Don't look for screens, look for drivers. Nvidia cards have this ability in the drivers - of course Ati never bothered adding this.

I use this myself because I got a widescreen with resolution 1680x1050 and a lot of old games only go up to 1280x960 which means that in a FPS, you'll move faster left and right than up and down which really messes things up. If you use the black border (1:1 pixel it's called I believe) it means perfect pixels.

I use this for Dosbox too by the way.

Actually, ATI does have such an option in the Catalyst driver control panel. In the Displays tab of the advanced display properties, in the FPD properties is a checkbox for "Scale image to panel size". However the option does not work for me on my Samsung panel, so either it's not implemented correctly or my panel scales the image anyway.

If you use the black border (1:1 pixel it's called I believe) it means perfect pixels.

Aye, but obviously that would mean too small an image, for most old games. What if (hypothetically) my flat panel's resolution is 1280x1024, and I'm playing a game with an original resolution of 320x200.. a stretching of *4 could still be done, leaving just a black border at the top and bottom (320x200 * 4 = 1280x800).

Actually, the resulting image would have to be stretched again vertically by a factor of 1.2 to maintain the original aspect ratio, making it 1280x960, which would probably necessitate some blurring.. that's the kind of problem I'm talking about. I guess my question is how to solve all this through an intelligent use of drivers + DOSbox scalers...[/quote]

You clearly don't alter the resolution then. You need to use openglnb to get no blurring and then alter the full screen resolution to match your desktop resolution - the window resolution is up to your own taste. Do this and you'll have a perfect image.

I heard that for Ati it doesn't work like it should - your screen needs to support it or something but the Nvidia way works on all screens I tried it on.

My Direct3D output supports something like this. It will stretch a 320x200 game to 1280x1000. This is closest to original res and does not blur the picture 😀

What I have found is that using ddraw for output with 1280x1024 fullscreen always blurs the image regardless of the scaler used. However with overlay for output, using the normal2x scaler blurs a lot less than no scaler. I imagine that if a normal4x scaler existed, a 320x200 resolution would be displayed through overlay with no blurring at 1280x800... although aspect correction would still cause some vertical blending of pixel edges, of course.

Unfortunately there are performance problems with ATI's opengl support, so I can't use those output methods without getting jerky scrolling. 😒

Thanks for the explanations, all... suppose it'll be a bit of trial and error!
Although jerky scrolling worries me a lot more than blurring does....

gulikoza wrote:

My Direct3D output supports something like this. It will stretch a 320x200 game to 1280x1000. This is closest to original res and does not blur the picture 😀

Meaning your CVS build? 😀

Here's an important and surprising note: As well as options in the graphics driver, there may be a scaling option in the BIOS (which tends to be enabled by default -- you'll want to disable it). It took me a long time to find the option the first time.. and then I encountered it again on another system. I suspect they do this because they want the low-res Windows bootup screen to scale to fit the screen.. which raises the question of how to control this behavior before Windows even boots.. 😉

So.. I normally disable all automatic scaling (BIOS, graphics driver, and monitor driver (well, I check for it.. because I'm paranoid from all the scaling trouble I used to have)), and then I let DOSBox handle it. I prefer gulikoza's direct3d output.

VileRancour wrote:

Meaning your CVS build? 😀

Meaning every build that has my Direct3D patch. Currently ykhwong has a slightly newer version that also works properly for widescreen monitors. Set your fullscreenres to your LCD native resolution, make sure aspect is set to false and it should work.

Hi!

red_avatar is right. You should be looking for drivers.

I recently had the opportunity to test both Catalyst und ForceWare regarding interpolation of non-native resolutions and if it can be customized.

First of all, let me point out, that the form factor of the LCD is also very important. Most 19" LCDs have a native resolution of 1280x1024 (so, you are not getting a 4:3 screen, but a 5:4, which would make its dimensions more quadratic compared to the TV-like aspect ratio). The same applies to 17" LCDs with that resolution.

You should also pay attention that you get a display with a digital graphics port (DVI) and make use of it. There are several versions of this connector, one of which is not desirable because it is only analogue (DVI-A). Just go look it up on Wikipedia.

Most LCDs have as good as no options or menus to affect interpolation and scaling behavior in any way, so tweaking drivers and software is the last resort.

ATI Catalyst

With the ATI drivers, it seems that DVI is a must, otherwise you cannot affect resolution scaling in any way. There are two options:

1. Center image without scaling (That would leave a big black border around any common DOS resolution.)

2. Stretch image to fit screen. Regardless of what you have (a 5:4 screen or a 16:10 screen, even), your DOS game would be stretched to fit its dimensions, thus not maintaining original aspect ratio. If you have a 4:3 LCD, you are in luck, though.

Adding to this, I have found, that the first option not always works as expected. If I choose a desktop resolution of 1024x768 the image would be scaled to fit my LCD, although I set the driver to center it.

I even contacted ATI's support over this problem. It definately is a bug, because with nVidia drivers, centering just works. But they didn't really understand me or didn't want to, I don't know. They just weren't able to assist me and didn't really listen to what I had to say, nor forwarded my request to 3rd level support, as I requested, because I am certain it is a bug.

nVidia ForceWare

Luckily now, I have upgraded to an nVidia card (much because of the annoying problem above and because it leaves me some more options considering interpolation). However, I don't know if they also apply to the analogue outputs.

1. Center image (equal to ATI setting 1)
2. Stretch image (equal to ATI setting 2)

Now come two settings that make use of a so called "Internal nVidia scaling":

3. Stretch image using internal nVidia method (equal to ATI setting 2)
4. Stretch image maintaining aspect ratio using internal nVidia method

I prefer option 4 and am very happy with it, since StarCraft and Diablo II for example can now be played in their original aspect ratio on 5:4 or even 16:10 LCDs, thus leaving small black bars at the top and bottom of the screen (respectively left and right borders on wide screens), but isn't that great?

I have tested the internal nVidia scaling with 3DMark06 by the way and didn't experience ANY performance drop. So they must have done it in hardware or I don't know how they do it, but it just works and they somehow have done something right!

Unfortunately, I figured that ATI setting 1 and nVidia setting 4 don't work as expected with a resolution of 320x240. The output is often strangely doubled in height. But this might be a bug of my monitor and I believe, it could be corrected with DOSBox' settings.

So, this all really is a complex and technally confusing matter. Maybe that's why ATI didn't really get what I was trying to explain to them.

I believe pixel-exact scaling is very hard to find and my experiences tell me that no driver or screen supports anything that comes close to it.

Actually, it's a shame that LCDs are so uncustomizable and unintelligent when it comes to interpolation and screen scaling. :( It's all just a big pain and nVidia's internal scaling is the best alternative for us.

Regards,
locutus

Thanks for all the detailed information, that's exactly what I was looking for.

I'm currently stuck with an ATI, so I foresee having to exhume this thread as soon as I get the monitor(s)... though between Locutus' findings and gulikoza's D3D patch I expect that something would work. 😉