script/dom/canvas/
imagedata.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
5use std::borrow::Cow;
6use std::vec::Vec;
7
8use base::generic_channel::GenericSharedMemory;
9use base::id::{ImageDataId, ImageDataIndex};
10use constellation_traits::SerializableImageData;
11use dom_struct::dom_struct;
12use euclid::default::{Rect, Size2D};
13use js::gc::CustomAutoRooterGuard;
14use js::jsapi::JSObject;
15use js::rust::HandleObject;
16use js::typedarray::{ClampedU8, HeapUint8ClampedArray, TypedArray, Uint8ClampedArray};
17use pixels::{Snapshot, SnapshotAlphaMode, SnapshotPixelFormat};
18use rustc_hash::FxHashMap;
19use script_bindings::trace::RootedTraceableBox;
20
21use crate::dom::bindings::buffer_source::{
22    HeapBufferSource, create_buffer_source, create_heap_buffer_source_with_length,
23};
24use crate::dom::bindings::codegen::Bindings::CanvasRenderingContext2DBinding::{
25    ImageDataMethods, ImageDataPixelFormat, ImageDataSettings, PredefinedColorSpace,
26};
27use crate::dom::bindings::error::{Error, Fallible};
28use crate::dom::bindings::reflector::{Reflector, reflect_dom_object_with_proto};
29use crate::dom::bindings::root::DomRoot;
30use crate::dom::bindings::serializable::Serializable;
31use crate::dom::bindings::structuredclone::StructuredData;
32use crate::dom::globalscope::GlobalScope;
33use crate::script_runtime::CanGc;
34
35#[dom_struct]
36pub(crate) struct ImageData {
37    reflector_: Reflector,
38    width: u32,
39    height: u32,
40    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata-data>
41    #[ignore_malloc_size_of = "mozjs"]
42    data: HeapBufferSource<ClampedU8>,
43    pixel_format: ImageDataPixelFormat,
44    color_space: PredefinedColorSpace,
45}
46
47impl ImageData {
48    pub(crate) fn new(
49        global: &GlobalScope,
50        width: u32,
51        height: u32,
52        mut data: Option<Vec<u8>>,
53        can_gc: CanGc,
54    ) -> Fallible<DomRoot<ImageData>> {
55        let len =
56            pixels::compute_rgba8_byte_length_if_within_limit(width as usize, height as usize)
57                .ok_or(Error::Range(
58                    c"The requested image size exceeds the supported range".to_owned(),
59                ))?;
60
61        let settings = ImageDataSettings {
62            colorSpace: Some(PredefinedColorSpace::Srgb),
63            pixelFormat: ImageDataPixelFormat::Rgba_unorm8,
64        };
65
66        if let Some(ref mut d) = data {
67            d.resize(len as usize, 0);
68
69            let cx = GlobalScope::get_cx();
70            rooted!(in(*cx) let mut js_object = std::ptr::null_mut::<JSObject>());
71            let _buffer_source =
72                create_buffer_source::<ClampedU8>(cx, &d[..], js_object.handle_mut(), can_gc)
73                    .map_err(|_| Error::JSFailed)?;
74            auto_root!(&in(cx) let data = TypedArray::<ClampedU8, *mut JSObject>::from(js_object.get()).map_err(|_| Error::JSFailed)?);
75
76            Self::Constructor_(global, None, can_gc, data, width, Some(height), &settings)
77        } else {
78            Self::Constructor(global, None, can_gc, width, height, &settings)
79        }
80    }
81
82    #[allow(clippy::too_many_arguments)]
83    /// <https://html.spec.whatwg.org/multipage/#initialize-an-imagedata-object>
84    fn initialize(
85        pixels_per_row: u32,
86        rows: u32,
87        settings: &ImageDataSettings,
88        source: Option<CustomAutoRooterGuard<Uint8ClampedArray>>,
89        default_color_space: Option<PredefinedColorSpace>,
90        global: &GlobalScope,
91        proto: Option<HandleObject>,
92        can_gc: CanGc,
93    ) -> Fallible<DomRoot<ImageData>> {
94        // 1. If source was given:
95        let data = if let Some(source) = source {
96            // 1. If settings["pixelFormat"] equals "rgba-unorm8" and source is not a Uint8ClampedArray,
97            // then throw an "InvalidStateError" DOMException.
