add feature boomerang gif

[patkan]

This PR fixes #159

It adds an additional capture mode that uses the preview-function of the connected camera to take a short succession of images and concatenates them together into a GIF. The feature can be disabled and configured over a settings menu, the standard configuration is disable.

As this uses the preview-function, the feature should work with any camera that can supply a preview picture.

@reuterbal Some parts of this code are somewhat hacked together, so I would be happy to iterate with you on this in case you would like to merge this feature.

[patkan]

I just realized that this feature leads to a crash of the QtGui when the GIF is shown on Raspberry Pi 4. On my x86-machine this works without problem. I will ammend my pull request if I find a solution, if anybody can test this on a Raspberry Pi 3B, this would be great (I don't have one currently)

[botyas]

in raspi 3B generates the gif and displays it, but the gif occupies almost 40Mb

[patkan]

Thank you very much for checking this. Maybe the crash on my system just comes from the large filesize. It seems to me that Pillow creates a new color palette for every new image. Maybe this leads to the large file size. I will try to see if I can reduce the size.

[botyas]

good night, today I reinstalled and reconfigured the photobooth from 0 and now the images I get are 5 or 6 MB. I have observed that when selecting a style other than the default, the waiting time exceeds 1 second per pass (for example, if I put 10 Sec, it may take 15 seconds to take the photo). I have also noticed that when you start it, a raspi-webgui Wi-Fi network is generated that you didn't have before. When trying to access, he asks me for a username and password but I can't find this data anywhere. It would also be nice to add the option to put another gui button for boomerang.

[patkan]

As far as I see it, the raspi-webgui should not come from these changes as I have only touched the software itself. Typically the username and password are that of your system user.

[botyas]

good afternoon, I have updated the installation for your branch patkan-photobooth and the gifs are again too large and gives the raspberry general error. What is the difference between these 2 versions patkan-photobooth and Feature-boomerang-gif in the gif generation. This includes the overlay option and the sound that I have already implemented in my photo booth, but the boomerang does not work.
I would also like to know if it is possible to assign a gpio to launch the boomerang since right now I can only use it by adding a pointer to click on the option.

Thank you for your work and greetings.

[patkan]

Generally, if you want to see the difference between two branches, you can use a git diff. Github has a feature for this too: patkan/photobooth@feature-boomerang-gif...patkan:patkan-photobooth
patkan-photobooth is just the branch that I use to track the version of the software that I am using on my own photobooth.

That means also that you won't see newer changes on this branch than on the branch that is linked here. Unfortunately I did not have the time to continue my work on this, so it is still in the same state.

For the GPIOs, please check #44. This feature is not implemented yet. You would need to add a handler in the GPIO-module that generates the event on button-press.