When using box shadows in repeaters, we end up creating multiple
distinct textures of the drop shadow. That's a waste of precious texture
memory if they have the same properties.
Instead, when creating box shadows in a frame, see if they can be
re-used across images. The texture still persistent in the image_cache,
via the explicitly shared skia_safe::Image and Rc<Texture>.
This works well when rendering repeated elements new top-down, but it's
not perfect. For example if a bunch of repeated elements are in a
flickable, only a portion of them are visible and the view is scroll up,
then the top-down rendering will not find a cache hit for the newly
visible element with drop shadows. Yet this is simple enough to help
with sharing in many cases.
Since the new version also depends on the ctirical-section 1.0 crate
we need to enable the relevant API in the cortex-m crate because the
rp2040-hal doesn't have it yet
and use Rc<dyn PlatformWindow> instead. The alias has to stay with the ffi
functions though and the item vtable definitions,
because we don't have an Rc<> template in C++.
One key difference to the Rust way is what `slint::Window` means. In
Rust that holds the `WindowInner` and `slint::Window` is only exposed as
`&slint::Window`. This is possible because the component owns the
`Rc<dyn PlatformWindow>`, which has a function to return the
`&slint::Window`.
In C++ `slint::Window` is also exposed as `slint::Window&` in the
`window()` getter, but there's no way to get a reference to a C++
wrapper for the Rust `&slint::Window` that the `PlatformWindow` trait
returns. Therefore in C++ `slint::Window` wraps `Rc<dyn
PlatformWindow>`.
Previously: Window is an Rc<WindowInner>, which has an Rc<dyn
PLatformWindow> - and weak references the other way around.
Now: Rc<dyn PlatformWindow> is the root of window ownership. The impl
PlatformWindow has a slint::api::Window, which just holds a WindowInner.
This change is incomplete on a few levels, mainly that neither of the
code generators nor the interpreter is ported.
For hide() we don't really need Rc<Self>, and for show() we had Rc<Self> because
for example for winit we need a Weak<Self> for the thread-local mapping of
window id to window.
However that can be encapsulated in the PlatformWindow impl using Rc::new_cyclic,
there's no need to expose this in the trait.
Move the self_weak of WindowInner into the impl of PlatformWindow. Most implementations already have it anyway.
While right now the method returns a `WindowRc`, at the end of the series
it should return a `&Window`.
From that `&Window` we can get to `&WindowInner` and all receivers there
are `&self`.
Because re-generating the Skia image is slow and there is no point
storing both the image buffer and the SkiaImage in the cache as it
is basically the same information.
The rotation-angle/rotation-origin-x/y properties are lowered to an
injected Rotate element, that we already had.
This needs further fixes for transforming input events and an
implementation of rotation in Skia.
This field duplicates the winit window's inner size. It is set on a
WindowEvent::Resized(), after which
`winit:🪟:Window::inner_size()` returns the same value.
When the renderer does not re-implement visit_clip, we call combine_clip.
Then we're missing out on an optimization the GL renderer does: When the resulting clip region
is empty, we do not need to recurse into children for rendering.
That itself reduces the property dependency chain and avoids unnecessary
updates when invisible (clipped) children change properties.
If we want to use the software renderer as a drop in replacement
for the GL renderer, we need to be able to render all images
without the compiler having to pre-render the textures
This was tested by hacking the compiler not to render the texture
with the mcu simulator
