is it possible create custom cell renderers?
emmanueltouzery opened this issue · comments
the process to create custom cell renderers is gtk is through inheritance.. I was searching for examples of custom cell renderers in gtk-rs and couldn't find any?
I need a virtualized list with custom rendering for the rows, because I'm having performance issues with ListBox with too many rows, at the same time I really need a custom rendering for the rows. If it's not possible to implement custom cell renderers I'm not sure what to do :-(
Thank you! Which other type can I use as reference for how subclassing works in gtk-rs? I didn't need subclassing so far.
There's this subclass example, for example: https://github.com/gtk-rs/examples/blob/master/src/bin/basic_subclass.rs It creates a subclass of a window and gtk::Application.
Please ask if something's not clear
Closing for now. Let me know if you run into any problems.
hello, yes indeed I've run into some problems :(
Based on your examples I got it to compile, but it fails compiling when I try to create the renderer using ::new. This is the code:
https://github.com/emmanueltouzery/cell_r
$ cargo run
thread 'main' panicked at 'not implemented', /home/emmanuel/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/macros.rs:13:23
when compiling with RUST_BACKTRACE=1, I get:
11: std::panicking::begin_panic
at /home/emmanuel/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/panicking.rs:438
12: glib::subclass::types::ObjectSubclass::new
at /home/emmanuel/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/macros.rs:13
13: glib::subclass::types::ObjectSubclass::with_class
at /home/emmanuel/.cargo/registry/src/github.com-1ecc6299db9ec823/glib-0.10.1/src/subclass/types.rs:371
14: glib::subclass::types::instance_init
at /home/emmanuel/.cargo/registry/src/github.com-1ecc6299db9ec823/glib-0.10.1/src/subclass/types.rs:429
15: g_type_create_instance
16: <unknown>
17: g_object_newv
18: glib::object::Object::new
at /home/emmanuel/.cargo/registry/src/github.com-1ecc6299db9ec823/glib-0.10.1/src/object.rs:1297
19: cell_r::MyRenderer::new
at src/main.rs:32
One idea that I have is that when you inherit from GtkApplication in the sample you gave me, you must call the "super" constructor, passing the 'application-id' and 'flags' parameters. But for GtkCellRenderer there is no ::new. There is one in GtkCellRendererText and other variants. Maybe inheriting from those would help, but generally speaking I think that inheriting from the base one is the correct move in my case.
I also think it's possible based on this C example which I found:
https://gitlab.gnome.org/GNOME/rhythmbox/-/blob/master/widgets/rb-cell-renderer-rating.c
Could you help maybe, as I'm really in over my head with all that gobject inheritance machinery :-(
Ah yes, I believe the relevant lines in my code are:
impl MyRenderer {
pub fn new() -> Self {
glib::Object::new(Self::static_type(), &[])
.expect("Failed to create MyRenderer")
.downcast()
.expect("Created MyRenderer is of wrong type")
}
}Can you put your current code up somewhere? I'll take a look then
You have to implement ObjectSubclass::new() or ::with_class() at least. One of the two is required but this can't be expressed in Rust currently.
yes that was it, thank you very much!