How to change font in NSTextContainer

Question

My application is setup as so.

Custom UIView inside a ScrollView.

The custom UIView is getting text generated on top of it with this code.

CoreDavening.m draw function

attStorage = [[NSTextStorage alloc]initWithAttributedString:string];

textContainer = [[NSTextContainer alloc]
                                  initWithSize:CGSizeMake(self.frame.size.width, FLT_MAX)];

layoutManager = [[NSLayoutManager alloc]init];
[layoutManager addTextContainer:textContainer];
[attStorage addLayoutManager:layoutManager];

NSRange glyphRange = [layoutManager
                      glyphRangeForTextContainer:textContainer];
[layoutManager drawGlyphsForGlyphRange: glyphRange atPoint: rect.origin];

In my ViewController.m I'm creating the view like so.

CoreDavening *davenView = [[CoreDavening alloc]initWithFrame:CGRectMake(0, 0,self.view.frame.size.width, [coreDavening heightForStringDrawing])];

    davenView.backgroundColor = [UIColor whiteColor];
    davenView.layer.borderColor = [[UIColor whiteColor]CGColor];
    scrollView.backgroundColor = [UIColor whiteColor];
    [scrollView addSubview:davenView];
    self.scrollView.contentSize = davenView.frame.size;

Im trying to find a way to 1) change the font size (just size) 2) have the scrollView and CustomView resize appropriately.

How can this be done?

EDIT 1: Im creating the custom view in my viewController like this.

CoreDavening *coreDavening = [[CoreDavening alloc]init];

     davenView = [[CoreDavening alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, [coreDavening heightForStringDrawing ])];

and updating/refreshing the custom view like this.

It get triggered when the slider I have set up changes value.

- (IBAction)sliderChanged:(id)sender {

    NSUserDefaults *prefs= [NSUserDefaults standardUserDefaults];
    [prefs setInteger:(long)self.Slider.value forKey:@"fontSize"];
    [prefs synchronize];

    [davenView setNeedsLayout];
}

My custom view controller has the font set up like.

THIS IS IN THE DRAW FUNCTION

attStorage = [[NSTextStorage alloc]initWithAttributedString:string];


    [attStorage addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:(long)[prefs integerForKey:@"fontSize"]] range:NSMakeRange(0, attStorage.length)];

    textContainer = [[NSTextContainer alloc]
                                      initWithSize:CGSizeMake(self.frame.size.width, FLT_MAX)];

    layoutManager = [[NSLayoutManager alloc]init];
    [layoutManager addTextContainer:textContainer];
    [attStorage addLayoutManager:layoutManager];

    NSRange glyphRange = [layoutManager
                          glyphRangeForTextContainer:textContainer];
    [layoutManager drawGlyphsForGlyphRange: glyphRange atPoint: rect.origin];

score 1 · Answer 1 · answered Jun 07 '15 at 04:55

1

It seems like you have the textStorage associated with the layoutManager already. NSTextStorage is the subclass of NSMutableAttributedString. So, this is the class which is responsible to hold the layout and styling information. How have you created your textStorage ? Besides, the styling, NSTextStorage also has methods to allow editing the contents and have dynamic styling.

You can simply set the attribute to your textStorage if you want to change the font.

[_textStorage addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:20.0] range:NSMakeRange(0, _textStorage.length)];

NSTextManager class has quite useful methods to find the bounds and glyphs informations. So, you could use method like below to find the bounds for your text,

- (CGRect)boundingRectWithSize:(CGSize)size
{
    self.textContainer.size = size;

    NSRange glyphRange = [self.layoutManager glyphRangeForTextContainer:self.textContainer];

    CGRect boundingRect = [self.layoutManager boundingRectForGlyphRange:glyphRange
                                                        inTextContainer:self.textContainer];
    boundingRect.origin.x = 0;
    boundingRect.origin.y = 0;

    return boundingRect;
}

answered Jun 07 '15 at 04:55

Sandeep

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Will this update the text right away? Or do i need to call setNeedsLayout or something – user2738258 Jun 07 '15 at 04:59
You need to draw it again using setNeedsLayout. – Sandeep Jun 07 '15 at 05:05
Its not updating. Ill post the code for creating the view and updating – user2738258 Jun 07 '15 at 05:08
If i go in and out of the view Controller the font changes but not when i change the slider – user2738258 Jun 07 '15 at 05:12
There might be something, put a breakpoint in the drawInRect method and see what is going on. – Sandeep Jun 07 '15 at 05:22
The draw function isn't getting called. There must be something wrong with the setNeedsLayout – user2738258 Jun 07 '15 at 05:28
Hey, I fixed it with setNeedsDisplay but the slider is causing major lag now. Any idea why? – user2738258 Jun 07 '15 at 05:29
Well just use UIControlEventTouchUpInside or UIControlEventTouchUpOutside to trigger the drawRect method. It makes less efficient if you just go on redrawing everytime the value changes. – Sandeep Jun 07 '15 at 06:12

How to change font in NSTextContainer

1 Answers1