VOGONS


First post, by videogamer555

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I tested this with the latest vanilla SVN Windows version (r4022, at the time of me writing this), that I downloaded from DOSBox EmuCR, as well as the standard release version of (0.74, at the time of me writing this). The video output mode I tested it in was Surface. Scaler was set to none (so only standard screen stretching was applied). Aspect Ratio was set to False (so pixel aspect ratio is 1:1). Note, that I didn't run any program that switched into graphics modes, nor 40x25 text mode, so I have only tested its behavior in standard text mode (80x25), which is the default mode DOSBox starts in (just like normal DOS).

When using the following display types (referred to as "machine" types in DOSBox), the DosBox screen is properly stretched to fit your screen:
CGA
Tandy
PCJr
SVGA_S3
SVGA_ET3000
SVGA_ET4000
SVGA_Paradise
VESA_NoLFB
VESA_OldVBE

It does not stretch completely (there's a gap at the top and bottom of the screen) when using the following display types:
Hercules
EGA
VGAOnly

So same problem exists for the standard DOSBox release version (0.74), and has not been corrected as of SVN version 4022.

I wanted to also test it with aspect ratio set to true, but it doesn't work in text modes with release version 0.74, and even in SVN version r4022 it doesn't work in text modes on all display types (for example EGA, when in text mode, with aspect set to true it still behaves just as if aspect ratio was still set to false).

Reply 1 of 9, by Ant_222

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Why do you think it is a bug? If you have

fullresolution=original

the stretching is performed by your videocard, which does not support all those graphical modes. EGA in text mode is 640x350, whereas CGA is 640x400 (or 640x200 double-height), so your graphics adapter cannot stretch the currently non-standard 640x350 to the whole screen.

Reply 2 of 9, by koverhbarc

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But all graphics adapters should still have 400-line mode, yet he reported vgaonly (400 lines for sure) as one with the problem. So it's not that simple. I personally know I have 400-line support, and get it in NTVDM and full-screen command prompts (which are not actually NTVDM, though might share code) but can't get it in DOSBox with any settings whatever. ZDoom has the same issue (320x200 and 640x400 are squashed), so I'm pretty sure it's my Windows drivers, which I can't change. So he's lucky compared to me!

I rely on 50-line text mode for a few applications, which is intolerable when squashed, so I'm stuck with NTVDM there.

Reply 4 of 9, by koverhbarc

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The hardware does it perfectly (and it's not emulated), as does the OS. It's only the damn proprietary drivers that mess it up. Nevertheless I will try the 'pixel perfect' thing, at least for the sake of investigation.

Reply 5 of 9, by Ant_222

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koverhbarc wrote:

The hardware does it perfectly (and it's not emulated), as does the OS.

What do you mean—that there is hardware-level and/or OS-level support for integer scaling that keeps the pixels sharp at the native LCD resolution?

Reply 6 of 9, by koverhbarc

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Who said I'm using an LCD? Anyway, I ignore the LCD's resampling when it doesn't affect aspect ratio, as did the OP here. This question is solely about aspect ratio, not whether the LCD is pixel-perfect - CRTs aren't either! Indeed the human eye probably prefers pixels not to be completely sharp.

Reply 7 of 9, by Ant_222

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koverhbarc wrote:

Who said I'm using an LCD?

Lucky you! But your time is limited. If your CRT and videocard support the desired graphical modes, you should be able to use DOSBox without any scalers—at the original resolution in full-screen mode.

Anyway, I ignore the LCD's resampling when it doesn't affect aspect ratio, as did the OP here.

At non-native resolutions LCDs look execrable to me.

This question is solely about aspect ratio

I see. You have a 4:3 CRT and expect it to work in DOSBox naturally.

not whether the LCD is pixel-perfect - CRTs aren't either! Indeed the human eye probably prefers pixels not to be completely sharp.

Well, LCDs are more pixel-perfect than CRT's, and I can't say I prefer one or the other. I do like sharp text, and therefore use raster fonts with no smoothing, but some low-resolution games look too pixelated on my large LCD, so I have to sit father away. It made me consider an adjustable limit to the magnification in the Pixel-perfect patch.

CRTs, on the other hand, introduce a soft and graceful blurring that is pleasing to the eye.

Reply 8 of 9, by Ant_222

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koverhbarc wrote:

I personally know I have 400-line support, and get it in NTVDM and full-screen command prompts (which are not actually NTVDM, though might share code) but can't get it in DOSBox with any settings whatever.

If NTVDM does it, I wonder why DOSBox does not. Maybe it is a problem with SDL? Have you tried all the available output types, including OpenGL and DirectX (if on Windows)?

Reply 9 of 9, by koverhbarc

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Yes, I have tried those among other plausible options. None change the behavior.

NTVDM must have low-level access that bypasses the drivers, since it can support mode X, text mode, and even 'modes' that mess up the display.