pixels/
lib.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5mod snapshot;
6
7use std::borrow::Cow;
8use std::io::Cursor;
9use std::ops::Range;
10use std::sync::Arc;
11use std::time::Duration;
12use std::{cmp, fmt, vec};
13
14use base::generic_channel::GenericSharedMemory;
15use euclid::default::{Point2D, Rect, Size2D};
16use image::codecs::{bmp, gif, ico, jpeg, png, webp};
17use image::error::ImageFormatHint;
18use image::imageops::{self, FilterType};
19use image::{
20    AnimationDecoder, DynamicImage, ImageBuffer, ImageDecoder, ImageError, ImageFormat,
21    ImageResult, Limits, Rgba,
22};
23use log::{debug, error};
24use malloc_size_of_derive::MallocSizeOf;
25use serde::{Deserialize, Serialize};
26pub use snapshot::*;
27use webrender_api::units::DeviceIntSize;
28use webrender_api::{
29    ImageDescriptor, ImageDescriptorFlags, ImageFormat as WebRenderImageFormat, ImageKey,
30};
31
32#[derive(Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
33pub enum FilterQuality {
34    /// No image interpolation (Nearest-neighbor)
35    None,
36    /// Low-quality image interpolation (Bilinear)
37    Low,
38    /// Medium-quality image interpolation (CatmullRom, Mitchell)
39    Medium,
40    /// High-quality image interpolation (Lanczos)
41    High,
42}
43
44#[derive(Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
45pub enum PixelFormat {
46    /// Luminance channel only
47    K8,
48    /// Luminance + alpha
49    KA8,
50    /// RGB, 8 bits per channel
51    RGB8,
52    /// RGB + alpha, 8 bits per channel
53    RGBA8,
54    /// BGR + alpha, 8 bits per channel
55    BGRA8,
56}
57
58/// Computes image byte length, returning None if overflow occurred or the total length exceeds
59/// the maximum image allocation size.
60pub fn compute_rgba8_byte_length_if_within_limit(width: usize, height: usize) -> Option<usize> {
61    // Maximum allowed image allocation size (2^31-1 ~ 2GB).
62    const MAX_IMAGE_BYTE_LENGTH: usize = 2147483647;
63
64    // The color components of each pixel must be stored in four sequential
65    // elements in the order of red, green, blue, and then alpha.
66    4usize
67        .checked_mul(width)
68        .and_then(|v| v.checked_mul(height))
69        .filter(|v| *v <= MAX_IMAGE_BYTE_LENGTH)
70}
71
72/// Copies the rectangle of the source image to the destination image.
73pub fn copy_rgba8_image(
74    src_size: Size2D<u32>,
75    src_rect: Rect<u32>,
76    src_pixels: &[u8],
77    dest_size: Size2D<u32>,
78    dest_rect: Rect<u32>,
79    dest_pixels: &mut [u8],
80) {
81    assert!(!src_rect.is_empty());
82    assert!(!dest_rect.is_empty());
83    assert!(Rect::from_size(src_size).contains_rect(&src_rect));
84    assert!(Rect::from_size(dest_size).contains_rect(&dest_rect));
85    assert!(src_rect.size == dest_rect.size);
86    assert_eq!(src_pixels.len() % 4, 0);
87    assert_eq!(dest_pixels.len() % 4, 0);
88
89    if src_size == dest_size && src_rect == dest_rect {
90        dest_pixels.copy_from_slice(src_pixels);
91        return;
92    }
93
94    let src_first_column_start = src_rect.origin.x as usize * 4;
95    let src_row_length = src_size.width as usize * 4;
96    let src_first_row_start = src_rect.origin.y as usize * src_row_length;
97
98    let dest_first_column_start = dest_rect.origin.x as usize * 4;
99    let dest_row_length = dest_size.width as usize * 4;
100    let dest_first_row_start = dest_rect.origin.y as usize * dest_row_length;
101
102    let (chunk_length, chunk_count) = (
103        src_rect.size.width as usize * 4,
104        src_rect.size.height as usize,
105    );
106
107    for i in 0..chunk_count {
108        let src = &src_pixels[src_first_row_start + i * src_row_length..][src_first_column_start..]
109            [..chunk_length];
110        let dest = &mut dest_pixels[dest_first_row_start + i * dest_row_length..]
