jpeg_encoder/
image_buffer.rs

1#![allow(clippy::identity_op)]
2
3use alloc::vec::Vec;
4
5use crate::encoder::JpegColorType;
6
7/// Conversion from RGB to YCbCr
8#[inline]
9pub fn rgb_to_ycbcr(r: u8, g: u8, b: u8) -> (u8, u8, u8) {
10    // To avoid floating point math this scales everything by 2^16 which gives
11    // a precision of approx 4 digits.
12    //
13    // Non scaled conversion:
14    // Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
15    // Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B  + 128
16    // Cr =  0.50000 * R - 0.41869 * G - 0.08131 * B  + 128
17
18    let r = r as i32;
19    let g = g as i32;
20    let b = b as i32;
21
22    let y = 19595 * r + 38470 * g + 7471 * b;
23    let cb = -11059 * r - 21709 * g + 32768 * b + (128 << 16);
24    let cr = 32768 * r - 27439 * g - 5329 * b + (128 << 16);
25
26    let y = (y + 0x7FFF) >> 16;
27    let cb = (cb + 0x7FFF) >> 16;
28    let cr = (cr + 0x7FFF) >> 16;
29
30    (y as u8, cb as u8, cr as u8)
31}
32
33/// Conversion from CMYK to YCCK (YCbCrK)
34#[inline]
35pub fn cmyk_to_ycck(c: u8, m: u8, y: u8, k: u8) -> (u8, u8, u8, u8) {
36    let (y, cb, cr) = rgb_to_ycbcr(c, m, y);
37    (y, cb, cr, 255 - k)
38}
39
40/// # Buffer used as input value for image encoding
41///
42/// Image encoding with [Encoder::encode_image](crate::Encoder::encode_image) needs an ImageBuffer
43/// as input for the image data. For convenience the [Encoder::encode](crate::Encoder::encode)
44/// function contains implementations for common byte based pixel formats.
45/// Users that needs other pixel formats or don't have the data available as byte slices
46/// can create their own buffer implementations.
47///
48/// ## Example: ImageBuffer implementation for RgbImage from the `image` crate
49/// ```no_compile
50/// use image::RgbImage;
51/// use jpeg_encoder::{ImageBuffer, JpegColorType, rgb_to_ycbcr};
52///
53/// pub struct RgbImageBuffer {
54///     image: RgbImage,
55/// }
56///
57/// impl ImageBuffer for RgbImageBuffer {
58///     fn get_jpeg_color_type(&self) -> JpegColorType {
59///         // Rgb images are encoded as YCbCr in JFIF files
60///         JpegColorType::Ycbcr
61///     }
62///
63///     fn width(&self) -> u16 {
64///         self.image.width() as u16
65///     }
66///
67///     fn height(&self) -> u16 {
68///         self.image.height() as u16
69///     }
70///
71///     fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]){
72///         for x in 0..self.width() {
73///             let pixel = self.image.get_pixel(x as u32 ,y as u32);
74///
75///             let (y,cb,cr) = rgb_to_ycbcr(pixel[0], pixel[1], pixel[2]);
76///
77///             // For YCbCr the 4th buffer is not used
78///             buffers[0].push(y);
79///             buffers[1].push(cb);
80///             buffers[2].push(cr);
81///         }
82///     }
83/// }
84///
85/// ```
86pub trait ImageBuffer {
87    /// The color type used in the image encoding
88    fn get_jpeg_color_type(&self) -> JpegColorType;
89
90    /// Width of the image
91    fn width(&self) -> u16;
92
93    /// Height of the image
94    fn height(&self) -> u16;
95
96    /// Add color values for the row to color component buffers
