Add SVG support via resvg

Dockerfile

@@ -1,10 +1,13 @@
 # https://github.com/emscripten-core/emsdk
 FROM docker.io/emscripten/emsdk:3.1.29
 
-# Avoid using bundled Node from emsdk
-ENV PATH=$EMSDK:$EMSDK/upstream/emscripten:$EMSDK/upstream/bin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
+ENV RUSTUP_TOOLCHAIN=nightly-2023-01-12
+
+ENV PATH=$EMSDK:$EMSDK/upstream/emscripten:$EMSDK/upstream/bin:/root/.rustup/toolchains/$RUSTUP_TOOLCHAIN-x86_64-unknown-linux-gnu/bin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
     # Enable Emscripten sysroot cache
     EM_CACHE=/src/build/emcache \
+    # Enable Rust cache
+    CARGO_HOME="/src/build/cargo-cache" \
     # Enable ccache
     CCACHE_DIR=/src/build/ccache \
     _EMCC_CCACHE=1
@@ -30,3 +33,6 @@ RUN apt-get update \
 RUN curl -Ls https://github.com/emscripten-core/emscripten/compare/3.1.29...kleisauke:wasm-vips-3.1.29.patch | patch -p1 -d /emsdk/upstream/emscripten && \
     curl -Ls https://github.com/emscripten-core/emscripten/compare/3.1.29...kleisauke:dylink-deno-compat.patch | patch -p1 -d /emsdk/upstream/emscripten && \
     emcc --clear-cache && embuilder build sysroot --force
+
+RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --profile minimal --target wasm32-unknown-emscripten --default-toolchain $RUSTUP_TOOLCHAIN --component rust-src
+RUN curl -Ls https://github.com/rust-lang/rust/pull/106779.patch | patch -p1 -d /root/.rustup/toolchains/$RUSTUP_TOOLCHAIN-x86_64-unknown-linux-gnu/lib/rustlib/src/rust

build.sh

@@ -56,6 +56,9 @@ JXL=true
 # Support for AVIF, enabled by default
 AVIF=true
 
+# Partial support for SVG via resvg, disabled by default because it's incomplete and relatively rarely useful feature.
+SVG=false
+
 # Build libvips C++ API, disabled by default
 LIBVIPS_CPP=false
 
@@ -72,6 +75,7 @@ while [ $# -gt 0 ]; do
     --disable-wasm-bigint) WASM_BIGINT=false ;;
     --disable-jxl) JXL=false ;;
     --disable-avif) AVIF=false ;;
+    --enable-svg) SVG=true ;;
     --disable-modules)
       PIC=false
       MODULES=false
@@ -105,6 +109,11 @@ if [ "$AVIF" = "true" ]; then
 else
   DISABLE_AVIF=true
 fi
+if [ "$SVG" = "true" ]; then
+  ENABLE_SVG=true
+else
+  DISABLE_SVG=true
+fi
 if [ "$LIBVIPS_CPP" = "true" ]; then
   ENABLE_LIBVIPS_CPP=true
 else
@@ -134,17 +143,27 @@ if [ "$PIC" = "true" ]; then PIC_FLAG=--pic; fi
 # Specify location where source maps are published (browser specific)
 #export LDFLAGS+=" --source-map-base http://localhost:3000/lib/"
 
+# Rust flags
+export RUSTFLAGS="-Ctarget-feature=+atomics,+bulk-memory,+mutable-globals,+nontrapping-fptoint"
+
 # Common compiler flags
 COMMON_FLAGS="-O3 -pthread"
-if [ "$LTO" = "true" ]; then COMMON_FLAGS+=" -flto"; fi
+if [ "$LTO" = "true" ]; then
+  COMMON_FLAGS+=" -flto"
+  export RUSTFLAGS+=" -Clto -Cembed-bitcode=yes"
+fi
 if [ "$WASM_EH" = "true" ]; then
   COMMON_FLAGS+=" -fwasm-exceptions -sSUPPORT_LONGJMP=wasm"
+  export RUSTFLAGS+=" -Ctarget-feature=+exception-handling"
 else
   COMMON_FLAGS+=" -fexceptions"
 fi
 
