確実に動作させることができなかったため、しばらくこれをいじっていました。ようやくコードが動くようになったので、返信として投稿したいと思います。
私のソリューションでは、出力がビューに追加されている間、手動でスクロールできます。NSTextView の一番下までスクロールするとすぐに、自動スクロールが再開されます (有効になっている場合)。
最初に、必要な場合にのみこれを #import するカテゴリ...
FSScrollToBottomExtensions.h:
@interface NSView (FSScrollToBottomExtensions)
- (float)distanceToBottom;
- (BOOL)isAtBottom;
- (void)scrollToBottom;
@end
FSScrollToBottomExtensions.m:
@implementation NSView (FSScrollToBottomExtensions)
- (float)distanceToBottom
{
NSRect visRect;
NSRect boundsRect;
visRect = [self visibleRect];
boundsRect = [self bounds];
return(NSMaxY(visRect) - NSMaxY(boundsRect));
}
// Apple's suggestion did not work for me.
- (BOOL)isAtBottom
{
return([self distanceToBottom] == 0.0);
}
// The scrollToBottom method provided by Apple seems unreliable, so I wrote this one
- (void)scrollToBottom
{
NSPoint pt;
id scrollView;
id clipView;
pt.x = 0;
pt.y = 100000000000.0;
scrollView = [self enclosingScrollView];
clipView = [scrollView contentView];
pt = [clipView constrainScrollPoint:pt];
[clipView scrollToPoint:pt];
[scrollView reflectScrolledClipView:clipView];
}
@end
... NSTextView のサブクラスである「OutputView」を自分で作成します。
FSOutputView.h:
@interface FSOutputView : NSTextView
{
BOOL scrollToBottomPending;
}
FSOutputView.m:
@implementation FSOutputView
- (id)setup
{
...
return(self);
}
- (id)initWithCoder:(NSCoder *)aCoder
{
return([[super initWithCoder:aCoder] setup]);
}
- (id)initWithFrame:(NSRect)aFrame textContainer:(NSTextContainer *)aTextContainer
{
return([[super initWithFrame:aFrame textContainer:aTextContainer] setup]);
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
[super dealloc];
}
- (void)awakeFromNib
{
NSNotificationCenter *notificationCenter;
NSView *view;
// viewBoundsDidChange catches scrolling that happens when the caret
// moves, and scrolling caused by pressing the scrollbar arrows.
view = [self superview];
[notificationCenter addObserver:self
selector:@selector(viewBoundsDidChangeNotification:)
name:NSViewBoundsDidChangeNotification object:view];
[view setPostsBoundsChangedNotifications:YES];
// viewFrameDidChange catches scrolling that happens because text
// is inserted or deleted.
// it also catches situations, where window resizing causes changes.
[notificationCenter addObserver:self
selector:@selector(viewFrameDidChangeNotification:)
name:NSViewFrameDidChangeNotification object:self];
[self setPostsFrameChangedNotifications:YES];
}
- (void)handleScrollToBottom
{
if(scrollToBottomPending)
{
scrollToBottomPending = NO;
[self scrollToBottom];
}
}
- (void)viewBoundsDidChangeNotification:(NSNotification *)aNotification
{
[self handleScrollToBottom];
}
- (void)viewFrameDidChangeNotification:(NSNotification *)aNotification
{
[self handleScrollToBottom];
}
- (void)outputAttributedString:(NSAttributedString *)aAttributedString
flags:(int)aFlags
{
NSRange range;
BOOL wasAtBottom;
if(aAttributedString)
{
wasAtBottom = [self isAtBottom];
range = [self selectedRange];
if(aFlags & FSAppendString)
{
range = NSMakeRange([[self textStorage] length], 0);
}
if([self shouldChangeTextInRange:range
replacementString:[aAttributedString string]])
{
[[self textStorage] beginEditing];
[[self textStorage] replaceCharactersInRange:range
withAttributedString:aAttributedString];
[[self textStorage] endEditing];
}
range.location += [aAttributedString length];
range.length = 0;
if(!(aFlags & FSAppendString))
{
[self setSelectedRange:range];
}
if(wasAtBottom || (aFlags & FSForceScroll))
{
scrollToBottomPending = YES;
}
}
}
@end
... フォーマットされた文字列を出力できるように、このクラスにさらにいくつかの便利なメソッドを追加できます (私はそれを取り除きました)。
- (void)outputString:(NSString *)aFormatString arguments:(va_list)aArguments attributeKey:(NSString *)aKey flags:(int)aFlags
{
NSMutableAttributedString *str;
str = [... generate attributed string from parameters ...];
[self outputAttributedString:str flags:aFlags];
}
- (void)outputLineWithFormat:(NSString *)aFormatString, ...
{
va_list args;
va_start(args, aFormatString);
[self outputString:aFormatString arguments:args attributeKey:NULL flags:FSAddNewLine];
va_end(args);
}