Moved tile cutting into an NSOperation to leverage all computing core…

…s. Still somewhat inefficient for large images, but should be faster.

NSInvocation-MCUtilities.h

@@ -0,0 +1,17 @@
+//
+//  NSInvocation-MCUtilities.h
+//  Visioneer
+//
+//  Created by jeff on 7/26/10.
+//  Copyright 2010 __MyCompanyName__. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+
+@interface NSInvocation(MCUtilities)
+-(void)invokeOnMainThreadWaitUntilDone:(BOOL)wait;
++(NSInvocation*)invocationWithTarget:(id)target
+                            selector:(SEL)aSelector
+                     retainArguments:(BOOL)retainArguments, ...;
+@end

NSInvocation-MCUtilities.m

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+//
+//  NSInvocation-MCUtilities.m
+//  Visioneer
+//
+
+//
+// Source: http://blog.jayway.com/2010/03/30/performing-any-selector-on-the-main-thread/
+//
+#import "NSInvocation-MCUtilities.h"
+
+
+@implementation NSInvocation(MCUtilities)
+-(void)invokeOnMainThreadWaitUntilDone:(BOOL)wait
+{
+    [self performSelectorOnMainThread:@selector(invoke)
+                           withObject:nil
+                        waitUntilDone:wait];
+}
++(NSInvocation*)invocationWithTarget:(id)target
+                            selector:(SEL)aSelector
+                     retainArguments:(BOOL)retainArguments, ...
+{
+    va_list ap;
+    va_start(ap, retainArguments);
+    char* args = (char*)ap;
+    NSMethodSignature* signature = [target methodSignatureForSelector:aSelector];
+    NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:signature];
+    if (retainArguments) {
+        [invocation retainArguments];
+    }
+    [invocation setTarget:target];
+    [invocation setSelector:aSelector];
+    for (int index = 2; index < [signature numberOfArguments]; index++) {
+        const char *type = [signature getArgumentTypeAtIndex:index];
+        NSUInteger size, align;
+        NSGetSizeAndAlignment(type, &size, &align);
+        NSUInteger mod = (NSUInteger)args % align;
+        if (mod != 0) {
+            args += (align - mod);
+        }
+        [invocation setArgument:args atIndex:index];
+        args += size;
+    }
+    va_end(ap);
+    return invocation;
+}
+@end