I have about 400 character length string with a heading called Details. In this 'Details' is to be bold and of fontsize 19. While all the remaining text starts in the next line and should be of fontSize 18 like the contents. How can I do all this by using a UILabel?
Plz help me...
You can't do it with a stock UILabel as of SDK 3.2. You can create an NSAttributedString that specifies particular styles (like bold) for particular parts of the string, but there isn't a simple way to actually render it. This is unlike In Max OS X, which has NSAttributedString(AppKitAdditions), which allows you to draw an attributed string in a single line of code. If you want to render it, you can, but you'll have to delve into one of the lower level APIs (such as Core Text).
You're probably much better off using two UILabels. Make the first one bold, and make the second one cover multiple lines.
Since UILabel does not support attributed strings, you have two options:
Subclass UILabel and override -drawRect:
Create 2 UILabels, one of which will display the heading, the other showing the rest of your text. You can choose to wrap the two labels into your own view if necessary.
You could use a UIWebView with an HTMLString of <strong>First part</strong> second part
Related
I'm developing an apple watch app - it consists of two tables that contain labels.
These labels have two lines of text, I want the second line of text to have a different font style to the top line
How can I do this in swift?
Thanks everyone
The easiest way to do this would be to create two labels in your storyboard, each with their own font style. Then, use setText to set the first and second lines.
Unfortunately, WKInterfaceLabel doesn't provide any typesetting metrics, so there's no built-in method to determine where a line-break occurs. If you need to determine where a line-break occurs, you'll likely have to perform your own typesetting in the Watch extension, then choose to set two different labels or a single label with an NSAttributedString.
I'm trying to solve a hairy problem with UILabel, and I've gotten most of it figured out, except for one thing: I'm having a challenge understanding what it means for a CTLine to have "string access".
The method that I'd like to use is CTLineGetOffsetForStringIndex. Here's a link to the documentation for the method.
Here's the part of the documentation that I don't understand (emphasis is mine):
The primary offset along the baseline for charIndex, or 0.0 if the
line does not support string access.
When I'm running this method, I'm getting 0.0 back, so I guess that means the line doesn't support string access - but what does that mean, exactly?
The statement "the line does not support string access" may be inferred as meaning that the line of text may not be treated as a sequence of characters that may be accessed by the index of each character.
This may open up a large discussion about visual characters versus non-visual characters, and glyphs versus characters. But to simplify the discussion, assume that a line of text may have one of the following states:
more than zero characters (characters which translate to either glyphs or whitespace within the same line) are present in the line of text in question
there are no characters in the line of text which occupy any "space"
Now to provide some rationale for this inference.
Apple's documentation provides a description of Text Kit, upon which UILabel is built:
The UIKit framework includes several classes whose purpose is to display text in an app’s user interface: UITextView, UITextField, and UILabel, as described in Displaying Text Content in iOS. Text views, created from the UITextView class, are meant to display large amounts of text. Underlying UITextView is a powerful layout engine called Text Kit. If you need to customize the layout process or you need to intervene in that behavior, you can use Text Kit. For smaller amounts of text and special needs requiring custom solutions, you can use alternative, lower-level technologies, as described in Lower Level Text-Handling Technologies.
Text Kit is a set of classes and protocols in the UIKit framework providing high-quality typographical services that enable apps to store, lay out, and display text with all the characteristics of fine typesetting, such as kerning, ligatures, line breaking, and justification. Text Kit is built on top of Core Text, so it provides the same speed and power. UITextView is fully integrated with Text Kit; it provides editing and display capabilities that enable users to input text, specify formatting attributes, and view the results. The other Text Kit classes provide text storage and layout capabilities. Figure 8-1 shows the position of Text Kit among other iOS text and graphics frameworks.
Figure 8-1 Text Kit Framework Position
Text Kit gives you complete control over text rendering in user interface elements. In addition to UITextView, UITextField and UILabel are built on top of Text Kit, and it seamlessly integrates with animations, UICollectionView and UITableView. Text Kit is designed with a fully extensible object-oriented architecture that supports subclassing, delegation, and a thorough set of notifications enabling deep customization.
The answer to the related question mentions several classes such as NSTextStorage, NSLayoutManager, and NSTextContainer.
Consider that the UILabel uses all the above classes to provide the end result of displaying text in the parent UIView, which the end user sees on the screen. A layout manager (an instance of NSLayoutManager) coordinates data flow between the text view, the text container, and the text storage, resulting in the display of characters in the view. The layout manager maps the characters to glyphs, and figures out which lines to use to lay out the glyphs. The layout manager also figures out how to display things like underline and strikethrough, which are not part of the glyphs.
