Add a Quartz Debug style redraw debugging feature

AppKit/NSGraphicsContext.h

@@ -70,3 +70,14 @@ typedef enum {
 
 @end
 
+@interface NSGraphicsContext (QuartzDebugging)
+
++ (void)setQuartzDebuggingEnabled:(BOOL)enabled;
+
++ (BOOL)quartzDebuggingIsEnabled;
+
++ (BOOL)inQuartzDebugMode;
+
++ (void)setQuartzDebugMode:(BOOL)mode;
+
+@end

AppKit/NSGraphicsContext.m

@@ -17,6 +17,22 @@ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLI
 
 @implementation NSGraphicsContext
 
++ (void)initialize
+{
+	NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
+	NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+	
+	BOOL enabled = [defaults boolForKey: @"NSQuartzDebugEnabled"];
+	
+	if (enabled) {
+		NSLog(@"enabling Quartz Debugging emulation");
+	}
+	
+	[NSGraphicsContext setQuartzDebuggingEnabled: enabled];
+	
+	[pool drain];
+}
+
 -initWithWindow:(NSWindow *)window {
    _graphicsPort=CGContextRetain([window cgContext]);
    _focusStack=[NSMutableArray new];
@@ -237,4 +253,29 @@ NSMutableArray *NSCurrentFocusStack() {
 
 @end
 
+static BOOL sQuartzDebuggingEnabled = NO;
+static BOOL sQuartzDebugging = NO;		
+				
+@implementation NSGraphicsContext (QuartzDebugging)
 
++ (void)setQuartzDebuggingEnabled:(BOOL)enabled
+{
+	sQuartzDebuggingEnabled = enabled;
+}
+
++ (BOOL)quartzDebuggingIsEnabled
+{
+	return sQuartzDebuggingEnabled;
+}
+
++ (BOOL)inQuartzDebugMode
+{
+	return sQuartzDebuggingEnabled && sQuartzDebugging;
+}
+
++ (void)setQuartzDebugMode:(BOOL)mode
+{
+	sQuartzDebugging = mode;
+}
+
+@end

AppKit/NSView.m

@@ -1642,6 +1642,9 @@ static void clearInvalidRects(NSView *self){
 }
 
 static void clearNeedsDisplay(NSView *self){
+	if ([NSGraphicsContext inQuartzDebugMode]) {
+		return;
+	}
    clearInvalidRects(self);
    self->_needsDisplay=NO;
 }
@@ -1873,8 +1876,13 @@ static NSGraphicsContext *graphicsContextForView(NSView *view){
    NSRect visibleRect=[self visibleRect];
 
    rect=NSIntersectionRect(rect,visibleRect);
-   removeRectFromInvalidInVisibleRect(self,rect,visibleRect);
 
+	if ([NSGraphicsContext inQuartzDebugMode]) {
+		// Don't do anything to interfere with what will be drawn in non-debug mode
+	} else {
+		removeRectFromInvalidInVisibleRect(self,rect,visibleRect);
+	}
+	
    if(NSIsEmptyRect(rect))
     return;
     
@@ -1888,7 +1896,12 @@ static NSGraphicsContext *graphicsContextForView(NSView *view){
 
     CGContextClipToRect(graphicsPort,rect);
 
-    [self drawRect:rect];
+	   if ([NSGraphicsContext inQuartzDebugMode]) {
+		   [[NSColor yellowColor] set];
+		   NSRectFill(rect);
+	   } else {
+		   [self drawRect:rect];
+	   }
     [self unlockFocus];
 
     NSInteger i,count=[_subviews count];

AppKit/NSWindow.m

@@ -1684,6 +1684,18 @@ NSString * const NSWindowDidAnimateNotification=@"NSWindowDidAnimateNotification
    if([self isVisible] && ![self isMiniaturized] && [self viewsNeedDisplay]){
     NSAutoreleasePool *pool=[NSAutoreleasePool new];
 
+	if ([NSGraphicsContext quartzDebuggingIsEnabled] == YES) {
+
+		// Show all the views getting redrawn
+	   [NSGraphicsContext setQuartzDebugMode: YES];
+	   [self disableFlushWindow];
+	   [_backgroundView displayIfNeeded];
+	   [self enableFlushWindow];
+	   [self flushWindowIfNeeded];
+	}
+
+	[NSGraphicsContext setQuartzDebugMode: NO];
+	   
     [self disableFlushWindow];
     [_backgroundView displayIfNeeded];
     [self enableFlushWindow];
@@ -1698,7 +1710,20 @@ NSString * const NSWindowDidAnimateNotification=@"NSWindowDidAnimateNotification
  */
    if([self isVisible]){
     NSAutoreleasePool *pool=[NSAutoreleasePool new];
-    [self disableFlushWindow];
+
+	if ([NSGraphicsContext quartzDebuggingIsEnabled] == YES) {
+
+		// Show all the views getting redrawn
+	   [NSGraphicsContext setQuartzDebugMode: YES];
+	   [self disableFlushWindow];
+	   [_backgroundView display];
+	   [self enableFlushWindow];
+	   [self flushWindowIfNeeded];
+	}
+
+	[NSGraphicsContext setQuartzDebugMode: NO];
+
+	[self disableFlushWindow];
     [_backgroundView display];
     [self enableFlushWindow];
     [self flushWindowIfNeeded];