To get running in crisp 1080p (or even 4K), you generally need a community-made patch, as the original "vanilla" PC release lacks native support for modern widescreen resolutions.
Using the ThirteenAG Widescreen Fix corrects the aspect ratio and scales the interface perfectly to 16:9 or 21:9 monitors. gta-san-andreas-1080p-resolution-fix-file
For a truly "definitive" feel on modern PCs, pair the resolution fix with SilentPatch . It fixes hundreds of bugs, restores the sun glare, and improves frame rate stability. To get running in crisp 1080p (or even