NSScrollView のスクロール位置を同期する

gistfile1.m

@interface SSRefrectingScrollView : NSScrollView

@property BOOL inRefrecting;
@property (assign)IBOutlet SSRefrectingScrollView* counterPartView;

@end


@implementation SSRefrectingScrollView

- (void)reflectScrolledClipView:(NSClipView *)aClipView
{
    [super reflectScrolledClipView:(NSClipView *)aClipView];
    
    if (!self.inRefrecting && ![self inLiveResize]) {
        self.inRefrecting=YES;
        if (!self.counterPartView.inRefrecting) {
            NSRect otherRect=[[self.counterPartView contentView]documentVisibleRect];
            NSRect rect=[aClipView documentVisibleRect];
            otherRect.origin.y=rect.origin.y;
            otherRect.size.height=rect.size.height;
            [[self.counterPartView documentView] scrollRectToVisible:otherRect];
        }
        self.inRefrecting=NO;
    }
}

@end