RBSplitView.m

Go to the documentation of this file.

//
//  RBSplitView.m version 1.2
//  RBSplitView
//
//  Created by Rainer Brockerhoff on 24/09/2004.
//  Copyright 2004-2009 Rainer Brockerhoff.
//  Some Rights Reserved under the Creative Commons Attribution License, version 2.5, and/or the MIT License.
//
 
#import "RBSplitView.h"
#import "RBSplitViewPrivateDefines.h"
 
// Please don't remove this copyright notice!
static const unsigned char RBSplitView_Copyright[] __attribute__ ((used)) =
    "RBSplitView 1.2 Copyright(c)2004-2009 by Rainer Brockerhoff <rainer@brockerhoff.net>.";
 
// This vector keeps currently used cursors. nil means the default cursor.
static NSCursor* cursors[RBSVCursorTypeCount] = {nil};
 
// Our own fMIN and fMAX
static inline CGFloat fMIN(CGFloat a,CGFloat b) {
    return a<b?a:b;
}
 
static inline CGFloat fMAX(CGFloat a,CGFloat b) {
    return a>b?a:b;
}
 
@implementation RBSplitView
 
// These class methods get and set the cursor used for each type.
// Pass in nil to reset to the default cursor for that type.
+ (NSCursor*)cursor:(RBSVCursorType)type {
    if ((type>=0)&&(type<RBSVCursorTypeCount)) {
        NSCursor* result = cursors[type];
        if (result) {
            return result;
        }
        switch (type) {
            case RBSVHorizontalCursor:
                return [NSCursor resizeUpDownCursor];
            case RBSVVerticalCursor:
                return [NSCursor resizeLeftRightCursor];
            case RBSV2WayCursor:
                return [NSCursor openHandCursor];
            case RBSVDragCursor:
                return [NSCursor closedHandCursor];
            default:
                break;
        }
    }
    return [NSCursor currentCursor];
}
 
+ (void)setCursor:(RBSVCursorType)type toCursor:(NSCursor*)cursor {
    if ((type>=0)&&(type<RBSVCursorTypeCount)) {
        [cursors[type] release];
        cursors[type] = [cursor retain];
    }
}
 
// This class method clears the saved state(s) for a given autosave name from the defaults.
+ (void)removeStateUsingName:(NSString*)name {
    if ([name length]) {
        NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
        [defaults removeObjectForKey:[[self class] defaultsKeyForName:name isHorizontal:NO]];
        [defaults removeObjectForKey:[[self class] defaultsKeyForName:name isHorizontal:YES]];
    }
}
 
// This class method returns the actual key used to store autosave data in the defaults.
+ (NSString*)defaultsKeyForName:(NSString*)name isHorizontal:(BOOL)orientation {
    return [NSString stringWithFormat:@"RBSplitView %@ %@",orientation?@"H":@"V",name];
}
 
// These methods get and set the autosave name, which allows restoring the subview's
// state from the user defaults.
// We take care not to allow nil autosaveNames.
- (NSString*)autosaveName {
    return autosaveName;
}
 
// Sets the autosaveName; this should be a unique key to be used to store the subviews' proportions
// in the user defaults. Default is @"", which doesn't save anything. Set flag to YES to set
// unique names for nested subviews. You are responsible for avoiding duplicates; avoid using
// the characters '[' and ']' in autosaveNames.
- (void)setAutosaveName:(NSString*)aString recursively:(BOOL)flag {
    BOOL clear;
    if ((clear = ![aString length])) {
        aString = @"";
    }
    [RBSplitView removeStateUsingName:autosaveName];
    [autosaveName autorelease];
    autosaveName = [aString retain];
    if (flag) {
        NSArray* subviews = [self subviews];
        NSUInteger subcount = [subviews count];
        NSUInteger i;
        for (i=0;i<subcount;i++) {
            RBSplitView* sv = [[subviews objectAtIndex:i] asSplitView];
            if (sv) {
                NSString* subst = clear?@"":[aString stringByAppendingFormat:@"[%ld]",i];
                [sv setAutosaveName:subst recursively:YES];
            }
        }
    }
}
 
// Saves the current state of the subviews if there's a valid autosave name set. If the argument
// is YES, it's then also called recursively for nested RBSplitViews. Returns YES if successful.
// You must call restoreState explicity at least once before saveState will begin working.
- (BOOL)saveState:(BOOL)recurse {
// Saving the state is also disabled while dragging.
    if (canSaveState&&![self isDragging]&&[autosaveName length]) {
        [[NSUserDefaults standardUserDefaults] setObject:[self stringWithSavedState] forKey:[[self class] defaultsKeyForName:autosaveName isHorizontal:[self isHorizontal]]];
        if (recurse) {
            for (RBSplitSubview* sub in [self subviews]){
                [[sub asSplitView] saveState:YES];
            }
        }
        return YES;
    }
    return NO;
}
 
// Restores the saved state of the subviews if there's a valid autosave name set. If the argument
// is YES, it's also called recursively for nested RBSplitViews. Returns YES if successful.
// It's good policy to call adjustSubviews immediately after calling restoreState.
- (BOOL)restoreState:(BOOL)recurse {
    BOOL result = NO;
    if ([autosaveName length]) {
        result = [self setStateFromString:[[NSUserDefaults standardUserDefaults] stringForKey:[[self class] defaultsKeyForName:autosaveName isHorizontal:[self isHorizontal]]]];
        if (result&&recurse) {
            for (RBSplitSubview* sub in [self subviews]){
                [[sub asSplitView] restoreState:YES];
            }
        }
    }
    canSaveState = YES;
    return result;
}
 
// Returns an array with complete state information for the receiver and all subviews, taking
// nesting into account. Don't store this array in a file, as its format might change in the
// future; this is for taking a state snapshot and later restoring it with setStatesFromArray.
- (NSArray*)arrayWithStates {
    NSMutableArray* array = [NSMutableArray array];
    [array addObject:[self stringWithSavedState]];
    for (RBSplitSubview* sub in [self subviews]){
        RBSplitView* suv = [sub asSplitView];
        if (suv) {
            [array addObject:[suv arrayWithStates]];
        } else {
            [array addObject:[NSNull null]];
        }
    }
    return array;
}
 
// Restores the state of the receiver and all subviews. The array must have been produced by a
// previous call to arrayWithStates. Returns YES if successful. This will fail if you have
// added or removed subviews in the meantime!
// You need to call adjustSubviews after calling this.
- (BOOL)setStatesFromArray:(NSArray*)array {
    NSArray* subviews = [self subviews];
    NSUInteger count = [array count];
    if (count==([subviews count]+1)) {
        NSString* me = [array objectAtIndex:0];
        if ([me isKindOfClass:[NSString class]]) {
            if ([self setStateFromString:me]) {
                NSUInteger i;
                for (i=1;i<count;i++) {
                    NSArray* item = [array objectAtIndex:i];
                    RBSplitView* suv = [[subviews objectAtIndex:i-1] asSplitView];
                    if ([item isKindOfClass:[NSArray class]]==(suv!=nil)) {
                        if (suv&&![suv setStatesFromArray:item]) {
                            return NO;
                        }
                    } else {
                        return NO;
                    }
                }
                return YES;
            }
        }
    }
    return NO;
}
 
// Returns a string encoding the current state of all direct subviews. Does not check for nesting.
// The string contains the number of direct subviews, then the dimension for each subview (which will
// be negative for collapsed subviews), all separated by blanks.
- (NSString*)stringWithSavedState {
    NSArray* subviews = [self subviews];
    NSMutableString* result = [NSMutableString stringWithFormat:@"%ld",[subviews count]];
    for (RBSplitSubview* sub in [self subviews]){
        double size = [sub dimension];
        if ([sub isCollapsed]) {
            size = -size;
        } else {
            size += +[sub RB___fraction];
        }
        [result appendFormat:[sub isHidden]?@" %gH":@" %g",size];
    }
    return result;
}
 
// Readjusts all direct subviews according to the encoded string parameter.
// The number of subviews must match. Returns YES if successful. Does not check for nesting.
- (BOOL)setStateFromString:(NSString*)aString {
    if ([aString length]) {
        NSArray* parts = [aString componentsSeparatedByString:@" "];
        NSArray* subviews = [self subviews];
        NSInteger subcount = [subviews count];
        NSInteger k = [parts count];
        if ((k-->1)&&([[parts objectAtIndex:0] intValue]==subcount)&&(k==subcount)) {
            NSInteger i;
            NSRect frame = [self frame];
            BOOL ishor = [self isHorizontal];
            for (i=0;i<subcount;i++) {
                NSString* part = [parts objectAtIndex:i+1];
                double size = [part doubleValue];
                BOOL hidden = [part hasSuffix:@"H"];
                BOOL negative = size<=0.0;
                if (negative) {
                    size = -size;
                }
                double fract = size;
                size = floor(size);
                fract -= size;
                DIM(frame.size) = size;
                RBSplitSubview* sub = [subviews objectAtIndex:i];
                [sub RB___setFrame:frame withFraction:fract notify:NO];
                if (negative) {
                    [sub RB___collapse];
                }
                [sub RB___setHidden:hidden];
            }
            [self setMustAdjust];
            return YES;
        }
    }
    return NO;
}
 
