| 41 | + let mut buf = Vec::<u8>::new(); |
| 42 | + loop { |
| 43 | + // check for timeout while polling to avoid blocking the main thread |
| 44 | + while unsafe { poll(&mut stdin_pollfd, 1, 0) < 1 } { |
| 45 | + if start_time.elapsed().as_millis() > 50 { |
| 46 | + unsafe { |
| 47 | + tcsetattr(STDIN_FILENO, TCSANOW, &old_attributes); |
| 48 | + } |
| 49 | + return false; |
| 50 | + } |
| 51 | + } |
| 52 | + let mut byte = 0; |
| 53 | + unsafe { |
| 54 | + read(STDIN_FILENO, &mut byte as *mut _ as *mut c_void, 1); |
| 55 | + } |
| 56 | + buf.push(byte); |
| 57 | + if buf.starts_with(&[0x1B, b'[', b'?']) && buf.ends_with(&[b'c']) { |
| 58 | + for attribute in buf[3..(buf.len() - 1)].split(|x| *x == b';') { |
| 59 | + if attribute == &[b'4'] { |
| 60 | + unsafe { |
| 61 | + tcsetattr(STDIN_FILENO, TCSANOW, &old_attributes); |
| 62 | + } |
| 63 | + return true; |
| 64 | + } |
| 65 | + } |
| 66 | + } |
| 67 | + } |
| 68 | + } |
| 69 | +} |
| 70 | + |
| 71 | +impl super::ImageBackend for SixelBackend { |
| 72 | + fn add_image(&self, lines: Vec<String>, image: &DynamicImage) -> String { |
| 73 | + let tty_size = unsafe { |
| 74 | + let tty_size: winsize = std::mem::zeroed(); |
| 75 | + ioctl(STDOUT_FILENO, TIOCGWINSZ, &tty_size); |
| 76 | + tty_size |
| 77 | + }; |
| 78 | + let width_ratio = tty_size.ws_col as f64 / tty_size.ws_xpixel as f64; |
| 79 | + let height_ratio = tty_size.ws_row as f64 / tty_size.ws_ypixel as f64; |
| 80 | + |
| 81 | + // resize image to fit the text height with the Lanczos3 algorithm |
| 82 | + let image = image.resize( |
| 83 | + u32::max_value(), |
| 84 | + (lines.len() as f64 / height_ratio) as u32, |
| 85 | + FilterType::Lanczos3, |
| 86 | + ); |
| 87 | + let image_columns = width_ratio * image.width() as f64; |
| 88 | + let image_rows = height_ratio * image.height() as f64; |
| 89 | + |
| 90 | + let rgba_image = image.to_rgba(); // convert the image to rgba samples |
| 91 | + let flat_samples = rgba_image.as_flat_samples(); |
| 92 | + let mut rgba_image = rgba_image.clone(); |
| 93 | + // reduce the amount of colors using dithering |
| 94 | + colorops::dither( |
| 95 | + &mut rgba_image, |
| 96 | + &NeuQuant::new(10, 16, flat_samples.image_slice().unwrap()), |
| 97 | + ); |
| 98 | + let rgb_image = ImageBuffer::from_fn(rgba_image.width(), rgba_image.height(), |x, y| { |
| 99 | + let rgba_pixel = rgba_image.get_pixel(x, y); |
| 100 | + let mut rgb_pixel = rgba_pixel.to_rgb(); |
| 101 | + for subpixel in &mut rgb_pixel.0 { |
| 102 | + *subpixel = (*subpixel as f32 / 255.0 * rgba_pixel[3] as f32) as u8; |
| 103 | + } |
| 104 | + rgb_pixel |
| 105 | + }); |
| 106 | + |
| 107 | + let mut image_data = Vec::<u8>::new(); |
| 108 | + image_data.extend("\x1BPq".as_bytes()); // start sixel data |
| 109 | + image_data.extend(format!("\"1;1;{};{}", image.width(), image.height()).as_bytes()); |
| 110 | + |
| 111 | + let mut colors = std::collections::HashMap::<Rgb<u8>, u8>::new(); |
| 112 | + // subtract 1 -> divide -> add 1 to round up the integer division |
| 113 | + for i in 0..((rgb_image.height() - 1) / 6 + 1) { |
| 114 | + let sixel_row = rgb_image.view( |
| 115 | + 0, |
| 116 | + i * 6, |
| 117 | + rgb_image.width(), |
| 118 | + std::cmp::min(6, rgb_image.height() - i * 6), |
| 119 | + ); |
| 120 | + for (_, _, pixel) in sixel_row.pixels() { |
| 121 | + if !colors.contains_key(&pixel) { |
| 122 | + // sixel uses percentages for rgb values |
| 123 | + let color_multiplier = 100.0 / 255.0; |
| 124 | + image_data.extend( |
| 125 | + format!( |
| 126 | + "#{};2;{};{};{}", |
| 127 | + colors.len(), |
| 128 | + (pixel[0] as f32 * color_multiplier) as u32, |
| 129 | + (pixel[1] as f32 * color_multiplier) as u32, |
| 130 | + (pixel[2] as f32 * color_multiplier) as u32 |
| 131 | + ) |
| 132 | + .as_bytes(), |
| 133 | + ); |
| 134 | + colors.insert(pixel, colors.len() as u8); |
| 135 | + } |
| 136 | + } |
| 137 | + for (color, color_index) in &colors { |
| 138 | + let mut sixel_samples = Vec::<u8>::with_capacity(sixel_row.width() as usize); |
| 139 | + sixel_samples.resize(sixel_row.width() as usize, 0); |
| 140 | + for (x, y, pixel) in sixel_row.pixels() { |
| 141 | + if color == &pixel { |
| 142 | + sixel_samples[x as usize] = sixel_samples[x as usize] | (1 << y); |
| 143 | + } |
| 144 | + } |
| 145 | + image_data.extend(format!("#{}", color_index).bytes()); |
| 146 | + image_data.extend(sixel_samples.iter().map(|x| x + 0x3F)); |
| 147 | + image_data.push('$' as u8); |
| 148 | + } |
| 149 | + image_data.push('-' as u8); |
| 150 | + } |
| 151 | + image_data.extend("\x1B\\".as_bytes()); |
| 152 | + |
| 153 | + image_data.extend(format!("\x1B[{}A", image_rows as u32 + 2).as_bytes()); // move cursor to top-left corner |
| 154 | + image_data.extend(format!("\x1B[{}C", image_columns as u32 + 1).as_bytes()); // move cursor to top-right corner of image |
| 155 | + let mut i = 0; |
| 156 | + for line in &lines { |
| 157 | + image_data.extend(format!("\x1B[s{}\x1B[u\x1B[1B", line).as_bytes()); |
| 158 | + i += 1; |
| 159 | + } |
| 160 | + image_data |
| 161 | + .extend(format!("\n\x1B[{}B", lines.len().max(image_rows as usize) - i).as_bytes()); // move cursor to end of image |
| 162 | + |
| 163 | + String::from_utf8(image_data).unwrap() |
| 164 | + } |
| 165 | +} |
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