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app: [macOS] implement non-blocking window resizing
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Despite the option to control the main thread event loop, some gestures
still block the event loop until completion. This change disables the
blocking resize gestures and implements a non-blocking replacement.

A complete replacement is left for future work, or the implementation of
golang/go#64755.

Signed-off-by: Elias Naur <[email protected]>
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@eliasnaur
eliasnaur committed Feb 8, 2024
1 parent 83e914b commit 602f423
Showing 1 changed file with 212 additions and 9 deletions.
221 changes: 212 additions & 9 deletions app/os_macos.m
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Original file line number Diff line number Diff line change
Expand Up @@ -69,6 +69,212 @@ static void handleMouse(GioView *view, NSEvent *event, int typ, CGFloat dx, CGFl
gio_onMouse(view.handle, (__bridge CFTypeRef)event, typ, event.buttonNumber, p.x, height - p.y, dx, dy, [event timestamp], [event modifierFlags]);
}

@interface GioApplication: NSApplication
@end

// Variables for tracking resizes.
static struct {
NSPoint dir;
NSEvent *lastMouseDown;
NSPoint off;
} resizeState = {};

static NSBitmapImageRep *nsImageBitmap(NSImage *img) {
NSArray<NSImageRep *> *reps = img.representations;
if ([reps count] == 0) {
return nil;
}
NSImageRep *rep = reps[0];
if (![rep isKindOfClass:[NSBitmapImageRep class]]) {
return nil;
}
return (NSBitmapImageRep *)rep;
}

static NSCursor *lookupPrivateNSCursor(SEL name) {
if (![NSCursor respondsToSelector:name]) {
return nil;
}
id obj = [NSCursor performSelector:name];
if (![obj isKindOfClass:[NSCursor class]]) {
return nil;
}
return (NSCursor *)obj;
}

static BOOL isEqualNSCursor(NSCursor *c1, SEL name2) {
NSCursor *c2 = lookupPrivateNSCursor(name2);
if (c2 == nil || !NSEqualPoints(c1.hotSpot, c2.hotSpot)) {
return NO;
}
NSImage *img1 = c1.image;
NSImage *img2 = c2.image;
if (!NSEqualSizes(img1.size, img2.size)) {
return NO;
}
NSBitmapImageRep *bit1 = nsImageBitmap(img1);
NSBitmapImageRep *bit2 = nsImageBitmap(img2);
if (bit1 == nil || bit2 == nil) {
return NO;
}
NSInteger n1 = bit1.numberOfPlanes*bit1.bytesPerPlane;
NSInteger n2 = bit1.numberOfPlanes*bit1.bytesPerPlane;
if (n1 != n2) {
return NO;
}
if (memcmp(bit1.bitmapData, bit2.bitmapData, n1) != 0) {
return NO;
}
return YES;
}

@implementation GioApplication
- (NSEvent *)nextEventMatchingMask:(NSEventMask)mask
untilDate:(NSDate *)expiration
inMode:(NSRunLoopMode)mode
dequeue:(BOOL)deqFlag {
if ([mode isEqualToString:NSEventTrackingRunLoopMode]) {
NSEvent *l = resizeState.lastMouseDown;
if (l != nil) {
//lastMouseDown = nil;
NSCursor *cur = [NSCursor currentSystemCursor];
NSPoint dir = {};
NSPoint off = {};
NSSize wsz = [l window].frame.size;
NSPoint center = NSMakePoint(wsz.width/2, wsz.height/2);
NSPoint p = [l locationInWindow];
if (p.x >= center.x) {
dir.x = 1;
off.x = p.x - wsz.width;
} else {
dir.x = -1;
off.x = p.x;
}
if (p.y >= center.y) {
dir.y = 1;
off.y = p.y - wsz.height;
} else {
dir.y = -1;
off.y = p.y;
}
// The button down coordinate distinguish the four quadrants. Use the
// cursor image to determine the precise direction.
SEL nw = @selector(_windowResizeNorthWestCursor);
SEL n = @selector(_windowResizeNorthCursor);
SEL ne = @selector(_windowResizeNorthEastCursor);
SEL e = @selector(_windowResizeEastCursor);
SEL se = @selector(_windowResizeSouthEastCursor);
SEL s = @selector(_windowResizeSouthCursor);
SEL sw = @selector(_windowResizeSouthWestCursor);
SEL w = @selector(_windowResizeWestCursor);
SEL ns = @selector(_windowResizeNorthSouthCursor);
SEL ew = @selector(_windowResizeEastWestCursor);
SEL nwse = @selector(_windowResizeNorthWestSouthEastCursor);
SEL nesw = @selector(_windowResizeNorthEastSouthWestCursor);
BOOL match = YES;
if (dir.x != 0 && (isEqualNSCursor(cur, ew) || isEqualNSCursor(cur, w) || isEqualNSCursor(cur, e))) {
dir.y = 0;
}
if (dir.y != 0 && (isEqualNSCursor(cur, ns) || isEqualNSCursor(cur, s) || isEqualNSCursor(cur, n))) {
dir.x = 0;
}
// If none of the cursors matched, we may deduce that the resize
// direction is one of the corners. However, to ensure that at least
// one cursor matches, check the corner cursors.
if (dir.x == 1 && dir.y == 1) {
if (!isEqualNSCursor(cur, nesw) && !isEqualNSCursor(cur, sw)) {
dir = NSZeroPoint;
}
} else if (dir.x == 1 && dir.y == -1) {
if (!isEqualNSCursor(cur, nwse) && !isEqualNSCursor(cur, nw)) {
dir = NSZeroPoint;
}
} else if (dir.x == -1 && dir.y == 1) {
if (!isEqualNSCursor(cur, nwse) && !isEqualNSCursor(cur, se)) {
dir = NSZeroPoint;
}
} else if (dir.x == -1 && dir.y == -1) {
if (!isEqualNSCursor(cur, nesw) && !isEqualNSCursor(cur, ne)) {
dir = NSZeroPoint;
}
}
if (!NSEqualPoints(dir, NSZeroPoint)) {
NSEvent *cancel = [NSEvent mouseEventWithType:NSEventTypeLeftMouseUp
location:l.locationInWindow
modifierFlags:l.modifierFlags
timestamp:l.timestamp
windowNumber:l.windowNumber
context:l.context
eventNumber:l.eventNumber
clickCount:l.clickCount
pressure:l.pressure];
resizeState.off = off;
resizeState.dir = dir;
return cancel;
}
}
}
return [super nextEventMatchingMask:mask untilDate:expiration inMode:mode dequeue:deqFlag];
}
@end

