servo/components/script/dom/htmlobjectelement.rs
Mukilan Thiyagarajan 8a20e42de4
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>
2025-05-27 11:02:40 +00:00

186 lines
5.8 KiB
Rust

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
use std::default::Default;
use dom_struct::dom_struct;
use html5ever::{LocalName, Prefix, local_name, ns};
use js::rust::HandleObject;
use pixels::RasterImage;
use servo_arc::Arc;
use crate::dom::attr::Attr;
use crate::dom::bindings::cell::DomRefCell;
use crate::dom::bindings::codegen::Bindings::HTMLObjectElementBinding::HTMLObjectElementMethods;
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::root::{DomRoot, MutNullableDom};
use crate::dom::bindings::str::DOMString;
use crate::dom::document::Document;
use crate::dom::element::{AttributeMutation, Element};
use crate::dom::htmlelement::HTMLElement;
use crate::dom::htmlformelement::{FormControl, HTMLFormElement};
use crate::dom::node::{Node, NodeTraits};
use crate::dom::validation::Validatable;
use crate::dom::validitystate::ValidityState;
use crate::dom::virtualmethods::VirtualMethods;
use crate::script_runtime::CanGc;
#[dom_struct]
pub(crate) struct HTMLObjectElement {
htmlelement: HTMLElement,
#[ignore_malloc_size_of = "Arc"]
#[no_trace]
image: DomRefCell<Option<Arc<RasterImage>>>,
form_owner: MutNullableDom<HTMLFormElement>,
validity_state: MutNullableDom<ValidityState>,
}
impl HTMLObjectElement {
fn new_inherited(
local_name: LocalName,
prefix: Option<Prefix>,
document: &Document,
) -> HTMLObjectElement {
HTMLObjectElement {
htmlelement: HTMLElement::new_inherited(local_name, prefix, document),
image: DomRefCell::new(None),
form_owner: Default::default(),
validity_state: Default::default(),
}
}
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub(crate) fn new(
local_name: LocalName,
prefix: Option<Prefix>,
document: &Document,
proto: Option<HandleObject>,
can_gc: CanGc,
) -> DomRoot<HTMLObjectElement> {
Node::reflect_node_with_proto(
Box::new(HTMLObjectElement::new_inherited(
local_name, prefix, document,
)),
document,
proto,
can_gc,
)
}
}
trait ProcessDataURL {
fn process_data_url(&self);
}
impl ProcessDataURL for &HTMLObjectElement {
// Makes the local `data` member match the status of the `data` attribute and starts
/// prefetching the image. This method must be called after `data` is changed.
fn process_data_url(&self) {
let element = self.upcast::<Element>();
// TODO: support other values
if let (None, Some(_uri)) = (
element.get_attribute(&ns!(), &local_name!("type")),
element.get_attribute(&ns!(), &local_name!("data")),
) {
// TODO(gw): Prefetch the image here.
}
}
}
impl HTMLObjectElementMethods<crate::DomTypeHolder> for HTMLObjectElement {
// https://html.spec.whatwg.org/multipage/#dom-object-type
make_getter!(Type, "type");
// https://html.spec.whatwg.org/multipage/#dom-object-type
make_setter!(SetType, "type");
// https://html.spec.whatwg.org/multipage/#dom-fae-form
fn GetForm(&self) -> Option<DomRoot<HTMLFormElement>> {
self.form_owner()
}
// https://html.spec.whatwg.org/multipage/#dom-cva-willvalidate
fn WillValidate(&self) -> bool {
self.is_instance_validatable()
}
// https://html.spec.whatwg.org/multipage/#dom-cva-validity
fn Validity(&self) -> DomRoot<ValidityState> {
self.validity_state()
}
// https://html.spec.whatwg.org/multipage/#dom-cva-checkvalidity
fn CheckValidity(&self, can_gc: CanGc) -> bool {
self.check_validity(can_gc)
}
// https://html.spec.whatwg.org/multipage/#dom-cva-reportvalidity
fn ReportValidity(&self, can_gc: CanGc) -> bool {
self.report_validity(can_gc)
}
// https://html.spec.whatwg.org/multipage/#dom-cva-validationmessage
fn ValidationMessage(&self) -> DOMString {
self.validation_message()
}
// https://html.spec.whatwg.org/multipage/#dom-cva-setcustomvalidity
fn SetCustomValidity(&self, error: DOMString) {
self.validity_state().set_custom_error_message(error);
}
}
impl Validatable for HTMLObjectElement {
fn as_element(&self) -> &Element {
self.upcast()
}
fn validity_state(&self) -> DomRoot<ValidityState> {
self.validity_state
.or_init(|| ValidityState::new(&self.owner_window(), self.upcast(), CanGc::note()))
}
fn is_instance_validatable(&self) -> bool {
// https://html.spec.whatwg.org/multipage/#the-object-element%3Abarred-from-constraint-validation
false
}
}
impl VirtualMethods for HTMLObjectElement {
fn super_type(&self) -> Option<&dyn VirtualMethods> {
Some(self.upcast::<HTMLElement>() as &dyn VirtualMethods)
}
fn attribute_mutated(&self, attr: &Attr, mutation: AttributeMutation, can_gc: CanGc) {
self.super_type()
.unwrap()
.attribute_mutated(attr, mutation, can_gc);
match *attr.local_name() {
local_name!("data") => {
if let AttributeMutation::Set(_) = mutation {
self.process_data_url();
}
},
local_name!("form") => {
self.form_attribute_mutated(mutation, can_gc);
},
_ => {},
}
}
}
impl FormControl for HTMLObjectElement {
fn form_owner(&self) -> Option<DomRoot<HTMLFormElement>> {
self.form_owner.get()
}
fn set_form_owner(&self, form: Option<&HTMLFormElement>) {
self.form_owner.set(form);
}
fn to_element(&self) -> &Element {
self.upcast::<Element>()
}
}