Screenshot from http://<frontendhost>:6547/MythFE/GetScreenShot does not work

[jason.chambers@…]

I noticed that [16532] (referenced in 0.22 release notes) mentions a screenshot can be captured via ​http://<frontendhost>:6547/MythFE/GetScreenShot.

However when trying this on my frontends my browser just gets an empty body (no content, but also no errors).

But I can successfully take screenshot using the "jump snapshot" command when connecting via telnet to port 6546, as well as by assigning and using a key on my remote.

The frontend log file shows some warnings and errors (e.g. "QPixmap: It is not safe to use pixmaps outside the GUI thread") when connecting to ​http://<frontendhost>:6547/MythFE/GetScreenShot is attached.

(NB some of the messages are captured on stderr, not stdout).

[beirdo]

(In [26240]) Create a signal/slot in the MythMainWindow to handle remote screen shots. As QPixmap doesn't want to capture from anything but the GUI thread, it is necessary to actually create it in the GUI thread. I used Qt::BlockingQueuedConnection to block the WorkerThread until the screen shot has completed.

Also changed it to use PNG rather than JPG for the remote screen shots as this can be helpful for people like themers without lossy encoding.

Fixes #8071

[beirdo]

(In [26242]) In the frontend remote screen shots:

• changed optional Width and Height parameters to width and height respectively (lower case)
• added an optional format parameter to indicate image format, defaulting to png. Supports jpg, png, gif.

Refs #8071