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Problem - Display Transformation in VNC client with Multi display options - AM335x, TI SDK 7.0

Kumara Raja S36
Intellectual 285 points

Hello,

 I am using TI-SDK-7 which has Qt 4.8 libraries in it.

 I am developing a Qt application which can run on my target board 7” LCD display.

 

By default application runs on landscape mode.

But my LCD is mounted on portrait mode.

 

So, I had to rotate my screen using QWS options to view it on portrait mode.

I use the option:

export QWS_DISPLAY="Transformed:Rot270"

 

Now, I would like to demonstrate my application on the target using VNC client to my management.

 

So, I am trying to run the Qt application on multi server mode using QWS option:

export QWS_DISPLAY="Multi: VNC:size=480x640:0 Transformed:Rot270:LinuxFb:size=480x640:1 Transformed:Rot270 :2"

 

With this, I could start my VNC client with the server port.

I can see the screen well in the VNC client. And also, I can operate the UI from VNC client very well.

 

Problem is that, when the Qt application has been run on multi server mode and operate the UI on the target board using touch inputs,

I see the weird behavior. I see that, the touch inputs are still as in “landscape mode”. Touch inputs are not rotated along with the screen.

 

I have been trying hard for this problem since many days.

 

Later, I came across a Qt bug which exactly says about that.

https://bugreports.qt.io/browse/QTBUG-12290

 

Someone have suggested to try with the patch. But even with that, I have not got any success. It is still same.

 

I have been trying different QWS options to see if anything can work for me.

 

At the last, I have tried the QWS option:

export QWS_DISPLAY="VNC:Transformed:Rot270"

 

With this setting,

In the LCD UI, touch works good, screen is transformed in a right way. It’s all good.

In the VNC client, I see that the screen was not rotated. So, I had used RealVNC client and rotated the screen to 270 by myself. With this, screen looks good touch works great. But the problem is, I see there is a lag in screen refreshing. Meaning, after I click a button, I see the immediate change in LCD UI but not in VNC client screen. It take huge time for the refresh.

 

I have no idea on what’s happening in the behind.

 

Please help me to fix this issue.

 

Thank you very much!

 

Best Regards,

Kumara

  • 0
    TI__Guru** 116100 points
    Hi,
    In my opinion, you must create the QT application with portrait mode.
    I hope , we have settings for that when we create the QT app.
    You can see, properties -> X and Y

    X -> 480
    Y -> 640

    Don't rotate, application itself should be created in portrait mode (QT app window)
  • 0 in reply to Titusrathinaraj Stalin
    Intellectual 285 points

    Hi Stalin,

    Thanks for your reply.

    To be clear,
    I have created my application on portrait mode. And as you mentioned, I am setting the size of my UI as 480x640.

    But the display works in landscape mode by default.

    That's the reason that I rotate my screen 90 degrees.

    For example, if you consider TI AM335x Evaluation Module, that comes with LCD display, works on landscape mode by default. So, to run my application in portrait mode, I should be rotating it.

    This is my understanding. Please let me know if you have any thoughts.

    Thanks,
    Kumara

  • 0 in reply to Kumara Raja S36
    TI__Expert 3520 points
    Hi Titus,

    Can you confirm the intent of the change you described in your reply? Is Kumara following your recommendations already?

    My interpretation of what you are saying is that no QWS rotation options should be utilized. Is this correct? Instead, the width and height of the screen should be set such that it displays "natively" in portrait mode.

    I am a little confused by this, as the physical LCD screen and its hardware connections map to a certain X,Y coordinate system. My understanding is that 0,0 will always be in the same corner for the hardware, and 640,480 in the opposite corner. How will only changing the size of the display in Qt map to a new X,Y coordinate system (0,0 in a new corner, 480,640 in the opposite corner) for the physical LCD?

    Any clarification is greatly appreciated, as I believe Kumara was essentially following your recommendation already but is still experiencing issues related to what I describe above.

    Best Regards,

    Mark-
  • 0 in reply to Mark Swanson
    TI__Expert 3520 points
    Hi Titus,

    Any feedback? Were you implying a hardware change to their system, remapping the LCD to operate in portrait mode instead of landscape? Is this possible with a hardware change if no software solutions can be found?

    Best Regards,

    Mark-
  • 0 in reply to Mark Swanson
    TI__Guru** 116100 points
    Hi Mark,
    We have to check with LCD vendor for this.
    To change portrait/landscape, we would use some commands to do that.
    I hope we can address this by sw itself.
  • 0 in reply to Titusrathinaraj Stalin
    Intellectual 285 points
    Hi Titus, Mark,

    Yes, as you mentioned, to rotate, we use the command
    export QWS_DISPLAY="Transformed:Rot270"

    This is for only transforming the LCD display UI.

    If we transform the screen for VNC as well, there lies the problem.

    As Mark mentioned, if we have rotated the display mode to Portrait natively, we may not face this problem. Unfortunately, we cannot natively rotate because of the LCD limitations. The vendor supports only landscape mode.

    As far as I understand, it is a Qt bug with respect to VNC rotate.
    Here is the link for Qt bug.
    bugreports.qt.io/.../QTBUG-12290

    But however, no clear answers on how to fix it.

    Thanks,
    Kumara
  • 0 in reply to Titusrathinaraj Stalin
    Intellectual 285 points
    Hi Titus,

    If you know the way on how to address this issue by software, can you please let me know? So that, I can quickly give a try over here?

    Thanks,
    Kumara
  • 0 in reply to Kumara Raja S36
    TI__Guru** 116100 points
    Hi Kumara,
    Actually what I meant is that we need to check with vendor, they have set of commands to change the LCD mode, but you said, vendor won't support portrait feature right, then it seems need to check with QT support team to fix that bug you mentioned.

    As Mark mentioned, if we have rotated the display mode to Portrait natively, we may not face this problem. Unfortunately, we cannot natively rotate because of the LCD limitations. The vendor supports only landscape mode.
  • 0 in reply to Titusrathinaraj Stalin
    Intellectual 285 points

    Hi,

    Is there any direct point of contact for Qt support?

    I have posted in Qt forum, and not much help. 

  • 0 in reply to Kumara Raja S36
    Intellectual 285 points
    Hello,

    Any further information, which I can try out here?

    Thanks,
    Kumara