backend_interface.rs

//! Interface implemented by backends

use crate::{AlphaMode, InitError, PixelFormat, Rect, SoftBufferError};

use raw_window_handle::{HasDisplayHandle, HasWindowHandle};
use std::num::NonZeroU32;

pub(crate) trait ContextInterface<D: HasDisplayHandle + ?Sized> {
    fn new(display: D) -> Result<Self, InitError<D>>
    where
        D: Sized,
        Self: Sized;
}

pub(crate) trait SurfaceInterface<D: HasDisplayHandle + ?Sized, W: HasWindowHandle + ?Sized> {
    type Context: ContextInterface<D>;
    type Buffer<'a>: BufferInterface
    where
        Self: 'a;

    fn new(window: W, context: &Self::Context) -> Result<Self, InitError<W>>
    where
        W: Sized,
        Self: Sized;

    /// Get the inner window handle.
    fn window(&self) -> &W;

    fn alpha_mode(&self) -> AlphaMode;

    /// Reconfigure the internal buffer(s).
    ///
    /// Returns `Some(byte_stride)` if the buffer was successfully resized, or `None` if the surface does not support the given pixel format.
    fn configure(
        &mut self,
        width: NonZeroU32,
        height: NonZeroU32,
        alpha_mode: AlphaMode,
        pixel_format: PixelFormat,
    ) -> Result<Option<u32>, SoftBufferError>;

    /// Get a mutable reference to the buffer.
    fn buffer_mut(&mut self) -> Result<Self::Buffer<'_>, SoftBufferError>;

    /// Fetch the buffer from the window.
    fn fetch(&mut self) -> Result<Vec<u32>, SoftBufferError> {
        Err(SoftBufferError::Unimplemented)
    }
}

pub(crate) trait BufferInterface {
    fn width(&self) -> NonZeroU32;
    fn height(&self) -> NonZeroU32;
    fn pixels_mut(&mut self) -> &mut [u32];
    fn age(&self) -> u8;
    fn present_with_damage(self, damage: &[Rect]) -> Result<(), SoftBufferError>;
    fn present(self) -> Result<(), SoftBufferError>;
}