CATextLayer number of lines?

问题

My CATextlayer support only 1 line otherwise the text is cut.

trying to set text content like UILabel Behaviour... is it possible?

set "number of lines"
adjust text size by static CATextLayer frame

CATextLayer *text_layer= [[CATextLayer alloc] init];
[text_layer setBackgroundColor:[UIColor clearColor].CGColor];
[text_layer setBackgroundColor:[UIColor blueColor].CGColor];
[text_layer setForegroundColor:layers.textColor.CGColor];
[text_layer setAlignmentMode:kCAAlignmentCenter];
[text_layer setBorderColor:layers.borderColor.CGColor];
[text_layer setFrame:CGRectMake(0,0,200,50)]; //note: frame must be static
[text_layer setString:@"thank you for your respond"];
 text_layer.wrapped = YES;
[text_layer setAlignmentMode:kCAAlignmentCenter];

回答1:

Your problem is this line right here, [text_layer setFrame:CGRectMake(0,0,200,50)];. I don't think a CATextLayer would lay itself out to accommodate multiple lines. It will only re-draw the text to wrap within the layer's bounds. Try adjusting your text layer's frame based on the text being set. You can create a UILabel instance, to calculate the frame for having multiline text with word wrapping and set it to your CATextLayer instance.

Here's a UILabel category to calculate text size for multiline text with word wrapping:

@interface UILabel (Height)

- (CGSize)sizeForWrappedText;

@end

@implementation UILabel (Height)

- (CGSize)sizeForWrappedText {
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, 0.0f, self.bounds.size.width, CGFLOAT_MAX)];
    label.numberOfLines = 0;
    label.font = self.font;
    label.text = self.text;
    [label sizeToFit];
    return label.frame.size;
}

@end

Create a UILabel instance, and use the sizeForWrappedText to get the size. Something like this:

// Make sure the someFrame here has the preferred width you want for your text_layer instance.
UILabel *label = [[UILabel alloc] initWithFrame:someFrame];
[label setText:@"My awesome text!"];

CGRect frame = text_layer.frame;
frame.size = [label sizeForWrappedText];
[text_layer setFrame:frame];

来源：https://stackoverflow.com/questions/47772963/catextlayer-number-of-lines

标签

objective-c

calayer

catextlayer