decoder: Load HEIC/x265 as plugin

Closes #85

Part-of: <https://gitlab.gnome.org/Incubator/loupe/-/merge_requests/123>

Cargo.lock

@@ -1801,12 +1801,13 @@ dependencies = [
 
 [[package]]
 name = "libheif-rs"
-version = "0.18.0"
+version = "0.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37d09b0d2d69da084eeeda9534662bc6b6096fbce3f307149750c0e572ad0ccd"
+checksum = "7fcb2c12bbd85e40a36c704003f353f193f99476985fe89251423b6d0778f5c4"
 dependencies = [
  "enumn",
  "four-cc",
+ "libc",
  "libheif-sys",
 ]
 

Cargo.toml

@@ -29,7 +29,7 @@ url = "2.3.1"
 
 # decoders
 image-rs = { package = "image", version = "*", git = "https://github.com/image-rs/image.git" }
-libheif-rs = "0.18.0"
+libheif-rs = "0.19.0"
 librsvg = { git = "https://gitlab.gnome.org/GNOME/librsvg.git" }
 
 [dependencies.ashpd]

build-aux/flatpak/org.gnome.Loupe.Devel.json

@@ -44,6 +44,19 @@
         "*.la",
         "*.a"
     ],
+    "add-extensions": {
+        /* Exile HEIC (x265) codec into extension */
+        "org.gnome.Loupe.Devel.HEIC" : {
+            /* Relative to app dir */
+            "directory" : "lib/libheif-heic",
+            /* Relative to directory above */
+            "add-ld-path" : "lib",
+            /* Remove extension data from main flatpak package */
+            "bundle" : true,
+            /* Remove this extension when Loupe is deinstalled */
+            "autodelete" : true
+        }
+    },
     "modules" : [
         {
             "name": "geocode-glib",
@@ -91,10 +104,42 @@
             ]
         },
         {
+            /* HEIC (x265) decoder */
+            "name" : "libde265",
+            "buildsystem" : "cmake",
+            "config-opts": [
+                /* Install into folder for extension */
+                "-DCMAKE_INSTALL_PREFIX=/app/lib/libheif-heic",
+                "-DENABLE_SDL=Off"
+            ],
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://github.com/strukturag/libde265.git",
+                    "tag" : "v1.0.11"
+                }
+            ]
+	},
+	{
             "name" : "libheif",
             "buildsystem" : "cmake",
             "config-opts": [
-
+                /* Build HEIC (x265) as plugin */
+                "-DWITH_LIBDE265_PLUGIN=On",
+                "-DPLUGIN_DIRECTORY=/app/lib/libheif-heic/lib",
+                "-DLIBDE265_INCLUDE_DIR=/app/lib/libheif-heic/include",
+                "-DLIBDE265_PKGCONF_LIBRARY_DIRS=/app/lib/libheif-heic/lib",
+                /* Turn all encoders off */
+                "-DWITH_X265=Off",
+                "-DWITH_SvtEnc=Off",
+                "-DWITH_SvtEnc_PLUGIN=Off",
+                "-DWITH_AOM_ENCODER=Off",
+                /* Turn off plugins for AV1 */
+                "-DWITH_RAV1E_PLUGIN=Off",
+                /* Turn off unused AV1 decoders */
+                "-DWITH_RAV1E=Off",
+                /* No need for examples */
+                "-DWITH_EXAMPLES=Off"
             ],
             "sources" : [
                 {

src/decoder/formats/heif.rs

@@ -7,7 +7,8 @@ use gtk::prelude::*;
 
 use anyhow::Context;
 use arc_swap::ArcSwap;
-use libheif_rs::{ColorSpace, HeifContext, Plane, RgbChroma};
+use libheif_rs::{ColorSpace, HeifContext, LibHeif, Plane, RgbChroma};
+use once_cell::sync::Lazy;
 
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -15,6 +16,9 @@ use std::sync::Arc;
 #[derive(Debug)]
 pub struct Heif;
 
+/// Loads plugins on first use
+static LIBHEIF: Lazy<LibHeif> = Lazy::new(LibHeif::new);
+
 impl Heif {
     pub fn new(
         path: PathBuf,
@@ -55,8 +59,8 @@ impl Heif {
                 RgbChroma::Rgb
             };
 
-            let mut image = handle
-                .decode(ColorSpace::Rgb(rgb_chroma), None)
+            let mut image = LIBHEIF
+                .decode(&handle, ColorSpace::Rgb(rgb_chroma), None)
                 .context(i18n("Failed to decode image"))?;
 
             let plane = image