Comment by makomk
4 years ago
It's more subtle than that. What the Microsoft engineers are saying is that the console's current approach to drawing text is inherently slow in this particular case, due to the way the text drawing library it's based on uses the GPU. The proposed solution requires the terminal to have its own text drawing code specific to the task of rendering a terminal, including handling all the nasty subtlties and edge-cases of Unicode, which must be maintained forever. This is not trivial at all; every piece of code ever written to handle this seems to end up having endless subtle bugs involving weird edge-cases (remember all those stories about character strings that crash iPhones and other devices - and the open source equivalents are no better). It's relatively easy to write one that seems to work for the cases that happen to be tested by the developer, but that's only a tiny part of the work.
I’m fairly sure noone in question wrote a new font renderer, but just rendered all available fonts upfront with a system library, and uploaded it to the GPU and let it use it as a bitmap.
Text rendering is still done mostly on the CPU side in the great majority of applications, since vector graphics are hard to do efficiently on GPUs.