tree e8b5cd022a1c891b5c5495bba954689c80226d84
parent 19e65028847461c3ac922aaad68efc79c4bd41ea
author xunchang <xunchang@google.com> 1544213537 -0800
committer xunchang <xunchang@google.com> 1544500418 -0800

recovery text image: use zopflipng to compress the generated images

Generate the images for recovery's wipe data menu. And use the lossless
tool zopflipng to compress the generated image. This saves space
in the boot image at the cost of the increase of build time. In practice,
it adds about ~20 seconds to build the bootimage with 32 threads.

zopflipng generally runs slower. Even with a predefined filters
strategy, it runs about 3 times slower than pngcrush, e.g. ~40s vs 15s
to compress a 1.8M png file. However, zopflipng also gives a better
compression: ~1.4M vs 1.6M for the same image. So I guess the time
consumption is a price worth paying.

Bug: 74397117
Test: build the bootimage and check the resource images
Change-Id: I3e71f8bedd3c183a3374b1a9464bf05500e1aa61