I have seen here people needing to calculate the size of the NSString given a size but I need to do the opposite.
Given a specified rect (or fixed UITextView, or multiline UILabel, no scrolling) I need to know:
if it managed to show all the chars of my NSString
if not, what is the last char shown
So that I can display the remaining text in another UITextView (of course if I could use a single UITextView I would not have this problem).
At first it seems a simple thing to do, but actually I am not finding a way, intuitively I think I could use either UITextView's:
textView.contentSize.height;
or NSString's:
sizeWithFont:constrainedToSize:lineBreakMode:
or a combination of the two, but I need to be precise and those methods do not help me in telling what is the last character that managed to fit the visible area of the UITextView.
Not sure if this is actually possible, but is a requirement of my client who thinks programming iOS is like printing a newspaper and expects to be able to format text around an image....
You could maybe get the maximum height of one line of text from a one character long string.
If you use that with sizeWithFont:constrainedToSize:lineBreakMode: then you should be able to know if your text runs onto more than one line (if the cgsize height is greater than the height of one line of text).
In order to find out the last character (or word) you would have to loop around the length of the string adding characters (or words) as you go and checking for when the cgsize height increases to add a new line, this will give you the character point when to split into multiple strings ( for multiple fields/labels/textviews ) or when to insert line breaks into the text ( if using a single multi-line textview or label ).
I hope you find an easier way...
Related
For a UILabel of certain width, with certain font and font size, i want to calculate amount of characters that would make 7 lines worth of text inside it + ... (three dots showing continuation). Is there a fancier way to achieve this? Currently what i'm trying is counting up to X amount of characters or 7 new line characters, which ever comes first and i cut on the text right there.
More Detail:
Trying to make an expandable row Cell which contains the UILabel, i'm achieving this with auto layout... So to control the cell expansion, i change the text to be full text or a substring of that, with a button below which toggles between the string vs substring. All of that is working. The problem i'm getting is my method of finding the substring isnt very neat. Its not consistent on how it handles text of different combination of characters or newlines. I get variations of how it looks and sometimes it just ends with three dots on a new line rather than finishing on the 7th line.
Even using auto layout you can still use the lines property of UILabel to limit the number of lines displayed by the label.
So set it 7 and you'll get 7 or less rows. Just assign the complete text.
I am trying to draw an NSAttributedString (actually, a constructed NSMutableAttributedString) where the "original" text has been struck and replacement text inserted above it (I'm trying to replicate the look/feel of an Ancient Greek manuscript).
My technique is a combination of NSBaselineOffsetAttributeName with NSKernAttributeName, but it appears that using a negative value for NSKernAttributeName "wipes away" the strikethrough of the text, even if the characters don't overlap.
If I put an extra space after the "A" character (in the original text), the "A" gets the strikethrough, but the "EI" is also offset to the right. So, it appears that the offset/kerning of the "EI" text affects how much of the strikethrough actually occurs.
Here's what I'd like to reproduce (I don't care about the angle; it's not about a picture-perfect reproduction; just the gist):
Here's what is currently happening:
This is when I add an extra space after the strikethrough:
So, the only other thing I can think of would be to render a separate NSAttributedString in the correct place, separate from the current one, but I have no idea how to calculate the location of a specific character in an NSAttributedString when it's drawn. I'm drawing to a PDF, not to any on-screen control like a UILabel. Alternatively, I could draw the "strikethrough" myself as a line, but that seems to still require knowing the coordinates for the text in question, which is calculated on-the-fly, and I hope to use this method to reproduce a large sample of ancient texts, which means doing it by hand just isn't a good answer here.
Anything I'm missing, or any out-of-the-box ideas to try?
For example, I have the following two string: "How Munched is That Birdie in the Window?" and "S22 - E7". I want to present in the label the following: "How Munched is That Birdie in ... S22 - E7" If the string is too large according to the label's size and doesn't fit it". How you can see, the three dots are placed always in the first string, the second string is always shown full.
How can I achieve this?