111            [dest_first_column_start..][..chunk_length];
112        dest.copy_from_slice(src);
113    }
114}
115
116/// Scales the source image to the required size, performing sampling filter algorithm.
117pub fn scale_rgba8_image(
118    size: Size2D<u32>,
119    pixels: &[u8],
120    required_size: Size2D<u32>,
121    quality: FilterQuality,
122) -> Option<Vec<u8>> {
123    let filter = match quality {
124        FilterQuality::None => FilterType::Nearest,
125        FilterQuality::Low => FilterType::Triangle,
126        FilterQuality::Medium => FilterType::CatmullRom,
127        FilterQuality::High => FilterType::Lanczos3,
128    };
129
130    let buffer: ImageBuffer<Rgba<u8>, &[u8]> =
131        ImageBuffer::from_raw(size.width, size.height, pixels)?;
132
133    let scaled_buffer =
134        imageops::resize(&buffer, required_size.width, required_size.height, filter);
135
136    Some(scaled_buffer.into_vec())
137}
138
139/// Flips the source image vertically in place.
140pub fn flip_y_rgba8_image_inplace(size: Size2D<u32>, pixels: &mut [u8]) {
141    assert_eq!(pixels.len() % 4, 0);
142
143    let row_length = size.width as usize * 4;
144    let half_height = (size.height / 2) as usize;
145
146    let (left, right) = pixels.split_at_mut(pixels.len() - row_length * half_height);
147
148    for i in 0..half_height {
149        let top = &mut left[i * row_length..][..row_length];
150        let bottom = &mut right[(half_height - i - 1) * row_length..][..row_length];
151        top.swap_with_slice(bottom);
152    }
153}
154
155pub fn rgba8_get_rect(pixels: &[u8], size: Size2D<u32>, rect: Rect<u32>) -> Cow<'_, [u8]> {
156    assert!(!rect.is_empty());
157    assert!(Rect::from_size(size).contains_rect(&rect));
158    assert_eq!(pixels.len() % 4, 0);
159    assert_eq!(size.area() as usize, pixels.len() / 4);
160    let area = rect.size.area() as usize;
161    let first_column_start = rect.origin.x as usize * 4;
162    let row_length = size.width as usize * 4;
163    let first_row_start = rect.origin.y as usize * row_length;
164    if rect.origin.x == 0 && rect.size.width == size.width || rect.size.height == 1 {
165        let start = first_column_start + first_row_start;
166        return Cow::Borrowed(&pixels[start..start + area * 4]);
167    }
168    let mut data = Vec::with_capacity(area * 4);
169    for row in pixels[first_row_start..]
170        .chunks(row_length)
171        .take(rect.size.height as usize)
172    {
173        data.extend_from_slice(&row[first_column_start..][..rect.size.width as usize * 4]);
174    }
175    data.into()
176}
177
178// TODO(pcwalton): Speed up with SIMD, or better yet, find some way to not do this.
179pub fn rgba8_byte_swap_colors_inplace(pixels: &mut [u8]) {
180    assert!(pixels.len() % 4 == 0);
181    for rgba in pixels.chunks_mut(4) {
182        rgba.swap(0, 2);
183    }
184}
185
186pub fn rgba8_byte_swap_and_premultiply_inplace(pixels: &mut [u8]) {
187    assert!(pixels.len() % 4 == 0);
188    for rgba in pixels.chunks_mut(4) {
189        let b = rgba[0];
190        rgba[0] = multiply_u8_color(rgba[2], rgba[3]);
191        rgba[1] = multiply_u8_color(rgba[1], rgba[3]);
192        rgba[2] = multiply_u8_color(b, rgba[3]);
193    }
194}
195
196/// Returns true if the pixels were found to be completely opaque.
197pub fn rgba8_premultiply_inplace(pixels: &mut [u8]) -> bool {
198    assert!(pixels.len() % 4 == 0);
199    let mut is_opaque = true;
200    for rgba in pixels.chunks_mut(4) {
201        rgba[0] = multiply_u8_color(rgba[0], rgba[3]);
202        rgba[1] = multiply_u8_color(rgba[1], rgba[3]);
203        rgba[2] = multiply_u8_color(rgba[2], rgba[3]);
204        is_opaque = is_opaque && rgba[3] == 255;
205    }
206    is_opaque
207}
208
209/// Returns a*b/255, rounding any fractional bits to nearest integer
210/// to reduce the loss of precision after multiple consequence alpha
211/// (un)premultiply operations.
