Determining the maximum font size for a UITextView

Question

Is it possible to determine the maximum font size for UITextViewwhich saves all the texts inside without cropping, while its containing text is already set and permanent.

Note . I use custom fonts and Swift.

Answer 1

You can calculate the height of the content. Then resize the frame.

CGSize strSize= [textView.text sizeWithFont:[UIFont systemFontOfSize:17.0] constrainedToSize:CGSizeMake(290.0,99999.0)];
frame.size.height = strSize.height

Answer 2

Try the following:

- (void)ff
{
    int minSize = 12; //define a minimum font size
    int maxSize = 60; //define a maximum font size
    int size = minSize;
    for (size = minSize; size < maxSize; size++) {
        UIFont *font = [UIFont fontWithName:@"your_font_name" size:size]; // init your font
        textView.font = font;
        [textView.layoutManager glyphRangeForTextContainer:textView.textContainer];
        NSRange visibleRange = [self visibleRangeOfTextView:textView];
        if (visibleRange.length < textView.text.length) {
            size--;
            break;
        }
    }

    NSLog(@"%d", size);

    return YES;
}

- (NSRange)visibleRangeOfTextView:(UITextView *)textView {
    CGRect bounds = textView.bounds;
    UITextPosition *start = [textView characterRangeAtPoint:bounds.origin].start;
    UITextPosition *end = [textView characterRangeAtPoint:CGPointMake(CGRectGetMaxX(bounds), CGRectGetMaxY(bounds))].end;
    return NSMakeRange([textView offsetFromPosition:textView.beginningOfDocument toPosition:start],
                       [textView offsetFromPosition:start toPosition:end]);
}

For best results, I suggest you reset textview paddings:

[textView setTextContainerInset:UIEdgeInsetsZero];
textView.textContainer.lineFragmentPadding = 0;

Answer 3

Max Min: -

static const CGFloat MAX_SIZE = 12.0;
static const CGFloat MIN_SIZE = 7.0;

-, viewDidLoad()

self.txtVw.font = [UIFont systemFontOfSize:MAX_SIZE]; 

-, textView : -

- (void)textDidChange:(UITextView*)textView
{
    // This will  to adjust this sizing as per your requirement.

    self.txtVw.font = [UIFont systemFontOfSize:MAX(
        MAX_SIZE - textView.text.length, 
        MIN_SIZE
    )];
}