Implement graphics scaling support for high DPI displays

[mariobalanica]

I've been meaning to look into implementing graphics scaling within EDK2 for high DPI displays and improved accessibility.

The general idea is having an EDKII_DISPLAY_INFO_PROTOCOL sitting on top of each EFI_GRAPHICS_OUTPUT_PROTOCOL handle, which will provide the current logical display resolution and physical pixel mapping helpers to consumers such as GraphicsConsoleDxe. This protocol will be installed by a separate driver that can determine the preferred scaling factor based on EFI_EDID_ACTIVE_PROTOCOL (if available), native physical resolution or user choice (via HII configuration).

This also gives the opportunity to drop the whole setup mode-setting logic copy-pasted throughout several built-in UI apps, which is limited to those particular apps and ends up looking less than ideal. Some GOP implementations don't even support modes lower than native.

Apart from the obvious necessary code changes in BootLogoLib and GraphicsConsoleDxe, we also need larger bitmap assets for the platform logo and system font.

For the platform logo, I believe the tianocore.org one would be fine.

For the font, well, here it gets tricky and I would really appreciate some input:

• The 8x19 LaffStd font is acceptable if we only support integer scaling (2x, 3x), but such factors can be overly large, e.g. in the case of a 14 inch 1080p panel. Maybe this isn't that big of a deal (and we also save some space on assets)?

• If we support fractional scaling, LaffStd would either need to be redesigned for those larger sizes in order to look reasonable (I do not have any plans for that) or simply replaced with another font. Terminus seems like a good alternative (somebody got it running in the graphics console before) and comes in various sizes to support 125%, 150% and 175% scaling. However, this is an 8x16 font, while the UEFI spec mandates an 8x19 system default font. So, we probably want to keep LaffStd around as default, even if we won't be using it anymore?

Thoughts?

[mariobalanica]

I've tried replacing the console font with Terminus Bold. Looks pretty good at 100%, 125%, 150% and 175% scaling on a 1080p screen. The plan is to support up to 500% (with one more fractional step at 250%)

HII really wants sysdefault to be a 8x19 font though, so we'll have to keep LaffStd as it is. That's probably for the better, since there may be legacy code hardcoding EFI_GLYPH_WIDTH/HEIGHT.

The question remains: are we okay with using a different font for the graphics console?