how much pixels dose a character takes in iOS? - ios

I'm trying to automatically layout text on a UILabel view.
The text (such as "abcdefghij") contains ten characters. I want to display it in one single line.
I turned off the Size Class and Auto Layout for convenience, and added following codes to layout the text on the UILabel. It should be ten characters in one line, and the width of the UILabel is equal to the width of the device.
let screenWidth = UIScreen.mainScreen().bounds.width
labelView.frame = CGRect(x: labelView.frame.origin.x, y: labelView.frame.origin.y, width: screenWidth, height: labelView.frame.height)
let string = "abcdefghij"
let stringLength = CGFloat(string.characters.count)
let characterSize = keyboardView.font.pointSize
let characterSpacing = (screenWidth - characterSize * stringLength) / stringLength
let content = NSAttributedString(string: string, attributes: [NSKernAttributeName: characterSpacing])
keyboardView.attributedText = content
But it turns out like this. The width of string is not equal to the screen
I think, the only could be wrong here is the pointSize. It equals to 13.8 while I set the font size to 17.
I don't understand it.
Give me some hints, please.
Thanks for your attention. 😄
By using sizeWithAttributes and boundingRectWithSize(_:options:context:), I finally figured out how it works. But my origin purpose is fitting the 10 characters in one line. The code should calculate the space between the characters, and all the space is same size. Could you give me some advices?
This is what I want to make

Each character occupies different amount of space depending on the character, font and size of the font.
Hence, you can use boundingRectWithSize(_:options:context:) to predict size of the string at runtime, and then take action according to your requirements.

Related

Get truncated text from UILabel in Swift [duplicate]

I have a single line UILabel. It has width = screen width and the content now is (the content of UILabel can change)
You have 30 seconds to make an impression during an interview
Currently, my UILabel is truncated tail and the word "duration" is not complete
self.nameLabel.lineBreakMode = NSLineBreakByTruncatingTail;
What I want is I want my UILabel still truncating tail and only display complete word.
Like the image below
Any help or suggestion would be great appreciated.
You can do something like this:
let labelWidth = CGRectGetWidth(label.bounds)
let str = "You will have 30 seconds till you give us a good impression" as NSString
let words = str.componentsSeparatedByString(" ")
var newStr = "" as NSString
for word in words{
let statement = "\(newStr) \(word) ..." as NSString
let size = statement.sizeWithAttributes([NSFontAttributeName:label.font])
if size.width < labelWidth {
newStr = "\(newStr) \(word)"
}
else{
break
}
}
newStr = newStr.stringByAppendingString(" ...")
self.label.text = newStr as String
Idea is: we split words and try check the width while appending from the beginning + the string "..." till we found the a word that will exceed the size, in the case we stop and use this new string
Ideally this is not possible,with default UILabel, when you set lineBreakMode to TruncatingTail, depending on the space required by the letter/word the OS will truncate it, one solution to fix the issue you can use following properties depending on your match.
Minimum Font Scale -- Use this property to specify the smallest multiplier for the current font size that yields an acceptable font size to use when displaying the label’s text. If you specify a value of 0 for this property, the current font size is used as the smallest font size.
Minimum Font Size -- When drawing text that might not fit within the bounding rectangle of the label, you can use this property to prevent the receiver from reducing the font size to the point where it is no longer legible.
i am not sure but try it:
nameLabel.adjustsFontSizeToFitWidth = NO;
nameLabel.lineBreakMode = NSLineBreakByWordWrapping;
OR
If you are using storyboard follow these steps i tried this and it working fine
Open Attribute Inspector
Change Line Breaks to Truncate Tail then
Change AutoShrink to Minimum Font Size
here are my screenshots of label after and before applying these properties
new output

How to set UITextField width constraint to have room for a certain string

I have a UITextField that will display floating point values between 0 and 1.0 with 3 digits after the decimal point. So the widest text it will show is something like "0.000". I'd like to set the auto layout width constraint so that the text field always has just enough room to display this value.
The code below is close, but does not work.
let biggestString = "0.000"
let textAttrs = [NSAttributedStringKey.font: myField.font]
let size = (biggestString as NSString).size(withAttributes: textAttrs)
myField.widthAnchor.constraint(equalToConstant: size.width).isActive = true
It ends up displaying "1.0..." I'm guessing this is because a UITextField has some kind of padding around the text, so so I need to set the width to be the string width + the padding. But, I don't see a property from which I can read this padding amount. Is there a way to get it?
Try searching for the 'intrinsicContentSize'. According to the documentation this is what has to be set to indicate to the auto-layout how big the content is.
There was also a more elaborate discussion on how this can actually if the layout settings do not allow the resizing to work, see other question here:
How to increase width of textfield according to typed text?