212#[inline(always)]
213pub fn multiply_u8_color(a: u8, b: u8) -> u8 {
214    let c = a as u32 * b as u32 + 128;
215    ((c + (c >> 8)) >> 8) as u8
216}
217
218pub fn clip(
219    mut origin: Point2D<i32>,
220    mut size: Size2D<u32>,
221    surface: Size2D<u32>,
222) -> Option<Rect<u32>> {
223    if origin.x < 0 {
224        size.width = size.width.saturating_sub(-origin.x as u32);
225        origin.x = 0;
226    }
227    if origin.y < 0 {
228        size.height = size.height.saturating_sub(-origin.y as u32);
229        origin.y = 0;
230    }
231    let origin = Point2D::new(origin.x as u32, origin.y as u32);
232    Rect::new(origin, size)
233        .intersection(&Rect::from_size(surface))
234        .filter(|rect| !rect.is_empty())
235}
236
237#[derive(PartialEq)]
238pub enum EncodedImageType {
239    Png,
240    Jpeg,
241    Webp,
242}
243
244impl From<String> for EncodedImageType {
245    // From: https://html.spec.whatwg.org/multipage/#serialising-bitmaps-to-a-file
246    // User agents must support PNG ("image/png"). User agents may support other
247    // types. If the user agent does not support the requested type, then it
248    // must create the file using the PNG format.
249    // Anything different than image/jpeg or image/webp is thus treated as PNG.
250    fn from(mime_type: String) -> Self {
251        let mime = mime_type.to_lowercase();
252        if mime == "image/jpeg" {
253            Self::Jpeg
254        } else if mime == "image/webp" {
255            Self::Webp
256        } else {
257            Self::Png
258        }
259    }
260}
261
262impl EncodedImageType {
263    pub fn as_mime_type(&self) -> String {
264        match self {
265            Self::Png => "image/png",
266            Self::Jpeg => "image/jpeg",
267            Self::Webp => "image/webp",
268        }
269        .to_owned()
270    }
271}
272
273/// Whether this response passed any CORS checks, and is thus safe to read from
274/// in cross-origin environments.
275#[derive(Clone, Copy, Debug, Deserialize, MallocSizeOf, PartialEq, Serialize)]
276pub enum CorsStatus {
277    /// The response is either same-origin or cross-origin but passed CORS checks.
278    Safe,
279    /// The response is cross-origin and did not pass CORS checks. It is unsafe
280    /// to expose pixel data to the requesting environment.
281    Unsafe,
282}
283
284/// A version of [`RasterImage`] that can be sent across IPC channels.
285#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
286pub struct SharedRasterImage {
287    pub metadata: ImageMetadata,
288    pub format: PixelFormat,
289    pub id: Option<ImageKey>,
290    pub cors_status: CorsStatus,
291    #[conditional_malloc_size_of]
292    pub bytes: Arc<GenericSharedMemory>,
293    pub frames: Vec<ImageFrame>,
294    /// Whether or not all of the frames of this image are opaque.
295    pub is_opaque: bool,
296}
297
298#[derive(Clone, MallocSizeOf)]
299pub struct RasterImage {
300    pub metadata: ImageMetadata,
301    pub format: PixelFormat,
302    pub id: Option<ImageKey>,
303    pub cors_status: CorsStatus,
304    #[conditional_malloc_size_of]
305    pub bytes: Arc<Vec<u8>>,
306    pub frames: Vec<ImageFrame>,
307    /// Whether or not all of the frames of this image are opaque.
308    pub is_opaque: bool,
309}
310
311fn sensible_delay(delay: Duration) -> Duration {
312    // Very small timeout values are problematic for two reasons: we don't want
313    // to burn energy redrawing animated images extremely fast, and broken tools
314    // generate these values when they actually want a "default" value, so such
315    // images won't play back right without normalization.
