macOS: use a subview, improve image handling

Author: lunixbochs

src/cg.rs

@@ -3,13 +3,15 @@ use raw_window_handle::{HasRawWindowHandle, AppKitHandle};
 use core_graphics::base::{kCGBitmapByteOrder32Little, kCGImageAlphaNoneSkipFirst, kCGRenderingIntentDefault};
 use core_graphics::color_space::CGColorSpace;
 use core_graphics::data_provider::CGDataProvider;
-use core_graphics::geometry::CGSize;
 use core_graphics::image::CGImage;
 
-use cocoa::base::id;
+use cocoa::base::{id, nil};
+use cocoa::appkit::{NSView, NSViewWidthSizable, NSViewHeightSizable};
 use cocoa::quartzcore::{CALayer, ContentsGravity};
 use foreign_types::ForeignType;
 
+use std::sync::Arc;
+
 pub struct CGImpl {
     layer: CALayer,
 }
@@ -18,19 +20,25 @@ impl CGImpl {
     pub unsafe fn new<W: HasRawWindowHandle>(handle: AppKitHandle) -> Result<Self, SoftBufferError<W>> {
         let view = handle.ns_view as id;
         let layer = CALayer::new();
+        let subview: id = NSView::alloc(nil).initWithFrame_(view.frame());
         layer.set_contents_gravity(ContentsGravity::TopLeft);
-        let _: () = msg_send![view, setLayer:layer.clone()];
+        layer.set_needs_display_on_bounds_change(false);
+        subview.setLayer(layer.id());
+        subview.setAutoresizingMask_(NSViewWidthSizable | NSViewHeightSizable);
+
+        view.addSubview_(subview); // retains subview (+1) = 2
+        let _: () = msg_send![subview, release]; // releases subview (-1) = 1
         Ok(Self{layer})
     }
 }
 
 impl GraphicsContextImpl for CGImpl {
     unsafe fn set_buffer(&mut self, buffer: &[u32], width: u16, height: u16) {
         let color_space = CGColorSpace::create_device_rgb();
-        let slice = std::slice::from_raw_parts(
+        let data = std::slice::from_raw_parts(
             buffer.as_ptr() as *const u8,
-            buffer.len() * 4);
-        let data_provider = CGDataProvider::from_slice(slice);
+            buffer.len() * 4).to_vec();
+        let data_provider = CGDataProvider::from_buffer(Arc::new(data));
         let image = CGImage::new(
             width as usize,
             height as usize,
@@ -43,17 +51,6 @@ impl GraphicsContextImpl for CGImpl {
             false,
             kCGRenderingIntentDefault,
         );
-
-        let size = CGSize::new(width as f64, height as f64);
-        let rep: id = msg_send![class!(NSCGImageRep), alloc];
-        let rep: id = msg_send![rep, initWithCGImage:image.as_ptr() size:size];
-
-        let nsimage: id = msg_send![class!(NSImage), alloc];
-        let nsimage: id = msg_send![nsimage, initWithSize:size];
-        let _: () = msg_send![nsimage, addRepresentation:rep];
-        let _: () = msg_send![rep, release];
-
-        self.layer.set_contents(nsimage);
-        let _: () = msg_send![nsimage, release];
+        self.layer.set_contents(image.as_ptr() as id);
     }
 }