Is there any method to determine how much of an NSString can be rendered in a given space?
I know about all the NSString sizeWithFont methods (e.g. sizeWithFont:constrainedToSize:lineBreakMode:). If the string is too long to fit though, these don't tell you what portion of the string was able to be rendered.
For example, if I have
NSString *testString = #"The brown dog";
And I call:
[testString sizeWithFont:[UIFont systemFontOfSize:17] constrainedtoSize:CGSizeMake(20, 20) lineBreakMode:UILineBreakModeWordWrap];
I may get back a CGSize = {20,20}. That tells me the string took at least the entire size, but it doesn't tell me if it was over, or how much was able to fit. If only "The brown" was able to fit, I'd like to know that.
Maybe some Core Foundation methods to do this?
One way to tell if it's going to truncate is to provide a very large height in the constrain rect. If the height that comes back is taller than the height of your label, you know it would be truncated. Something like this:
// myLabel is a UILabel*
CGSize labelSize = myLabel.frame.size;
labelSize.height = 9999;
CGSize newSize = [newLabel sizeWithFont:[UIFont systemFontOfSize:17.0]
constrainedToSize:labelSize
lineBreakMode:UILineBreakModeWordWrap];
if( newSize.height > labelSize.height ) {
// Whoops, too big!
}
That will tell you if it would be truncated, but it won't tell you how much of it would be. Only way I can think to do that would be to do this in a loop, removing a word off the end each time until it fits.
Related
I'm making my app transition to iOS 7 and have this method (already modified for iOS 7, using boundingRectWithSize...):
+ (CGSize)messageSize:(NSString*)message {
NSDictionary *attributes = #{NSFontAttributeName : [UIFont fontWithName:#"Futura-Medium" size:13]};
CGRect frame = [message boundingRectWithSize:CGSizeMake([PTSMessagingCell maxTextWidth], CGFLOAT_MAX) options:NSStringDrawingUsesFontLeading attributes:attributes context:nil];
return frame.size;
}
I am getting this appearance:
The message UILabel is being cut. It feels like line spacing is too big. It tried many other answers I found but none of them work.
If someone knows how to help me, I appreciate! ;)
Thanks!
Try changing NSStringDrawingUsesFontLeading as your option to NSStringDrawingUsesLineFragmentOrigin.
If you were only supporting iOS 6 and iOS 7, then I would definitely change all of your NSString's sizeWithFont:... to the NSAttributeString's boundingRectWithSize. Starting in iOS 6, the NSAttributedString's NSStringDrawing functions were introduced and they're threadsafe unlike the old NSString+UIKit methods we're used to (eg. sizeWithFont:..., etc), which were UIStringDrawing functions (and act unpredictably when you use them from a non-main thread. It'll save you a lot of headache if you happen to have a weird multi-threading corner case! Here's how I converted NSString's sizeWithFont:constrainedToSize::
What used to be:
NSString *text = ...;
CGFloat width = ...;
UIFont *font = ...;
CGSize size = [text sizeWithFont:font
constrainedToSize:(CGSize){width, CGFLOAT_MAX}];
Can be replaced with:
NSString *text = ...;
CGFloat width = ...;
UIFont *font = ...;
NSAttributedString *attributedText =
[[NSAttributedString alloc]
initWithString:text
attributes:#
{
NSFontAttributeName: font
}];
CGRect rect = [attributedText boundingRectWithSize:(CGSize){width, CGFLOAT_MAX}
options:NSStringDrawingUsesLineFragmentOrigin
context:nil];
CGSize size = rect.size;
Please note the documentation mentions:
In iOS 7 and later, this method returns fractional sizes (in the size
component of the returned CGRect); to use a returned size to size
views, you must use raise its value to the nearest higher integer
using the ceil function.
So to pull out the calculated height or width to be used for sizing views, I would use:
CGFloat height = ceilf(size.height);
CGFloat width = ceilf(size.width);
I think you are updating your label frame from either viewDidLoad or viewWillAppear, so it is not working.
if you will update frame of label from viewDidAppear method then you will get updated frame of label.
I am not sure why this is happened, I think it is iOS 7 bug.
Try this
+ (CGSize)messageSize:(NSString*)message {
CGSize nameSize = [message sizeWithFont:[UIFont fontWithName:#"Futura-Medium" size:13]
constrainedToSize:CGSizeMake(maxWidth, maxHeight) lineBreakMode:NSLineBreakByWordWrapping];
NSLog(#"width = %f, height = %f", nameSize.width, nameSize.height);
return nameSize;
}
I need to work out the height of a UITextView from the top down to the cursor. I am trimming the text it contains (so it only goes up to the cursor) and then using NSString's sizeWithFont:constrainedToSize:lineBreakMode: method to work out the height, like so:
NSRange range;
range.location = noteTextView.selectedRange.location;
range.length = noteTextView.text.length - range.location;
NSString *string = [noteTextView.text stringByReplacingCharactersInRange:range withString:#""];
CGSize size = [string sizeWithFont:noteTextView.font
constrainedToSize:noteTextView.frame.size
lineBreakMode:UILineBreakModeWordWrap];
NSLog(#"height is: %f \n", size.height);
It does this every time I type anything.
