Investigate pdfium as a possible replacement PDF loader

[jcupitt]

pdfium is a very fast PDF rendering library, perhaps 2x to 5x faster than poppler.

https://pdfium.googlesource.com/pdfium/

https://github.com/nathanstitt/dc-pdf-raster-test

It's currently a little immature in terms of packaging -- when there's an official Debian package, investigate a pdfload using this instead of poppler.

[jcupitt]

Tried to build with these steps:

Install depot tools

    cd GIT
    git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
    export PATH=`pwd`/depot_tools:"$PATH"

Fetch PDFium

    gclient config --unmanaged https://pdfium.googlesource.com/pdfium.git
    gclient sync

Pull in other deps

    cd pdfium
    ./build/install-build-deps.sh

Fails saying Ubuntu 17.04 is not a supported build platform.

Links

http://www.chromium.org/developers/how-tos/install-depot-tools
https://pdfium.googlesource.com/pdfium/

[BoLaMN]

i put together a build script you can throw in docker to make it easier to get a packaged lib will generate a tar.gz with the include & lib folders

#!/usr/bin/env bash

set -e

PLATFORM=linux-x64
LIBNAME="libpdfium-dev"

git=$(which git)

BUILD_DIR="$(pwd)/build"
BUILD_PKG="$(pwd)/package"

BUILD_PDFIUM="${BUILD_DIR}/pdfium-${VERSION_PDFIUM}"
BUILD_RES="out/Release_${PLATFORM}"

TARGET_PDFIUM="$(pwd)/target"

mkdir -p ${BUILD_DIR}
cd ${BUILD_DIR}

DEPOT_TOOLS="${BUILD_DIR}/depot_tools"

if [ ! -d "${DEPOT_TOOLS}" ]; then
    ${git} clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
fi

export PATH="${DEPOT_TOOLS}":"$PATH"

gclient config --unmanaged https://pdfium.googlesource.com/pdfium.git
gclient sync

cd pdfium

gn gen "${BUILD_RES}" --args='pdf_bundle_freetype = true pdf_enable_v8 = false pdf_enable_xfa = false pdf_use_skia = false pdf_use_skia_paths = false is_component_build = true pdf_is_complete_lib = true'

ninja -C "${BUILD_RES}"

if [ -d ${BUILD_PDFIUM} ]; then
    rm -rf ${BUILD_PDFIUM}
fi

mkdir -p ${BUILD_PDFIUM}

if [ -d ${TARGET_PDFIUM} ]; then
    rm -rf ${TARGET_PDFIUM}
fi

mkdir -p ${TARGET_PDFIUM}
mkdir -p "${TARGET_PDFIUM}/lib"
mkdir -p "${TARGET_PDFIUM}/include"

find ${BUILD_RES} -name '*.a' -not -path "**/testing/*" -not -path "**/build/*" -not -name 'libtest_support.a' -exec cp {} ${TARGET_PDFIUM}/lib \;

cp public/*.h ${TARGET_PDFIUM}/include

if [ -d ${BUILD_PKG} ]; then
    rm -rf ${BUILD_PKG}
fi

mkdir -p ${BUILD_PKG}

cd ${TARGET_PDFIUM}

tar czf /${BUILD_PKG}/libpdfium-${VERSION_PDFIUM}-${PLATFORM}.tar.gz include lib

i noticed libreoffice now use pdfium for rendering pdfs as images too

https://github.com/LibreOffice/core/blob/master/vcl/source/filter/ipdf/pdfread.cxx

[jcupitt]

I made a repo with a tweaked version of @BoLaMN 's nice script:

https://github.com/jcupitt/build-pdfium

It makes a libpdfium.tar.gz, and I included the binary for convenience. I had to turn off sysroot and patch some v8 flags. I don't know much about Docker, no doubt it can be fixed up.

Of course it's built for xenial, so you'll probaly need to build on that as well, which is a pain.

[BoLaMN]

Nice! I'll see if I can wire up some travis-ci builds

it built successfully on OS X but atm I don't have a windows box to write a script against but it should be pretty similar with something like https://gist.github.com/BoLaMN/e26ac403cbe7a6057f488f895f3a2785

[tomasc]

It would be fantastic to improve the speed of PDF rendering in libvips.

I have been using libpoppler backed libvips, however with any larger PDF (100MB+) rendering a single page might take up to 10 seconds or even more.

For now, the work around I am using is to pre-render the page using MuPDF to PNG (mutool convert does not support JPG among others) and then use libvips for JPG conversion. The performance gain is significant and corresponds to the findings in the raters tests.

[swftvsn]

This change would be really appreciated! Any news about this lately? And can I help in it somehow? (I have fairly limited experience here..)

[jcupitt]

I had another look: pdfium now builds on current Ubuntu, so that's a good step forward. I updated my build-pdfium repo and I now have a binary for my platform.

I'll make a branch to experiment with it in.

[swftvsn]

Awesome news! Don't know if this is obvious, but here's an example how they render to png in their tests: https://pdfium.googlesource.com/pdfium/+/master/samples/pdfium_test.cc (And ppm and what not)

[tomasc]

Just to add to this – I am currently rerouting to MuPDF for conversion and then loading the result back to libvips. Having libvips fast by default would be super!

[swftvsn]

I just built by hand the pdfium test package and am using it to preprocess stuff before libvips until this hits stable. So far it's proven to be both faster and to produce better quality when fed our library of problematic PDFs! Really excited!

[jcupitt]

Branch here:

https://github.com/jcupitt/libvips/tree/pdfium-experiment

Though it doesn't do much yet. I can't even get a basic pdfium "hello world" program to link correctly :(

[jcupitt]

... it's now detecting and linking to PDFium, at least if it's been packaged by the build-pdfium repo above. I'll have a quick go at a load operation.