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---
title: "The next challenge is overscan safety, since real non-VGA CRTs will be used in d"
author: "NOTimothyLottes"
handle: "@NOTimothyLottes"
post_url: "https://x.com/NOTimothyLottes/status/1688022114962374656"
post_id: "1688022114962374656"
timestamp: "2023-08-06 03:00:08"
post_count: 4
reply_count: 0
repost_count: 0
like_count: 1
view_count: 340
---

# @NOTimothyLottes — The next challenge is overscan safety, since real non-VGA CRTs will be used in d

## Post 1 (2023-08-06 02:45:18)

1st SPC project: to be based on vintage 640x480 render (VGA style), +fallback to 640x240 for 15 KHz arcade CRTs (PGM-esk), and CRT shader scaling on Deck and OLED/LCD. Use mix of render pixel aspect changes, running less than 480 lines, and letter-box to keep integer Y scaling.

![Media 1](./media/1688018382543597568_1.png)

## Post 2 (2023-08-06 02:50:32) — reply to Post 1

My 15 KHz CRT output path when docked is HD Fury Nano (won't do <480p) doing HDMI to VGA, with a sync combiner (to workaround GBS-C bug), into GBS-C which line drops 480p ~60Hz to 240p ~60Hz and outputs component. The 640 width gets maintained even if some CRTs cannot resolve it.

## Post 3 (2023-08-06 02:57:50) — reply to Post 2

Presents issues for UI, namely that my bitmap fonts need to look good in both 480p and 240p modes, so for editor (assembler) I'm going with a font that uses right angles and designed around 2x2 stroke width, in a 8x16 (pow2) bitmap, so 640x240p still gets a readable 8x8 (below)

![Media 1](./media/1688021533904510976_1.png)

## Post 4 (2023-08-06 03:00:08) — reply to Post 3

The next challenge is overscan safety, since real non-VGA CRTs will be used in development. The Y axis has an easy fix, simply keep cursor pinned in the 'safe' zone, but still print lines in the overscan area (so they can be seen when attached to non-overscan CRTs/etc too).