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

script/dom/canvas/
imagedata.rs