97    fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]);
98}
99
100pub(crate) struct GrayImage<'a>(pub &'a [u8], pub u16, pub u16);
101
102impl<'a> ImageBuffer for GrayImage<'a> {
103    fn get_jpeg_color_type(&self) -> JpegColorType {
104        JpegColorType::Luma
105    }
106
107    fn width(&self) -> u16 {
108        self.1
109    }
110
111    fn height(&self) -> u16 {
112        self.2
113    }
114
115    fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]) {
116        let line = get_line(self.0, y, self.width(), 1);
117
118        for &pixel in line {
119            buffers[0].push(pixel);
120        }
121    }
122}
123
124#[inline(always)]
125fn get_line(data: &[u8], y: u16, width: u16, num_colors: usize) -> &[u8] {
126    let width = usize::from(width);
127    let y = usize::from(y);
128
129    let start = y * width * num_colors;
130    let end = start + width * num_colors;
131
132    &data[start..end]
133}
134
135macro_rules! ycbcr_image {
136    ($name:ident, $num_colors:expr, $o1:expr, $o2:expr, $o3:expr) => {
137        pub struct $name<'a>(pub &'a [u8], pub u16, pub u16);
138
139        impl<'a> ImageBuffer for $name<'a> {
140            fn get_jpeg_color_type(&self) -> JpegColorType {
141                JpegColorType::Ycbcr
142            }
143
144            fn width(&self) -> u16 {
145                self.1
146            }
147
148            fn height(&self) -> u16 {
149                self.2
150            }
151
152            #[inline(always)]
153            fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]) {
154                let line = get_line(self.0, y, self.width(), $num_colors);
155
156                // Doing the convertion in chunks allows the compiler to vectorize the code
157                // A size of 16 seems optimal for SSE and AVX capable hardware
158                const CHUNK_SIZE: usize = 16;
159
160                let mut y_buffer = [0; CHUNK_SIZE];
161                let mut cb_buffer = [0; CHUNK_SIZE];
162                let mut cr_buffer = [0; CHUNK_SIZE];
163
164                for chuck in line.chunks_exact($num_colors * CHUNK_SIZE) {
165                    for i in (0..CHUNK_SIZE) {
166                        let (y, cb, cr) = rgb_to_ycbcr(
167                            chuck[i * $num_colors + $o1],
168                            chuck[i * $num_colors + $o2],
169                            chuck[i * $num_colors + $o3],
170                        );
171
172                        y_buffer[i] = y;
173                        cb_buffer[i] = cb;
174                        cr_buffer[i] = cr;
175                    }
176
177                    buffers[0].extend_from_slice(&y_buffer);
178                    buffers[1].extend_from_slice(&cb_buffer);
179                    buffers[2].extend_from_slice(&cr_buffer);
180                }
181
182                // Add the remaining pixels in case the number of
183                // pixels is not a multiple of CHUNK_SIZE
184                let pixel = line.len() / $num_colors;
185                for i in pixel / CHUNK_SIZE * CHUNK_SIZE..pixel {
186                    let (y, cb, cr) = rgb_to_ycbcr(
187                        line[i * $num_colors + $o1],
188                        line[i * $num_colors + $o2],