316    // https://searchfox.org/firefox-main/rev/c79acad610ddbb31bd92e837e056b53716f5ccf2/image/FrameTimeout.h#35
317    if delay <= Duration::from_millis(10) {
318        Duration::from_millis(100)
319    } else {
320        delay
321    }
322}
323
324#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
325pub struct ImageFrame {
326    pub delay: Option<Duration>,
327    /// References a range of the `bytes` field from the image that this
328    /// frame belongs to.
329    pub byte_range: Range<usize>,
330    pub width: u32,
331    pub height: u32,
332}
333
334impl ImageFrame {
335    pub fn delay(&self) -> Option<Duration> {
336        self.delay.map(sensible_delay)
337    }
338}
339
340/// A non-owning reference to the data of an [ImageFrame]
341pub struct ImageFrameView<'a> {
342    pub delay: Option<Duration>,
343    pub bytes: &'a [u8],
344    pub width: u32,
345    pub height: u32,
346}
347
348impl ImageFrameView<'_> {
349    pub fn delay(&self) -> Option<Duration> {
350        self.delay.map(sensible_delay)
351    }
352}
353
354impl RasterImage {
355    pub fn should_animate(&self) -> bool {
356        self.frames.len() > 1
357    }
358
359    fn frame_view<'image>(&'image self, frame: &ImageFrame) -> ImageFrameView<'image> {
360        ImageFrameView {
361            delay: frame.delay,
362            bytes: self.bytes.get(frame.byte_range.clone()).unwrap(),
363            width: frame.width,
364            height: frame.height,
365        }
366    }
367
368    pub fn frame(&self, index: usize) -> Option<ImageFrameView<'_>> {
369        self.frames.get(index).map(|frame| self.frame_view(frame))
370    }
371
372    pub fn first_frame(&self) -> ImageFrameView<'_> {
373        self.frame(0)
374            .expect("All images should have at least one frame")
375    }
376
377    pub fn as_snapshot(&self) -> Snapshot {
378        let size = Size2D::new(self.metadata.width, self.metadata.height);
379        let format = match self.format {
380            PixelFormat::BGRA8 => SnapshotPixelFormat::BGRA,
381            PixelFormat::RGBA8 => SnapshotPixelFormat::RGBA,
382            pixel_format => {
383                unimplemented!("unsupported pixel format ({pixel_format:?})");
384            },
385        };
386
387        let alpha_mode = SnapshotAlphaMode::Transparent {
388            premultiplied: true,
389        };
390
391        Snapshot::from_arc_vec(
392            size.cast(),
393            format,
394            alpha_mode,
395            self.bytes.clone(),
396            self.frames[0].byte_range.clone(),
397        )
398    }
399
400    pub fn frame_data(&self, index: usize) -> Option<&ImageFrame> {
401        self.frames.get(index)
402    }
403
404    pub fn webrender_image_descriptor_and_data_for_frame(
405        &self,
406        frame_index: usize,
407    ) -> (ImageDescriptor, GenericSharedMemory) {
408        let frame = self
409            .frames
410            .get(frame_index)
411            .expect("Asked for a frame that did not exist: {frame_index:?}");
412
413        let (format, data) = match self.format {
414            PixelFormat::BGRA8 => (
415                WebRenderImageFormat::BGRA8,
416                GenericSharedMemory::from_bytes(&self.bytes),
417            ),
418            PixelFormat::RGBA8 => (
419                WebRenderImageFormat::RGBA8,
420                GenericSharedMemory::from_bytes(&self.bytes),
421            ),
422            PixelFormat::RGB8 => {
423                let frame_bytes = &self.bytes[frame.byte_range.clone()];
424                let mut bytes = Vec::with_capacity(frame_bytes.len() / 3 * 4);
425                for rgb in frame_bytes.chunks(3) {
426                    bytes.extend_from_slice(&[rgb[2], rgb[1], rgb[0], 0xff]);
427                }
428                (
429                    WebRenderImageFormat::BGRA8,
430                    GenericSharedMemory::from_bytes(&bytes),
431                )
432            },
433            PixelFormat::K8 | PixelFormat::KA8 => {
434                panic!("Not support by webrender yet");
435            },
436        };
437        let mut flags = ImageDescriptorFlags::ALLOW_MIPMAPS;
438        flags.set(ImageDescriptorFlags::IS_OPAQUE, self.is_opaque);
439
440        let size = DeviceIntSize::new(self.metadata.width as i32, self.metadata.height as i32);
441        let descriptor = ImageDescriptor {
442            size,
443            stride: None,
444            format,
445            offset: frame.byte_range.start as i32,
446            flags,
447        };
448        (descriptor, data)
449    }
450
451    /// For animations the image already exists in a cache in 'Painter'. We just send the description.
