Auto-matting only *some* images

[jgodfrey]

Originally, the auto-matting feature was either ON (all images were matted) or OFF (no images were matted). Helge has since added an experimental mat_portraits_only feature that's designed to auto-mat only portrait images.

(As we've discussed elsewhere), I think we need a more general way to control the matting of only some images - likely based on comparing the aspect ratio of the image to that of the screen. For example, we could auto-mat images whose aspect ratio doesn't match the screen's aspect ratio (within some specified tolerance).

Assuming we add such a feature (and I think we should), does that eliminate the need for Helge's explicit _mat_portraits_only addition? I think it does, as it'd allow images that don't fit the screen to be auto-matted, which I think is the main motivation behind Helge's addition.

Also, it seems a bit more flexible as it'd allow landscape images (that didn't fit the screen aspect) to be auto-matted too.

Of course, all of this would require that the mat_images property was set to True to start with. That is, you don't have to mat anything if you don't want to.

Really, just trying to decide whether this new option needs to coexist with the mat_portraits_only feature, or whether it can replace it...

[paddywwoof]

My initial feeling is that matting_non_display_shaped_images trumps mat_portraits_only in pretty much all circumstances. So for the sake of simplicity I would suggest opting for a replacement of the code and the config option. (With a punchier name)

[paddywwoof]

And even now I get confused about "fit": whether it stretches the images so it fits but some gets cropped or whether is shrinks the image so it fits but leaves a gap (I know Wolfgang and Helge just make all their images the same size as the screen!). We should probably change the name of that whole_picture_leave_gap:False or crop_picture_no_gap:True

This is probably relevant to the threshold for matting. If the user chooses crop_picture... then they probably don't mind having 5% sliced off the top and bottom but if they choose whole_picture... they might be annoyed by 1% of blur or reflected image

[sapnho]

Oh yes, the "Fit" parameter is indeed very confusing, but that is the case with the commercial photo frames as well. What the heck is "Fit to screen"? :-) Some call it "Fill screen" but do not specify that this entails cropping.
So what would be terminology that everybody can understand? Tricky..

[jgodfrey]

On the auto matting config mechanism, I have some code working as described above. Specifically...

• If mat_images is True, all images are matted.
• If mat_images is False, no images are matted.
• If mat_images is a valid real value, only images whose aspect is mismatched from the screen by more than that value are matted.

We'll need to decide what the default config value should be, but I'm currently running with 0.01. So, images off by more than 1% will be matted.

Behind the scenes, I'm turning the single mat_images config value into 2 values. One value indicates whether the auto-mat feature is ON or OFF and the other value is the aspect tolerance (assuming the feature is on). That's done like:

• If the config value is (some form of) True, the features is on and the tolerance is set to -1. This will mat everything.
• If the config value is (some form of) False, the feature is off. In this case, the tolerance value doesn't matter.
• If the config value is a valid real number, the features is on and the value is the tolerance.
• If the config value is none of the above (so, garbage), I issue a log warning and use the defaults (feature on, 0.01 tolerance).

Any objections?

[sapnho]

I guess, we'll have to see how it works in real life but I believe you have tested it with different aspect ratios already, have you? If not, I can include a fat "Give the author feedback" button in my article and we'll find out quickly how it turns out. :-)

[jgodfrey]

I believe you have tested it with different aspect ratios already, have you?

Certainly. I'm testing with a completely uncurated set of images. So, no special cropping, some "free" cropping, multiple orientations, and varying devices. So, probably dozens of different aspect ratios.

[sapnho]

Hi @jgodfrey, just posted my article on the Matting feature: https://www.thedigitalpictureframe.com/activate-the-power-of-the-magic-matting-feature-on-your-raspberry-pi-picture-frame/

I noticed that in our default configuration.yaml file the styles are not exactly the same as in the Wiki and we should probably align the two.

"A string containing the mat types to choose from when matting images. It can consist of any or all of 'float float_polaroid single_bevel double_bevel double_flat' (null or '' will use all mat types)"

Matting is a superb new feature of PictureFrame. Thank you!

[jgodfrey]

Really nice article Wolfgang - well done! Regarding the matting styles definition being incorrect in the default config file, I think that should be fixed with this commit from 9 days ago. I assume it just hasn't made it into packaged release...

7b16e4e

Regarding this statement from your article:

Currently, there are six different styles (“mat-type”) included. You can either specify your favorite style or use all of them at random.

It doesn't have to be either all or one. You can also simply list the styles you want to use. So, for example, if you don't like 2 of the styles, you can set mat_type to a string that contains the 4 styles you do like. The styles listed in the string will be chosen from at random during matting - whether that's one style, all styles, or somewhere in between...

[jgodfrey]

I assume it just hasn't made it into packaged release...

After getting through all of my email this morning, I see this was released today.

[sapnho]

It doesn't have to be either all or one. You can also simply list the styles you want to use. So, for example, if you don't like 2 of the styles, you can set mat_type to a string that contains the 4 styles you do like. The styles listed in the string will be chosen from at random during matting - whether that's one style, all styles, or somewhere in between...

How would that look? Because when I enter "mat_type: "float float_polaroid"" it only shows the polaroid style.

[jgodfrey]

How would that look? Because when I enter "mat_type: "float float_polaroid"" it only shows the polaroid style.

Exactly that should work (or separated by commas). Are you sure it doesn't? Let it run a little longer, as it may repeat one of the styles a few times. Also, make sure you don't have a typo in a style name as it'll simply be ignored (though, it'll log a DEBUG level message for any style names it doesn't recognize).

[sapnho]

Hi @jgodfrey, not sure what it may have been (me being impatient..) but it works as advertised now! Thanks! :-)