189                        line[i * $num_colors + $o3],
190                    );
191
192                    buffers[0].push(y);
193                    buffers[1].push(cb);
194                    buffers[2].push(cr);
195                }
196            }
197        }
198    };
199}
200
201ycbcr_image!(RgbImage, 3, 0, 1, 2);
202ycbcr_image!(RgbaImage, 4, 0, 1, 2);
203ycbcr_image!(BgrImage, 3, 2, 1, 0);
204ycbcr_image!(BgraImage, 4, 2, 1, 0);
205
206pub(crate) struct YCbCrImage<'a>(pub &'a [u8], pub u16, pub u16);
207
208impl<'a> ImageBuffer for YCbCrImage<'a> {
209    fn get_jpeg_color_type(&self) -> JpegColorType {
210        JpegColorType::Ycbcr
211    }
212
213    fn width(&self) -> u16 {
214        self.1
215    }
216
217    fn height(&self) -> u16 {
218        self.2
219    }
220
221    fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]) {
222        let line = get_line(self.0, y, self.width(), 3);
223
224        for pixel in line.chunks_exact(3) {
225            buffers[0].push(pixel[0]);
226            buffers[1].push(pixel[1]);
227            buffers[2].push(pixel[2]);
228        }
229    }
230}
231
232pub(crate) struct CmykImage<'a>(pub &'a [u8], pub u16, pub u16);
233
234impl<'a> ImageBuffer for CmykImage<'a> {
235    fn get_jpeg_color_type(&self) -> JpegColorType {
236        JpegColorType::Cmyk
237    }
238
239    fn width(&self) -> u16 {
240        self.1
241    }
242
243    fn height(&self) -> u16 {
244        self.2
245    }
246
247    fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]) {
248        let line = get_line(self.0, y, self.width(), 4);
249
250        for pixel in line.chunks_exact(4) {
251            buffers[0].push(255 - pixel[0]);
252            buffers[1].push(255 - pixel[1]);
253            buffers[2].push(255 - pixel[2]);
254            buffers[3].push(255 - pixel[3]);
255        }
256    }
257}
258
259pub(crate) struct CmykAsYcckImage<'a>(pub &'a [u8], pub u16, pub u16);
260
261impl<'a> ImageBuffer for CmykAsYcckImage<'a> {
262    fn get_jpeg_color_type(&self) -> JpegColorType {
263        JpegColorType::Ycck
264    }
265
266    fn width(&self) -> u16 {
267        self.1
268    }
269
270    fn height(&self) -> u16 {
271        self.2
272    }
273
274    fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]) {
275        let line = get_line(self.0, y, self.width(), 4);
276
277        for pixel in line.chunks_exact(4) {
278            let (y, cb, cr, k) = cmyk_to_ycck(pixel[0], pixel[1], pixel[2], pixel[3]);
279
280            buffers[0].push(y);
281            buffers[1].push(cb);
282            buffers[2].push(cr);
283            buffers[3].push(k);
284        }
285    }
286}
287
288pub(crate) struct YcckImage<'a>(pub &'a [u8], pub u16, pub u16);
289
290impl<'a> ImageBuffer for YcckImage<'a> {
291    fn get_jpeg_color_type(&self) -> JpegColorType {
292        JpegColorType::Ycck
293    }
294
295    fn width(&self) -> u16 {
296        self.1
297    }
298
299    fn height(&self) -> u16 {
300        self.2
301    }
302
303    fn fill_buffers(&self, y: u16, buffers: &mut [Vec<u8>; 4]) {
304        let line = get_line(self.0, y, self.width(), 4);
305
306        for pixel in line.chunks_exact(4) {
