From ce63f67de14800b3dd95c8c0172ad2792580ff09 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Wed, 23 Sep 2009 07:18:02 +0000
Subject: [PATCH] Fixed bug #719

 Mike Blaguszewski      2009-03-23 13:32:22 PDT

Patch to 1.2 HEAD that fixes the issue

Fixes bug in SDL 1.2.13 where clicking on an app's title bar to activate the
app, when cursor capturing is enabled, will cause the window to jump. This is
because SDL's handler for activate events calls a low-level Quartz function to
move the cursor. Calling this when the mouse is down in the title bar confuses
the WindowServer into thinking the title bar has been dragged. The patch defers
processing of activate events in this case.

The bottom line is that CGWarpMouseCursorPosition() is not safe to call when
the mouse in down in a window's title bar.
---
 src/video/quartz/SDL_QuartzWindow.h |  4 ++++
 src/video/quartz/SDL_QuartzWindow.m | 24 ++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/src/video/quartz/SDL_QuartzWindow.h b/src/video/quartz/SDL_QuartzWindow.h
index a1939ba7d..ce850251d 100644
--- a/src/video/quartz/SDL_QuartzWindow.h
+++ b/src/video/quartz/SDL_QuartzWindow.h
@@ -27,6 +27,10 @@ typedef unsigned int NSUInteger;
 
 /* Subclass of NSWindow to fix genie effect and support resize events  */
 @interface SDL_QuartzWindow : NSWindow
+{
+	BOOL watchForMouseUp;
+}
+
 - (void)miniaturize:(id)sender;
 - (void)display;
 - (void)setFrame:(NSRect)frameRect display:(BOOL)flag;
diff --git a/src/video/quartz/SDL_QuartzWindow.m b/src/video/quartz/SDL_QuartzWindow.m
index 1b006bfc4..ff757bd91 100644
--- a/src/video/quartz/SDL_QuartzWindow.m
+++ b/src/video/quartz/SDL_QuartzWindow.m
@@ -128,6 +128,30 @@ - (void)setFrame:(NSRect)frameRect display:(BOOL)flag
     }
 }
 
+/* QZ_DoActivate() calls a low-level CoreGraphics routine to adjust
+   the cursor position, if input is being grabbed. If app activation is
+   triggered by a mouse click in the title bar, then the window manager
+   gets confused and thinks we're dragging the window. The solution
+   below postpones the activate event to avoid this scenario. */
+- (void)becomeKeyWindow
+{
+	NSEvent *event = [self currentEvent];
+	if ([event type] == NSLeftMouseDown && [event window] == self)
+		watchForMouseUp = YES;
+	else
+		[super becomeKeyWindow];
+}
+
+- (void)sendEvent:(NSEvent *)event
+{
+	[super sendEvent:event];
+	if (watchForMouseUp && [event type] == NSLeftMouseUp)
+	{
+		watchForMouseUp = NO;
+		[super becomeKeyWindow];
+	}
+}
+
 - (void)appDidHide:(NSNotification*)note
 {
     SDL_PrivateAppActive (0, SDL_APPACTIVE);