Originally posted by **otiv-wannes-vanleemput** February 28, 2024
I want to visualise a Gstreamer pipeline which runs in a Rust backed. To start off, I would like to update a QImage with the current frame outputted by the pipeline. However, I'm unable to wrap a QImage in a custom rust struct.
This is my cxxqt_object.rs file:
```
#[cxx_qt::bridge]
pub mod qobject {
unsafe extern "C++" {
include!("cxx-qt-lib/qimage.h");
type QImage = cxx_qt_lib::QImage;
}
extern "RustQt" {
#[qobject]
#[qml_element]
#[qproperty(QImage, video_frame)]
type MyObject = super::MyObjectRust;
}
impl cxx_qt::Constructor<(QImage,), NewArguments=(QImage,)> for MyObject {}
unsafe extern "RustQt" {
#[qinvokable]
fn video_frame_from_slice(self: Pin<&mut MyObject>, image: &[u8]);
}
}
use core::pin::Pin;
use cxx_qt_lib::{QImage};
pub struct MyObjectRust {
video_frame: QImage,
}
impl cxx_qt::Constructor<(QImage,)> for qobject::MyObject {
type BaseArguments = ();
type InitializeArguments = ();
type NewArguments = (QImage,);
fn route_arguments(args: (QImage, )) -> (Self::NewArguments, Self::BaseArguments, Self::InitializeArguments) {
(args, (), ())
}
fn new((video_frame,): (QImage,)) -> MyObjectRust {
MyObjectRust {
video_frame,
}
}
}
impl qobject::MyObject {
pub fn video_frame_from_slice(self: Pin<&mut Self>, image: &[u8]) {
self.video_frame = QImage::from_data(image, None).unwrap();
}
}
```
I tried deriving the Default trait, but this resulted in a build error. Thats why I used the constructor.
However, I still get the following build error:
```
error[E0369]: binary operation `==` cannot be applied to type `cxx_qt_lib::QImage`
--> src/cxxqt_object.rs:3:1
|
3 | #[cxx_qt::bridge]
| ^^^^^^^^^^^^^^^^^
|
= note: this error originates in the attribute macro `cxx_qt::bridge` (in Nightly builds, run with -Z macro-backtrace for more info)
For more information about this error, try `rustc --explain E0369`.
```
Should I fork the repository and add the PartialEq trait to QImage, or am I using it incorrectly?
This is required because when the type is a
Q_PROPERTYwe generate Rust code that has==Discussed in https://github.com/KDAB/cxx-qt/discussions/871