I would like to align the start of the text of two UILabels. I aligned the two UILabels (with the yellow and grey background) and used sizeToFit: to shrink the UILabels to the content but the text is not perfectly left aligned. There is a gap on the left. The gap is bigger or smaller depending on the first character. I would like to align the red lines in the following picture. There is even a small gap with the small font in the grey UILabel but it's barely visible.
With the Z character the gap is smaller but still visible by the yellow area left to the Z
A simple UILabel alignment does not help for my specific problem, because the text content is dynamic and not static. So there could be any combination depending on the data I get from the backend. Therefore I was hoping for a UIFont or UILabel attribute that could return the size of the gap based on the current rendering of the text.
I know that there are great UIFont related attributes like baseline, capHeight and ascender one can access to align text but there seems to be no attribute that would return the value of this gap on the left.
If this doesn’t need to be two UILabels, you could have one with attributed text. Then both lines would be subject to the same layout.
I haven't tried the GUI which people have been posting Screen Shots of, however... the behaviour is consistent with the very nature of typography.
The font sizes are completely different, therefore the width of an em is different, subsequently the letter-spacing is also different.
See this: http://www.w3.org/WAI/GL/css2em.htm for more information.
I know this answer doesn't give you what you have asked for, however it should explain why this is happening.
For customisation such as this (if HTML and CSS) I would use a negative / positive margin on the sub text, however seeing as you are using backgrounds use padding (or the equivalent in your GUI).
Use attributed text of UILabel
set indentation as per your requirement
ref screen shot
Select both the labels and add a constraint called align leading edges.
Related
please see the image below for two examples of what is to be achived
the alignment should be on the Center Y of the first lines of each UILabels and should work regardless of font size or font. currently we have implemented this with different constraints to the top of the super view for different font and font size combinations.
the constraint to align the center of the two UILabels does not work since the text of the second UILabel is not fixed and can have several lines.
also the text is dynamic, so it is not known where the text will wrap to create the first line, thus it cannot be shown in an one line UILabel with the rest of the text in another one below.
currently this is implemented using UIKit, but if there is an easy solution in SwiftUI we can put these two labels in a SwiftUI component. so a SwiftUI solution would also be welcomed.
Your comments said "it should be on the glyphs" ... but, without additional information, my guess is that "real world" usage would not really need that level of precision.
For example:
While the glyphs are not perfectly center-Y aligned, it seems unlikely you'd run into a case where the first line of the "rightLabel" is " ' " ' " or . , . , ..
This layout can be easily done with only a few constraints - no need to do any calculations:
The "Positioning" label would, of course, be set .hidden = true so it would never be seen.
If you really, really want glyph-precision, you'll need to calculate
the Glyph bounding box for the left-label
the Glyph bounding box for first line of the right-label
calculate the "character box" offsets to align the Glyph Y-centers
and then position the two labels accordingly, or use Core Text to draw the text (instead of using UILabel).
Probably more work than necessary -- unless your actual use-case demands it.
That's an interesting problem! You can try using the centerYAnchor for the label on the left, and the firstBaselineAnchor for the label on the right... that will align the center Y with the text baseline, which isn't quite what you want.
To find the correct offset to apply, you can use the information from UIFont about the size of the characters. I'd probably start with capHeight * 0.5 and see if that looks or feels right. Something like:
leftLabel.centerYAnchor.constraint(equalTo: rightLabel.firstBaseLineAnchor, constant: rightFont.capHeight * 0.5)
This is a more difficult problem in SwiftUI, I think, because resolved font metrics aren't directly available to you.
When using Auto Layout to position a label, I always get very imprecise results. In the example below, I have aligned the top and left edges of a UILabel to a parent UIView:
There is empty space on all four sides of the text, but the amount of empty space at the top and bottom is especially horrible. It is very tedious to take screenshots and figure out how many points I would need to offset the constraint's constant value to make the text line up properly. Is there any way to for the UILabel to properly reflect the rendered text in its frame?
