[Feature Request] Options to crop internal core image

Hi,

I have a feature request for players on CRTs / retro handhelds that both have limited display resolution. For instance:

• TVs (480i/240p) do support 480x240x60p (progressive) which would be the best resolution for PSP - with a minor vertical crop of 12%.
• Handhelds with a 640x480 screen would be able to scale Gameboy Advance - with a minor horizontal crop of 12%.

So, the option I'm suggesting is the following:
On the scaling settings, setting Aspect Ratio to custom currently give access to x/y position and width/height.
I'm asking for the addition of 2 new options: X/Y crop, that would crop the internal core image. For instance, the internal core image for PSP would be 480x240, this will also help with automatic modelines generation on CRTs.

Any chance you'd consider this?

Thanks.

Start with the scaling settings and the custom Aspect Ratio controls described in the issue. Trace how the existing x/y position and width/height options reach video output, then determine how X/Y crop should apply to the PSP and Gameboy Advance examples. Done means the new crop options work with custom scaling and support the intended CRT modeline use case.