452    /// Currently we do not support 'PixelFormat::RGB8'
453    pub fn webrender_image_descriptor_and_offset_for_frame(&self) -> Option<ImageDescriptor> {
454        if self.format == PixelFormat::RGB8 ||
455            self.format == PixelFormat::K8 ||
456            self.format == PixelFormat::KA8
457        {
458            return None;
459        }
460        let format = match self.format {
461            PixelFormat::BGRA8 => WebRenderImageFormat::BGRA8,
462            PixelFormat::RGBA8 => WebRenderImageFormat::RGBA8,
463            PixelFormat::RGB8 => WebRenderImageFormat::BGRA8,
464            PixelFormat::KA8 | PixelFormat::K8 => {
465                error!("Pixel format currently not supported");
466                return None;
467            },
468        };
469        let mut flags = ImageDescriptorFlags::ALLOW_MIPMAPS;
470        flags.set(ImageDescriptorFlags::IS_OPAQUE, self.is_opaque);
471
472        let size = DeviceIntSize::new(self.metadata.width as i32, self.metadata.height as i32);
473        let descriptor = ImageDescriptor {
474            size,
475            stride: None,
476            format,
477            offset: 0,
478            flags,
479        };
480        Some(descriptor)
481    }
482
483    pub fn to_shared(&self) -> Arc<SharedRasterImage> {
484        Arc::new(SharedRasterImage {
485            metadata: self.metadata,
486            format: self.format,
487            id: self.id,
488            cors_status: self.cors_status,
489            bytes: Arc::new(GenericSharedMemory::from_bytes(&self.bytes)),
490            frames: self.frames.clone(),
491            is_opaque: self.is_opaque,
492        })
493    }
494}
495
496impl fmt::Debug for RasterImage {
497    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
498        write!(
499            f,
500            "Image {{ width: {}, height: {}, format: {:?}, ..., id: {:?} }}",
501            self.metadata.width, self.metadata.height, self.format, self.id
502        )
503    }
504}
505
506#[derive(Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
507pub struct ImageMetadata {
508    pub width: u32,
509    pub height: u32,
510}
511
512// FIXME: Images must not be copied every frame. Instead we should atomically
513// reference count them.
514
515pub fn load_from_memory(buffer: &[u8], cors_status: CorsStatus) -> Option<RasterImage> {
516    if buffer.is_empty() {
517        return None;
518    }
519
520    let image_fmt_result = detect_image_format(buffer);
521    match image_fmt_result {
522        Err(msg) => {
523            debug!("{}", msg);
524            None
525        },
526        Ok(format) => {
527            let Ok(image_decoder) = make_decoder(format, buffer) else {
528                return None;
529            };
530            match image_decoder {
531                GenericImageDecoder::Png(png_decoder) => {
532                    if png_decoder.is_apng().unwrap_or_default() {
533                        let Ok(apng_decoder) = png_decoder.apng() else {
534                            return None;
535                        };
536                        decode_animated_image(cors_status, apng_decoder)
537                    } else {
538                        decode_static_image(cors_status, *png_decoder)
539                    }
540                },
541                GenericImageDecoder::Gif(animation_decoder) => {
542                    decode_animated_image(cors_status, *animation_decoder)
543                },
544                GenericImageDecoder::Webp(webp_decoder) => {
545                    if webp_decoder.has_animation() {
546                        decode_animated_image(cors_status, *webp_decoder)
547                    } else {
548                        decode_static_image(cors_status, *webp_decoder)
549                    }
550                },
551                GenericImageDecoder::Bmp(image_decoder) => {
552                    decode_static_image(cors_status, *image_decoder)
553                },
554                GenericImageDecoder::Jpeg(image_decoder) => {
555                    decode_static_image(cors_status, *image_decoder)
556                },
557                GenericImageDecoder::Ico(image_decoder) => {
558                    decode_static_image(cors_status, *image_decoder)
559                },
560            }
561        },
562    }
563}
564
565// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img
566pub fn detect_image_format(buffer: &[u8]) -> Result<ImageFormat, &str> {
567    if is_gif(buffer) {
568        Ok(ImageFormat::Gif)
569    } else if is_jpeg(buffer) {
570        Ok(ImageFormat::Jpeg)
571    } else if is_png(buffer) {
