Add RGB565 rendering function to the C++ software renderer

api/cpp/include/slint_platform.h

@@ -295,6 +295,19 @@ class SoftwareRenderer : public AbstractRenderer
         cbindgen_private::slint_software_renderer_render_rgb8(
                 inner, &window.window_handle().inner, buffer.data(), buffer.size(), pixel_stride);
     }
+
+    /// Render the window scene into an RGB 565 encoded pixel buffer
+    ///
+    /// The buffer must be at least as large as the associated slint::Window
+    ///
+    /// The stride is the amount of pixels between two lines in the buffer.
+    /// It is must be at least as large as the width of the window.
+    void render_rgb565(const Window &window, std::span<uint16_t> buffer,
+                       std::size_t pixel_stride) const
+    {
+        cbindgen_private::slint_software_renderer_render_rgb565(
+                inner, &window.window_handle().inner, buffer.data(), buffer.size(), pixel_stride);
+    }
 };
 
 /// An opaque, low-level window handle that internalizes everything necessary to exchange messages

api/cpp/platform.rs

@@ -8,7 +8,7 @@ use i_slint_core::api::{PhysicalSize, Window};
 use i_slint_core::graphics::{IntSize, Rgb8Pixel};
 use i_slint_core::platform::{Platform, PlatformError};
 use i_slint_core::renderer::Renderer;
-use i_slint_core::software_renderer::{RepaintBufferType, SoftwareRenderer};
+use i_slint_core::software_renderer::{RepaintBufferType, Rgb565Pixel, SoftwareRenderer};
 use i_slint_core::window::ffi::WindowAdapterRcOpaque;
 use i_slint_core::window::{WindowAdapter, WindowAdapterInternal};
 
@@ -295,6 +295,21 @@ pub unsafe extern "C" fn slint_software_renderer_render_rgb8(
     renderer.render(buffer, pixel_stride);
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn slint_software_renderer_render_rgb565(
+    r: SoftwareRendererOpaque,
+    window_adapter: *const WindowAdapterRcOpaque,
+    buffer: *mut u16,
+    buffer_len: usize,
+    pixel_stride: usize,
+) {
+    let buffer = core::slice::from_raw_parts_mut(buffer as *mut Rgb565Pixel, buffer_len);
+    let renderer = &*(r as *const SoftwareRenderer);
+    let window_adapter = &*(window_adapter as *const Rc<dyn WindowAdapter>);
+    renderer.set_window(window_adapter.window());
+    renderer.render(buffer, pixel_stride);
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn slint_software_renderer_handle(r: SoftwareRendererOpaque) -> RendererPtr {
     let r = (r as *const SoftwareRenderer) as *const dyn Renderer;