// This is the designated initializer for creating RBSplitViews programmatically. You can set the
// divider image and other parameters afterwards.
- (id)initWithFrame:(NSRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        dividers = NULL;
        isCoupled = YES;
        isDragging = NO;
        isInScrollView = NO;
        canSaveState = NO;
        [self setVertical:YES];
        [self setDivider:nil];
        [self setAutosaveName:nil recursively:NO];
        [self setBackground:nil];
    }
    return self;
}
 
// This convenience initializer adds any number of subviews and adjusts them proportionally.
- (id)initWithFrame:(NSRect)frame andSubviews:(NSUInteger)count {
    self = [self initWithFrame:frame];
    if (self) {
        while (count-->0) {
            [self addSubview:[[[RBSplitSubview alloc] initWithFrame:frame] autorelease]];
        }
        [self setMustAdjust];
    }
    return self;
}
 
// Frees retained objects when going away.
- (void)dealloc {
    if (dividers) {
        free(dividers);
    }
    [autosaveName release];
    [divider release];
    [background release];
    [super dealloc];
}
 
// Sets and gets the coupling between the view and its containing RBSplitView (if any). Coupled
// RBSplitViews take some parameters, such as divider images, from the containing view. The default
// is for nested RBSplitViews is YES; however, isCoupled returns NO if we're not nested.
- (void)setCoupled:(BOOL)flag {
    if (flag!=isCoupled) {
        isCoupled = flag;
// If we've just been uncoupled and there's no divider image, we copy it from the containing view. 
        if (!isCoupled&&!divider) {
            [self setDivider:[[self splitView] divider]];
        }
        [self setMustAdjust];
    }
}
 
- (BOOL)isCoupled {
    return isCoupled&&([super splitView]!=nil);
}
 
// This returns the containing splitview if they are coupled. It's guaranteed to return a RBSplitView or nil.
- (RBSplitView*)couplingSplitView {
    return isCoupled?[super couplingSplitView]:nil;
}
 
// This returns self.
- (RBSplitView*)asSplitView {
    return self;
}
 
// This return self if we're really coupled to the owning splitview.
- (RBSplitView*)coupledSplitView {
    return [self isCoupled]?self:nil;
}
 
// We always return NO, but do special handling in RBSplitSubview's mouseDown: method.
- (BOOL)mouseDownCanMoveWindow {
    return NO;
}
 
// RBSplitViews must be flipped to work properly for horizontal dividers. As the subviews are never
// flipped, this won't make your life harder.
- (BOOL)isFlipped {
    return YES;
}
 
// Call this method to make sure that the subviews and divider rectangles are recalculated
// properly before display.
- (void)setMustAdjust {
    mustAdjust = YES;
    [self setNeedsDisplay:YES];
}
 
// Returns YES if there's a pending adjustment.
- (BOOL)mustAdjust {
    return mustAdjust;
}
 
// Returns YES if we're in a dragging loop.
- (BOOL)isDragging {
    return isDragging;
}
 
// Returns YES if the view is directly contained in an NSScrollView.
- (BOOL)isInScrollView {
    return isInScrollView;
}
 
// This pair of methods allows you to move the dividers for background windows while holding down
// the command key, without bringing the window to the foreground.
- (BOOL)acceptsFirstMouse:(NSEvent*)theEvent {
    return ([theEvent modifierFlags]&NSCommandKeyMask)==0;
}
 
- (BOOL)shouldDelayWindowOrderingForEvent:(NSEvent*)theEvent {
    return ([theEvent modifierFlags]&NSCommandKeyMask)!=0;
}
 
// These 3 methods handle view background colors and opacity. The default is the window background.
// Pass nil or a completely transparent color to setBackground to use transparency. If you set any
// other background color, it will completely fill the RBSplitView (including subviews and dividers).
// The view will be considered opaque only if its alpha is equal to 1.0.
// For a nested, coupled RBSplitView, background and opacity are copied from the containing RBSplitView,
// and setting the background has no effect.
- (NSColor*)background {
    RBSplitView* sv = [self couplingSplitView];
    return sv?[sv background]:background;
}
 
- (void)setBackground:(NSColor*)color {
    if (![self couplingSplitView]) {
        [background autorelease];
        background = color?([color alphaComponent]>0.0?[color retain]:nil):nil;
        [self setNeedsDisplay:YES];
    }
}
 
- (BOOL)isOpaque {
    RBSplitView* sv = [self couplingSplitView];
    return sv?[sv isOpaque]:(background&&([background alphaComponent]>=1.0));
}
 
// This will make debugging a little easier by appending the state string to the
// default description.
- (NSString*)description {
    return [NSString stringWithFormat:@"%@ {%@}",[super description],[self stringWithSavedState]];
}
 
// The following 4 methods handle divider orientation. The actual stored trait is horizontality,
// but verticality is used for setting to conform to the NSSplitView convention.
// For a nested RBSplitView, orientation is perpendicular to the containing RBSplitView, and
// setting it has no effect.
// After changing the orientation you may want to restore the state with restoreState:.
- (BOOL)isHorizontal {
    RBSplitView* sv = [self splitView];
    return sv?[sv isVertical]:isHorizontal;
}
 
- (void)setHorizontal:(BOOL)flag {
    if (![self splitView]&&(isHorizontal!=flag)) {
        BOOL ishor = isHorizontal = flag;
        NSSize size = divider?[divider size]:NSZeroSize;
        [self setDividerThickness:DIM(size)];
        [self setMustAdjust];
    }
}
 
- (BOOL)isVertical {
    return ![self isHorizontal];
}
 
- (void)setVertical:(BOOL)flag {
    [self setHorizontal:!flag];
}
 
// Returns the subview which a given identifier.
- (RBSplitSubview*)subviewWithIdentifier:(NSString*)anIdentifier {
    for (RBSplitSubview* sub in [self subviews]){
        if ([anIdentifier isEqualToString:[sub identifier]]) {
            return sub;
        }
    }
    return nil;
}
 
// Returns the subview at a given position
- (RBSplitSubview*)subviewAtPosition:(NSUInteger)position {
    NSArray* subviews = [super subviews];
    NSUInteger subcount = [subviews count];
    if (position<subcount) {
        return [subviews objectAtIndex:position];
    }
    return nil;
}
 
// This pair of methods gets and sets the delegate object. Delegates aren't retained.
- (id)delegate {
    return delegate;
}
 
- (void)setDelegate:(id)anObject {
    delegate = anObject;
}
 
// This pair of methods gets and sets the divider image. Setting the image automatically adjusts the
// divider thickness. A nil image means a 0-pixel wide divider, unless you set a thickness explicitly.
// For a nested RBSplitView, the divider is copied from the containing RBSplitView, and
// setting it has no effect. The returned image is always flipped.
- (NSImage*)divider {
    RBSplitView* sv = [self couplingSplitView];
    return sv?[sv divider]:divider;
}
 
- (void)setDivider:(NSImage*)image {
    if (![self couplingSplitView]) {
        [divider autorelease];
        if ([image isFlipped]) {
// If the image is flipped, we just retain it.
            divider = [image retain];
        } else {
// if the image isn't flipped, we copy the image instead of retaining it, and flip the copy.
            divider = [image copy];
            [divider setFlipped:YES];
        }
// We set the thickness to 0.0 so the image dimension will prevail.
        [self setDividerThickness:0.0];
        [self setMustAdjust];
    }
}
 
// This pair of methods gets and sets the divider thickness. It should be an integer value and at least
// 0.0, so we make sure. Set it to 0.0 to make the image dimensions prevail.
- (CGFloat)dividerThickness {
    if (dividerThickness>0.0) {
        return dividerThickness;
    }
    NSImage* divdr = [self divider];
    if (divdr) {
        NSSize size = [divdr size];
        BOOL ishor = [self isHorizontal];
        return DIM(size);
    }
    return 0.0;
}
 
- (void)setDividerThickness:(CGFloat)thickness {
    CGFloat t = fMAX(0.0,floor(thickness));
    if ((NSInteger)dividerThickness!=(NSInteger)t) {
        dividerThickness = t;
        [self setMustAdjust];
    }
}
 
