Reduce flags SVG assets size

[G00fY2]

Currently the flag svg drawables (which are only used for 24x24px) images in the country selection view of the validity check are way to large.

Uncompressed file sizes:

• flag_rs.xml - 1600 KB !
• flag_sv.xml - 730 KB
• flag_do.xml - 600 KB

Suggested Enhancement

Replace the large assets (ideally all) with a optimized SVG representations. E.g. the Serbian flag over here has the same details but the file has only 72 KB: https://github.com/hampusborgos/country-flags/blob/main/svg/rs.svg

Expected Benefits

Smaller APK size, better memory footprint and performance.

[MikeMcC399]

@G00fY2
I also noticed about the large size of flag_rs.xml when I reported and looked at the crash issue #105 in CovPass 1.12.0. I saw that this issue was resolved in 1.13.2.

In the release/1.13.x branch flag_rs.xml was reduced in size and I'm now seeing 212KB in 1.13.x instead of 1647KB in 1.12.x (or main).

That still seems excessive for use in a thumbnail size display.

(According to https://github.com/Digitaler-Impfnachweis/covpass-android/blob/main/README.md#release-policy-and-branches there may be delays in publishing the released code into the main branch and currently it is lagging behind the version 1.13.3 which has been published to the Google Play Store.)

[G00fY2]

It should be way more efficient in size and performance to generate the flags as PNG/WebP drawables, because all the vector paths to draw the emblems are not visibile at this scale. I just run a short test to see the total size of the xxxhdpi folder for all flags in 24x24px PNG -> 218 KB

[oliver-steinbrecher]

Thanks for raising this. As you already stated we've improved the sizing in release 1.13.2 . There is still room for improvements but it's a matter of priority in comparison to other topics. We're working hard to define the best priorities. Please provide more insights when you experience performance issues with the current app version. Especially share details about your device / setup.

[pucherd]

Hello @G00fY2, Thank you for your contribution, this will be part of release 1.40.0