@interface GioWindow: NSWindow
@end

@implementation GioWindow
- (void)sendEvent:(NSEvent *)evt {
if (evt.type == NSEventTypeLeftMouseDown) {
resizeState.lastMouseDown = evt;
}
NSPoint dir = resizeState.dir;
if (NSEqualPoints(dir, NSZeroPoint)) {
[super sendEvent:evt];
return;
}
switch (evt.type) {
default:
return;
case NSEventTypeLeftMouseUp:
resizeState.dir = NSZeroPoint;
resizeState.lastMouseDown = nil;
return;
case NSEventTypeLeftMouseDragged:
// Ok to proceed.
break;
}
NSPoint loc = evt.locationInWindow;
NSPoint off = resizeState.off;
loc.x -= off.x;
loc.y -= off.y;
NSRect frame = [self frame];
NSSize min = [self minSize];
NSSize max = [self maxSize];
CGFloat width = frame.size.width;
if (dir.x > 0) {
width = loc.x;
} else if (dir.x < 0) {
width -= loc.x;
}
width = MIN(max.width, MAX(min.width, width));
if (dir.x < 0) {
frame.origin.x += frame.size.width - width;
}
frame.size.width = width;
CGFloat height = frame.size.height;
if (dir.y > 0) {
height = loc.y;
} else if (dir.y < 0) {
height -= loc.y;
}
height = MIN(max.height, MAX(min.height, height));
if (dir.y < 0) {
frame.origin.y += frame.size.height - height;
}
frame.size.height = height;
[self setFrame:frame display:YES animate:NO];
}
@end

@implementation GioView
- (void)setFrameSize:(NSSize)newSize {
[super setFrameSize:newSize];
Expand Down Expand Up @@ -255,14 +461,11 @@ void gio_showCursor() {
// some cursors are not public, this tries to use a private cursor
// and uses fallback when the use of private cursor fails.
static void trySetPrivateCursor(SEL cursorName, NSCursor* fallback) {
if ([NSCursor respondsToSelector:cursorName]) {
id object = [NSCursor performSelector:cursorName];
if ([object isKindOfClass:[NSCursor class]]) {
[(NSCursor*)object set];
return;
}
NSCursor *cur = lookupPrivateNSCursor(cursorName);
if (cur == nil) {
cur = fallback;
}
[fallback set];
[cur set];
}

void gio_setCursor(NSUInteger curID) {
Expand Down Expand Up @@ -361,7 +564,7 @@ CFTypeRef gio_createWindow(CFTypeRef viewRef, CGFloat width, CGFloat height, CGF
NSMiniaturizableWindowMask |
NSClosableWindowMask;

NSWindow* window = [[NSWindow alloc] initWithContentRect:rect
GioWindow* window = [[GioWindow alloc] initWithContentRect:rect
styleMask:styleMask
backing:NSBackingStoreBuffered
defer:NO];
Expand Down Expand Up @@ -416,7 +619,7 @@ - (void)applicationDidFinishLaunching:(NSNotification *)aNotification {

void gio_main() {
@autoreleasepool {
[NSApplication sharedApplication];
[GioApplication sharedApplication];
GioAppDelegate *del = [[GioAppDelegate alloc] init];
[NSApp setDelegate:del];

Expand Down

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