Olivier found the following steps that reproduce the crash with Skia:
1. Open the gallery and select the "Text Edit" tab.
2. In the first text edit widget, select the first three letters.
3. Click into the second text edit (while the first one shows the selected text)
4. At the beginning of the text, insert the letter "ù" a few times.
This sequence would result in the cursor_position property get out of
sync. Since it represents a byte offset in the utf-8 text, it would
point straight into a utf-8 sequence, resulting in a panic when the
renderer would try to create a slice of the selected text.
As a remedy, this patch renames the cursor_position and anchor_position
properties and provides wrapper getter accessors for use within the
TextInput to safely bound the stored offset.
Eventually we need to intercept changes to the text property and adjust
the cursor and anchor position properties accordingly, so that they
remain valid. However this requires that the compiler is aware that a
property is not accessible directly but has a setter that needs to be
called instead.
This likely/hopefully also fixes#1707.
This removes the special code for the generated property getters and
ensures type safety in the run-time library for property value setting.
In the Rust generated code we continue to do arithmetic on the scalar
values, that means we immediately extract the scalar, do arithmetic and
rely on the compiler to only allow compatible units.
Danger zone alert: In the interpreter Value::Number can now be converted
to LogicalLength as-is.
Known caveats:
- winit doesn't forward mouse events to the IME, so clicking
with the mouse while composing results in funny effects such
as the pre-edit text following the cursor.
- With FemtoVG there's no text decoration support, thus no underlining
of the preedit area.
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++.
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.
This simplifies the renderer handling - the FontRequest arriving there
will always be resolved.
And this reduces the amount of property dependencies: If a Text elements
specifies a font-family, no dependency to the window's
default-font-family is created.
Every backend will do something different with the string that needs to go into the clipboard.
Qt will convert it to a QString, copypasta to a String, in theory it could be written
directly to a socket.
Given that we don't know what the perfect representation on the backend side is, passing
a string slice avoids any immediate conversions.