// These three methods add subviews. If aView isn't a RBSplitSubview, one is automatically inserted above
// it, and aView's frame and resizing mask is set to occupy the entire RBSplitSubview.
- (void)addSubview:(NSView*)aView {
    if ([aView isKindOfClass:[RBSplitSubview class]]) {
        [super addSubview:aView];
    } else {
        [aView setFrameOrigin:NSZeroPoint];
        RBSplitSubview* sub = [[[RBSplitSubview alloc] initWithFrame:[aView frame]] autorelease];
        [aView setAutoresizingMask:NSViewWidthSizable|NSViewHeightSizable];
        [sub addSubview:aView];
        [super addSubview:sub];
    }
    [self setMustAdjust];
}
 
- (void)addSubview:(NSView*)aView positioned:(NSWindowOrderingMode)place relativeTo:(NSView*)otherView {
    if ([aView isKindOfClass:[RBSplitSubview class]]) {
        [super addSubview:aView positioned:place relativeTo:otherView];
    } else {
        [aView setFrameOrigin:NSZeroPoint];
        RBSplitSubview* sub = [[[RBSplitSubview alloc] initWithFrame:[aView frame]] autorelease];
        [aView setAutoresizingMask:NSViewWidthSizable|NSViewHeightSizable];
        [sub addSubview:aView];
        [super addSubview:sub positioned:place relativeTo:otherView];
        [aView setAutoresizingMask:NSViewWidthSizable|NSViewHeightSizable];
    }
    [self setMustAdjust];
}
 
- (void)addSubview:(NSView*)aView atPosition:(NSUInteger)position {
    RBSplitSubview* suv = [self subviewAtPosition:position];
    if (suv) {
        [self addSubview:aView positioned:NSWindowBelow relativeTo:suv];
    } else {
        [self addSubview:aView];
    }
}
 
// This keeps the isInScrollView flag up-to-date.
- (void)viewDidMoveToSuperview {
    [super viewDidMoveToSuperview];
    NSScrollView* scrollv = [self enclosingScrollView];
    isInScrollView = scrollv?[scrollv documentView]==self:NO;
}
 
// This makes sure the subviews are adjusted after a subview is removed.
- (void)willRemoveSubview:(NSView*)subview {
    if ([subview respondsToSelector:@selector(RB___stopAnimation)]) {
        [(RBSplitSubview*)subview RB___stopAnimation];
    }
    [super willRemoveSubview:subview];
    [self setMustAdjust];
}
 
// RBSplitViews never resize their subviews automatically.
- (BOOL)autoresizesSubviews {
    return NO;
}
 
// This adjusts the subviews when the size is set. setFrame: calls this, so all is well. It calls
// the delegate if implemented.
- (void)setFrameSize:(NSSize)size {
//  NSLog(@"setFrameSize of %@ to %@",self,NSStringFromSize(size));
    NSSize oldsize = [self frame].size;
    [super setFrameSize:size];
    [self setMustAdjust];
    if ([delegate respondsToSelector:@selector(splitView:wasResizedFrom:to:)]) {
        BOOL ishor = [self isHorizontal];
        CGFloat olddim = DIM(oldsize);
        CGFloat newdim = DIM(size);
// The delegate is not called if the dimension hasn't changed.
        if (((NSInteger)newdim!=(NSInteger)olddim)) {
            [delegate splitView:self wasResizedFrom:olddim to:newdim];
        }
    }
// We adjust the subviews only if the delegate didn't.
    if (mustAdjust&&!isAdjusting) {
        [self adjustSubviews];
    }
}
 
// This method handles dragging and double-clicking dividers with the mouse. While dragging, the
// "closed hand" cursor is shown. Double clicks are handled separately. Nothing will happen if
// no divider image is set.
- (void)mouseDown:(NSEvent*)theEvent {
    if (!dividers) {
        return;
    }
    NSArray* subviews = [self RB___subviews];
    NSUInteger subcount = [subviews count];
    if (subcount<2) {
        return;
    }
// If the mousedown was in an alternate dragview, or if there's no divider image, handle it in RBSplitSubview.
    if ((actDivider<NSNotFound)||![self divider]) {
        [super mouseDown:theEvent];
        return;
    }
    NSPoint where = [self convertPoint:[theEvent locationInWindow] fromView:nil];
    BOOL ishor = [self isHorizontal];
    NSUInteger i;
    --subcount;
// Loop over the divider rectangles.
    for (i=0;i<subcount;i++) {
        NSRect* divdr = &dividers[i];
        if ([self mouse:where inRect:*divdr]) {
// leading points at the subview immediately leading the divider being tracked.
            RBSplitView* leading = [subviews objectAtIndex:i];
// trailing points at the subview immediately trailing the divider being tracked.
            RBSplitView* trailing = [subviews objectAtIndex:i+1];
            if ([delegate respondsToSelector:@selector(splitView:shouldHandleEvent:inDivider:betweenView:andView:)]) {
                if (![delegate splitView:self shouldHandleEvent:theEvent inDivider:i betweenView:leading andView:trailing]) {
                    return;
                }
            }
// If it's a double click, try to expand or collapse one of the neighboring subviews.
            if ([theEvent clickCount]>1) {
// If both are collapsed, we do nothing. If one of them is collapsed, we try to expand it.
                if ([trailing isCollapsed]) {
                    if (![leading isCollapsed]) {
                        [self RB___tryToExpandTrailing:trailing leading:leading delta:-[trailing dimension]];
                    }
                } else {
                    if ([leading isCollapsed]) {
                        [self RB___tryToExpandLeading:leading divider:i trailing:trailing delta:[leading dimension]];
                    } else {
// If neither are collapsed, we check if both are collapsible.
                        BOOL lcan = [leading canCollapse];
                        BOOL tcan = [trailing canCollapse];
                        CGFloat ldim = [leading dimension];
                        if (lcan&&tcan) {
// If both are collapsible, we try asking the delegate.
                            if ([delegate respondsToSelector:@selector(splitView:collapseLeading:orTrailing:)]) {
                                RBSplitSubview* sub = [delegate splitView:self collapseLeading:leading orTrailing:trailing];
// If the delegate returns nil, neither view will collapse.
                                lcan = sub==leading;
                                tcan = sub==trailing;
                            } else {
// Otherwise we try collapsing the smaller one. If they're equal, the trailing one will be collapsed.
                                lcan = ldim<[trailing dimension];
                            }
                        }
// At this point, we'll try to collapse the leading subview.
                        if (lcan) {
                            [self RB___tryToShortenLeading:leading divider:i trailing:trailing delta:-ldim always:NO];
                        }
// If the leading subview didn't collapse for some reason, we try to collapse the trailing one.
                        if (!mustAdjust&&tcan) {
                            [self RB___tryToShortenTrailing:trailing divider:i leading:leading delta:[trailing dimension] always:NO];
                        }
                    }
                }
// If the subviews have changed, clear the fractions, adjust and redisplay
                if (mustAdjust) {
                    [self RB___setMustClearFractions];
                    RBSplitView* sv = [self splitView];
                    [sv?sv:self adjustSubviews];
                    [super display];
                }
            } else {
// Single click; record the offsets within the divider rectangle and check for nesting.
                CGFloat divt = [self dividerThickness];
                CGFloat offset = DIM(where)-DIM(divdr->origin);
// Check if the leading subview is nested and if yes, if one of its two-axis thumbs was hit.
                NSInteger ldivdr = NSNotFound;
                CGFloat loffset = 0.0;
                NSPoint lwhere = where;
                NSRect lrect = NSZeroRect;
                if ((leading = [leading coupledSplitView])) {
                    ldivdr = [leading RB___dividerHitBy:lwhere relativeToView:self thickness:divt];
                    if (ldivdr!=NSNotFound) {
                        lrect = [leading RB___dividerRect:ldivdr relativeToView:self];
                        loffset = OTHER(lwhere)-OTHER(lrect.origin);
                    }
                }
// Check if the trailing subview is nested and if yes, if one of its two-axis thumbs was hit.
                NSInteger tdivdr = NSNotFound;
                CGFloat toffset = 0.0;
                NSPoint twhere = where;
                NSRect trect = NSZeroRect;
                if ((trailing = [trailing coupledSplitView])) {
                    tdivdr = [trailing RB___dividerHitBy:twhere relativeToView:self thickness:divt];
                    if (tdivdr!=NSNotFound) {
                        trect = [trailing RB___dividerRect:tdivdr relativeToView:self];
                        toffset = OTHER(twhere)-OTHER(trect.origin);
                    }
                }
// Now we loop handling mouse events until we get a mouse up event, while showing the drag cursor.
                [[RBSplitView cursor:RBSVDragCursor] push];
                [self RB___setDragging:YES];
                while ((theEvent = [NSApp nextEventMatchingMask:NSLeftMouseDownMask|NSLeftMouseDraggedMask|NSLeftMouseUpMask untilDate:[NSDate distantFuture] inMode:NSEventTrackingRunLoopMode dequeue:YES])&&([theEvent type]!=NSLeftMouseUp)) {
// Set up a local autorelease pool for the loop to prevent buildup of temporary objects.
                    NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
                    NSDisableScreenUpdates();
// Track the mouse along the main coordinate. 
                    [self RB___trackMouseEvent:theEvent from:where withBase:NSZeroPoint inDivider:i];
                    if (ldivdr!=NSNotFound) {
// Track any two-axis thumbs for the leading nested RBSplitView.
                        [leading RB___trackMouseEvent:theEvent from:[self convertPoint:lwhere toView:leading] withBase:NSZeroPoint inDivider:ldivdr];
                    }
                    if (tdivdr!=NSNotFound) {
// Track any two-axis thumbs for the trailing nested RBSplitView.
                        [trailing RB___trackMouseEvent:theEvent from:[self convertPoint:twhere toView:trailing] withBase:NSZeroPoint inDivider:tdivdr];
                    }
                    if (mustAdjust||[leading mustAdjust]||[trailing mustAdjust]) {
// The mouse was dragged and the subviews changed, so we must redisplay, as
// several divider rectangles may have changed.
                        RBSplitView* sv = [self splitView];
                        [sv?sv:self adjustSubviews];
                        [super display];
                        divdr = &dividers[i];
// Adjust to the new cursor coordinates.
                        DIM(where) = DIM(divdr->origin)+offset;
                        if ((ldivdr!=NSNotFound)&&![leading isCollapsed]) {
// Adjust for the leading nested RBSplitView's thumbs while it's not collapsed.
                            lrect = [leading RB___dividerRect:ldivdr relativeToView:self];
                            OTHER(lwhere) = OTHER(lrect.origin)+loffset;
                        }
                        if ((tdivdr!=NSNotFound)&&![trailing isCollapsed]) {
// Adjust for the trailing nested RBSplitView's thumbs while it's not collapsed.
                            trect = [trailing RB___dividerRect:tdivdr relativeToView:self];
                            OTHER(twhere) = OTHER(trect.origin)+toffset;
                        }
                    }
                    NSEnableScreenUpdates();
                    [pool drain];
                }
                [self RB___setDragging:NO];
// Redisplay the previous cursor.
                [NSCursor pop];
            }
        }
    }
}
 