98            // 2. If settings["pixelFormat"] is "rgba-float16" and source is not a Float16Array,
99            // then throw an "InvalidStateError" DOMException.
100            if !matches!(settings.pixelFormat, ImageDataPixelFormat::Rgba_unorm8) {
101                // we currently support only rgba-unorm8
102                return Err(Error::InvalidState(None));
103            }
104            // 3. Initialize the data attribute of imageData to source.
105            HeapBufferSource::<ClampedU8>::from_view(source)
106        } else {
107            // 2. Otherwise (source was not given):
108            match settings.pixelFormat {
109                ImageDataPixelFormat::Rgba_unorm8 => {
110                    // 1. If settings["pixelFormat"] is "rgba-unorm8",
111                    // then initialize the data attribute of imageData to a new Uint8ClampedArray object.
112                    // The Uint8ClampedArray object must use a new ArrayBuffer for its storage,
113                    // and must have a zero byte offset and byte length equal to the length of its storage, in bytes.
114                    // The storage ArrayBuffer must have a length of 4 × rows × pixelsPerRow bytes.
115                    // 3. If the storage ArrayBuffer could not be allocated,
116                    // then rethrow the RangeError thrown by JavaScript, and return.
117                    create_heap_buffer_source_with_length(
118                        GlobalScope::get_cx(),
119                        4 * rows * pixels_per_row,
120                        can_gc,
121                    )?
122                },
123                // 3. Otherwise, if settings["pixelFormat"] is "rgba-float16",
124                // then initialize the data attribute of imageData to a new Float16Array object.
125                // The Float16Array object must use a new ArrayBuffer for its storage,
126                // and must have a zero byte offset and byte length equal to the length of its storage, in bytes.
127                // The storage ArrayBuffer must have a length of 8 × rows × pixelsPerRow bytes.
128                // not implemented yet
129            }
130        };
131        // 3. Initialize the width attribute of imageData to pixelsPerRow.
132        let width = pixels_per_row;
133        // 4. Initialize the height attribute of imageData to rows.
134        let height = rows;
135        // 5. Initialize the pixelFormat attribute of imageData to settings["pixelFormat"].
136        let pixel_format = settings.pixelFormat;
137        // 6. If settings["colorSpace"] exists,
138        // then initialize the colorSpace attribute of imageData to settings["colorSpace"].
139        let color_space = settings
140            .colorSpace
141            // 7. Otherwise, if defaultColorSpace was given,
142            // then initialize the colorSpace attribute of imageData to defaultColorSpace.
143            .or(default_color_space)
144            // 8. Otherwise, initialize the colorSpace attribute of imageData to "srgb".
145            .unwrap_or(PredefinedColorSpace::Srgb);
146
147        Ok(reflect_dom_object_with_proto(
148            Box::new(ImageData {
149                reflector_: Reflector::new(),
150                width,
151                height,
152                data,
153                pixel_format,
154                color_space,
155            }),
156            global,
157            proto,
158            can_gc,
159        ))
160    }
161
162    pub(crate) fn is_detached(&self) -> bool {
163        self.data.is_detached_buffer(GlobalScope::get_cx())
164    }
165
166    pub(crate) fn get_size(&self) -> Size2D<u32> {
167        Size2D::new(self.Width(), self.Height())
168    }
169
170    /// Nothing must change the array on the JS side while the slice is live.
171    #[expect(unsafe_code)]
172    pub(crate) unsafe fn as_slice(&self) -> &[u8] {
173        assert!(self.data.is_initialized());
174        let internal_data = self
175            .data
176            .get_typed_array()
177            .expect("Failed to get Data from ImageData.");
178        // NOTE(nox): This is just as unsafe as `as_slice` itself even though we
179        // are extending the lifetime of the slice, because the data in
180        // this ImageData instance will never change. The method is thus unsafe
181        // because the array may be manipulated from JS while the reference
182        // is live.