572        Ok(ImageFormat::Png)
573    } else if is_webp(buffer) {
574        Ok(ImageFormat::WebP)
575    } else if is_bmp(buffer) {
576        Ok(ImageFormat::Bmp)
577    } else if is_ico(buffer) {
578        Ok(ImageFormat::Ico)
579    } else {
580        Err("Image Format Not Supported")
581    }
582}
583
584pub fn unmultiply_inplace<const SWAP_RB: bool>(pixels: &mut [u8]) {
585    for rgba in pixels.chunks_mut(4) {
586        let a = rgba[3] as u32;
587        let mut b = rgba[2] as u32;
588        let mut g = rgba[1] as u32;
589        let mut r = rgba[0] as u32;
590
591        if a > 0 {
592            r = r * 255 / a;
593            g = g * 255 / a;
594            b = b * 255 / a;
595
596            if SWAP_RB {
597                rgba[2] = r as u8;
598                rgba[1] = g as u8;
599                rgba[0] = b as u8;
600            } else {
601                rgba[2] = b as u8;
602                rgba[1] = g as u8;
603                rgba[0] = r as u8;
604            }
605        }
606    }
607}
608
609#[repr(u8)]
610pub enum Multiply {
611    None = 0,
612    PreMultiply = 1,
613    UnMultiply = 2,
614}
615
616pub fn transform_inplace(pixels: &mut [u8], multiply: Multiply, swap_rb: bool, clear_alpha: bool) {
617    match (multiply, swap_rb, clear_alpha) {
618        (Multiply::None, true, true) => generic_transform_inplace::<0, true, true>(pixels),
619        (Multiply::None, true, false) => generic_transform_inplace::<0, true, false>(pixels),
620        (Multiply::None, false, true) => generic_transform_inplace::<0, false, true>(pixels),
621        (Multiply::None, false, false) => generic_transform_inplace::<0, false, false>(pixels),
622        (Multiply::PreMultiply, true, true) => generic_transform_inplace::<1, true, true>(pixels),
623        (Multiply::PreMultiply, true, false) => generic_transform_inplace::<1, true, false>(pixels),
624        (Multiply::PreMultiply, false, true) => generic_transform_inplace::<1, false, true>(pixels),
625        (Multiply::PreMultiply, false, false) => {
626            generic_transform_inplace::<1, false, false>(pixels)
627        },
628        (Multiply::UnMultiply, true, true) => generic_transform_inplace::<2, true, true>(pixels),
629        (Multiply::UnMultiply, true, false) => generic_transform_inplace::<2, true, false>(pixels),
630        (Multiply::UnMultiply, false, true) => generic_transform_inplace::<2, false, true>(pixels),
631        (Multiply::UnMultiply, false, false) => {
632            generic_transform_inplace::<2, false, false>(pixels)
633        },
634    }
635}
636
637pub fn generic_transform_inplace<
638    const MULTIPLY: u8, // 1 premultiply, 2 unmultiply
639    const SWAP_RB: bool,
640    const CLEAR_ALPHA: bool,
641>(
642    pixels: &mut [u8],
643) {
644    for rgba in pixels.chunks_mut(4) {
645        match MULTIPLY {
646            1 => {
647                let a = rgba[3];
648
649                rgba[0] = multiply_u8_color(rgba[0], a);
650                rgba[1] = multiply_u8_color(rgba[1], a);
651                rgba[2] = multiply_u8_color(rgba[2], a);
652            },
653            2 => {
654                let a = rgba[3] as u32;
655
656                if a > 0 {
657                    rgba[0] = (rgba[0] as u32 * 255 / a) as u8;
658                    rgba[1] = (rgba[1] as u32 * 255 / a) as u8;
659                    rgba[2] = (rgba[2] as u32 * 255 / a) as u8;
660                }
661            },
662            _ => {},
663        }
664        if SWAP_RB {
665            rgba.swap(0, 2);
666        }
667        if CLEAR_ALPHA {
668            rgba[3] = u8::MAX;
669        }
670    }
671}
672
673fn is_gif(buffer: &[u8]) -> bool {
674    buffer.starts_with(b"GIF87a") || buffer.starts_with(b"GIF89a")
675}
676
677fn is_jpeg(buffer: &[u8]) -> bool {
678    buffer.starts_with(&[0xff, 0xd8, 0xff])
679}
680
681fn is_png(buffer: &[u8]) -> bool {
682    buffer.starts_with(&[0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A])
683}
684
685fn is_bmp(buffer: &[u8]) -> bool {
686    buffer.starts_with(&[0x42, 0x4D])
687}
688
689fn is_ico(buffer: &[u8]) -> bool {
690    buffer.starts_with(&[0x00, 0x00, 0x01, 0x00])
691}
692
693fn is_webp(buffer: &[u8]) -> bool {
694    // https://developers.google.com/speed/webp/docs/riff_container
695    // First four bytes: `RIFF`, header size 12 bytes
696    if !buffer.starts_with(b"RIFF") || buffer.len() < 12 {
697        return false;
698    }
699    let size: [u8; 4] = [buffer[4], buffer[5], buffer[6], buffer[7]];
700    // Bytes 4..8 are a little endian u32 indicating
701    // > The size of the file in bytes, starting at offset 8.