// This will be called before the view will be redisplayed, so we adjust subviews if necessary.
- (BOOL)needsDisplay {
    if (mustAdjust&&!isAdjusting) {
        [self adjustSubviews];
        return YES;
    }
    return [super needsDisplay];
}
 
// We implement awakeFromNib to restore the state. This works if an autosaveName is set in the nib.
- (void)awakeFromNib {
    if ([RBSplitSubview instancesRespondToSelector:@selector(awakeFromNib)]) {
        [super awakeFromNib];
    }
    if (![self splitView]) {
        [self restoreState:YES];
    }
}
 
// We check if subviews must be adjusted before redisplaying programmatically.
- (void)display {
    if (mustAdjust&&!isAdjusting) {
        [self adjustSubviews];
    }
    [super display];
}
 
// This method draws the divider rectangles and then the two-axis thumbs if there are any.
- (void)drawRect:(NSRect)rect {
    [super drawRect:rect];
    if (!dividers) {
        return;
    }
    NSArray* subviews = [self RB___subviews];
    NSUInteger subcount = [subviews count];
// Return if there are no dividers to draw.
    if (subcount<2) {
        return;
    }
    --subcount;
    NSUInteger i;
// Cache the divider image.
    NSImage* divdr = [self divider];
    CGFloat divt = [self dividerThickness];
// Loop over the divider rectangles.
    for (i=0;i<subcount;i++) {
// Check if we need to draw this particular divider.
        if ([self needsToDrawRect:dividers[i]]) {
            RBSplitView* leading = [subviews objectAtIndex:i];
            RBSplitView* trailing = [subviews objectAtIndex:i+1];
            BOOL lexp = divdr?![leading isCollapsed]:NO;
            BOOL texp = divdr?![trailing isCollapsed]:NO;
// We don't draw the divider image if either of the neighboring subviews is a non-collapsed
// nested split view.
            BOOL nodiv = (lexp&&[leading coupledSplitView])||(texp&&[trailing coupledSplitView]);
            [self drawDivider:nodiv?nil:divdr inRect:dividers[i] betweenView:leading andView:trailing];
            if (divdr) {
// Draw the corresponding two-axis thumbs if the leading view is a nested RBSplitView.
                if ((leading = [leading coupledSplitView])&&lexp) {
                    [leading RB___drawDividersIn:self forDividerRect:dividers[i] thickness:divt];
                }
// Draw the corresponding two-axis thumbs if the trailing view is a nested RBSplitView.
                if ((trailing = [trailing coupledSplitView])&&texp) {
                    [trailing RB___drawDividersIn:self forDividerRect:dividers[i] thickness:divt];
                }
            }
        }
    }
}
 
// This method draws dividers. You should never call it directly but you can override it when
// subclassing, if you need custom dividers. It draws the divider image centered in the divider rectangle.
// If we're drawing a two-axis thumb leading and trailing will be nil, and the rectangle
// will be the thumb rectangle.
// If there are nested split views this will be called once to draw the main divider rect,
// and again for every thumb.
- (void)drawDivider:(NSImage*)anImage inRect:(NSRect)rect betweenView:(RBSplitSubview*)leading andView:(RBSplitSubview*)trailing {
// Fill the view with the background color (if there's any). Don't draw the background again for
// thumbs.
    if (leading||trailing) {
        NSColor* bg = [self background];
        if (bg) {
            [bg set];
            NSRectFillUsingOperation(rect,NSCompositeSourceOver);
        }
    }
// Center the image, if there is one.
    NSRect imrect = NSZeroRect;
    NSRect dorect = NSZeroRect;
    if (anImage) {
        imrect.size = dorect.size = [anImage size];
        dorect.origin = NSMakePoint(floor(rect.origin.x+(rect.size.width-dorect.size.width)/2),
                                    floor(rect.origin.y+(rect.size.height-dorect.size.height)/2));
    }
// Ask the delegate for the final rect where the image should be drawn.
    if ([delegate respondsToSelector:@selector(splitView:willDrawDividerInRect:betweenView:andView:withProposedRect:)]) {
        dorect = [delegate splitView:self willDrawDividerInRect:rect betweenView:leading andView:trailing withProposedRect:dorect];
    }
// Draw the image if the delegate returned a non-empty rect.
    if (!NSIsEmptyRect(dorect)) {
        [anImage drawInRect:dorect fromRect:imrect operation:NSCompositeSourceOver fraction:1.0];
    }
}
 
// This method should be called only from within the splitView:wasResizedFrom:to: delegate method
// to keep some specific subview the same size.
- (void)adjustSubviewsExcepting:(RBSplitSubview*)excepting {
    [self RB___adjustSubviewsExcepting:[excepting isCollapsed]?nil:excepting];
}
 
// This method adjusts subviews and divider rectangles.
- (void)adjustSubviews {
    [self RB___adjustSubviewsExcepting:nil];
}
 
// This resets the appropriate cursors for each divider according to the orientation.
// No cursors are shown if there is no divider image.
- (void)resetCursorRects {
    if (!dividers) {
        return;
    }
    id del = [delegate respondsToSelector:@selector(splitView:cursorRect:forDivider:)]?delegate:nil;
    NSArray* subviews = [self RB___subviews];
    NSInteger divcount = [subviews count]-1;
    if ((divcount<1)||![self divider]) {
        [del splitView:self cursorRect:NSZeroRect forDivider:0];
        return;
    }
    NSInteger i;
    NSCursor* cursor = [RBSplitView cursor:[self isVertical]?RBSVVerticalCursor:RBSVHorizontalCursor];
    CGFloat divt = [self dividerThickness];
    for (i=0;i<divcount;i++) {
        RBSplitView* sub = [[subviews objectAtIndex:i] coupledSplitView];
// If the leading subview is a nested RBSplitView, add the thumb rectangles first.
        if (sub) {
            [sub  RB___addCursorRectsTo:self forDividerRect:dividers[i] thickness:divt];
        }
        sub = [[subviews objectAtIndex:i+1] coupledSplitView];
// If the trailing subview is a nested RBSplitView, add the thumb rectangles first.
        if (sub) {
            [sub  RB___addCursorRectsTo:self forDividerRect:dividers[i] thickness:divt];
        }
// Now add the divider rectangle.
        NSRect divrect = dividers[i];
        if (del) {
            divrect = [del splitView:self cursorRect:divrect forDivider:i];
        }
        if (!NSIsEmptyRect(divrect)) {
            [self addCursorRect:divrect cursor:cursor];
        }
    }
}
 