183        unsafe {
184            let ptr: *const [u8] = internal_data.as_slice() as *const _;
185            &*ptr
186        }
187    }
188
189    /// Nothing must change the array on the JS side while the slice is live.
190    #[expect(unsafe_code)]
191    pub(crate) unsafe fn get_rect(&self, rect: Rect<u32>) -> Cow<'_, [u8]> {
192        pixels::rgba8_get_rect(unsafe { self.as_slice() }, self.get_size().to_u32(), rect)
193    }
194
195    #[expect(unsafe_code)]
196    pub(crate) fn get_snapshot_rect(&self, rect: Rect<u32>) -> Snapshot {
197        Snapshot::from_vec(
198            rect.size,
199            SnapshotPixelFormat::RGBA,
200            SnapshotAlphaMode::Transparent {
201                premultiplied: false,
202            },
203            unsafe { self.get_rect(rect).into_owned() },
204        )
205    }
206
207    #[expect(unsafe_code)]
208    pub(crate) fn to_shared_memory(&self) -> GenericSharedMemory {
209        // This is safe because we copy the slice content
210        GenericSharedMemory::from_bytes(unsafe { self.as_slice() })
211    }
212
213    #[expect(unsafe_code)]
214    pub(crate) fn to_vec(&self) -> Vec<u8> {
215        // This is safe because we copy the slice content
216        unsafe { self.as_slice() }.to_vec()
217    }
218}
219
220impl Serializable for ImageData {
221    type Index = ImageDataIndex;
222    type Data = SerializableImageData;
223
224    /// <https://html.spec.whatwg.org/multipage/#the-imagedata-interface:serializable-objects>
225    fn serialize(&self) -> Result<(ImageDataId, Self::Data), ()> {
226        // Step 1 Set serialized.[[Data]] to the sub-serialization of the value of value's data attribute.
227        let data = self.to_vec();
228
229        // Step 2 Set serialized.[[Width]] to the value of value's width attribute.
230        // Step 3 Set serialized.[[Height]] to the value of value's height attribute.
231        // Step 4 Set serialized.[[ColorSpace]] to the value of value's colorSpace attribute.
232        // Step 5 Set serialized.[[PixelFormat]] to the value of value's pixelFormat attribute.
233        // Note: Since we don't support Float16Array and display-p3 color space
234        // we don't need to serialize colorSpace and pixelFormat
235        let serialized = SerializableImageData {
236            data,
237            width: self.width,
238            height: self.height,
239        };
240        Ok((ImageDataId::new(), serialized))
241    }
242
243    /// <https://html.spec.whatwg.org/multipage/#the-imagedata-interface:deserialization-steps>
244    fn deserialize(
245        owner: &GlobalScope,
246        serialized: Self::Data,
247        can_gc: CanGc,
248    ) -> Result<DomRoot<Self>, ()> {
249        // Step 1 Initialize value's data attribute to the sub-deserialization of serialized.[[Data]].
250        // Step 2 Initialize value's width attribute to serialized.[[Width]].
251        // Step 3 Initialize value's height attribute to serialized.[[Height]].
252        // Step 4 Initialize value's colorSpace attribute to serialized.[[ColorSpace]].
253        // Step 5 Initialize value's pixelFormat attribute to serialized.[[PixelFormat]].
