NSTextField (multiline) grow horizontally after filling all lines - cocoa

Question

I have multiline NSTexField, that I use to show static text, that may have different length on each showing of window. This NSTextField has a height constrain, that limits it to two lines.
I want to setup behaviour, that NSTextField will grow horizontally only just so much, that it will fill those two horizontal lines.
Now when I set up horizontal compression resistance higher, text field width grows so much to display all the text on one line. Is this possible to achieve only by using autolayout constrains or do I have to calculate nstextfield width somehow?
I tried overloading "layout" method in superview. But its not working as I expect.
- (void)layout
{
[self solveLayoutForView:self];
}
- (void)solveLayoutForView:(NSView*)view
{
for (NSView* subView in [view subviews])
{
if (subView.subviews.count)
[self solveLayoutForView:subView];
else
{
NSLayoutConstraint* height = [subView constraintForAttribute:NSLayoutAttributeHeight];
if (height && height.constant > 17 && [subView isKindOfClass:[NSTextField class]]) // seems like multiline nstextfield
{
NSTextField* textField = (NSTextField*)subView;
textField.preferredMaxLayoutWidth = 0;
[super layout];
textField.preferredMaxLayoutWidth = NSWidth([textField alignmentRectForFrame:textField.frame]);
[super layout];
}
}
}
}

Answer 1

I ended up calculating it by myself.
I overload setStringValue in subclass of NSTextField.
"PreferGrowingHorizontally" is a subclass property if I ever need to skip this calculation (e.g.: in case I would like it to grow horizontally)
- (void)setStringValue:(NSString *)stringValue
{
BOOL changed = ![self.stringValue isEqualToString:stringValue] ? YES : NO;
[super setStringValue:stringValue];
if (stringValue.length && changed)
{
if (self.frame.size.height > 17 && self.preferGrowingHorizontally)
[self compensateWidth];
}
}
- (void)compensateWidth
{
float requiredHeight = FLT_MAX;
int widthCompensation = 0;
while (requiredHeight > self.frame.size.height)
requiredHeight = [self heightForStringDrawing:self.stringValue Font:self.font Width:self.frame.size.width + widthCompensation++];
if (--widthCompensation)
{
NSLayoutConstraint* width = [self constraintForAttribute:NSLayoutAttributeWidth];
if (width)
width.constant = self.frame.size.width + widthCompensation;
NSLog(#"requiredHeight: %f width compensation: %d for textField: %#", requiredHeight, widthCompensation, self.stringValue);
}
}
- (float)heightForStringDrawing:(NSString*)myString Font:(NSFont*)myFont Width:(float)myWidth
{
NSTextStorage *textStorage = [[[NSTextStorage alloc] initWithString:myString] autorelease];
NSTextContainer *textContainer = [[[NSTextContainer alloc] initWithContainerSize:NSMakeSize(myWidth, FLT_MAX)] autorelease];
NSLayoutManager *layoutManager = [[[NSLayoutManager alloc] init] autorelease];
[layoutManager addTextContainer:textContainer];
[textStorage addLayoutManager:layoutManager];
[textStorage addAttribute:NSFontAttributeName value:myFont
range:NSMakeRange(0, [textStorage length])];
[textContainer setLineFragmentPadding:0.0];
textContainer.lineBreakMode = NSLineBreakByWordWrapping;
(void) [layoutManager glyphRangeForTextContainer:textContainer];
return [layoutManager usedRectForTextContainer:textContainer].size.height;
}