media-libs/libavif: new package

libavif is a library to work with .AVIF files.
In order to save AVIF file you need one
of the following live ebuilds:
media-libs/libaom-9999
media-video/rav1e-9999

Package-Manager: Portage-2.3.89, Repoman-2.3.20
RepoMan-Options: --force
Signed-off-by: Daniel Novomesky <dnovomesky@gmail.com>

media-libs/libavif/Manifest

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+DIST libavif-0.6.4.tar.gz 2880753 BLAKE2B d42e106a67aa82e4e9cd28488e6393e100e78bf381f8db6f9563c8563eec8c8afe64dedd4b3cdcadc296f15472995cee979469230085aa27a19a48f2d01f5e6a SHA512 ccd9ef462b9a235914f08a75f7acefc1592037e14967089bbc118838ba3603aa527f20b842c658b357f159de28dede15ab80e27f08a19ad3456247970c0ad822

media-libs/libavif/libavif-0.6.4.ebuild

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+# Copyright 1999-2020 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+inherit cmake
+
+DESCRIPTION="Library for encoding and decoding .avif files"
+HOMEPAGE="https://github.com/AOMediaCodec/libavif"
+SRC_URI="https://github.com/AOMediaCodec/libavif/archive/v${PV}.tar.gz -> ${P}.tar.gz"
+
+LICENSE="BSD-2"
+SLOT="0"
+KEYWORDS="~amd64"
+IUSE="dav1d +libaom rav1e"
+
+REQUIRED_USE="|| ( dav1d libaom )"
+
+DEPEND="dav1d? ( media-libs/dav1d )
+	libaom? ( >=media-libs/libaom-1.1 )
+	rav1e? ( media-video/rav1e[capi] )
+	media-libs/libpng
+"
+RDEPEND="${DEPEND}"
+BDEPEND=""
+
+src_configure() {
+	local mycmakeargs=(
+		-DAVIF_CODEC_DAV1D=$(usex dav1d ON OFF)
+		-DAVIF_CODEC_AOM=$(usex libaom ON OFF)
+		-DAVIF_CODEC_RAV1E=$(usex rav1e ON OFF)
+		-DBUILD_SHARED_LIBS=ON
+		-DAVIF_BUILD_APPS=ON
+	)
+	cmake_src_configure
+}
+
+pkg_postinst() {
+	if ! use libaom && ! use rav1e ; then
+		ewarn "libaom and rav1e flags are not set,"
+		ewarn "libavif will work in read-only mode."
+		ewarn "Enable libaom or rav1e flag if you want to save .AVIF files."
+	fi
+
+	if use libaom ; then
+		elog "When you upgrade libaom in the future,"
+		elog " you may need to re-emerge libavif again"
+		elog " to ensure correct AVIF import/export functions."
+	fi
+
+	if use rav1e ; then
+		elog "When you upgrade rav1e in the future,"
+		elog " you may need to re-emerge libavif again"
+		elog " to ensure correct AVIF export function."
+	fi
+}

media-libs/libavif/metadata.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM 'http://www.gentoo.org/dtd/metadata.dtd'>
+<pkgmetadata>
+	<maintainer type="person">
+		<email>dnovomesky@gmail.com</email>
+		<name>Daniel Novomesky</name>
+		<description>Library for encoding and decoding .avif files</description>
+	</maintainer>
+	<use>
+		<flag name="dav1d">Enable faster decoding via dav1d</flag>
+		<flag name="libaom">Use encoding/decoding via libaom</flag>
+		<flag name="rav1e">Allow encoding via rav1e</flag>
+	</use>
+</pkgmetadata>