What's the reason of "b" being larger in height than capital "P"?

Question

I have a simple WinForm with a Label (text: tabPage).

In 100% scale:

However when I move the form to a 250% display:

As you can see, "P" is smaller in height than "b".

• Font is standard Windows11 font: Segoe UI 9pt
• Form is set to Dpi in its AutoScaleMode
• CSProj has PerMonitorV2 option defined
• .NET SDK 7
• VS2022
• 2 displays (100%, 250%)
• Start on 100%, move to 250%

What's the sense behind this kind of scaling these letters?

Answer 1

It is fairly common for fonts to be designed visually so the lowercase letters are taller than the capitalized letters. This is a design choice for visual effect. So the b is always supposed to be larger if you have the resolution to accomplish that (e.g. 600 DPI laser printer).

At 100% your letters are 9 pixels high. So if the b scales to 9.1 pixels and the P scales to 8.9 pixels they both have to be displayed at 9 pixels. At 250% 9.1 becomes 22.75 and 8.9 becomes 22.25 so the b becomes 23 pixels and the P is 22 pixels.

Note the numbers are just hypothetical examples, I don't have the exact values.

This link outlines the reasons for the lowercase being larger - Quora Answer.