Build error when using the git repo in Cargo.toml

[amcelroy]

Hi,

I'm trying to use the latest version of the repo that uses embedded-graphics version 0.8.0. The crates.io version of lvgl (version 0.6.2) seems to be using embedded-graphics version 0.7.1 and is causing dependency collisions. The Cargo.toml for the project looks like:

[dependencies.lvgl]
# path = "./lv_binding_rust/lvgl"
# version = "0.6.2"
git = "https://github.com/lvgl/lv_binding_rust"
default-features = false
features = ["embedded_graphics", "unsafe_no_autoinit", "lvgl_alloc"]

However, the following error is generated:

error[E0599]: no method named `into_raw` found for struct `Box<lv_style_t>` in the current scope
   --> /Users/myname/.cargo/git/checkouts/lv_binding_rust-d86feb7597e107b7/45cafea/lvgl/src/lv_core/style.rs:459:58
    |
459 |             lvgl_sys::lv_style_get_prop(self.raw.clone().into_raw() as *const _, prop.bits(), ptr)
    |                                         -----------------^^^^^^^^--
    |                                         |                |
    |                                         |                this is an associated function, not a method
    |                                         help: use associated function syntax instead: `Box::<lv_style_t>::into_raw(self.raw.clone())`
    |
    = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
    = note: the candidate is defined in an impl for the type `Box<T, A>`

For more information about this error, try `rustc --explain E0599`.
error: could not compile `lvgl` (lib) due to 1 previous error
make: *** [build] Error 101

Edit: My build command is:

DEP_LV_CONFIG_PATH=`pwd` RUST_BACKTRACE=full cargo build -Zfeatures=build_dep --target thumbv7em-none-eabihf

[CFSworks]

I have just encountered this issue as well.

The problem is that the lvgl crate includes its own implementation of Box (which represents memory allocations managed by LVGL). This implementation includes into_raw() as an instance method (with self), contrary to Rust's implementation as an associated function (without self) and thus must be used as Box::into_raw(...). This is intentionally done by the language designers to avoid confusion in cases where the inner type might define "into_raw" as an instance method of its own.

When the lvgl_alloc feature is activated, the LVGL memory management code takes over as the global allocator. This makes the LVGL custom Box type redundant since all boxes are in LVGL's heap already. So LVGL just switches over to the standard alloc implementation instead. But .into_raw() is not the correct way to access real boxes, leading to this error.

To resolve this issue, the LVGL box should be updated to match the Rust convention of making into_raw an associated function, not an instance method. Eventually, when the allocator_api language feature is stabilized, the core Box type will allow boxes to live in allocators besides the global one, and LVGL should remove its bespoke Box type in favor of this new mechanism.