The problem is, when I watch the NSLog as I type, it doesn't register a change of height until I have typed 4 characters on the new line. It is as if the sizeWithFont method is exactly four characters out. Here's a couple of screenshots showing what I mean:
Can anyone tell me what is going on?
#Vladimir's comment is right I think - an NSString doesn't take into account the margins of a UITextField.
You could try getting the text preceding the cursor and creating a new UITextField that only contains that text.
Then if you call [tempTextField sizeToFit] on your new text field then it's bounds should be the size you are looking for.
A "quicky": how can I get the size (width) of a NSString?
I'm trying to see if the string width of a string to see if it is bigger than a given width of screen, case in which I have to "crop" it and append it with "...", getting the usual behavior of a UILabel. string.length won't do the trick since AAAAAAAA and iiiiii have the same length but different sizes (for example).
I'm kind of stuck.
Thanks a lot.
This is a different approach. Find out the minimum size of the text so that it won't wrap to more than one line. If it wraps to over one line, you can find out using the height.
You can use this code:
CGSize maximumSize = CGSizeMake(300, 9999);
NSString *myString = #"This is a long string which wraps";
UIFont *myFont = [UIFont fontWithName:#"Helvetica" size:14];
CGSize myStringSize = [myString sizeWithFont:myFont
constrainedToSize:maximumSize
lineBreakMode:self.myLabel.lineBreakMode];
300 is the width of the screen with a little space for margins. You should substitute your own values for font and size, and for the lineBreakMode if you're not using IB.
Now myStringSize will contain a height which you can check against the height of something you know is only 1 line high (using the same font and size). If it's bigger, you'll need to cut the text. Note that you should add a ... to the string before you check it again (adding the ... might push it over the limit again).
Put this code in a loop to cut the text, then check again for the correct height.
Use below method.
Objective-C
- (CGSize)findHeightForText:(NSString *)text havingWidth:(CGFloat)widthValue andFont:(UIFont *)font {
CGSize size = CGSizeZero;
if (text) {
CGRect frame = [text boundingRectWithSize:CGSizeMake(widthValue, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:#{ NSFontAttributeName:font } context:nil];
size = CGSizeMake(frame.size.width, frame.size.height + 1);
}
return size;
}
Swift 3.0
func findHeight(forText text: String, havingWidth widthValue: CGFloat, andFont font: UIFont) -> CGSize {
var size = CGSizeZero
if text {
var frame = text.boundingRect(withSize: CGSize(width: widthValue, height: CGFLOAT_MAX), options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
size = CGSize(width: frame.size.width, height: frame.size.height + 1)
}
return size
}
You need to use Core Graphics to measure the string, as rendered in your specified font and size. See the answers to Measuring the pixel width of a string for a walkthrough.
sizeWithFont:constrainedToSize:lineBreakMode
is deprecated now. Use below code snippet,
UIFont *font=[UIFont fontWithName:#"Arial" size:16.f];
NSString *name = #"APPLE";
CGSize size = [name sizeWithAttributes:#{NSFontAttributeName:font}];
For whatever its worth --- I think the OP takes the wrong way to get there... if the measurement of width only serves to find the place where text should be clipped, and followed by ellipsis --- then OP should be aware of that this facility is implemented in all Text Views in Cocoa...
Pay attention to this enumeration:
typedef NS_ENUM(NSUInteger, NSLineBreakMode) {
NSLineBreakByWordWrapping = 0, // Wrap at word boundaries, default
NSLineBreakByCharWrapping, // Wrap at character boundaries
NSLineBreakByClipping, // Simply clip
NSLineBreakByTruncatingHead, // Truncate at head of line: "...wxyz"
NSLineBreakByTruncatingTail, // Truncate at tail of line: "abcd..."
NSLineBreakByTruncatingMiddle // Truncate middle of line: "ab...yz"
} API_AVAILABLE(macos(10.0), ios(6.0), watchos(2.0), tvos(9.0));
By setting the line breaking mode of your text-field or text view to NSLineBreakByTruncatingTail, you'll achieve what you want, and probably at higher quality, without implementing yourself.
I know there is this one:
sizeWithFont:minFontSize:actualFontSize:forWidth:lineBreakMode:
But since the CGSize always has the same height and doesn't adjust to any shrinked text or whatsoever, the CGSize is not telling how heigh the text is.
