Add support for static SVG images using resvg crate (#36721)

This change adds support for rendering static SVG images using the
`resvg` crate, allowing svg sources in the `img` tag and in CSS
`background` and `content` properties. There are some limitations in
using resvg:

1. There is no support for animations or interactivity as these would
require implementing the full DOM layer of SVG specification.
2. Only system fonts can be used for text rendering. There is some
mechanism to provide a custom font resolver to usvg, but that is not
explored in this change.
3. resvg's handling of certain edge cases involving lack of explicit
`width` and `height` on the root svg element deviates from what the
specification expects from browsers. For example, resvg uses the values
in `viewBox` to derive the missing width or height dimension, but
without scaling that dimension to preserve the aspect ratio. It also
doesn't allow overriding this behavior.

Demo screenshot:
![servo - resvg
img](https://github.com/user-attachments/assets/8ecb2de2-ab7c-48e2-9f08-2d09d2cb8791)

<details>
<summary>Source</summary>

```
<style>
 #svg1 {
   border: 1px solid red;
 }

 #svg2 {
   border: 1px solid red;
   width: 300px;
 }
 #svg3 {
   border: 1px solid red;
   width: 300px;
   height: 200px;
   object-fit: contain;
 }
 #svg4 {
   border: 1px solid red;
   width: 300px;
   height: 200px;
   object-fit: cover;
 }
 #svg5 {
   border: 1px solid red;
   width: 300px;
   height: 200px;
   object-fit: fill;
 }
 #svg6 {
   border: 1px solid red;
   width: 300px;
   height: 200px;
   object-fit: none;
 }
</style>
</head>
<body>
        <div>
          <img id="svg1" src="https://raw.githubusercontent.com/servo/servo/refs/heads/main/resources/servo.svg" alt="Servo logo">
        </div>
        <div>
          <img id="svg2" src="https://raw.githubusercontent.com/servo/servo/refs/heads/main/resources/servo.svg" alt="Servo logo">
          <img id="svg3" src="https://raw.githubusercontent.com/servo/servo/refs/heads/main/resources/servo.svg" alt="Servo logo">
          <img id="svg4" src="https://raw.githubusercontent.com/servo/servo/refs/heads/main/resources/servo.svg" alt="Servo logo">
        </div>
        <div>
          <img id="svg5" src="https://raw.githubusercontent.com/servo/servo/refs/heads/main/resources/servo.svg" alt="Servo logo">
          <img id="svg6" src="https://raw.githubusercontent.com/servo/servo/refs/heads/main/resources/servo.svg" alt="Servo logo">
        </div>
</body>
```

</details>

---------

Signed-off-by: Mukilan Thiyagarajan <mukilan@igalia.com>
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
This commit is contained in:
Mukilan Thiyagarajan 2025-05-27 16:32:40 +05:30 committed by GitHub
parent 324196351e
commit 8a20e42de4
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
267 changed files with 2374 additions and 544 deletions

View file

@ -121,9 +121,8 @@ pub enum CorsStatus {
}
#[derive(Clone, Deserialize, MallocSizeOf, Serialize)]
pub struct Image {
pub width: u32,
pub height: u32,
pub struct RasterImage {
pub metadata: ImageMetadata,
pub format: PixelFormat,
pub id: Option<ImageKey>,
pub cors_status: CorsStatus,
@ -149,7 +148,7 @@ pub struct ImageFrameView<'a> {
pub height: u32,
}
impl Image {
impl RasterImage {
pub fn should_animate(&self) -> bool {
self.frames.len() > 1
}
@ -170,17 +169,17 @@ impl Image {
}
}
impl fmt::Debug for Image {
impl fmt::Debug for RasterImage {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"Image {{ width: {}, height: {}, format: {:?}, ..., id: {:?} }}",
self.width, self.height, self.format, self.id
self.metadata.width, self.metadata.height, self.format, self.id
)
}
}
#[derive(Clone, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
#[derive(Clone, Copy, Debug, Deserialize, Eq, MallocSizeOf, PartialEq, Serialize)]
pub struct ImageMetadata {
pub width: u32,
pub height: u32,
@ -189,7 +188,7 @@ pub struct ImageMetadata {
// FIXME: Images must not be copied every frame. Instead we should atomically
// reference count them.
pub fn load_from_memory(buffer: &[u8], cors_status: CorsStatus) -> Option<Image> {
pub fn load_from_memory(buffer: &[u8], cors_status: CorsStatus) -> Option<RasterImage> {
if buffer.is_empty() {
return None;
}
@ -212,9 +211,11 @@ pub fn load_from_memory(buffer: &[u8], cors_status: CorsStatus) -> Option<Image>
width: rgba.width(),
height: rgba.height(),
};
Some(Image {
width: rgba.width(),
height: rgba.height(),
Some(RasterImage {
metadata: ImageMetadata {
width: rgba.width(),
height: rgba.height(),
},
format: PixelFormat::BGRA8,
frames: vec![frame],
bytes: IpcSharedMemory::from_bytes(&rgba),
@ -374,7 +375,7 @@ fn is_webp(buffer: &[u8]) -> bool {
buffer[8..].len() >= len && &buffer[8..12] == b"WEBP"
}
fn decode_gif(buffer: &[u8], cors_status: CorsStatus) -> Option<Image> {
fn decode_gif(buffer: &[u8], cors_status: CorsStatus) -> Option<RasterImage> {
let Ok(decoded_gif) = GifDecoder::new(Cursor::new(buffer)) else {
return None;
};
@ -430,9 +431,8 @@ fn decode_gif(buffer: &[u8], cors_status: CorsStatus) -> Option<Image> {
bytes.extend_from_slice(frame.buffer());
}
Some(Image {
width,
height,
Some(RasterImage {
metadata: ImageMetadata { width, height },
cors_status,
frames,
id: None,