Font code refactor

[ceeac]

This patch refactors font loading and rendering. I also updated variable names to follow the freetype naming conventions from this page where possible.

[Dwachs]

Thanks! What was the reason to work on this?

It would be nice if the font-code would enable larger than 16 x 23 pixels per letter.

[prissi]

The font system is more broken: There are all the "large_font" remainder, even though there is no small font used anymore. I would also define functions like "get_glyph_height" etc. inline in the "*.h" file, since those are used a lot in the UI code. Especially if they only return a const. Otherwise many compiler will no inline them.

Also no hex fonts used anymore, so one can safely remove this code. (Also the latin2 languages schould probably switch to a bdf font a some point.)

[ceeac]

What was the reason to work on this?

Preparation for GPU assisted rendering.

I would also define functions like "get_glyph_height" etc. inline

Done. I have not inlined get_glyph_data etc. because I have not noticed a performance difference and doing it this way is much more readable.

Also no hex fonts used anymore, so one can safely remove this code.

Done.

[ceeac]

Patch updated. Notable changes:

• Fixed crashes when reading corrupted bdf files
• Fixed debug printing of characters more than 8 pixels wide
• Fixed compile error when COLOUR_DEPTH==0
• Removed get_glyph_height
• Renamed large_font -> default_font in simgraph16.cc
• Renamed GLYPH_HEIGHT -> GLYPH_BITMAP_HEIGHT
• Renamed font_t::get_glyph_data -> font_t::get_glyph_bitmap

As far as I am concerned, this is finished now. (I think)

It would be nice if the font-code would enable larger than 16 x 23 pixels per letter.

I can do this in a follow-up patch, I believe this patch is big enough as-is.

[prissi]

std::min and std::max does not work on my system, so I replace them with min and max. Otherwise committed in r9042, Thank you.