Elliptical gauges instead of circular gauges

[billko]

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Rod wrote:

Hi,

Like others, I'm sure that the problem is due to the monitor settings, and a wide/narrow screen effect, a bit like looking at a standard width TV signal filling a wide-screen television which stretches the picture out horizontally.

The PC setting you have is effectively gives a narrow-screen signal, so you monitor needs to be narrow screen to get a correct picture

If the signal and the monitor are different, the effect is that you pixels are no longer square, but are elongated in oe direction or the other. A circle has the same number of pixels in both directions, but if your pixels are elongated in obe direction, so will your circle.

Try measuring the picture height and width. With the monitor resolution you're using, the width:height ratio should be 4:3. If it isn't your pixels won't be square and the picture will be stretched. A wide-screen monitor would stretch in the horizontal direction. You'll need to alter the monitor, or PC display settings until the height:width ratio is the same on both the PC and the screen.

Rod.

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Rod:

Thanks for explaining exactly what I had trouble explaining!  Kudos!

[MogaRaghu]

The monitor is a Dell DO22 17" LCD type. The width to height ratio is 16:10.

The PC is a Advantech 610L. (P4 with an Intel chipset.)

I have tried all possible resolutions available in the settings but none of them help to produce a circular gauge. Some are streched on the width and some on the height.

I opened Paint and could draw a perfect circle.

I also know it is not a problem with LV. I guess its a problem with the display drivers of the PC. But wish I knew what that problem was.

[billko]

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Raghunathan wrote:

The monitor is a Dell DO22 17" LCD type. The width to height ratio is 16:10.

The PC is a Advantech 610L. (P4 with an Intel chipset.)

I have tried all possible resolutions available in the settings but none of them help to produce a circular gauge. Some are streched on the width and some on the height.

I opened Paint and could draw a perfect circle.

I also know it is not a problem with LV. I guess its a problem with the display drivers of the PC. But wish I knew what that problem was.

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Ahhh, I see the issue!  According to my research, the  Advantech 610L is a specialized rack-mounted server-type PC.  These are notorious for having weak graphics crds, since all they expect you to be using is maybe a little 15" monitor for... well... monitoring.  In fact, it probably expects to be running without a monitor half the time!  Heck, where I work, our servers we bought just this year from Dell needed to have the graphics card upgraded to support wide-screen resolutions.  We're talking quad core RAID5 servers.

The manual for this thing just got finished downloading - the manual is dated 2004.  And it has ISA slots (cool, very retro).  Wow, looking at the picture, I think we have a few of these in the storage room.  Coolness.  All this points to a video card that cannot support wide-screen resolutions properly.  I bet if you saved the picture you drew in paint, the circle would be squished on your laptop.  The easy solution is to set your monitor up to do a 4:3 aspect ration.  This will leave black bars on the sides of your screen but it should make everything display correctly on both PCs.

Bill

[billko]

Or, of course, use a monitor with a 4:3 aspect ratio.

[MogaRaghu]

Hi Bill,

Thanks for the input. But I can't believe that  the 610L graphics capability is so poor that it can't show a circular gauge as it is ! I am not asking for high end 3-d image rendering.

You said : >>The easy solution is to set your monitor up to do a 4:3 aspect ration. 

So how do you do it ? I have tried all valid resolutions that the monitor allows in both 16bit and 32 bit .

Is there amny practical way out of this mess ??

[billko]

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Raghunathan wrote:

Hi Bill,

Thanks for the input. But I can't believe that  the 610L graphics capability is so poor that it can't show a circular gauge as it is ! I am not asking for high end 3-d image rendering.

You said : >>The easy solution is to set your monitor up to do a 4:3 aspect ration. 

So how do you do it ? I have tried all valid resolutions that the monitor allows in both 16bit and 32 bit .

Is there amny practical way out of this mess ??

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The ability to set a wide-screen monitor's aspect ratio is in the monitor's menu itself, usually accessed by one or more buttons on the monitor itself.  Unfortunately there is no standard button array - every model of every manufacturer semms to have a different scheme.  If you don't have the manual, you can probably find it at the Dell website.

Good luck!  🙂

Bill

[MogaRaghu]

Solution in sight. My screen has a width of 370mm, height of 230mm and runs at a resolution of 1280 x 960.

Created three gauges :

1. One gauge with corrected aspect ratio ( Height : Width = 1.15 :1.00 )

2. One gauge with equal aspect ratio of Height and Width.

3. One gauge unmodified and as placed by LV.

Observations :

- The gauge with aspect ratio correction appears round on my screen.

- The other two gauges appear elliptical.

But there is a new problem that has cropped up . I am able to programmaticaly change the height and width of the housing but the scale circumference change is possible only in design mode. Is there any way that I can link the scale to follow the housing ?? The attached VI ( 7.1) should explain my problem...

Thanks.

[RavensFan]

The solution is to use the correct resolution for your screen.

You say the screen is 370x230 mm.  That is a 1.6:1 ratio (16:10) meaning it is a widescreen monitor.

You say your resolution is 1280x960.  That is a 1.333:1 ratio (4:3), which is meant for an ordinary, old school, non-widescreen monitor.

So what happens is that your monitor is stretching the video signal wider to make it fit the screen and thus making the circles look like wide ellipses.

Set your resolution to 1280 x 800 (1.6:1), which will make the circles look correct.

As several of us have been saying, but you haven't been hearing, is that you have a mismatch between the resolution your video driver is using and the aspect ratio of your monitor.  If you right click on your desktop and go to display properties, it will bring up the video driver.  Look for the 1280 x 800 resolution.  If you can't find it, try downloading the latest version of your video driver and try again.

You are wasting too much time trying to hack the LabVIEW controls which are perfectly fine rather than trying to fix the root cause of your problem.

Message Edited by Ravens Fan on 09-26-2009 12:31 AM

[MogaRaghu]

I am aware that if the resolution aspect ratio and monitor display aspect ratio are the same then circles will be circles. And also that the LV indicator has no problem.

If I was able to get a video driver for my mother board that can provide 1280 x 800 then there is no problem. I have either 1280 x 720 or 1280 x 768 and reason why I am running in circles to find a way out, hacking or otherwise.

[RavensFan]

Then wouldn't it be easier to buy either a 17" or 19" monitor that is the normal aspect ratio?  You could get a flat screen LCD version of one of those for about $100-200.  You've already spent more than that in time trying to hack the controls.