Dynamically center 2 lines of text programmatically with roughly equal length per row

My situation is that I have a line of text that can vary in length due to localization. This will need to be displayed on the screen such that each line is roughly of equal length, and is centered.
This is my very long line.
Should look like this
This is my
very long line.
So I took a crack at this and got something that works the way I want it now.
I take a localized string, set it to an empty label, and find out what it's size is. (The orange is just for illustrative purposes)
With the size of the label, I then divide it by 1.8 which gives me some buffer room to account for inconsistent word sizes (again, I don't know what will be here in advance). Finally, I multiply the height by 2.0, and set that as my new frame. Finally, I add it to the view.
This has held up with a few sample strings, though it would need to be revised to handle more than 2 lines (currently, not an issue).
let text = NSLocalizedString("This is my very long line of text.", comment: "")
let instructionLabel = UILabel()
instructionLabel.text = text
instructionLabel.textAlignment = .center
instructionLabel.backgroundColor = .orange
instructionLabel.numberOfLines = 0
let size = instructionLabel.intrinsicContentSize
let newSize = CGSize(width: size.width / 1.8, height: size.height * 2.0)
let rect = CGRect(x: 20, y: 100, width: newSize.width, height: newSize.height)
instructionLabel.frame = rect
view.addSubview(instructionLabel)
Which produces the following output:
And an even longer one:
Just for some variety, this is the second string above, but in Arabic:
You could do this to set alignment.
myLabel.textAlignment = .center
Also set the number of lines to 0. And if you want a specific width, set the preferredMaxLayoutWidth property like so:
myLabel.preferredMaxLayoutWidth = 80
myLabel.numberOfLines = 0
If you want it to work for arbitrary localizations (assuming languages that use spaces), you would need an algorithm that split the text on spaces and then loop through each combination of top and bottom text, measuring its width, to see what gave the most evenly distributed sizing. This feels like overkill.
Having done a fair amount of localization, the better bet is to manually insert \n characters in the .strings file to adjust breaks that aren't visually pleasing. Relying on a fixed width will work for many languages, but won't give you the flexibility you're looking for.

How to make multi-line UILabel text fit within predefined width without wrapping mid-word