// These two methods encode and decode RBSplitViews. One peculiarity is that we encode the divider image's
// bitmap representation as data; this makes the nib files larger, but the user can just paste any image
// into the RBSplitView inspector - or use the default divider image - without having to include it into the
// project, too.
- (void)encodeWithCoder:(NSCoder *)coder {
    [super encodeWithCoder:coder];
    if ([coder allowsKeyedCoding]) {
        [coder encodeConditionalObject:delegate forKey:@"delegate"];
        [coder encodeObject:autosaveName forKey:@"autosaveName"];
        [coder encodeObject:[divider TIFFRepresentation] forKey:@"divider"];
        [coder encodeObject:background forKey:@"background"];
        [coder encodeDouble:dividerThickness forKey:@"dividerThickness"];
        [coder encodeBool:isHorizontal forKey:@"isHorizontal"];
        [coder encodeBool:isCoupled forKey:@"isCoupled"];
    } else {
        [coder encodeConditionalObject:delegate];
        [coder encodeObject:autosaveName];
        [coder encodeObject:[divider TIFFRepresentation]];
        [coder encodeObject:background];
        [coder encodeValueOfObjCType:@encode(typeof(dividerThickness)) at:&dividerThickness];
        [coder encodeValueOfObjCType:@encode(typeof(isHorizontal)) at:&isHorizontal];
        [coder encodeValueOfObjCType:@encode(typeof(isCoupled)) at:&isCoupled];
    }
}
 
- (id)initWithCoder:(NSCoder *)coder {
    if ((self = [super initWithCoder:coder])) {
        NSData* data = nil;
        CGFloat divt = 0.0;
        isCoupled = YES;
        isDragging = NO;
        isInScrollView = NO;
        canSaveState = NO;
        if ([coder allowsKeyedCoding]) {
            isCoupled = [coder decodeBoolForKey:@"isCoupled"];
            [self setDelegate:[coder decodeObjectForKey:@"delegate"]];
            [self setAutosaveName:[coder decodeObjectForKey:@"autosaveName"] recursively:NO];
            data = [coder decodeObjectForKey:@"divider"];
            [self setBackground:[coder decodeObjectForKey:@"background"]];
            divt = [coder decodeDoubleForKey:@"dividerThickness"];
            isHorizontal = [coder decodeBoolForKey:@"isHorizontal"];
        } else {
            [self setDelegate:[coder decodeObject]];
            [self setAutosaveName:[coder decodeObject] recursively:NO];
            data = [coder decodeObject];
            [self setBackground:[coder decodeObject]];
            [coder decodeValueOfObjCType:@encode(typeof(divt)) at:&divt];
            [coder decodeValueOfObjCType:@encode(typeof(isHorizontal)) at:&isHorizontal];
            [coder decodeValueOfObjCType:@encode(typeof(isCoupled)) at:&isCoupled];
        }
        dividers = NULL;
        if (data) {
            NSBitmapImageRep* rep = [NSBitmapImageRep imageRepWithData:data];
            NSImage* image = [[[NSImage alloc] initWithSize:[rep size]] autorelease];
            [image setFlipped:YES];
            [image addRepresentation:rep];
            [self setDivider:image];
        } else {
            [self setDivider:nil];
        }
        [self setDividerThickness:divt];
        [self setMustAdjust];
        [self performSelector:@selector(viewDidMoveToSuperview) withObject:nil afterDelay:0.0];
        [self performSelector:@selector(RB___adjustOutermostIfNeeded) withObject:nil afterDelay:0.0];
    }
    return self;
}
 
- (BOOL)isAdjusting {
    return isAdjusting;
}
 
@end
 
@implementation RBSplitView (RB___ViewAdditions)
 
// This sets the dragging status flag. After clearing the flag, the state must be saved explicitly.
- (void)RB___setDragging:(BOOL)flag {
    BOOL save = isDragging&&!flag;
    isDragging = flag;
    if (save) {
        [self saveState:NO];
    }
}
 
// This returns the number of visible subviews.
- (NSUInteger)RB___numberOfSubviews {
    NSUInteger result = 0;
    for (RBSplitSubview* sub in [self subviews]) {
        if (![sub isHidden]) {
            ++result;
        }
    }
    return result;
}
 
// This returns the origin coordinate of the Nth divider.
- (CGFloat)RB___dividerOrigin:(NSUInteger)indx {
    CGFloat result = 0.0;
    if (dividers) {
        BOOL ishor = [self isHorizontal];
        result = DIM(dividers[indx].origin);
    }
    return result;
}
 
// This returns an array with all non-hidden subviews.
- (NSArray*)RB___subviews {
    NSMutableArray* result = [NSMutableArray arrayWithArray:[self subviews]];
    NSInteger i;
    for (i=[result count]-1;i>=0;i--) {
        RBSplitSubview* view = [result objectAtIndex:i];
        if ([view isHidden]) {
            [result removeObjectAtIndex:i];
        }
    }
    return result;
}
 
// This returns the actual value set in dividerThickness. 
- (CGFloat)RB___dividerThickness {
    return dividerThickness;
}
 
// This method returns the actual dimension occupied by the subviews; that is, without dividers.
- (CGFloat)RB___dimensionWithoutDividers {
    BOOL ishor = [self isHorizontal];
    NSSize size = [self frame].size;
    return fMAX(1.0,DIM(size)-[self dividerThickness]*([self RB___numberOfSubviews]-1));
}
 
// This method returns one of the divider rectangles, or NSZeroRect if the index is invalid.
// If view is non-nil, the rect will be expressed in that view's coordinates. We assume
// that view is a superview of self.
- (NSRect)RB___dividerRect:(NSUInteger)indx relativeToView:(RBSplitView*)view {
    if (dividers&&(indx<[self RB___numberOfSubviews]-1)) {
        NSRect result = dividers[indx];
        if (view&&(view!=self)) {
            result = [self convertRect:result toView:view];
        }
        return result;
    }
    return NSZeroRect;
}
 
// Returns the index of the divider hit by the point, or NSNotFound if none.
// point is in coordinates relative to view. delta is the divider thickness added
// to both ends of the divider rect, to accomodate two-axis thumbs.
- (NSUInteger)RB___dividerHitBy:(NSPoint)point relativeToView:(RBSplitView*)view thickness:(CGFloat)delta {
    if (!dividers) {
        return NSNotFound;
    }
    NSInteger divcount = [self RB___numberOfSubviews]-1;
    if (divcount<1) {
        return NSNotFound;
    }
    NSInteger i;
    BOOL ishor = [self isHorizontal];
    point = [self convertPoint:point fromView:view];
    for (i=0;i<divcount;i++) {
        NSRect divdr = dividers[i];
        OTHER(divdr.origin) -= delta;
        OTHER(divdr.size) += 2*delta;
        if ([self mouse:point inRect:divdr]) {
            return i;
        }
    }
    return NSNotFound;
}
 
// This method sets a flag to clear all fractions before adjusting.
- (void)RB___setMustClearFractions {
    mustClearFractions = YES;
}
 
// This local method asks the delegate if we should resize the trailing subview or the window
// when a divider is dragged. Not called if we're inside an NSScrollView.
- (BOOL)RB___shouldResizeWindowForDivider:(NSUInteger)indx betweenView:(RBSplitSubview*)leading andView:(RBSplitSubview*)trailing willGrow:(BOOL)grow {
    if (!isInScrollView&&[delegate respondsToSelector:@selector(splitView:shouldResizeWindowForDivider:betweenView:andView:willGrow:)]) {
        return [delegate splitView:self shouldResizeWindowForDivider:indx betweenView:leading andView:trailing willGrow:grow];
    }
    return NO;
}
 
