Add macOS support using Core Graphics

src/cg.rs

@@ -0,0 +1,55 @@
+use crate::{GraphicsContextImpl, SoftBufferError};
+use raw_window_handle::{HasRawWindowHandle, AppKitHandle};
+use objc::runtime::Object;
+use core_graphics::base::{kCGBitmapByteOrder32Little, kCGImageAlphaNoneSkipFirst, kCGRenderingIntentDefault};
+use core_graphics::color_space::CGColorSpace;
+use core_graphics::context::CGContext;
+use core_graphics::data_provider::CGDataProvider;
+use core_graphics::geometry::{CGPoint, CGSize, CGRect};
+use core_graphics::image::CGImage;
+use core_graphics::sys;
+
+pub struct CGImpl;
+
+impl CGImpl {
+    pub unsafe fn new<W: HasRawWindowHandle>(handle: AppKitHandle) -> Result<Self, SoftBufferError<W>> {
+        let window = handle.ns_window as *mut Object;
+        let cls = class!(NSGraphicsContext);
+        let graphics_context: *mut Object = msg_send![cls, graphicsContextWithWindow:window];
+        if graphics_context.is_null() {
+            return Err(SoftBufferError::PlatformError(Some("Graphics context is null".into()), None));
+        }
+        let _: () = msg_send![cls, setCurrentContext:graphics_context];
+        Ok(Self)
+    }
+}
+
+impl GraphicsContextImpl for CGImpl {
+    unsafe fn set_buffer(&mut self, buffer: &[u32], width: u16, height: u16) {
+        let cls = class!(NSGraphicsContext);
+        let graphics_context: *mut Object = msg_send![cls, currentContext];
+        let context_ptr: *mut sys::CGContext = msg_send![graphics_context, CGContext];
+        let context = CGContext::from_existing_context_ptr(context_ptr);
+        let color_space = CGColorSpace::create_device_rgb();
+        let slice = std::slice::from_raw_parts(
+            buffer.as_ptr() as *const u8,
+            buffer.len() * 4);
+        let data_provider = CGDataProvider::from_slice(slice);
+        let image = CGImage::new(
+            width as usize,
+            height as usize,
+            8,
+            32,
+            (width * 4) as usize,
+            &color_space,
+            kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipFirst,
+            &data_provider,
+            false,
+            kCGRenderingIntentDefault,
+        );
+        let origin = CGPoint { x: 0f64, y: 0f64 };
+        let size = CGSize { width: width as f64, height: height as f64 };
+        let rect = CGRect { origin, size };
+        context.draw_image(rect, &image);
+    }
+}