Font sizes spreadsheet about swash

[SamHFrancis]

Hi Chris, I don't think these size ramps are documented anywhere. I got them by running an app with the Accessibility Inspector and changing the text size settings. You can override traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) like the sample app does and print the values as you change the setting. Something like this, maybe with better formatting:

let defaultSizes: [UIFont.TextStyle: CGFloat] =
[.caption2: 11,
 .caption1: 12,
 .footnote: 13,
 .subheadline: 15,
 .callout: 16,
 .body: 17,
 .headline: 17,
 .title3: 20,
 .title2: 22,
 .title1: 28,
 .largeTitle: 34]

for (textStyle, defaultSize) in defaultSizes {
    let size = UIFontMetrics(forTextStyle: textStyle)
        .scaledValue(for: defaultSize)

    print(traitCollection.preferredContentSizeCategory, textStyle, size)
}

I made a spreadsheet for two text styles just for the blog post, but I don't have it on me right now. Also bear in mind that these values are subject to change with new versions of iOS.

[SamHFrancis]

Okay, I had some time so I made a table. I found that .scaledValue(for:) may return a decimal, while .scaledFont(for:) returns a font which always has a whole number for pointSize. Here are the values I got for iOS using the default sizes from the HIG. These would be different for watchOS and tvOS.

	Caption2	Caption1	Footnote	Subheadline	Callout	Body	Headline	Title3	Title2	Title1	Large Title
XS	11	10	12	12	14	15	15	18	19	26	32
S	11	10	12	14	14	15	15	18	20	26	32
M	11	10	12	14	15	16	16	19	20	27	33
L (Default)	11	12	13	15	16	17	17	20	22	28	34
XL	15	14	14	17	18	19	19	22	24	30	36
XXL	17	16	16	18	19	20	20	24	25	31	38
XXXL	19	17	17	20	21	22	22	26	27	34	40
AccessibilityM	21	20	21	23	24	26	26	30	32	38	43
AccessibilityL	25	24	24	27	30	31	31	35	37	42	47
AccessibilityXL	30	29	29	32	35	37	37	41	41	47	51
AccessibilityXXL	35	33	33	38	40	43	39	46	46	50	55
AccessibilityXXXL	41	38	38	44	46	48	48	52	52	56	58

[AccuPhoenix01]

Thanks Sam, I hadn't seen you made this. I pulled the values from Apple's website and made this:
iOSAccessibilityFontSizing.pdf

[SamHFrancis]

Oh, cool! That's a nice reference, thanks. It looks like the system font values in the HIG differ slightly from those produced by UIFontMetrics, so that's good to be aware of.