// This local method tries to expand the leading subview (which is assumed to be collapsed). Delta should be positive.
- (void)RB___tryToExpandLeading:(RBSplitSubview*)leading divider:(NSUInteger)indx trailing:(RBSplitSubview*)trailing delta:(CGFloat)delta {
    NSWindow* window = nil;
    NSView* document = nil;
    NSSize maxsize = NSMakeSize(WAYOUT,WAYOUT);
    NSRect frame = NSZeroRect;
    NSRect screen = NSMakeRect(0,0,WAYOUT,WAYOUT);
    BOOL ishor = NO;
// First we ask the delegate, if there's any, if the window should resize.
    BOOL dowin = ([self RB___shouldResizeWindowForDivider:indx betweenView:leading andView:trailing willGrow:YES]);
    if (dowin) {
// We initialize the other local variables only if we need them for the window.
        ishor = [self isHorizontal];
        document = [[self enclosingScrollView] documentView];
        if (document) {
            frame = [document frame];
        } else {
            window = [self window];
            frame = [window frame];
            maxsize = [window maxSize];
            screen = [[NSScreen mainScreen] visibleFrame];
        }
    }
// The mouse has to move over half of the expanded size (plus hysteresis) and the expansion shouldn't
// reduce the trailing subview to less than its minimum size (or grow the window beyond its maximum).
    CGFloat limit = [leading minDimension];
    CGFloat dimension = 0.0;
    if (dowin) {
        CGFloat maxd = fMAX(0.0,(ishor?frame.origin.y-screen.origin.y:(screen.origin.x+screen.size.width)-(frame.origin.x+frame.size.width)));
        dimension = fMIN(DIM(maxsize)-DIM(frame.size),maxd);
    } else {
        dimension = trailing?[trailing dimension]:WAYOUT;
    }
    if (limit>dimension) {
        return;
    }
    if (!dowin&&trailing) {
        limit += [trailing minDimension];
        if (limit>dimension) {
// If the trailing subview is going below its minimum, we try to collapse it first.
// However, we don't collapse if that would cause the leading subview to become larger than its maximum.
            if (([trailing canCollapse])&&(delta>(0.5+HYSTERESIS)*dimension)&&([leading maxDimension]<=dimension)) {
                delta = -[trailing RB___collapse];
                [leading changeDimensionBy:delta mayCollapse:NO move:NO];
            }
            return;
        }
    }
// The leading subview may be expanded normally.
    delta = -[leading changeDimensionBy:delta mayCollapse:NO move:NO];
    if (dowin) {
// If it does expand, we widen the window.
        DIM(frame.size) -= delta;
        if (ishor) {
            DIM(frame.origin) += delta;
        }
        if (document) {
            [document setFrame:frame];
            [document setNeedsDisplay:YES];
        } else {
            [window setFrame:frame display:YES];
        }
        [self setMustAdjust];
    } else {
// If it does expand, we shorten the trailing subview.
        [trailing changeDimensionBy:delta mayCollapse:NO move:YES];
    }
}
 
// This local method tries to shorten the leading subview. Both subviews are assumed to be expanded.
// delta should be negative. If always is NO, the subview will be shortened only if it might also be
// collapsed; otherwise, it's shortened as much as possible.
- (void)RB___tryToShortenLeading:(RBSplitSubview*)leading divider:(NSUInteger)indx trailing:(RBSplitSubview*)trailing delta:(CGFloat)delta always:(BOOL)always {
    NSWindow* window = nil;
    NSView* document = nil;
    NSSize minsize = NSZeroSize;
    NSRect frame = NSZeroRect;
    BOOL ishor = NO;
// First we ask the delegate, if there's any, if the window should resize.
    BOOL dowin = ([self RB___shouldResizeWindowForDivider:indx betweenView:leading andView:trailing willGrow:NO]);
    if (dowin) {
// We initialize the other local variables only if we need them for the window.
        ishor = [self isHorizontal];
        document = [[self enclosingScrollView] documentView];
        if (document) {
            frame = [document frame];
        } else {
            window = [self window];
            frame = [window frame];
            minsize = [window minSize];
        }
    }
// We avoid making the trailing subview larger than its maximum, or the window smaller than its minimum.
    CGFloat limit = 0.0;
    if (dowin) {
        limit = DIM(frame.size)-DIM(minsize);
    } else {
        limit = trailing?([trailing maxDimension]-[trailing dimension]):WAYOUT;
    }
    if (-delta>limit) {
        if (always) {
            delta = -limit;
        } else {
            return;
        }
    }
    BOOL okl = limit>=[leading dimension];
    if (always||okl) {
// Resize leading.
        delta = -[leading changeDimensionBy:delta mayCollapse:okl move:NO];
        if (dowin) {
// Resize the window.
            DIM(frame.size) -= delta;
            if (ishor) {
                DIM(frame.origin) += delta;
            }
            if (document) {
                [document setFrame:frame];
                [document setNeedsDisplay:YES];
            } else {
                [window setFrame:frame display:YES];
            }
            [self setMustAdjust];
        } else {
// Otherwise, resize trailing.
            [trailing changeDimensionBy:delta mayCollapse:NO move:YES];
        }
    }
}
 
// This local method tries to shorten the trailing subview. Both subviews are assumed to be expanded.
// delta should be positive. If always is NO, the subview will be shortened only if it might also be
// collapsed; otherwise, it's shortened as much as possible.
- (void)RB___tryToShortenTrailing:(RBSplitSubview*)trailing divider:(NSUInteger)indx leading:(RBSplitSubview*)leading delta:(CGFloat)delta always:(BOOL)always {
    NSWindow* window = nil;
    NSView* document = nil;
    NSSize maxsize = NSMakeSize(WAYOUT,WAYOUT);
    NSRect frame = NSZeroRect;
    NSRect screen = NSMakeRect(0,0,WAYOUT,WAYOUT);
    BOOL ishor = NO;
// First we ask the delegate, if there's any, if the window should resize.
    BOOL dowin = ([self RB___shouldResizeWindowForDivider:indx betweenView:leading andView:trailing willGrow:YES]);
    if (dowin) {
// We initialize the other local variables only if we need them for the window.
        ishor = [self isHorizontal];
        document = [[self enclosingScrollView] documentView];
        if (document) {
            frame = [document frame];
        } else {
            window = [self window];
            frame = [window frame];
            maxsize = [window maxSize];
            screen = [[NSScreen mainScreen] visibleFrame];
        }
    }
// We avoid making the leading subview larger than its maximum, or the window larger than its maximum.
    CGFloat limit = 0.0;
    if (dowin) {
        CGFloat maxd = fMAX(0.0,(ishor?frame.origin.y-screen.origin.y:(screen.origin.x+screen.size.width)-(frame.origin.x+frame.size.width)));
        limit = fMIN(DIM(maxsize)-DIM(frame.size),maxd);
    } else {
        limit = [leading maxDimension]-[leading dimension];
    }
    if (delta>limit) {
        if (always) {
            delta = limit;
        } else {
            return;
        }
    }
    BOOL okl = dowin||(limit>=(trailing?[trailing dimension]:WAYOUT));
    if (always||okl) {
        if (dowin) {
// If we should resize the window, resize leading, then the window.
            delta = [leading changeDimensionBy:delta mayCollapse:NO move:NO];
            DIM(frame.size) += delta;
            if (ishor) {
                DIM(frame.origin) -= delta;
            }
            if (document) {
                [document setFrame:frame];
                [document setNeedsDisplay:YES];
            } else {
                [window setFrame:frame display:YES];
            }
            [self setMustAdjust];
        } else {
// Otherwise, resize trailing, then leading.
            if (trailing) {
                delta = -[trailing changeDimensionBy:-delta mayCollapse:okl move:YES];
            }
            [leading changeDimensionBy:delta mayCollapse:NO move:NO];
        }
    }
}
 
// This method tries to expand the trailing subview (which is assumed to be collapsed).
- (void)RB___tryToExpandTrailing:(RBSplitSubview*)trailing leading:(RBSplitSubview*)leading delta:(CGFloat)delta {
// The mouse has to move over half of the expanded size (plus hysteresis) and the expansion shouldn't
// reduce the leading subview to less than its minimum size. If it does, we try to collapse it first.
// However, we don't collapse if that would cause the trailing subview to become larger than its maximum.
    CGFloat limit = trailing?[trailing minDimension]:0.0;
    CGFloat dimension = [leading dimension];
    if (limit>dimension) {
        return;
    }
    limit += [leading minDimension];
    if (limit>dimension) {
        if ([leading canCollapse]&&(-delta>(0.5+HYSTERESIS)*dimension)&&((trailing?[trailing maxDimension]:0.0)<=dimension)) {
            delta = -[leading RB___collapse];
            [trailing changeDimensionBy:delta mayCollapse:NO move:YES];
        }
        return;
    }
// The trailing subview may be expanded normally. If it does expand, we shorten the leading subview.
    if (trailing) {
        delta = -[trailing changeDimensionBy:-delta mayCollapse:NO move:YES];
    }
    [leading changeDimensionBy:delta mayCollapse:NO move:NO];
}
 