254        ImageData::new(
255            owner,
256            serialized.width,
257            serialized.height,
258            Some(serialized.data),
259            can_gc,
260        )
261        .map_err(|_| ())
262    }
263
264    fn serialized_storage<'a>(
265        reader: StructuredData<'a, '_>,
266    ) -> &'a mut Option<FxHashMap<ImageDataId, Self::Data>> {
267        match reader {
268            StructuredData::Reader(r) => &mut r.image_data,
269            StructuredData::Writer(w) => &mut w.image_data,
270        }
271    }
272}
273
274impl ImageDataMethods<crate::DomTypeHolder> for ImageData {
275    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata>
276    fn Constructor(
277        global: &GlobalScope,
278        proto: Option<HandleObject>,
279        can_gc: CanGc,
280        sw: u32,
281        sh: u32,
282        settings: &ImageDataSettings,
283    ) -> Fallible<DomRoot<Self>> {
284        // 1. If one or both of sw and sh are zero, then throw an "IndexSizeError" DOMException.
285        if sw == 0 || sh == 0 {
286            return Err(Error::IndexSize(None));
287        }
288
289        // When a constructor is called for an ImageData that is too large, other browsers throw
290        // IndexSizeError rather than RangeError here, so we do the same.
291        pixels::compute_rgba8_byte_length_if_within_limit(sw as usize, sh as usize)
292            .ok_or(Error::IndexSize(None))?;
293
294        // 2. Initialize this given sw, sh, and settings.
295        // 3. Initialize the image data of this to transparent black.
296        Self::initialize(sw, sh, settings, None, None, global, proto, can_gc)
297    }
298
299    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata-with-data>
300    fn Constructor_(
301        global: &GlobalScope,
302        proto: Option<HandleObject>,
303        can_gc: CanGc,
304        data: CustomAutoRooterGuard<Uint8ClampedArray>,
305        sw: u32,
306        sh: Option<u32>,
307        settings: &ImageDataSettings,
308    ) -> Fallible<DomRoot<Self>> {
309        // 1. Let bytesPerPixel be 4 if settings["pixelFormat"] is "rgba-unorm8"; otherwise 8.
310        let bytes_per_pixel = match settings.pixelFormat {
311            ImageDataPixelFormat::Rgba_unorm8 => 4,
312        };
313        // 2. Let length be the buffer source byte length of data.
314        let length = data.len();
315        if length == 0 {
316            return Err(Error::InvalidState(None));
317        }
318        // 3. If length is not a nonzero integral multiple of bytesPerPixel,
319        // then throw an "InvalidStateError" DOMException.
320        if length % bytes_per_pixel != 0 {
321            return Err(Error::InvalidState(None));
322        }
323        // 4. Let length be length divided by bytesPerPixel.
324        let length = length / bytes_per_pixel;
325        // 5. If length is not an integral multiple of sw, then throw an "IndexSizeError" DOMException.
326        if sw == 0 || length % sw as usize != 0 {
327            return Err(Error::IndexSize(None));
328        }
329        // 6. Let height be length divided by sw.
330        let height = length / sw as usize;
331        // 7. If sh was given and its value is not equal to height, then throw an "IndexSizeError" DOMException.
332        if sh.is_some_and(|x| height != x as usize) {
333            return Err(Error::IndexSize(None));
334        }
335        // 8. Initialize this given sw, sh, settings, and source set to data.
336        Self::initialize(
337            sw,
338            height as u32,
339            settings,
340            Some(data),
341            None,
342            global,
343            proto,
344            can_gc,
345        )
346    }
347
348    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata-width>
349    fn Width(&self) -> u32 {
350        self.width
351    }
352
353    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata-height>
354    fn Height(&self) -> u32 {
355        self.height
356    }
357
358    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata-data>
359    fn GetData(
360        &self,
361        _: script_bindings::script_runtime::JSContext,
362    ) -> Fallible<RootedTraceableBox<HeapUint8ClampedArray>> {
363        self.data.get_typed_array().map_err(|_| Error::JSFailed)
364    }
365
366    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata-pixelformat>
367    fn PixelFormat(&self) -> ImageDataPixelFormat {
368        self.pixel_format
369    }
370
371    /// <https://html.spec.whatwg.org/multipage/#dom-imagedata-colorspace>
372    fn ColorSpace(&self) -> PredefinedColorSpace {
373        self.color_space
374    }
375}
script/dom/canvas/imagedata.rs

script/dom/canvas/
imagedata.rs