307            buffers[0].push(pixel[0]);
308            buffers[1].push(pixel[1]);
309            buffers[2].push(pixel[2]);
310            buffers[3].push(pixel[3]);
311        }
312    }
313}
314
315#[cfg(test)]
316mod tests {
317    use crate::rgb_to_ycbcr;
318
319    fn assert_rgb_to_ycbcr(rgb: [u8; 3], ycbcr: [u8; 3]) {
320        let (y, cb, cr) = rgb_to_ycbcr(rgb[0], rgb[1], rgb[2]);
321        assert_eq!([y, cb, cr], ycbcr);
322    }
323
324    #[test]
325    fn test_rgb_to_ycbcr() {
326        assert_rgb_to_ycbcr([0, 0, 0], [0, 128, 128]);
327        assert_rgb_to_ycbcr([255, 255, 255], [255, 128, 128]);
328        assert_rgb_to_ycbcr([255, 0, 0], [76, 85, 255]);
329        assert_rgb_to_ycbcr([0, 255, 0], [150, 44, 21]);
330        assert_rgb_to_ycbcr([0, 0, 255], [29, 255, 107]);
331
332        // Values taken from libjpeg for a common image
333
334        assert_rgb_to_ycbcr([59, 109, 6], [82, 85, 111]);
335        assert_rgb_to_ycbcr([29, 60, 11], [45, 109, 116]);
336        assert_rgb_to_ycbcr([57, 114, 26], [87, 94, 107]);
337        assert_rgb_to_ycbcr([30, 60, 6], [45, 106, 117]);
338        assert_rgb_to_ycbcr([41, 75, 11], [58, 102, 116]);
339        assert_rgb_to_ycbcr([145, 184, 108], [164, 97, 115]);
340        assert_rgb_to_ycbcr([33, 85, 7], [61, 98, 108]);
341        assert_rgb_to_ycbcr([61, 90, 40], [76, 108, 118]);
342        assert_rgb_to_ycbcr([75, 127, 45], [102, 96, 109]);
343        assert_rgb_to_ycbcr([30, 56, 14], [43, 111, 118]);
344        assert_rgb_to_ycbcr([106, 142, 81], [124, 104, 115]);
345        assert_rgb_to_ycbcr([35, 59, 11], [46, 108, 120]);
346        assert_rgb_to_ycbcr([170, 203, 123], [184, 94, 118]);
347        assert_rgb_to_ycbcr([45, 87, 16], [66, 100, 113]);
348        assert_rgb_to_ycbcr([59, 109, 21], [84, 92, 110]);
349        assert_rgb_to_ycbcr([100, 167, 36], [132, 74, 105]);
350        assert_rgb_to_ycbcr([17, 53, 5], [37, 110, 114]);
351        assert_rgb_to_ycbcr([226, 244, 220], [236, 119, 121]);
352        assert_rgb_to_ycbcr([192, 214, 120], [197, 85, 125]);
353        assert_rgb_to_ycbcr([63, 107, 22], [84, 93, 113]);
354        assert_rgb_to_ycbcr([44, 78, 19], [61, 104, 116]);
355        assert_rgb_to_ycbcr([72, 106, 54], [90, 108, 115]);
356        assert_rgb_to_ycbcr([99, 123, 73], [110, 107, 120]);
357        assert_rgb_to_ycbcr([188, 216, 148], [200, 99, 120]);
358        assert_rgb_to_ycbcr([19, 46, 7], [33, 113, 118]);
359        assert_rgb_to_ycbcr([56, 95, 40], [77, 107, 113]);
360        assert_rgb_to_ycbcr([81, 120, 56], [101, 103, 114]);
361        assert_rgb_to_ycbcr([9, 30, 0], [20, 117, 120]);
362        assert_rgb_to_ycbcr([90, 118, 46], [101, 97, 120]);
363        assert_rgb_to_ycbcr([24, 52, 0], [38, 107, 118]);
364        assert_rgb_to_ycbcr([32, 69, 9], [51, 104, 114]);
365        assert_rgb_to_ycbcr([74, 134, 33], [105, 88, 106]);
366        assert_rgb_to_ycbcr([37, 74, 7], [55, 101, 115]);
367        assert_rgb_to_ycbcr([69, 119, 31], [94, 92, 110]);
368        assert_rgb_to_ycbcr([63, 112, 21], [87, 91, 111]);
369        assert_rgb_to_ycbcr([90, 148, 17], [116, 72, 110]);
370        assert_rgb_to_ycbcr([50, 97, 30], [75, 102, 110]);
371        assert_rgb_to_ycbcr([99, 129, 72], [114, 105, 118]);