 
// This method is called by the mouseDown:method for every tracking event. It's separated out as it used
// to be called from the Interface Builder plugin in a slightly different way, and also if you have a
// separate drag view designated by the delegate. You'll never need to call this directly.
// theEvent is the event (which should be a NSLeftMouseDragged event).
// where is the point where the original mouse-down happened, corrected for the current divider position,
// and expressed in local coordinates.
// base is an offset (x,y) applied to the mouse location (usually will be zero)
// indx is the number of the divider that's being dragged.
- (void)RB___trackMouseEvent:(NSEvent*)theEvent from:(NSPoint)where withBase:(NSPoint)base inDivider:(NSUInteger)indx {
    NSArray* subviews = [self RB___subviews];
    NSUInteger subcount = [subviews count];
// Make sure that the divider number is valid.
    if (indx>=subcount) {
        return;
    }
    NSPoint result;
    NSUInteger k;
// leading and trailing point at the subviews immediately leading and trailing the divider being tracked
    RBSplitSubview* leading = [subviews objectAtIndex:indx];
    RBSplitSubview* trailing = [subviews objectAtIndex:indx+1];
// Convert the mouse coordinates to apply to the same system the divider rects are in.
    NSPoint mouse = [self convertPoint:[theEvent locationInWindow] fromView:nil];
    mouse.x -= base.x;
    mouse.y -= base.y;
    result.x = mouse.x-where.x;
    result.y = mouse.y-where.y;
// delta is the actual amount the mouse has moved in the relevant coordinate since the last event.
    BOOL ishor = [self isHorizontal];
    CGFloat delta = DIM(result);
    if (delta<0.0) {
// Negative delta means the mouse is being moved left or upwards.
// firstLeading will point at the first expanded subview to the left (or upwards) of the divider.
// If there's none (all subviews are collapsed) it will point at the nearest subview.
        RBSplitSubview* firstLeading = leading;
        k = indx;
        while (![firstLeading canShrink]) {
            if (k==0) {
                firstLeading = leading;
                break;
            }
            firstLeading = [subviews objectAtIndex:--k];
        }
        if (isInScrollView) {
            trailing = nil;
        }
// If the trailing subview is collapsed, it might be expanded if some conditions are met.
        if ([trailing isCollapsed]) {
            [self RB___tryToExpandTrailing:trailing leading:firstLeading delta:delta];
        } else {
            [self RB___tryToShortenLeading:firstLeading divider:indx trailing:trailing delta:delta always:YES];
        }
    } else if (delta>0.0) {
// Positive delta means the mouse is being moved right or downwards.
// firstTrailing will point at the first expanded subview to the right (or downwards) of the divider.
// If there's none (all subviews are collapsed) it will point at the nearest subview.
        RBSplitSubview* firstTrailing = nil;
        if (!isInScrollView) {
            firstTrailing = trailing;
            k = indx+1;
            while (![firstTrailing canShrink]) {
                if (++k>=subcount) {
                    firstTrailing = trailing;
                    break;
                }
                firstTrailing = [subviews objectAtIndex:k];
            }
        }
// If the leading subview is collapsed, it might be expanded if some conditions are met.
        if ([leading isCollapsed]) {
            [self RB___tryToExpandLeading:leading divider:indx trailing:firstTrailing delta:delta];
        } else {
// The leading subview is not collapsed, so we try to shorten or even collapse it
            [self RB___tryToShortenTrailing:firstTrailing divider:indx leading:leading delta:delta always:YES];
        }
    }
}
 
// This is called for nested RBSplitViews, to add the cursor rects for the two-axis thumbs.
- (void)RB___addCursorRectsTo:(RBSplitView*)masterView forDividerRect:(NSRect)rect thickness:(CGFloat)delta {
    if (dividers&&[self divider]) {
        NSArray* subviews = [self RB___subviews];
        NSInteger divcount = [subviews count]-1;
        if (divcount<1) {
            return;
        }
        NSInteger i;
        NSCursor* cursor = [RBSplitView cursor:RBSV2WayCursor];
        BOOL ishor = [self isHorizontal];
// Loop over the divider rectangles, intersect them with the view's own, and add the thumb rectangle
// to the containing split view.
        for (i=0;i<divcount;i++) {
            NSRect divdr = dividers[i];
            divdr.origin = [self convertPoint:divdr.origin toView:masterView];
            OTHER(divdr.origin) -= delta;
            OTHER(divdr.size) += 2*delta;
            divdr = NSIntersectionRect(divdr,rect);
            if (!NSIsEmptyRect(divdr)) {
                [masterView addCursorRect:divdr cursor:cursor];
            }
        }
    }
}
 
// This is called for nested RBSplitViews, to draw the two-axis thumbs.
- (void)RB___drawDividersIn:(RBSplitView*)masterView forDividerRect:(NSRect)rect thickness:(CGFloat)delta {
    if (!dividers) {
        return;
    }
    NSArray* subviews = [self RB___subviews];
    NSInteger divcount = [subviews count]-1;
    if (divcount<1) {
        return;
    }
    NSInteger i;
    BOOL ishor = [self isHorizontal];
// Get the outer split view's divider image.
    NSImage* image = [masterView divider];
// Loop over the divider rectangles, intersect them with the view's own, and draw the thumb there.
    for (i=0;i<divcount;i++) {
        NSRect divdr = dividers[i];
        divdr.origin = [self convertPoint:divdr.origin toView:masterView];
        OTHER(divdr.origin) -= delta;
        OTHER(divdr.size) += 2*delta;
        divdr = NSIntersectionRect(divdr,rect);
        if (!NSIsEmptyRect(divdr)) {
            [masterView drawDivider:image inRect:divdr betweenView:nil andView:nil];
        }
    }
}
 
// This is usually called from initWithCoder to ensure that the outermost RBSplitView is
// properly adjusted when first displayed.
- (void)RB___adjustOutermostIfNeeded {
    RBSplitView* sv = [self splitView];
    if (sv) {
        [sv RB___adjustOutermostIfNeeded];
        return;
    }
    if (mustAdjust&&!isAdjusting) {
        [self adjustSubviews];
    }
}
 