Example: Make a UILabel with 320 x 55 points and put a loooooooooooooong text in there. Let the label shrink the text down. Surprise: CGSize.height remains the same height even if the text is so tiny that you need a microscope.
Ok so after banging my head against my macbook pro which is half way broken now, the only think that can help is that nasty actualFontSize. But the font size is in pica I think, it's not really what you get on the screen, isn't it?
When that font size is 10, is my text really 10 points heigh at maximum? Once in a while I tried exactly that, and as soon as the text had a y or some character that extends to below (like that tail of an y does), it is out of bounds and the whole text is bigger than 10 points.
So how would you calculate the real text height for a single line uilabel without getting a long beard and some hospital experience?
Try this code:
CGSize maximumSize = CGSizeMake(300, 9999);
NSString *myString = #"This is a long string which wraps";
UIFont *myFont = [UIFont fontWithName:#"Helvetica" size:14];
CGSize myStringSize = [myString sizeWithFont:myFont
constrainedToSize:maximumSize
lineBreakMode:self.myLabel.lineBreakMode];
from my answer here
It uses a different method, and sets up a very high CGSize at the start (which is then shrunk to fit the string)
Important: As of iOS 7.0 the following method is deprecated.
sizeWithFont:minFontSize:actualFontSize:forWidth:lineBreakMode:
Use the below code instead
CGRect frame = [cellText boundingRectWithSize:CGSizeMake(568,320) options:NSStringDrawingUsesLineFragmentOrigin attributes:#{NSFontAttributeName:[UIFont systemFontOfSize:32.0f]} context:nil];
float height = frame.size.height;
Sounds like after you get the actual font size from that function call, you need to call again with that new size:
NSString* yourString = #"SomeString";
float actualSize;
[yourString sizeWithFont:yourFont
minFontSize:minSize
actualFontSize:&actualSize
forWidth:rectWidth
lineBreakMode:breakMode];
CGSize size = [yourString sizeWithFont:[UIFont fontWithName:fontName size:actualSize]];
Also have you set label.numberOfLines = 0; ?
After running this code frame.size will have the height and width of your nsstring exactly..
NSString *text = #"This is my Mac";
textFont = [NSFont fontWithName:#"HelveticaNeue-Medium" size: 80.f];
textColor = [NSColor yellowColor];
NSDictionary *attribs = #{ NSForegroundColorAttributeName:textColor,
NSFontAttributeName: textFont };
CGRect frame = [text boundingRectWithSize:CGSizeMake(0,0) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesDeviceMetrics attributes:attribs context:nil];
In this question I asked for a good way to truncate a string to fit a given UITextView. Since there was no way provided by the SDK directly, I've ended up writing the recursive method below (only called by the following public method). However, this doesn't work unless I subtract a fudge factor of 15 (kFudgeFactor) from the field width when calculating the string's height. If I don't do that, the string returned is actually too long for the field, and displays in an extra line below it. Anyone any idea why, and what I should really use instead of this fudge factor?
#pragma mark Size string to fit the new view
#define kFudgeFactor 15.0
#define kMaxFieldHeight 9999.0
// recursive method called by the main API
-(NSString*) sizeStringToFit:(NSString*)aString min:(int)aMin max:(int)aMax
{
if ((aMax-aMin) <= 1)
{
NSString* subString = [aString substringToIndex:aMin];
return subString;
}
int mean = (aMin + aMax)/2;
NSString* subString = [aString substringToIndex:mean];
CGSize tallerSize = CGSizeMake(self.frame.size.width-kFudgeFactor,kMaxFieldHeight);
CGSize stringSize = [subString sizeWithFont:self.font constrainedToSize:tallerSize lineBreakMode:UILineBreakModeWordWrap];
if (stringSize.height <= self.frame.size.height)
return [self sizeStringToFit:aString min:mean max:aMax]; // too small
else
return [self sizeStringToFit:aString min:aMin max:mean];// too big
}
-(NSString*)sizeStringToFit:(NSString*)aString
{
CGSize tallerSize = CGSizeMake(self.frame.size.width-kFudgeFactor,kMaxFieldHeight);
CGSize stringSize = [aString sizeWithFont:self.font constrainedToSize:tallerSize lineBreakMode:UILineBreakModeWordWrap];
// if it fits, just return
if (stringSize.height < self.frame.size.height)
return aString;
// too big - call the recursive method to size it
NSString* smallerString = [self sizeStringToFit:aString min:0 max:[aString length]];
return smallerString;
}
UIScrollView seems to use a fixed 8-pixel inset on both sides. This is independent of alignment or font size (based on testing & observation, not any explicit knowledge of the internals).
So it seems you are right to use your fudge factor, but it should probably be 16.0, not 15.0.
This is probably because the frame of the UIView is not the same size as the content view.
UITextView subclasses from UIScrollView.