372        assert_rgb_to_ycbcr([161, 196, 57], [170, 64, 122]);
373        assert_rgb_to_ycbcr([10, 26, 1], [18, 118, 122]);
374        assert_rgb_to_ycbcr([87, 128, 68], [109, 105, 112]);
375        assert_rgb_to_ycbcr([111, 155, 73], [132, 94, 113]);
376        assert_rgb_to_ycbcr([33, 75, 11], [55, 103, 112]);
377        assert_rgb_to_ycbcr([70, 122, 51], [98, 101, 108]);
378        assert_rgb_to_ycbcr([22, 74, 3], [50, 101, 108]);
379        assert_rgb_to_ycbcr([88, 142, 45], [115, 89, 109]);
380        assert_rgb_to_ycbcr([66, 107, 40], [87, 101, 113]);
381        assert_rgb_to_ycbcr([18, 45, 0], [32, 110, 118]);
382        assert_rgb_to_ycbcr([163, 186, 88], [168, 83, 124]);
383        assert_rgb_to_ycbcr([47, 104, 4], [76, 88, 108]);
384        assert_rgb_to_ycbcr([147, 211, 114], [181, 90, 104]);
385        assert_rgb_to_ycbcr([42, 77, 18], [60, 104, 115]);
386        assert_rgb_to_ycbcr([37, 72, 6], [54, 101, 116]);
387        assert_rgb_to_ycbcr([84, 140, 55], [114, 95, 107]);
388        assert_rgb_to_ycbcr([46, 98, 25], [74, 100, 108]);
389        assert_rgb_to_ycbcr([48, 97, 20], [74, 98, 110]);
390        assert_rgb_to_ycbcr([189, 224, 156], [206, 100, 116]);
391        assert_rgb_to_ycbcr([36, 83, 0], [59, 94, 111]);
392        assert_rgb_to_ycbcr([159, 186, 114], [170, 97, 120]);
393        assert_rgb_to_ycbcr([75, 118, 46], [97, 99, 112]);
394        assert_rgb_to_ycbcr([193, 233, 158], [212, 97, 114]);
395        assert_rgb_to_ycbcr([76, 116, 48], [96, 101, 114]);
396        assert_rgb_to_ycbcr([108, 157, 79], [133, 97, 110]);
397        assert_rgb_to_ycbcr([180, 208, 155], [194, 106, 118]);
398        assert_rgb_to_ycbcr([74, 126, 53], [102, 100, 108]);
399        assert_rgb_to_ycbcr([72, 123, 46], [99, 98, 109]);
400        assert_rgb_to_ycbcr([71, 123, 34], [97, 92, 109]);
401        assert_rgb_to_ycbcr([130, 184, 72], [155, 81, 110]);
402        assert_rgb_to_ycbcr([30, 61, 17], [47, 111, 116]);
403        assert_rgb_to_ycbcr([27, 71, 0], [50, 100, 112]);
404        assert_rgb_to_ycbcr([45, 73, 24], [59, 108, 118]);
405        assert_rgb_to_ycbcr([139, 175, 93], [155, 93, 117]);
406        assert_rgb_to_ycbcr([11, 38, 0], [26, 114, 118]);
407        assert_rgb_to_ycbcr([34, 87, 15], [63, 101, 107]);
408        assert_rgb_to_ycbcr([43, 76, 35], [61, 113, 115]);
409        assert_rgb_to_ycbcr([18, 35, 7], [27, 117, 122]);
410        assert_rgb_to_ycbcr([69, 97, 48], [83, 108, 118]);
411        assert_rgb_to_ycbcr([139, 176, 50], [151, 71, 120]);
412        assert_rgb_to_ycbcr([21, 51, 7], [37, 111, 117]);
413        assert_rgb_to_ycbcr([209, 249, 189], [230, 105, 113]);
414        assert_rgb_to_ycbcr([32, 66, 14], [50, 108, 115]);
415        assert_rgb_to_ycbcr([100, 143, 67], [121, 97, 113]);
416        assert_rgb_to_ycbcr([40, 96, 14], [70, 96, 107]);
417        assert_rgb_to_ycbcr([88, 130, 64], [110, 102, 112]);
418        assert_rgb_to_ycbcr([52, 112, 14], [83, 89, 106]);
419        assert_rgb_to_ycbcr([49, 72, 25], [60, 108, 120]);
420        assert_rgb_to_ycbcr([144, 193, 75], [165, 77, 113]);
421        assert_rgb_to_ycbcr([49, 94, 1], [70, 89, 113]);
422    }
423}
jpeg_encoder/image_buffer.rs

jpeg_encoder/
image_buffer.rs
