Why does minimum font base size need to be smaller than maximum font base size?

[timcase]

There is a validation, "Min font size must be less than max font size", and I'm wondering why can't the base size be the same for both min and max. For example what if base font size for both is 16px where the containers have a different type scale value for min and max, in my case 1.125 and 1.2. Essentially I want to have the min and max container have the same base font size but different typescales and I'm seeing that it isn't possible due to the validation. I'm still learning responsive typography using clamp, and I'm unsure of what I'm doing that's why I'm asking.

Why can't min and max base font size be the same?

Thanks for your effort on this it's a very useful tool, and I'm grateful.

[AleksandrHovhannisyan]

Good question! The idea is that you generally want to scale all font sizes proportionally, rather than having one outlier font size (in this case, the base step) that's static and never changes. With that said, it looks like similar tools like utopia.fyi don't enforce any constraints. So maybe I should relax it a bit and allow the min and max font sizes to be equal. I'll think about this a bit more and get back to you.

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This also made me realize my validation isn't working correctly because it only errors in one direction (if you change the min font size relative to the max). If you set the max font size to be the same as the min, it doesn't error. Will look into that.

[saas786]

Although this is not directly related to font size but rather to the "Type scale ratio," the same logic applies.

Why enforce validation that requires one value to be smaller than the other?

For instance, if I want to use "1" as the scale factor for both Minimum (mobile) and Maximum (desktop), the current validation prevents me from doing so, even though it aligns with my intended scale.

A more flexible validation approach would be beneficial.

[AleksandrHovhannisyan]

@saas786 If you use a ratio of 1 for both the minimum and maximum steps, then all font sizes at all steps will be the same as the base step, which is the same as just having a single font size. That's if they're both 1. If the ratios are equal but not 1, you'd get a type scale, but the minimum and maximum of each step would be identical, which is the same as not using clamp/fluid sizes.

[saas786]

Here’s my usage example:

Fluid Type Scale Example

As you mentioned, I may be thinking about this incorrectly, and it might not work as expected.

However, using 0.9999 gives me exactly the intended size, so I assume that using 1 would generate the perfect size—or would it not work at all?

[AleksandrHovhannisyan]

@saas786 If you just need a single size step like in that example, the ratios won't matter, so you can use anything. You can verify this by changing the ratio inputs and observing that the output doesn't change. The ratios only come into play when you add more than one step in the type scale. They're how we determine the new min and max font sizes of each step above and below the base step.