I have a multiline UILabel that I'd like to look similar on different devices (iPhone only). If it was a single line, I'd simply place the auto layout constraints and enable Autoshrink and set the Minimum Font Scale.
The height of the label is dynamic is calculated based on text. To do that, I need the font, which should also be dynamic. The hack I could do is place an invisible label, and set the text I want to fit in a single line into it and calculate the font, but it seems too hacky.
Another thing I'm not that familiar with are size classes. But from what I've read, the same class is shared between all portraits, meaning 3.5, 4, 4.7 and 5.5 inch devices would be bound to the same class, therefore I couldn't use the separate font value?
How would I implement the 'font scaling' for multiline labels so I'm getting similar look on different screen sizes?
If by similar look you mean that the same words appear on each line, I don't think it's possible.
If the label height is dynamic based on the amount of text, the label will simply expand to the height required to show the text with the specified font size.
Font scaling only kicks in when there is not enough space to display the text with the specified font size. Therefore, you must constrain the height or number of lines.
I was able to approximate this using a multiline UILabel with font scale of .5. I set an Equal Heights constraint between it and its superview, with a multiplier of .25. See screenshots below.
In this approach, you would have to dynamically change the Equal Heights multiplier based on the amount of text you have.
In an iOS app I need to use a specific font but each character needs to be taller, thinner, and the spacing closed up to fit correctly. Is it possible to stretch/squish a font programmatically?
When you're adding text to a PDF file there are multiple ways to influence how the text is going to appear. The most generic way (and the way that might actually be sufficient for you) is to scale the text matrix:
void CGContextSetTextMatrix ( CGContextRef c, CGAffineTransform t );
As mentioned in the comment by #mkl, you can provide a matrix that will scale up in the Y direction while scaling down in the X direction. The effect will be that the letters are stretched out vertically and squished horizontally.
Normally I would expect you don't have to touch the spacing in that case, as spacing will be "squished" together just as the other characters.
Just in case that isn't sufficient, PDF actually does provide a way to change the spacing between characters too:
void CGContextSetCharacterSpacing ( CGContextRef context, CGFloat spacing );
While Apple's description talks about "additional space" to add between characters, the PDF specification and I suspect Apple's implementation as a result allows the spacing value to be both positive and negative. A negative value would have the effect of moving the characters closer together.
Seems like the best option would be to create your own custom font.
You are able to change the kerning of your font (the space between the letters) and the thickness/thinness of the font, however you probably aren't able to edit the height of the font, unless you edit the bounding box the font is inside of to scale the letters differently.
You might also want to consider using a different font...or if you're REALLY hardcore you can edit the font yourself using photoshop/illustrator.
I am using a custom .ttf font called Classic Robot in my iOS app. I am trying to add Japanese translation and this font appears to not support Japanese characters. This is not a problem initially because it appears iOS automatically changes the font to the system default font which can support Japanese.
My issue is that these two fonts have different vertical alignment when rendered by iOS as in the below pictures. As you can see, the Japanese font is aligned near the top of the white box (which is the frame) whereas the English font sits somewhere near the middle. This makes it difficult for me to layout text properly. Does anyone know why this might be the case?
I believe it might have to do with the ascender and descender properties on the iOS font I cannot be certain.
Your question is: "Does anyone know why this might be the case?"
The answer is that the ascender property of the Japanese font is smaller than the Classic Robot one. This can be fixed by generating a custom Japanese font that has an ascender property large enough to make it match the spacing you get from the other font. This can be done by downloading the Apple Font Tool Suite and following the instructions posted in this answer.
Also for buttons you can solve the issue by increasing the insets:
myButton.contentEdgeInsets = UIEdgeInsetsMake(15.0, 0.0, 0.0, 0.0);
You can specify a different value for each of the four insets (top, left, bottom, right). A positive value shrinks, or insets, that edge—moving it closer to the center of the button. A negative value expands, or outsets, that edge. This works for the button image and button title.