allow upscaling of retreived artwork

[nico1080]

as reference to my post on coreelec forum:
https://discourse.coreelec.org/t/graphical-front-panel-display/12932/210

Artwork do not get upscaled (only downscaled)
This could be problematic on display with high pixel density as the displayed size is limited by the resilution of the thumb retreived from kodi.

Of course upscaling will decrease quality but it should stay acceptable.
I personally plan to use a 12/15" display with 1920x1080 resolution.

Is there anyway to upscale the retrieved picture?

[mattblovell]

Upsizing would need to use resize() rather than the current thumbnail() code:

Pillow Image.resize

Back in the commit history, kodi_display_panel.py originally used resize(), but care was needed to ensure that the existing aspect ratio was maintained. The thumbnail() function takes care of that automatically, but only wants to go one direction – smaller.

All of the resampling filters listed for both resize() and thumbnail() are concerned with the mapping of multiple input pixels to a single output pixel (i.e., downsizing):

Pillow Filters

So, I don't know if upsizing is actually possible or not and, if possible, I don't know what the result would like look. The line I've often heard is that resizing cannot "fill in" information that isn't present; the result may therefore just look blocky.

[mattblovell]

The "Resizing Images" section of this page

https://auth0.com/blog/image-processing-in-python-with-pillow/#Resizing-Images

states the following:

Another significant difference between the resize() and thumbnail() functions is that the resize() function 'blows up' an image if given parameters that are larger than the original image, while the thumbnail() function doesn't. For example, given an image of size 400x200, a call to resize((1200, 600)) will create a larger-sized image 1200x600; thus, the image will have lost some definition and is likely to be blurry compared to the original. On the other hand, a call to thumbnail((1200, 600)) using the original image will result in an image that keeps its size 400x200 since both the width and height are less than the specified maximum width and height.

Note the "[larger image] is likely to be blurry compared to the original" description.

[mattblovell]

I'll look at digging up the older code that used resize() and adding it to the relatively-new paste_artwork() function.

Enlarging will likely be qualified with an additional key (mutually exclusive with the existing center_sm functionality).

[mattblovell]

Should be possible in kodi_panel v1.41

[nico1080]

What is the correct syntax; in my TOML file I have the following

[shared_element.thumb] # artwork / movie poster
posx = 0
posy = 0
width = 1000
height = 1000
#size = 900
center_sm = 1
display_ifnot = [ "VideoPlayer.Cover", "DefaultVideoCover.png"]
enlarge = 1

It does not enlarge the picture.
I also tried to specify size instead of width and height item same result, artwork get displayed to ist full size with out upscaling

[mattblovell]

Please try kodi_panel v1.48. There was a bug that was introduced into get_artwork() when I was separating the handling of AirPlay cover art and introducing the new callback functions for art.

What is the correct syntax;

For audio artwork going through a thumb element or making use of the element_audio_cover() callback, only size is expected (as audio covers are generally square). I did just introduce code to check for width and height if size is not present.

All video covers and the element_generic_artwork() callback only check for width and height.

Finally, only one of center_sm or enlarge needs to be specified. They are mutually-exclusive options (since, if enlarge is specified, then center_sm never has a reason to get examined).

[nico1080]

I confirm it work with 1.48. (both audio with size and video with width and height )

Thanks