[Devel] pixel size, hinting and scaling

[Graham Asher]

Can someone explain how, and if, the problem of pixel size and scaling is
solved, when a font transformation has some scaling component? I noticed
that when TrueType glyphs are rendered certain important parameters
affecting hinting depend on the number of pixels per em - that is, the pixel
size. These parameters are set when FT_Set_Char_Size is called but not when
FT_Set_Transform is called. FT_Set_Transform can also affect the pixel size.
Thus a transform applied to a font can prevent hinting from working as
intended.

There are other, more difficult issues when pixels are not square or when
the transformation causes some skewing or rotation.

I hope I have simply misunderstood some part of FreeType. If not, there is a
defect here.

Graham Asher