In the FreeType API, it defines the ascent and descent in the in the TT_HoriHeader table as follows:
Ascender: The font's ascender, i.e., the distance from the baseline to the top-most of all glyph points found in the font.
Descender: The font's descender, i.e., the distance from the baseline to the bottom-most of all glyph points found in the font. It is negative.
How does the rendering engine reconcile these values with the yMax and the yMin in the TT_Header table? It appears that the definitions for the ascent and descent are the same as what yMax and yMin are understood to mean. Is the rendering engine making the two sets the same?
Also, does the rendering engine ensure that the Units_Per_EM (UPM) is scaled to the point size specified by the application. For example, if the UPM is 1000, and the application specifies the point size to be 11 pt, will the rendering engine ensure 1000 Funits is scaled to exactly 11 pts, no more and no less?
Thank you,
Mark