Calculate the size of text for draw in context(Core Graphics)? - swift

Question

I need to know the size of my text that I am going to draw in context. How we can find the size of created text inside context?
What I should put for sizeOfText?
this is my code:
let text = "Some test"
let locationOfText: CGPoint = .zero
let fontOFText: CGFloat = 30
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.alignment = .left
let attrib: [NSAttributedString.Key: Any] = [
.font: UIFont.boldSystemFont(ofSize: fontOFText),
.paragraphStyle: paragraphStyle]
let sizeOfComponent = labelSimulator(withThisFont: UIFont.boldSystemFont(ofSize: fontOFText), withThisText: text)
let sizeOfText = CGSize(width: sizeOfComponent.width, height: sizeOfComponent.height)
text.draw(in: CGRect(origin: locationOfText, size: sizeOfText), withAttributes: Attrib)
This part is my way to find the Size of text, do you know better way, hit me!
//█ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █
func labelSimulator(withThisFont: UIFont, withThisText: String) -> CGSize
{
//▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
let simulator = UILabel()
simulator.font = withThisFont
simulator.text = withThisText
//▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
//▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
return simulator.sizeThatFits(CGSize(width: CGFloat.greatestFiniteMagnitude, height: CGFloat.greatestFiniteMagnitude))
//▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
}
//█ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █

Answer 1

I have already shown to you how to calculate the height of your text on your last question. You just need to add a margin to it and move on. The width you choose will determine the final height:
let pdfFormat = UIGraphicsPDFRendererFormat()
let metaData: [CFString : Any] = [
kCGPDFContextTitle: "Hello, World!",
kCGPDFContextAuthor: "Omid",
kCGPDFContextCreator: "PDF Creator"]
pdfFormat.documentInfo = metaData as [String: Any]
// your PDF page size
let size: CGSize = .init(width: 8.5 * 72.0, height: 11 * 72.0)
let bounds: CGRect = .init(origin: .zero, size: size)
let pdfRenderer = UIGraphicsPDFRenderer(bounds: bounds, format: pdfFormat)
let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let data = pdfRenderer.pdfData { (context) in
context.beginPage()
let text = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum."
let fontOFText: CGFloat = 30
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.alignment = .left
let attrib: [NSAttributedString.Key: Any] = [
.font: UIFont.boldSystemFont(ofSize: fontOFText),
.paragraphStyle: paragraphStyle]
let margin: CGFloat = 20
let attributedText = NSAttributedString(string: text, attributes: attrib)
let textCanvas = bounds.insetBy(dx: margin, dy: 0).size
let textSize = attributedText.boundingRect(with: textCanvas,
options: [.usesFontLeading, .usesLineFragmentOrigin],
context: nil).size
let rect = CGRect(origin: .init(x: margin/2, y: 0), size: textSize)
text.draw(in: rect, withAttributes: attrib)
let nextTextYPosition = rect.origin.y + rect.size.height
print("nextTextYPosition", nextTextYPosition)
"NEXT TEXT".draw(in: .init(origin: .init(x: margin/2, y: nextTextYPosition), size: CGSize.init(width: 200, height: 200)), withAttributes: attrib)
}
let fileURL = documentDirectory.appendingPathComponent("test.pdf")
try data.write(to: fileURL)

Answer 2

For the specific situation you've described, the size you generally want is CGSize(width: .greatestFiniteMagnitude, height: .greatestFiniteMagnitude). Depending on the context you're drawing into, you may want to constrain the height. If you want it to wrap, then you can constrain the width.
The in: parameter here is a constraining box. It's the largest box allowed. It doesn't have to tightly match the text.
If you need the actual size (in order to put an outline around it for example), you can compute that using .boundingRect(with:options:attributes:context:).
(Noting your edit, you seem to have the right idea. You just don't need a label. You can ask the string directly.)
For example, based on your code, there's no need for labelSimulator:
let sizeOfText = CGSize(width: CGFloat.greatestFiniteMagnitude, height: .greatestFiniteMagnitude)
text.draw(in: CGRect(origin: locationOfText, size: sizeOfText), withAttributes: attrib)