title: how to convert font units (with certain font size) to pixels?
body: <p>i have a font.ttf which i need to calculate the value of its unit to pixels when using this font with certain font size lets say 100,</p>
  <p>as you see this is a gylph in some software for fonts editing, and the selected coordinates is presented in font units which are dynamic to how big is the font when using, Is there an equation to calculate the units in pixels when font is used with given size ?</p>
  <p><a href="https://i.stack.imgur.com/y0mWG.png" rel="nofollow noreferrer">example</a></p>