702    // > The maximum value of this field is 2^32 minus 10 bytes and thus the size
703    // > of the whole file is at most 4 GiB minus 2 bytes.
704    let len: usize = u32::from_le_bytes(size) as usize;
705    buffer[8..].len() >= len && &buffer[8..12] == b"WEBP"
706}
707
708enum GenericImageDecoder<R: std::io::BufRead + std::io::Seek> {
709    Png(Box<png::PngDecoder<R>>),
710    Gif(Box<gif::GifDecoder<R>>),
711    Webp(Box<webp::WebPDecoder<R>>),
712    Jpeg(Box<jpeg::JpegDecoder<R>>),
713    Bmp(Box<bmp::BmpDecoder<R>>),
714    Ico(Box<ico::IcoDecoder<R>>),
715}
716
717fn make_decoder(
718    format: ImageFormat,
719    buffer: &[u8],
720) -> ImageResult<GenericImageDecoder<Cursor<&[u8]>>> {
721    let limits = Limits::default();
722    let reader = Cursor::new(buffer);
723    Ok(match format {
724        ImageFormat::Png => {
725            GenericImageDecoder::Png(Box::new(png::PngDecoder::with_limits(reader, limits)?))
726        },
727        ImageFormat::Gif => GenericImageDecoder::Gif(Box::new(gif::GifDecoder::new(reader)?)),
728        ImageFormat::WebP => GenericImageDecoder::Webp(Box::new(webp::WebPDecoder::new(reader)?)),
729        ImageFormat::Jpeg => GenericImageDecoder::Jpeg(Box::new(jpeg::JpegDecoder::new(reader)?)),
730        ImageFormat::Bmp => GenericImageDecoder::Bmp(Box::new(bmp::BmpDecoder::new(reader)?)),
731        ImageFormat::Ico => GenericImageDecoder::Ico(Box::new(ico::IcoDecoder::new(reader)?)),
732        _ => {
733            return Err(ImageError::Unsupported(
734                ImageFormatHint::Exact(format).into(),
735            ));
736        },
737    })
738}
739
740fn decode_static_image(
741    cors_status: CorsStatus,
742    mut image_decoder: impl ImageDecoder,
743) -> Option<RasterImage> {
744    let orientation = image_decoder.orientation();
745
746    let Ok(mut dynamic_image) = DynamicImage::from_decoder(image_decoder) else {
747        debug!("Image decoding error");
748        return None;
749    };
750
751    if let Ok(orientation) = orientation {
752        dynamic_image.apply_orientation(orientation);
753    }
754
755    let mut rgba = dynamic_image.into_rgba8();
756
757    // Store pre-multiplied data as that prevents having to do conversions of the data at later
758    // times. This does cause an issue with some canvas APIs. See:
759    // https://github.com/servo/servo/issues/40257
760    let is_opaque = rgba8_premultiply_inplace(&mut rgba);
761
762    let frame = ImageFrame {
763        delay: None,
764        byte_range: 0..rgba.len(),
765        width: rgba.width(),
766        height: rgba.height(),
767    };
768    Some(RasterImage {
769        metadata: ImageMetadata {
770            width: rgba.width(),
771            height: rgba.height(),
772        },
773        format: PixelFormat::RGBA8,
774        frames: vec![frame],
775        bytes: Arc::new(rgba.to_vec()),
776        id: None,
777        cors_status,
778        is_opaque,
779    })
780}
781
782fn decode_animated_image<'a, T>(
783    cors_status: CorsStatus,
784    animated_image_decoder: T,
785) -> Option<RasterImage>
786where
787    T: AnimationDecoder<'a>,
788{
789    let mut width = 0;
790    let mut height = 0;
791
792    // This uses `map_while`, because the first non-decodable frame seems to
793    // send the frame iterator into an infinite loop. See
794    // <https://github.com/image-rs/image/issues/2442>.