// Here we try to keep all subviews adjusted in as natural a manner as possible, given the constraints.
// The main idea is to always keep the RBSplitView completely covered by dividers and subviews, have at
// least one expanded subview, and never make a subview smaller than its minimum dimension, or larger
// than its maximum dimension.
// We try to account for most unusual situations but this may fail under some circumstances. YMMV.
- (void)RB___adjustSubviewsExcepting:(RBSplitSubview*)excepting {
    mustAdjust = NO;
    NSArray* subviews = [self RB___subviews];
    NSUInteger subcount = [subviews count];
    if (subcount<1) {
        return;
    }
    NSRect bounds = [self bounds];
// Never adjust if the splitview itself is collapsed.
    if ((bounds.size.width<1.0)||(bounds.size.height<1.0)) {
        return;
    }
// Prevents adjustSubviews being called recursively, which unfortunately may happen otherwise.
    if (isAdjusting) {
        return;
    }
    isAdjusting = YES;
// Tell the delegate we're about to adjust subviews.
    if ([delegate respondsToSelector:@selector(willAdjustSubviews:)]) {
        [delegate willAdjustSubviews:self];
        bounds = [self bounds];
    }
    NSUInteger divcount = subcount-1;
    if (divcount<1) {
// No dividers at all.
        if (dividers) {
            free(dividers);
            dividers = NULL;
        }
    } else {
// Try to allocate or resize if we already have a dividers array.
        NSUInteger divsiz = sizeof(NSRect)*divcount;
        dividers = (NSRect*)(dividers?reallocf(dividers,divsiz):malloc(divsiz));
        if (!dividers) {
            return;
        }
    }
// This C array of subviewCaches is used to cache the subview information.
    subviewCache* caches = (subviewCache*)malloc(sizeof(subviewCache)*subcount);
    double realsize = 0.0;
    double expsize = 0.0;
    CGFloat newsize = 0.0;
    CGFloat effsize = 0.0;
    CGFloat limit;
    subviewCache* curr;
    NSUInteger i;
    BOOL ishor = [self isHorizontal];
    CGFloat divt = [self dividerThickness];
// First we loop over subviews and cache their information.
    for (i=0;i<subcount;i++) {
        curr = &caches[i];
        [[subviews objectAtIndex:i] RB___copyIntoCache:curr];
    }
// This is a counter to limit the outer loop to three iterations (six if excepting is non-nil).
    NSInteger sanity = excepting?-3:0;
    while (sanity++<3) {
// We try to accomodate the exception for the first group of loops, turn it off for the second.
        if (sanity==1) {
            excepting = nil;
        }
// newsize is the available space for actual subviews (so dividers don't count). It will be an integer.
// Same as calling [self RB___dimensionWithoutDividers].
        NSUInteger smallest = 0;
        CGFloat smalldim = -1.0;
        BOOL haveexp = NO;
// Loop over subviews and sum the expanded dimensions into expsize, including fractions.
// Also find the collapsed subview with the smallest minimum dimension.
        for (i=0;i<subcount;i++) {
            curr = &caches[i];
            curr->constrain = NO;
            if (curr->size>0.0) {
                expsize += curr->size;
                if (!isInScrollView) {
// ignore fractions if we're in a NSScrollView, however.
                    expsize += curr->fraction;
                }
                haveexp = YES;
            } else {
                limit = [curr->sub minDimension];
                if (smalldim>limit) {
                    smalldim = limit;
                    smallest = i;
                }
            }
        }
// haveexp should be YES at this point. If not, all subviews were collapsed; can't have that, so we 
// expand the smallest subview (or the first, if all have the same minimum).
        curr = &caches[smallest];
        if (!haveexp) {
            curr->size = [curr->sub minDimension];
            curr->fraction = 0.0;
            expsize += curr->size;
        }
        if (isInScrollView) {
// If we're inside an NSScrollView, we just grow the view to accommodate the subviews, instead of 
// the other way around.
            DIM(bounds.size) = expsize;
            break;
        } else {
// If the total dimension of all expanded subviews is less than 1.0 we set the dimension of the smallest
// subview (which we're sure is expanded at this point) to the available space.
            newsize = DIM(bounds.size)-divcount*divt;
            if (expsize<1.0) {
                curr->size = newsize;
                curr->fraction = 0.0;
                expsize = newsize;
            }
// Loop over the subviews and check if they're within the limits after scaling. We also recalculate the
// exposed size and repeat until no more subviews hit the constraints during that loop.
            BOOL constrained;
            effsize = newsize;// we're caching newsize here, this is an integer.
            do {
// scale is the scalefactor by which all views should be scaled - assuming none have constraints.
// It's a double to (hopefully) keep rounding errors small enough for all practical purposes.
                double scale = newsize/expsize;
                constrained = NO;
                realsize = 0.0;
                expsize = 0.0;
                for (i=0;i<subcount;i++) {
// Loop over the cached subview info.
                    curr = &caches[i];
                    if (curr->size>0.0) {
// Check non-collapsed subviews only.
                        if (!curr->constrain) {
// Check non-constrained subviews only; calculate the proposed new size.
                            CGFloat cursize = (curr->size+curr->fraction)*scale;
// Check if we hit a limit. limit will contain either the max or min dimension, whichever was hit.
                            if (([curr->sub RB___animationData:NO resize:NO]&&((limit = curr->size)>=0.0))||
                                ((curr->sub==excepting)&&((limit = [curr->sub dimension])>0.0))||
                                (cursize<(limit = [curr->sub minDimension]))||
                                (cursize>(limit = [curr->sub maxDimension]))) {
// If we hit a limit, we mark the view and set to repeat the loop; non-constrained subviews will
// have to be recalculated.
                                curr->constrain = constrained = YES;
// We set the new size to the limit we hit, and subtract it from the total size to be subdivided.
                                cursize = limit;
                                curr->fraction = 0.0;
                                newsize -= cursize;
                            } else {
// If we didn't hit a limit, we round the size to the nearest integer and recalculate the fraction. 
                                double rem = fmod(cursize,1.0);
                                cursize -= rem;
                                if (rem>0.5) {
                                    ++cursize;
                                    --rem;
                                }
                                expsize += cursize;
                                curr->fraction = rem;
                            }
// We store the new size in the cache.
                            curr->size = cursize;
                        }
// And add the full size with fraction to the actual sum of all expanded subviews.
                        realsize += curr->size+curr->fraction;
                    }
                }
// At this point, newsize will be the sum of the new dimensions of non-constrained views.
// expsize will be the sum of the recalculated dimensions of the same views, if any.
// We repeat the loop if any view has been recently constrained, and if there are any
// unconstrained views left.
            } while (constrained&&(expsize>0.0));
// At this point, the difference between realsize and effsize should be less than 1 pixel.
// realsize is the total size of expanded subviews as recalculated above, and
// effsize is the value realsize should have.
            limit = realsize-effsize;
            if (limit>=1.0) {
// If realsize is larger than effsize by 1 pixel or more, we will need to collapse subviews to make room.
// This in turn might expand previously collapsed subviews. So, we'll try collapsing constrained subviews
// until we're back into range, and then recalculate everything from the beginning.
                for (i=0;i<subcount;i++) {
                    curr = &caches[i];
                    if (curr->constrain&&(curr->sub!=excepting)&&([curr->sub RB___animationData:NO resize:NO]==nil)&&[curr->sub canCollapse]) {
                        realsize -= curr->size;
                        if (realsize<1.0) {
                            break;
                        }
                        curr->size = 0.0;
                        if ((realsize-effsize)<1.0) {
                            break;
                        }
                    }
                }
            } else if (limit<=-1.0) {
// If realsize is smaller than effsize by 1 pixel or more, we will need to expand subviews.
// This in turn might collapse previously expanded subviews. So, we'll try expanding collapsed subviews
// until we're back into range, and then recalculate everything from the beginning.
                for (i=0;i<subcount;i++) {
                    curr = &caches[i];
                    if (curr->size<=0.0) {
                        curr->size = [curr->sub minDimension];
                        curr->fraction = 0.0;
                        realsize += curr->size;
                        if ((realsize-effsize)>-1.0) {
                            break;
                        }
                    }
                }
            } else {
// The difference is less than 1 pixel, meaning that in all probability our calculations are
// exact or off by at most one pixel after rounding, so we break the loop here.
                break;
            }
        }
// After passing through the outer loop a few times, the frames may still be wrong, but there's nothing
// else we can do about it. You probably should avoid this by some other means like setting a minimum
// or maximum size for the window, for instance, or leaving at least one unlimited subview.
    }
// newframe is used to reset all subview frames. Subviews always fill the entire RBSplitView along the
// current orientation.
    NSRect newframe = NSMakeRect(0.0,0.0,bounds.size.width,bounds.size.height);
// We now loop over the subviews yet again and set the definite frames, also recalculating the
// divider rectangles as we go along, and collapsing and expanding subviews whenever requested.
    RBSplitSubview* last = nil;
// And we make a note if there's any nested RBSplitView.
    NSInteger nested = NSNotFound;
//  newsize = DIM(bounds.size)-divcount*divt;
    for (i=0;i<subcount;i++) {
        curr = &caches[i];
// If we have a nested split view store its index.
        if ((nested==NSNotFound)&&([curr->sub asSplitView]!=nil)) {
            nested = i;
        }
// Adjust the subview to the correct origin and resize it to fit into the "other" dimension.
        curr->rect.origin = newframe.origin;
        OTHER(curr->rect.size) = OTHER(newframe.size);
        DIM(curr->rect.size) = curr->size;
// Clear fractions for expanded subviews if requested.
        if ((curr->size>0.0)&&mustClearFractions) {
            curr->fraction = 0.0;
        }
// Ask the subview to do the actual moving/resizing etc. from the cache.
        [curr->sub RB___updateFromCache:curr withTotalDimension:effsize];
// Step to the next position and record the subview if it's not collapsed.
        DIM(newframe.origin) += curr->size;
        if (curr->size>0.0) {
            last = curr->sub;
        }
        if (i==divcount) {
// We're at the last subview, so we now check if the actual and calculated dimensions
// are the same.
            CGFloat remain = DIM(bounds.size)-DIM(newframe.origin);
            if (last&&(fabs(remain)>0.0)) {
// We'll resize the last expanded subview to whatever it takes to squeeze within the frame.
// Normally the change should be at most one pixel, but if too many subviews were constrained,
// this may be a large value, and the last subview may be resized beyond its constraints;
// there's nothing else to do at this point.
                newframe = [last frame];
                DIM(newframe.size) += remain;
                [last RB___setFrameSize:newframe.size withFraction:[last RB___fraction]-remain];
// And we loop back over the rightmost dividers (if any) to adjust their offsets.
                while ((i>0)&&(last!=[subviews objectAtIndex:i])) {
                    DIM(dividers[--i].origin) += remain;
                }
                break;
            }
        } else {
// For any but the last subview, we just calculate the divider frame.
            DIM(newframe.size) = divt;
            if (dividers) {     // test for NULL to satisfy the analyzer
                dividers[i] = newframe;
            }
            DIM(newframe.origin) += divt;
        }
    }
// We resize our frame at this point, if we're inside an NSScrollView.
    if (isInScrollView) {
        [super setFrameSize:bounds.size];
    }
// If there was at least one nested RBSplitView, we loop over the subviews and adjust those that need it.
    for (i=nested;i<subcount;i++) {
        curr = &caches[i];
        RBSplitView* sv = [curr->sub asSplitView];
        if ([sv mustAdjust]) {
            [sv adjustSubviews];
        }
    }
// Free the cache array.
    free(caches);
// Clear cursor rects.
    mustAdjust = NO;
    mustClearFractions = NO;
    [[self window] invalidateCursorRectsForView:self];
// Save the state for all subviews.
    if (!isDragging) {
        [self saveState:NO];
    }
// If we're a nested RBSplitView, also invalidate cursorRects for the superview.
    RBSplitView* sv = [self couplingSplitView];
    if (sv) {
        [[self window] invalidateCursorRectsForView:sv];
    }
    isAdjusting = NO;
// Tell the delegate we're finished.
    if ([delegate respondsToSelector:@selector(didAdjustSubviews:)]) {
        [delegate didAdjustSubviews:self];
    }
}
 
@end