Ok, so after some more testing, I found out it's not a matter of graphics vs. text mode, but of horizontal resolution: each mode with 320 pixels reflects whatever scaler is selected, but each 640 pixel mode is seemingly locked to normal2x. Not sure if that helps for coming up with a solution...

Usually you don't mix both scalers and shaders, but if you really want a scaler to always be applied regardless of the resolution add "forced" after the name.

Well, a few things:

1. The normal2x scaler does come in handy for simulating the scanline doubling on VGA and other computer displays. I haven't found a way to make that happen with just CRT-Royale by itself.
2. In this instance, however, I'm trying to force the scaler off, rather than on. From what I read in some other threads, DOSBox overrides the user's scaler selection with normal2x (even if that selection is "none") for certain modes.
3. I did read about appending "forced" and attempted to use "none forced" in the dosbox_svn_scaler setting in my .opt file, but it sees it as an invalid value and reverts it to "none". Same with any other scaler selection.

With the machine=cga setting there is an internal line-doubling scaler on 640x200 modes, which includes mode 6 graphics and text modes. The internal scaler overrides any user scaler setting (even "none") and can't be disabled.

Ah, that's a bummer. I imagine it was implemented that way to simplify the displaying of 640x200's oblong pixels when running pure DOSBox.

Thanks for the reply, though - and thanks for all your contributions to DOSBox!

I got it to work!

Thank goodness for FOSS ^^ All I ended up doing was replacing the contents of ScaleNormalDh (I figured Dh = Double height) with the contents of ScaleNormal1x in render_scalers.cpp.

Looks so much more like the real thing now!

I think another workaround, since you're using RetroArch, is to have a shader preset manually altered to scale the height down, i.e.:

1scale_type_y0 = "absolute"
2scale_y0 = "200"

with a 'stock' shader

Ah, yeah that's an idea that had crossed my mind. My shader knowledge is pretty lacking so I wasn't sure how I would go about that. Thanks for the tip!