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Scaling and Overlays Tool for handheld systems
Rion edited this page Feb 5, 2026
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This tool provides handheld-optimized scaling + overlays, designed to make small native handheld resolutions look better on CRTs and other low-resolution displays.
It ships with system-specific overlays, and in some cases multiple overlay variants per system.
Currently supported:
- Arduboy
- Atari Lynx (horizontal support only, Libretro-HANDY only)
- Game Gear
- Game Boy
- Game Boy Advance
- Game Boy Color
- Neo Geo Pocket Color
- Nintendo DS (single-screen support only)
- PICO-8
- Super Game Boy (mGBA only; replaces the default overlay — can be disabled with Hotkey + R3)
Some systems include more than one overlay.
- Switch overlay: hold Hotkey + R3
- Disable overlay completely: hold Hotkey + R3 (cycles through variants and OFF, depending on system)
Tip: If you want a specific overlay to always be used, set your preferred overlay once and leave it.
On a horizontally oriented CRT, progressive resolutions only allow one DS screen at a time.
This setup supports single-screen display, and you can swap between the top and bottom screen while playing.
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Swap screen button (default):
R3 -
Change the binding here:
Quick Menu -> Controls -> Port 1 Controls- Quick Screen Switch
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Swap screen button (default):
R2 -
Change the binding here:
Quick Menu -> Controls -> Port 1 Controls- Swap Screens