I have a UILabel carefully laid out in Interface Builder with proper height and width constraints. The number of lines is set to 4. The wrapping is set to word wrap. The text is "CHECKED". The font size is very large and thus it only fits "CHECKE" and the "D" is on the second line. Writing "Checked" instead of "CHECKED" lets the font shrink (as intended) so that the whole word fits. But (the text is user given and it can be expected that the user writes fully uppercase words) having uppercase words the label does not break it/shrink the font as expected.
Do you have a suggestion as to what I might have missed? Capitalising the words (thusly only having the first letter uppercase) does work, but is not what the client wants.
Updated question
The problem seems to be unrelated to having uppercase or lowercase text. My problem could be solved by an answer to the following question:
How to make (ideally with the help of only Interface Builder) the UILabel text shrink trying to fit full words within all available lines without wrapping the text mid-word?
If the text "CHECKED" is too wide for a label (with more than 1 line available) it should shrink the font size instead of breaking the "D" and wrapping the single letter to the next line.
If the text is "one CHECKED two" and the single word "CHECKED" is already too wide for a label (with more than 1 line available) it should break between all words and shrinking the font size so that "CHECKED" still fits the middle line.
Avoiding:
one
CHECKE
D two
Thank you very much!
Here is a UILabel subclass that will find the largest word in the labels text, use the boundingRect function of NSString to see how large that one word will be with the current font, and drop the font size until it fits the width.
class AutosizingMultilineLabel: UILabel {
override func layoutSubviews() {
super.layoutSubviews()
self.adjustFontToFitWidth()
}
func adjustFontToFitWidth() {
guard let currentFont = self.font else { return }
let minimumFontSize: CGFloat = floor(self.minimumScaleFactor * currentFont.pointSize)
var newFontSize = currentFont.pointSize
var theNewFont = currentFont
if let text = self.text, let longestWord = text.components(separatedBy: " ").max(by: {$1.count > $0.count})?.replacingOccurrences(of: "\n", with: "") {
let nsString = longestWord as NSString
while newFontSize > minimumFontSize {
theNewFont = currentFont.withSize(newFontSize)
let boundingRect = nsString.boundingRect(with: CGSize(width: CGFloat.greatestFiniteMagnitude, height: CGFloat.greatestFiniteMagnitude),
options: NSStringDrawingOptions.usesLineFragmentOrigin,
attributes: [.font: theNewFont],
context: nil)
if ceil(boundingRect.size.width) <= self.bounds.size.width {
break
}
newFontSize -= 1
}
self.font = theNewFont
}
}
}
When the word is bigger than the line, word wrap doesn't work. If it doesn't fit on this line, it won't fit on the next line. (same word, same size, same line size). To make it fit, the label will start putting letters on the next line.
If you allow multiple lines on your label, the OS will try to fill the lines before adjusting the font size.
I think you're just running into a limitation on Autoshrink.
In Interface Builder:
add a new UILabel with Width: 230 and Height: 280
set the Font to System 44.0
set Line Break: Truncate Tail
set Autoshrink: Minimum Font Scale at 0.15
set the text of the label to test CHECKED lines
Now, drag the handle on the right edge of the label left and right... when it gets too narrow, the word CHECKED will break onto the next line.
Change CHECKED to checked and do the same thing. You should see the same behavior.
Now, try dragging the Bottom edge up and down. With either CHECKED or checked, you should see the Font Size auto shrink.
So... to do what you're trying to do, you might have to skip Autoshrink and instead do some code calculations.
Edit: further visual of what goes on...
Start with above values, but set the Height of the label to 170 - gives it just a little vertical padding.
Now, drag the left edge to make it narrower.
When you reach the end of the word CHECKED, and keep going, you will see the font shrink until it gets small enough that there is space for it to wrap to a 4th line.
I think you're going to need some code to get exactly what you need.

UILabel truncate tail and skip not complete word

I have a single line UILabel. It has width = screen width and the content now is (the content of UILabel can change)
You have 30 seconds to make an impression during an interview
Currently, my UILabel is truncated tail and the word "duration" is not complete
self.nameLabel.lineBreakMode = NSLineBreakByTruncatingTail;
What I want is I want my UILabel still truncating tail and only display complete word.
Like the image below
Any help or suggestion would be great appreciated.
You can do something like this:
let labelWidth = CGRectGetWidth(label.bounds)
let str = "You will have 30 seconds till you give us a good impression" as NSString
let words = str.componentsSeparatedByString(" ")
var newStr = "" as NSString
for word in words{
let statement = "\(newStr) \(word) ..." as NSString
let size = statement.sizeWithAttributes([NSFontAttributeName:label.font])
if size.width < labelWidth {
newStr = "\(newStr) \(word)"
}
else{
break
}
}
newStr = newStr.stringByAppendingString(" ...")
self.label.text = newStr as String
Idea is: we split words and try check the width while appending from the beginning + the string "..." till we found the a word that will exceed the size, in the case we stop and use this new string
Ideally this is not possible,with default UILabel, when you set lineBreakMode to TruncatingTail, depending on the space required by the letter/word the OS will truncate it, one solution to fix the issue you can use following properties depending on your match.
Minimum Font Scale -- Use this property to specify the smallest multiplier for the current font size that yields an acceptable font size to use when displaying the label’s text. If you specify a value of 0 for this property, the current font size is used as the smallest font size.
Minimum Font Size -- When drawing text that might not fit within the bounding rectangle of the label, you can use this property to prevent the receiver from reducing the font size to the point where it is no longer legible.
i am not sure but try it:
nameLabel.adjustsFontSizeToFitWidth = NO;
nameLabel.lineBreakMode = NSLineBreakByWordWrapping;
OR
If you are using storyboard follow these steps i tried this and it working fine
Open Attribute Inspector
Change Line Breaks to Truncate Tail then
Change AutoShrink to Minimum Font Size
here are my screenshots of label after and before applying these properties
new output

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