Switching between full screen and window

To use DOSBox in full screen, press the ALT key and, while pressing the ALT key, press the Enter key. Do this again, and you return to the DOSBox window. To enhance image quality, continue reading.

Changing the DOSBox resolution and image quality

DOSBox window resolution 1280x960 - Leisure Suit Larry 1.Here at DOSGamers, we like our DOS games to look clear and just like the original. As most DOS games are made for screens with a resolution of 320x240 pixels, DOSBox needs to scale the image. With default settings, DOSBox in full screen looks blurry or fuzzy and squashed in case of wide screens. At startup, the window is also kind of small. So what did we do?

  • Open the DOSBox configuration file:
    • Windows 7: Press CTRL + ESC (or Start button), type in dosbox and the options file should appear in the search results, click it
    • Windows 8 and Windows 10: Press the Windows key + Q, type in dosbox, and the options file DOSBox 0.7x Options should appear in the search results, click it
  • Look for the [sdl] section
  • Use fullscreen=true for full screen
  • Use fullscreen=false for DOSBox in a window
  • Change fullresolution=original to fullresolution=desktop
  • When using a window, change windowresolution=original to windowresolution=1280x960 (or use 1024x768 for a smaller window). You can enter any resolution you want but remember that DOS games were made for screens with a 4:3 width/height aspect ratio. See also the aspect setting below.
  • Change output=surface to output=openglnb (uses graphics hardware and maintains crisp image with scaling). You might try output=ddraw if your hardware doesn't support OpenGL. In some cases ddraw also has a lower CPU load.
  • Scroll down to the [render] section
  • Change aspect=false to aspect=true if you run DOSBox in full screen mode (this maintains 4:3 aspect ratio. If you've set a resolution with another aspect ratio, like 1280x480, this will be converted to 640x480. In the same way your desktop resolution like 1920x1080 will be converted to 1440x1080. Otherwise keep on false if you like the aspect ratio of your resolution setting.)
  • Save the configuration file with CTRL+S (or File - Save)
  • (Re)start DOSBox
Comments from the retro community
stugpanzer · 18-12-2014 · 19:49 CET · [#]
Just curious Jeff....what financial software are you using?
dismapsuxlol · 16-05-2015 · 03:07 CET · [#]
I just created an account to say thank you for this information! My dosbox resolution was working fine and then one day without warning a bombshell must have went off in my program and the resolution / aspect ratio suddenly got all messed up. I've been banging my head against the wall for years trying to figure out how to fix it. This is a lifesaver, now I can finally be once again immersed in my old games.
DOSGamers
DOSGamers · @DOSGamers · 18-05-2015 · 16:49 CET · [#]
Thank you for taking the time to create an account and say thanks! Much appreciated!
Nirxnmirxn · 29-10-2015 · 01:45 CET · [#]
...just created an account too to say thank you for the instruction. DosBOX was running fine quite some time and all of a sudden it "crashed" by changing the resolution, forcing me to "alt-tab" out of it, "alt-tab" into it and "alt-enter" again. Figured out I was lucky all the time 'cause I can't remember doing anything to the config, just "alt-enter" to get fullscreen smile After doing the changes in config no error for nearly an hour. I consider myself lucky again, although I have to get used to the new look smile
DOSGamers
DOSGamers · @DOSGamers · 29-10-2015 · 14:47 CET · [#]
Sudden screen issues with DOSBox could very well relate to the software/game you run on it. Anyway, what was the "old look" looking like, and did you like that better? There are quite some options to tweak the DOSBox video output that haven't been mentioned on this page (yet) wink
Nirxnmirxn · 29-10-2015 · 15:12 CET · [#]
The "old look" basically was a "dull widescreen" version of any game. I got used to it, the less you can see the more your imagination has to work it out. Now, with settings closer to the original version, for the first time I can identify single pixel bigsmile The new look is like watching HD, compared to what I had on the screen before smile
KvotheTBL · 19-06-2016 · 07:06 CET · [#]
Hey guys, sorry for the necro, but I'm following your guide and having some issues. I'm running Windows 10 64bit with dosbox 0.74 and this is what my options settings look like:

fullscreen=true
fulldouble=true
fullresolution=desktop
windowresolution=original
output=openglnb
autolock=true
sensitivity=100
waitonerror=true
priority=higher,normal
mapperfile=mapper-0.74.map
usescancodes=true

frameskip=0
aspect=true
scaler=normal2x

When I run DosBox, I use run as administrator, it still opens full screen in the original resolution. I've tinkered with the settings for a couple of hours and I can't really get any change in resolution. Any extra pointers for people running this on Windows 10?
DOSGamers
DOSGamers · @DOSGamers · 19-06-2016 · 09:59 CET · [#]
Hey KvotheTBL, thanks for your message! This isn't a forum, this is a site that tries to keep retro gaming alive, and all comments are relevant smile Your settings look ok. I think you're talking about game resolution, correct? The article above is about DOSBox screen and window resolution. You can't change the game's resolution, which for most DOS games is 320x200, or for later games 640x480. You can use another scaler (hq3x, 2xsai or similar) to make the game look smoother (less pixelated or blocky), but that's not necessarily better. Depending on the game, there could be a source port available, which allows you change the game's resolution. Like DXRebirth for Descent, or Doomsday for Doom. For most older games there's no such thing. But we all love those pixels right? wink
Ant_222 · 25-09-2016 · 23:45 CET · [#]
The only way to achieve a pixel-perfect image with an old low-resolution game on a modern LCD display is to represent each source pixel as a sharp rectangle of m by n pixels, where m and n approximate the pixel aspect ratio (PAR) of the emulated game. And the display should of course work at its native resolution. The current official version of DOSBox, 0.74, can only do it for m = n, i.e. for a unity PAR, and even then it relies on a limited set of hard-coded scalers:

[sdl]
fullresolution=desktop
output=surface

[render]
scaler=normal<n>x
aspect=false

Setting 'aspect' to 'true' causes DOSBox to apply nearest-neighbor upscaling vertially, which implies variable magnification of the image rows.

All other values of 'output' either interpolate and introduce blur, or apply nearest-neighbor upscaling, which results in sharp but irregular pixels. A common technique is to use a high normalx scaler to enlarge the image beyond the display dimensions and then let the SDL renderer shrink it back to fit. It produces less blur, but does not eliminate it completely.

Furthermore, this approach is nonscalable (the pun intended) in that it relies on high-order normal scalers available in unofficial releases and patches, which must be updated as larger display dimensions are introduced.

I am working on a patch that shall overcome the said limitations and provide true pixel-perfect scaling. Its alpha version is included in the enhanced build by Yesterplay80 (see the readme file for configuration).

Feedback is most welcome in the dedicated thread at the DOSBox forums.
DOSGamers
DOSGamers · @DOSGamers · 26-09-2016 · 22:21 CET · [#]
Thanks Ant_222 for your comment! I was quite content with my solution in the article above, until I read your message. The pixels indeed look a bit rectangular in our LSL image. I'll keep an eye on the custom Yesterplay80 build!

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