Here is how to do it.
yourlabel.adjustsFontSizeToFitWidth = false
yourlabel.lineBreakMode = .byTruncatingMiddle
You can set the UILabel's ParagraphStyle LineBreakMode to byTruncatingMiddle, which will probably work in most cases with carefully planned label size. From the docs:
The line is displayed so that the beginning and end fit in the container and the missing text in the middle is indicated by an ellipsis glyph. This mode is used for single-line layout
If you want to guarantee none of the "S22 - E7" string is truncated, you would have more control using two labels and setting layout constraints such that the width of the protected label is preserved so that it can display the full string whenever possible, but that is probably overkill in most cases.
You may also find this answer helpful if decide to go a different route by manually manipulating the displayed string based on detecting how many characters will be visible given the width and font.
A multiline auto typing text box class (which uses an SKNode as the parent) is created using basically 2 elements:
an SKSpriteNode that acts as text box frame & background image/texture holder.
an NSMutableArray containing a set limited amount (rows) of NSStrings that each have a set character length.
After modifying this text box class so that it can be initialized with any frame width & height, I realized I didn't program the NSMutableArray to automatically change its content in a such way that it nicely fits within the background node (with a bit of padding involved as well). So here I am wondering how to do that since NSString's can only return the character count and not the width & height of each string in points (points could have maybe helped me create character constraints in some way).
Right now, the NSMutableArray uses a hardcoded maximum character count per NSString & a maximum row count for the entire array (it's 5 rows right now and when that limit is reached, a new "page"/array is created). This forces me to manually re-adjust these parameters every time I change the background node frame size which defeats the purpose of the class allowing the background frame to change.
Thing is, I'm trying to solve this in such a way that when I post this class on github, I want the solution to take into consideration any fontName & fontSize.
What are my options for solving this problem?
I've done something similar to this. It doesn't work 100% as to what you want, but should be similar enough. It uses a root node and from there, it will build multi-line text using an array of NSString which will in turn be used to build the SKLabelNode.
I'll outline what I did. I should also say I only run this when new text is set. In other words, I do not incur the penalty of deriving the information every frame. Only once.
The generalized steps are:
You will iterate over each character in the text string. Note I do this because my code supports word wrapping as well as other alignment capabilities. So for me, I want that level of control. As this is being done only upon creation, I'm fine with the overhead. If you don't want to word wrap you could always just create an array of words and work from there.
As you iterate over each character, you'll be generating an array of lines. Where each line in the array is a line that will fit in your frame. For now let's not worry about vertical constraints. So here we are primarily worried about width. For the current line, each character you are iterating over will get added to the current line. For this potential line string, you will use NSString's sizeWithAttributes, which is configured for your font. For example in my code it is an NSDictionary which contains: NSFontAttributeName : [UIFont fontWithName:self.fontName size:self.size]. This will be used to check the width, if that width exceeds the frame width, you are overrunning the line.
So the code may look something like:
size = [line sizeWithAttributes:attributes];
if (size.width > maxTextWidth) {
needNewline = YES;
}
If you have overrun a line, you need to determine if you are word wrapping. If you are, you can just add the current line (minus one character) to the lines array. If not you have prune off the last word in the current line and then add that to the array of lines.
The tricky parts are dealing with whitespace and handling non-word wrapped overflow. I have not addressed whitespace but you need to consider this very much in your code. Additionally, you also do want to factor in leading pixels, etc.
Once you have your array of lines, you can then create your children SKLabelNodes. I add them to the root, which allows me to move the group anywhere it needs to be.
The real key here is the lines array generation.
I have a font where unfortunately the numbers and letters are different heights. I need to display a reference code which is a mix of letters and numbers and the uneven heights of the characters looks jarring. Is it possible with core text (or another technology on iOS) to render certain characters with a slightly stretched height so that it looks even numbers and letters are displayed together.
E.g i have the string '23Rt59RQ' I need the 2,3,5,9 to be rendered with a larger height.
AFAICT, there's nothing in the CGContext API (which is what you'd want to use for laying out sets of glyphs) which would directly, easily facilitate this.
If it's really very important to use the font you are using, you could make separate calls to CGContextShowGlyphsAtPositions for alphabetic and numeral characters, calling CGContextSetFontSize each time so that the end result ends up matching, but this is a lot of overhead for just drawing text, and will probably result in undesirable performance.
My real advice would be to pick a better font so that this isn't even an issue :)
In the end of used regex to identify the character groups and then created an attributed string varying the font size in the font given in the NSFontAttributeName attribute according to which characters were to be displayed.
Kinda hacky but it had the desired effect.