This commit resolves two issues with high-DPI display rendering:
1. The coordinates were not scaled properly, resulting in tiny output
and misalignment of actual cursor position with apparent position;
this is fixed by calling SDL_SetRenderScale with appropriate scaling
factors determined by comparing the window size to the renderer's
output size
2. The fonts were not oversampled, resulting in excessively blurry text;
this is fixed by setting oversample_h and oversample_v on the
font_config according to the scaling factors
Addresses an issue where the Metal render driver (macOS) could not handle the clipping rectangle {-8192, -8192, 16384, 16384} and would simply draw nothing to the screen. The solution is to ensure the cliprect coordinates are not negative, which also doesn't break the other render drivers.
Co-authored-by: Kristian Bolino <kbolino@kbolino.com>