Important to this discussion is the fact that the Layout Manager lays out lines of text. If that line of text is selectable, the user may select visible characters in the line. In this particular case, there is "string access" for the line.
A similar concept is the method posted in the solution to related question:
func boundingRect(forGlyphRange glyphRange: NSRange, in container: NSTextContainer) -> CGRect
Returns a single bounding rectangle (in container coordinates) enclosing all glyphs and other marks drawn in the given text container for the given glyph range, including glyphs that draw outside their line fragment rectangles and text attributes such as underlining.
Finally, the reference discussion for the function CTLineGetOffsetForStringIndex speaks about graphical offsets which are suitable for drawing custom carets. The carets may be used to show insertion points or text selection. The primary and secondary offsets may be thought of as beginning and end indices for a string -- a sequence of characters. If there is no sequence of characters for a given line, there can be no selected characters, no carets, no range of glyphs. Therefore no "string access".
I have a requirement to display a somewhat large amount of text, read only to the user. It can be up to a maximum of 500 characters, which isn't excessive, but it's still a lot. Since it's read only I was thinking of a label a versus text area box, if it can handle that much. Is there a better way to do this than I'm not aware of?
Thanks,
James
Label works fine. Just remember that the default css for white-space collapses whitespace rather aggressively. If your text includes line breaks you may want to switch to pre or pre-wrap.
The most straightforward (if not necessarily most correct) way to do that is:
Label myLabel = new Label();
myLabel.getElement().getStyle().setProperty("whiteSpace", "pre");
Note the Camel Case on the CSS attribute.
Either a Label or a TextBox will definitely be able to handle 500 characters.
Think of all the blog posts, Wikipedia articles, Stack Overflow questions, longer than that that have been written. They were all composed in a text box and displayed in a div. You'll be fine.
500 chars is no big deal so it will be ok. Label is ultimately calling element.innerHTML = text which is a browser-native Javacript function that can handle any amount of text.
I'm trying to set up a CTFrame that exactly matches my UITextView's text format in iPad.
First of all, I converted UITextView's text to an attributed string. Then I set up a width and a height of drawing box in which Core Text will draw text.
I succeeded to draw text using Core Text, but UITextView and Core Text show slightly different results even though I used the same font and size.
Specifically, when I used [UIFont systemFontOfSize:21], each space in UITextView has one more pixel than Core Text's result.
It's okay for a short sentence or word, but if UITextView and Core Text have multiple lines, their result become very different. For example, UITextView performs word-wrapping for one word at the end of line, while Core Text keeps that word in the same line. If you see the attached picture, the start positions of the last word "paragraph" are already very different (8 pixel gap due to 8 space characters).
More badly, if I use different fonts such as a custom font added to my project, each character in UITextView has 1 pixel more.
I'm using Core Text to find the pixel-position of the current cursor in UITextView, so both of them should perfectly match each other, containing the same number of characters and words in each line.
Question: Is there a way to make Core Text object that perfectly matches UITextView's text format?
Thank you!
Here's a code how I set up attributed string. (I just followed Core Text Guide.)
CTFontRef font = CTFontCreateWithName((CFStringRef) [UIFont systemFontOfSize:21.0].fontName, 21.0, NULL);
CFMutableAttributedStringRef attrString2 = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
CFAttributedStringReplaceString (attrString2, CFRangeMake(0, 0), (CFStringRef) string);
CFAttributedStringSetAttribute(attrString2, CFRangeMake(0, [string length]),kCTFontAttributeName, font);
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Here's a picture.
Your solution might work for a specific font at a specific point size, but you can't rely on it in general.
CoreText is simply not compatible with normal UILabels, UITextView:s or UIStringDrawing, so you can't mix them.
Either you have to use only CT functions for all string handling (including implementing custom input if that is what you need) or not use them at all.
Answer to myself.
I just found very simple solution! Using any font editor, you can just change the width of space character (ascii value 32); an original font for UITextView and a modified font for Core Text or vice versa. I used a freeware font editor FontForge. Though I still have to do some extreme-case tests such as writing Japanese characters and English alphabets in the same line and so on, now it becomes almost possible to find a pixel-position of a cursor/caret in UITextView.
Is it possible to get the first line of text from a UITextView. I have looked through the UITextView and NSString Class References and can't find any methods that could accomplish this.
The only way to accomplish this is through a process of iteration using the multi line text methods detailed in "NSString UIKit Additions Reference". Extract the first few words from your string and start compositing these gradually until the " sizeWithFont:constrainedToSize:lineBreakMode:" returns a size which height is higher than that of a line with just 1 word.