[jira] [Comment Edited] (GUACAMOLE-1311) Context menus appear diagonally warped via RDP

["Mike Jumper (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GUACAMOLE-1311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17302778#comment-17302778 ] 

Mike Jumper edited comment on GUACAMOLE-1311 at 3/16/21, 6:26 PM:
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{quote}
Upon googling I found this bug which seems potentially related: https://jira.glyptodon.com/browse/GUAC-256?attachmentViewMode=list
{quote}

Well ... to be clear, there has never been a bug within Guacamole that resulted in this behavior. The above issue was still an issue in the remote desktop, and the fix as far as Guacamole was concerned was to work around that issue.

The problem was that older versions of RDP (Windows XP) assumed that the display width would always be a multiple of 4. If a display size was requested that was _not_ a multiple of 4, the connection would succeed, but all further updates would be skewed. Guacamole was rendering the data it received correctly, it was just receiving incorrect data from the RDP server, and the only way to avoid that was to round down the display width.

{quote}
I'm afraid I can't test RDP directly due to network constraints, hence why we are using Guacamole and why it works well for us
{quote}

If you can use the Windows standard RDP client through non-direct means like an SSH tunnel, that really is necessary to verify that this behavior is Guacamole-specific. I can try to reproduce what you're seeing by deploying what I hope to be an identical configuration (Apache Guacamole 1.3.0 + CentOS 8 + XRDP 0.9.15 + GNOME), but if things work as expected then there will be nothing for us to work from.

For an issue related to RDP, the steps needed to eliminate other factors are generally:

# Test with the Windows RDP client, to verify that the issue isn't a bug in the RDP server.
# Test with the FreeRDP client from the same version of FreeRDP as Guacamole was built against, to verify that the issue isn't a bug in FreeRDP.

Based on the issue description and the screenshots, my expectation is that this is a bug in XRDP, with the RDP server sending incorrect image data where the width of the image is incorrect vs. the image data actually sent, resulting in skew.

{quote}
I am using XRDP (v0.9.15), via Centos 8 with the Gnome desktop.
{quote}

Can you confirm the OS, version of FreeRDP, etc. that you are using on the Guacamole server (if not using the Docker images)?


was (Author: mike.jumper):
{quote}
Upon googling I found this bug which seems potentially related: https://jira.glyptodon.com/browse/GUAC-256?attachmentViewMode=list
{quote}

Well ... to be clear, there has never been a bug within Guacamole that resulted in this behavior. The above issue was still an issue in the remote desktop, and the fix as far as Guacamole was concerned was to work around that issue.

The problem was that older versions of RDP (Windows XP) assumed that the display width would always be a multiple of 4. If a display size was requested that was _not_ a multiple of 4, the connection would succeed, but all further updates would be skewed. Guacamole was rendering the data it received correctly, it was just receiving incorrect data from the RDP server, and the only way to avoid that was to round down the display width.

{quote}
I'm afraid I can't test RDP directly due to network constraints, hence why we are using Guacamole and why it works well for us
{quote}

If you can use the Windows standard RDP client through non-direct means like an SSH tunnel, that really is necessary to verify that this behavior is Guacamole-specific. I can try to reproduce what you're seeing by deploying what I hope to be an identical configuration (Apache Guacamole 1.3.0 + CentOS 8 + XRDP 0.9.15 + GNOME), but if things work as expected then there will be nothing for us to work from.

Based on the issue description and the screenshots, my expectation is that this is a bug in XRDP, with the RDP server sending incorrect image data where the width of the image is incorrect vs. the image data actually sent, resulting in skew.

{quote}
I am using XRDP (v0.9.15), via Centos 8 with the Gnome desktop.
{quote}

Can you confirm the OS, version of FreeRDP, etc. that you are using on the Guacamole server (if not using the Docker images)?

> Context menus appear diagonally warped via RDP
> ----------------------------------------------
>
>                 Key: GUACAMOLE-1311
>                 URL: https://issues.apache.org/jira/browse/GUACAMOLE-1311
>             Project: Guacamole
>          Issue Type: Bug
>          Components: guacamole-client
>    Affects Versions: 1.0.0
>            Reporter: Paul M
>            Priority: Minor
>         Attachments: image-2021-03-15-08-35-39-201.png, image-2021-03-15-08-35-39-268.png, image-2021-03-15-08-35-39-324.png
>
>
> When opening some context menus they are diagonally warped which means the text becomes almost unreadable. This only happens for some menus and not others, it seems to depend on the screen location. It affects all context menus including within programs, drop down boxes and right click menus. For example within Visual Studio code the File menu is warped, but the edit menu next to it is not (see screenshots). I have also seen this affect the dev tools window within Google Chrome, however I can no longer seem to re-create that.
> Upon googling I found this bug which seems potentially related: [https://jira.glyptodon.com/browse/GUAC-256?attachmentViewMode=list]
> I am using XRDP (v0.9.15), via Centos 8 with the Gnome desktop.
>  



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