Patch to properly scale preview video and images

[Bill <cizek@…>]

In the Watch Recordings screen the Preview image and live video don't always scale well. This generally happens if the aspect ratio or the size of the image doesn't match the aspect / size of the theme's preview area. In this case I see a bunch of leftover images as I scroll through the available recordings.

The attached patch fixes this by doing the following:

• Expand the image to fill the video area (while preserving the aspect ratio)
  
• Letterbox or Pillarbox the resulting image to remove the leftover images mentioned above.

This works on both the live video and the still preview image.

[Bill <cizek@…>]

Updated patch

[Bill <cizek@…>]

After SVN 14822 the display is still flaky when showing 4:3 images on a 16:9 display. The updated patch fixes this.

-Bill

[stuartm]

Thanks for the patch, I've actually got a fix for this issue in my local tree along with some other follow up changes to what was committed in [14823].

I'll close this ticket when they are committed.

[stuartm]

(In [14865]) More preview image scaling tweaks and fixes. This should now correctly scale and position 4:3 images in 16:9 frames as well as 16:9 in 4:3.

Previews will now use a blackhole widget instead of the container area if it is specified. Not only is this more logical from a theme point of view, it also allows additional images and text to be placed in the video container for display with the preview image e.g. A frame around the preview. Anything placed in the video container will not be displayed unless preview images or video are enabled.

See ​http://miffteevee.co.uk/imagebin/theme_fullscreen59.png for an example.

Some credit should go to Bill cizek@ as he wrote and submitted a patch to do the same thing long before I independantly started working on fixes. His patch was not used because I saw it too late.

Closes #3771