Juan Vuletich wrote:
Hi Andreas,
Andreas Raab wrote:
Hi Juan -
This is mostly to Juan but others might be able to help as well. I noticed that the Cuis fonts disagree in their pixel sizes significantly with that we get from the plain DejaVu true type fonts in Squeak. A bit of math reveals that at the (assumed) screen resolution of 96dpi a 12pt font should result in 16px high font (12*96/72 see Eqn. 3 in [1]). The corresponding Bitmap DejaVu 12pt font, however, is 19px high which would mean a screen resolution of 114dpi (19*72/12).
Is this choice intentional? Unfortunately, none of the pixel sizes for Bitmap DejaVu correspond exactly to a point size when assuming 96dpi.
The BitmapDejaVu 12 has the glyphs rendered by FreeType when requested for 12 pt. In those glyphs, the H (for example) is 12 pixels high. Max ascent for uppercase letters with Latin umlauts is 15 pixels. Max descent in those glyphs is 4. Therefore instances of BitmapDejaVu 12 StrikeFont answer 15 to #ascent, 4 to #descent and 19 (15+4) to #height.
I never found a clear specification of the meaning of '12 point', and I'm totally for making the fonts behave properly. So, the first question is: Are the glyphs correct? I mean, are the glyphs for DejaVu 12 rendered by Squeak TTF and Freetype the same size? If so, how does Squeak TTF fit glyphs that might need up to 19 pixels (15+4) in 16? I suspect that FreeType and Squeak TTF don't agree on the meaning of point size, but I don't have time right now for checking.
I'll have time for this on Monday. I guess the first thing to do is to understand what is the correct font for '12 point'. I mean, the correct ascent/descent and line grid, and the correct shape of the glyphs. Some specification of mean kerning / length of strings would be nice too. I'll read the link you sent. I want to understand and get this right!
According to http://www.emdpi.com/fontsize.html , the example *"Arial 12pt at 96 dpi:"*a 12pt font at 96 dpi should have a "font size" of 16 pixels, but a "font height" of 18 and not 16... I guess neither TTF nor FreeType got it right...
Cheers, Juan Vuletich