Multi monitors with different resolutions?

Support for the Geminus graphics products

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evanallen
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Multi monitors with different resolutions?

Post by evanallen » Sun May 14, 2006 6:13 pm

I have two LCD monitors. One 1024 x 768 and the other 1280 x 1024. Is it possible to use the Geminus multi monitor feature with these two.

admin
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Post by admin » Sun May 14, 2006 9:24 pm

If the 1024 x 768 monitor can be rotated into a portrait orientation, making it 768 x 1024, then the answer is an unreserved yes. You would need the multi-monitor and screen rotation features of Geminus and get a screen area of 2048 x 1024 (because 1280 + 768 = 2048).

To use them both in landscape orientation would give you an area of the screen that is not visible (being off the top of the 1024 x 768 monitor) because RISC OS only understands rectangular desktops/screens. Whilst Geminus can be configured to use such a mode, it does tend to cause screen corruptions if you drag a window through the invisible area and back onto a screen and it's not terribly practical because you need to be able to see window title bars, in particular, in order to move the windows around.

Personally, I don't recommend using modes with invisible areas (what I call 'hole modes') and it's only something that we do at shows to avoid breaking the pivots by rotating them for every user who stops by ;)

simon_smith
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Post by simon_smith » Thu May 25, 2006 1:17 pm

Is there anything to prevent setting up a
2284 x 768 graphics mode, i.e. using the better LCD at lower res?
Don't many of them automatically resize? Or is a letterbox mode possible?

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Post by admin » Fri May 26, 2006 3:41 pm

I think you mean 2048 x 768 (where 2048 = 1024 + 1024), and that should work, yes. LCDs will automatically resample the video signal to scale it to the screen but the results can be visually unacceptable. Of course that's subjective. Some monitors will produce better results than others, but really it's better to drive them at their native resolution.

simon_smith
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Post by simon_smith » Sat May 27, 2006 8:30 pm

Actually, no, I meant 1024x768 on one screen, 1280x768 on the other, i.e. with a large black border top and bottom on the higher-res screen. (2x172 pixels high). It might have helped my example if I had got the right answer when adding 1024+1280 together.

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Post by admin » Sat May 27, 2006 9:31 pm

Oh right, yes Geminus can do that. Here's a possible starting point for the 1280 x 768 mode:

# 1280 x 768 (75Hz)
startmode
mode_name:1280 x 768
x_res:1280
y_res:768
pixel_rate:137500
h_timings:172,90,100,1280,40,36
v_timings:3,32,128,768,128,3
sync_pol:0
endmode


To use any combination of screens of any size properly we really need changes to the WindowManager to make it aware of multiple screens. The WindowManager could then also be modified to maximise windows to a single screen rather than the whole desktop, and to display error boxes centrally on a single screen rather than - in the case of dual screen modes - split across multiple screens.

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