ui/cocoa: Add cursor composition

Add accelerated cursor composition to ui/cocoa. This does not only
improve performance for display devices that exposes the capability to
the guest according to dpy_cursor_define_supported(), but fixes the
cursor display for devices that unconditionally expects the availability
of the capability (e.g., virtio-gpu).

The common pattern to implement accelerated cursor composition is to
replace the cursor and warp it so that the replaced cursor is shown at
the correct position on the guest display for relative pointer devices.
Unfortunately, ui/cocoa cannot do the same because warping the cursor
position interfers with the mouse input so it uses CALayer instead;
although it is not specialized for cursor composition, it still can
compose images with hardware acceleration.

Co-authored-by: Phil Dennis-Jordan <phil@philjordan.eu>
Tested-by: Phil Dennis-Jordan <phil@philjordan.eu>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-ID: <20240715-cursor-v3-3-afa5b9492dbf@daynix.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

meson.build

@@ -1070,7 +1070,8 @@ if get_option('attr').allowed()
   endif
 endif
 
-cocoa = dependency('appleframeworks', modules: ['Cocoa', 'CoreVideo'],
+cocoa = dependency('appleframeworks',
+                   modules: ['Cocoa', 'CoreVideo', 'QuartzCore'],
                    required: get_option('cocoa'))
 
 vmnet = dependency('appleframeworks', modules: 'vmnet', required: get_option('vmnet'))

ui/cocoa.m

@@ -25,6 +25,7 @@
 #include "qemu/osdep.h"
 
 #import <Cocoa/Cocoa.h>
+#import <QuartzCore/QuartzCore.h>
 #include <crt_externs.h>
 
 #include "qemu/help-texts.h"
@@ -79,12 +80,16 @@ static void cocoa_switch(DisplayChangeListener *dcl,
                          DisplaySurface *surface);
 
 static void cocoa_refresh(DisplayChangeListener *dcl);
+static void cocoa_mouse_set(DisplayChangeListener *dcl, int x, int y, bool on);
+static void cocoa_cursor_define(DisplayChangeListener *dcl, QEMUCursor *cursor);
 
 static const DisplayChangeListenerOps dcl_ops = {
     .dpy_name          = "cocoa",
     .dpy_gfx_update = cocoa_update,
     .dpy_gfx_switch = cocoa_switch,
     .dpy_refresh = cocoa_refresh,
+    .dpy_mouse_set = cocoa_mouse_set,
+    .dpy_cursor_define = cocoa_cursor_define,
 };
 static DisplayChangeListener dcl = {
     .ops = &dcl_ops,
@@ -308,6 +313,11 @@ @interface QemuCocoaView : NSView
     BOOL isAbsoluteEnabled;
     CFMachPortRef eventsTap;
     CGColorSpaceRef colorspace;
+    CALayer *cursorLayer;
+    QEMUCursor *cursor;
+    int mouseX;
+    int mouseY;
+    bool mouseOn;
 }
 - (void) switchSurface:(pixman_image_t *)image;
 - (void) grabMouse;
@@ -364,6 +374,12 @@ - (id)initWithFrame:(NSRect)frameRect
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_VERSION_14_0
         [self setClipsToBounds:YES];
 #endif
+        [self setWantsLayer:YES];
+        cursorLayer = [[CALayer alloc] init];
+        [cursorLayer setAnchorPoint:CGPointMake(0, 1)];
+        [cursorLayer setAutoresizingMask:kCALayerMaxXMargin |
+                                         kCALayerMinYMargin];
+        [[self layer] addSublayer:cursorLayer];
 
     }
     return self;
@@ -382,6 +398,8 @@ - (void) dealloc
     }
 
     CGColorSpaceRelease(colorspace);
+    [cursorLayer release];
+    cursor_unref(cursor);
     [super dealloc];
 }
 
@@ -426,6 +444,72 @@ - (void) unhideCursor
     [NSCursor unhide];
 }
 
+- (void)setMouseX:(int)x y:(int)y on:(bool)on
+{
+    CGPoint position;
+
+    mouseX = x;
+    mouseY = y;
+    mouseOn = on;
+
+    position.x = mouseX;
+    position.y = screen.height - mouseY;
+
+    [CATransaction begin];
+    [CATransaction setDisableActions:YES];
+    [cursorLayer setPosition:position];
+    [cursorLayer setHidden:!mouseOn];
+    [CATransaction commit];
+}
+
+- (void)setCursor:(QEMUCursor *)given_cursor
+{
+    CGDataProviderRef provider;
+    CGImageRef image;
+    CGRect bounds = CGRectZero;
+
+    cursor_unref(cursor);
+    cursor = given_cursor;
+
+    if (!cursor) {
+        return;
+    }
+
+    cursor_ref(cursor);
+
+    bounds.size.width = cursor->width;
+    bounds.size.height = cursor->height;
+
+    provider = CGDataProviderCreateWithData(
+        NULL,
+        cursor->data,
+        cursor->width * cursor->height * 4,
+        NULL
+    );
+
+    image = CGImageCreate(
+        cursor->width, //width
+        cursor->height, //height
+        8, //bitsPerComponent
+        32, //bitsPerPixel
+        cursor->width * 4, //bytesPerRow
+        colorspace, //colorspace
+        kCGBitmapByteOrder32Little | kCGImageAlphaFirst, //bitmapInfo
+        provider, //provider
+        NULL, //decode
+        0, //interpolate
+        kCGRenderingIntentDefault //intent
+    );
+
+    CGDataProviderRelease(provider);
+    [CATransaction begin];
+    [CATransaction setDisableActions:YES];
+    [cursorLayer setBounds:bounds];
+    [cursorLayer setContents:(id)image];
+    [CATransaction commit];
+    CGImageRelease(image);
+}
+
 - (void) drawRect:(NSRect) rect
 {
     COCOA_DEBUG("QemuCocoaView: drawRect\n");
@@ -2015,6 +2099,21 @@ static void cocoa_refresh(DisplayChangeListener *dcl)
     [pool release];
 }
 
+static void cocoa_mouse_set(DisplayChangeListener *dcl, int x, int y, bool on)
+{
+    dispatch_async(dispatch_get_main_queue(), ^{
+        [cocoaView setMouseX:x y:y on:on];
+    });
+}
+
+static void cocoa_cursor_define(DisplayChangeListener *dcl, QEMUCursor *cursor)
+{
+    dispatch_async(dispatch_get_main_queue(), ^{
+        BQL_LOCK_GUARD();
+        [cocoaView setCursor:qemu_console_get_cursor(dcl->con)];
+    });
+}
+
 static void cocoa_display_init(DisplayState *ds, DisplayOptions *opts)
 {
     NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];