Drawing text with Core Graphics

Oct 24, 2025

About

I've learned to draw text with SwiftUI's Text view.

I've learned to draw text using AppKit and TextKit.

I've also learned to draw text using CoreText.

Is it time to learn to draw text using Core Graphics? Yes.

Code

I'll just dump the code here for posterity and go walk the dog now.

import CoreText
import SwiftUI

class FoobarView: NSView {
    override func draw(_ dirtyRect: NSRect) {
        let font = CTFont(.system, size: 12, language: nil)
        let helloworld = Array("foo".utf16)
        var glyphs = [CGGlyph](repeating: 0, count: helloworld.count)
        let success = CTFontGetGlyphsForCharacters(
            font,
            helloworld,
            &glyphs,
            helloworld.count
        )

        if let context = NSGraphicsContext.current?.cgContext, success {
            // XXX: On the CGFont, it says that the context won't draw unless this is called.
            // XXX: https://developer.apple.com/documentation/coregraphics/cgfont/init(_:)-1p4b#Discussion
            // XXX: It doesn't mention that setFontSize also needs to be called though.
            let font = CTFontCopyGraphicsFont(font, nil)
            context.setFont(font)
            context.setFontSize(12)
            context.showGlyphs(
                glyphs,
                at: [
                    CGPoint(x: 0, y: 0),
                    CGPoint(x: 8, y: 0),
                    CGPoint(x: 16, y: 0),
                ]
            )
        }
    }
}

struct FoobarRepresentableView: NSViewRepresentable {
    func makeNSView(context: Context) -> some NSView {
        FoobarView()
    }

    func updateNSView(_ nsView: NSViewType, context: Context) {}
}
struct ContentView: View {
    var body: some View {
        FoobarRepresentableView()
            .padding()
    }
}

#Preview {
    ContentView()
}