795    let mut frame_data = vec![];
796    let mut total_number_of_bytes = 0;
797    let mut is_opaque = true;
798    let frames: Vec<ImageFrame> = animated_image_decoder
799        .into_frames()
800        .map_while(|decoded_frame| {
801            let mut animated_frame = match decoded_frame {
802                Ok(decoded_frame) => decoded_frame,
803                Err(error) => {
804                    debug!("decode Animated frame error: {error}");
805                    return None;
806                },
807            };
808
809            // Store pre-multiplied data as that prevents having to do conversions of the data at later
810            // times. This does cause an issue with some canvas APIs. See:
811            // https://github.com/servo/servo/issues/40257
812            is_opaque = rgba8_premultiply_inplace(animated_frame.buffer_mut()) && is_opaque;
813
814            let frame_start = total_number_of_bytes;
815            total_number_of_bytes += animated_frame.buffer().len();
816
817            // The image size should be at least as large as the largest frame.
818            let frame_width = animated_frame.buffer().width();
819            let frame_height = animated_frame.buffer().height();
820            width = cmp::max(width, frame_width);
821            height = cmp::max(height, frame_height);
822
823            let frame = ImageFrame {
824                byte_range: frame_start..total_number_of_bytes,
825                delay: Some(Duration::from(animated_frame.delay())),
826                width: frame_width,
827                height: frame_height,
828            };
829
830            frame_data.push(animated_frame);
831
832            Some(frame)
833        })
834        .collect();
835
836    if frames.is_empty() {
837        debug!("Animated Image decoding error");
838        return None;
839    }
840
841    // Coalesce the frame data into one single shared memory region.
842    let mut bytes = Vec::with_capacity(total_number_of_bytes);
843    for frame in frame_data {
844        bytes.extend_from_slice(frame.buffer());
845    }
846
847    Some(RasterImage {
848        metadata: ImageMetadata { width, height },
849        cors_status,
850        frames,
851        id: None,
852        format: PixelFormat::RGBA8,
853        bytes: Arc::new(bytes),
854        is_opaque,
855    })
856}
857
858#[cfg(test)]
859mod test {
860    use super::detect_image_format;
861
862    #[test]
863    fn test_supported_images() {
864        let gif1 = [b'G', b'I', b'F', b'8', b'7', b'a'];
865        let gif2 = [b'G', b'I', b'F', b'8', b'9', b'a'];
866        let jpeg = [0xff, 0xd8, 0xff];
867        let png = [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A];
868        let webp = [
869            b'R', b'I', b'F', b'F', 0x04, 0x00, 0x00, 0x00, b'W', b'E', b'B', b'P',
870        ];
871        let bmp = [0x42, 0x4D];
872        let ico = [0x00, 0x00, 0x01, 0x00];
873        let junk_format = [0x01, 0x02, 0x03, 0x04, 0x05];
874
875        assert!(detect_image_format(&gif1).is_ok());
876        assert!(detect_image_format(&gif2).is_ok());
877        assert!(detect_image_format(&jpeg).is_ok());
878        assert!(detect_image_format(&png).is_ok());
879        assert!(detect_image_format(&webp).is_ok());
880        assert!(detect_image_format(&bmp).is_ok());
881        assert!(detect_image_format(&ico).is_ok());
882        assert!(detect_image_format(&junk_format).is_err());
883    }
884}
pixels/lib.rs

pixels/
lib.rs