 export CFLAGS="$COMMON_FLAGS -mnontrapping-fptoint"
-if [ "$SIMD" = "true" ]; then export CFLAGS+=" -msimd128 -DWASM_SIMD_COMPAT_SLOW"; fi
+if [ "$SIMD" = "true" ]; then
+  export CFLAGS+=" -msimd128 -DWASM_SIMD_COMPAT_SLOW"
+  export RUSTFLAGS+=" -Ctarget-feature=+simd128"
+fi
 if [ "$WASM_BIGINT" = "true" ]; then
   # libffi needs to detect WASM_BIGINT support at compile time
   export CFLAGS+=" -DWASM_BIGINT"
@@ -188,6 +207,7 @@ VERSION_WEBP=1.2.4          # https://chromium.googlesource.com/webm/libwebp
 VERSION_TIFF=4.5.0          # https://gitlab.com/libtiff/libtiff
 VERSION_AOM=3.5.0           # https://aomedia.googlesource.com/aom
 VERSION_HEIF=1.14.2         # https://github.com/strukturag/libheif
+VERSION_RESVG=0.28.0        # https://github.com/RazrFalcon/resvg
 VERSION_VIPS=8.13.3         # https://github.com/libvips/libvips
 
 # Remove patch version component
@@ -403,6 +423,22 @@ node --version
   make install SUBDIRS='libtiff' noinst_PROGRAMS= dist_doc_DATA=
 )
 
+[ -f "$TARGET/lib/libresvg.a" ] || [ -n "$DISABLE_SVG" ] || (
+  stage "Compiling resvg"
+  mkdir -p $DEPS/resvg
+  curl -Ls https://github.com/RazrFalcon/resvg/releases/download/v$VERSION_RESVG/resvg-$VERSION_RESVG.tar.xz | tar xJC $DEPS/resvg --strip-components=1
+  cd $DEPS/resvg/c-api
+  # Vendor dir doesn't work with -Zbuild-std right now due to https://github.com/rust-lang/wg-cargo-std-aware/issues/23
+  # Just delete the config so that all deps are downloaded off the internet.
+  rm ../.cargo/config
+  # We don't want to build the shared library
+  sed -i 's/crate-type = .*/crate-type = ["staticlib"]/' Cargo.toml
+  # Note: --release dosn't work right now due to https://github.com/rust-lang/rust/issues/91628
+  cargo build --release --target wasm32-unknown-emscripten --locked -Zbuild-std=panic_abort,std --no-default-features --features filter,raster-images
+  cp $DEPS/resvg/target/wasm32-unknown-emscripten/release/libresvg.a $TARGET/lib/
+  cp $DEPS/resvg/c-api/resvg.h $TARGET/include/
+)
+
 [ -f "$TARGET/lib/pkgconfig/aom.pc" ] || [ -n "$DISABLE_AVIF" ] || (
   stage "Compiling aom"
   mkdir $DEPS/aom
@@ -452,13 +488,18 @@ node --version
   else
     sed -i "/subdir('cplusplus')/d" meson.build
   fi
+  if [ -n "$ENABLE_SVG" ]; then
+    # resvg patch
+    curl -Ls https://github.com/RReverser/libvips/compare/wasm-vips..wasm-vips-resvg.patch | patch -p1
+  fi
   # Disable building man pages, gettext po files, tools, and (fuzz-)tests
   sed -i "/subdir('man')/{N;N;N;N;d;}" meson.build
   meson setup _build --prefix=$TARGET --cross-file=$MESON_CROSS --default-library=static --buildtype=release \
     -Ddeprecated=false -Dintrospection=false -Dauto_features=disabled ${ENABLE_MODULES:+-Dmodules=enabled} \
     -Dcgif=enabled -Dexif=enabled -Dimagequant=enabled -Djpeg=enabled ${ENABLE_JXL:+-Djpeg-xl=enabled} \
     -Djpeg-xl-module=enabled -Dlcms=enabled -Dspng=enabled -Dtiff=enabled -Dwebp=enabled -Dnsgif=true \
-    -Dppm=true -Danalyze=true -Dradiance=true ${ENABLE_AVIF:+-Dheif=enabled} -Dheif-module=enabled
+    -Dppm=true -Danalyze=true -Dradiance=true \
+    ${ENABLE_SVG:+-Dresvg=enabled} ${ENABLE_AVIF:+-Dheif=enabled} -Dheif-module=enabled
   meson install -C _build --tag runtime,devel
   # Emscripten requires linking to side modules to find the necessary symbols to export
   module_dir=$(printf '%s\n' $TARGET/lib/vips-modules-* | sort -n | tail -1)