pdfium-render
provides an idiomatic high-level Rust interface to Pdfium, the C++ PDF library
used by the Google Chromium project. With this library, you can render pages in PDF files to
bitmaps, load, edit, and extract text and images from existing PDF files, and create new PDF files
from scratch.
use pdfium_render::prelude::*;
fn export_pdf_to_jpegs(path: &str, password: Option<&str>) -> Result<(), PdfiumError> {
// Renders each page in the given test PDF file to a separate JPEG file.
// Bind to a Pdfium library in the same directory as our Rust executable;
// failing that, fall back to using a Pdfium library provided by the operating system.
let pdfium = Pdfium::new(
Pdfium::bind_to_library(Pdfium::pdfium_platform_library_name_at_path("./"))
.or_else(|_| Pdfium::bind_to_system_library())?,
);
// Load the document...
let document = pdfium.load_pdf_from_file(path, password)?;
// ... set rendering options that will be applied to all pages...
let render_config = PdfRenderConfig::new()
.set_target_width(2000)
.set_maximum_height(2000)
.rotate_if_landscape(PdfBitmapRotation::Degrees90, true);
// ... then render each page to a bitmap image, saving each image to a JPEG file.
for (index, page) in document.pages().iter().enumerate() {
page.render_with_config(&render_config)?
.as_image() // Renders this page to an image::DynamicImage...
.as_rgba8() // ... then converts it to an image::Image...
.ok_or(PdfiumError::ImageError)?
.save_with_format(
format!("test-page-{}.jpg", index),
image::ImageFormat::Jpeg
) // ... and saves it to a file.
.map_err(|_| PdfiumError::ImageError)?;
}
Ok(())
}
pdfium-render
binds to a Pdfium library at run-time, allowing for flexible selection of
system-provided or bundled Pdfium libraries and providing idiomatic Rust error handling in
situations where a Pdfium library is not available. A key advantage of binding to Pdfium at run-time
rather than compile-time is that a Rust application using pdfium-render
can be compiled to WASM
for running in a browser alongside a WASM-packaged build of Pdfium.
pdfium-render
aims to eventually provide bindings to all non-interactive functionality provided
by Pdfium. This is a work in progress that will be completed by version 1.0 of this crate.
Short, commented examples that demonstrate all the major Pdfium document handling features are available at https://github.com/ajrcarey/pdfium-render/tree/master/examples. These examples demonstrate:
- Rendering pages to bitmaps.
- Text and image extraction.
- Page object introspection.
- Page annotation introspection.
- Creation of new documents and new pages.
- Creation of page objects for text, paths, and bitmaps.
- Document concatenation.
- Multi-page tiled output.
- Watermarking.
- Thread safety.
- Compiling to WASM.
Version 0.7.15 adds additional functions for working with page annotations, including retrieval of annotation names, author names, comments, creation and modification timestamps, and text and character ranges linked to annotations.
Version 0.7.14 adds compatibility with web workers to the WASM implementation of pdfium-render
,
thanks to an excellent contribution from https://github.com/NyxCode.
Version 0.7.13 adds transformation functions to PdfRenderConfig
, allowing a page to be optionally
moved, scaled, rotated, and skewed during rendering, and adds clipping support to PdfRenderConfig
,
allowing for rendering of only a portion of a page.
Version 0.7.12 adds additional page rendering functions PdfPage::render_into_bitmap()
and
PdfPage::render_into_bitmap_with_config()
. These functions offer higher performance as they
allow re-using an existing PdfBitmap
object rather than creating (and allocating memory for)
a new PdfBitmap
on every page render.
pdfium-render
does not include Pdfium itself. You have several options:
- Bind to a dynamically-built Pdfium library provided by the operating system.
- Bind to a dynamically-built Pdfium library packaged alongside your Rust executable.
- Bind to a statically-built Pdfium library linked to your executable at compile time.
When compiling to WASM, packaging an external build of Pdfium as a separate WASM module is essential.
Binding to a dynamically-built Pdfium library is the simplest option. On Android, a system-provided
libpdfium.so
is packaged as part of the operating system (although recent versions of Android no
longer permit user applications to access it); alternatively, you can package a pre-built
dynamic library appropriate for your operating system alongside your Rust executable.
- Native (i.e. non-WASM) builds of Pdfium for all major platforms: https://github.com/bblanchon/pdfium-binaries/releases
- WASM builds of Pdfium: https://github.com/paulocoutinhox/pdfium-lib/releases
If you are compiling a native (i.e. non-WASM) build, and you place an appropriate Pdfium library in the same folder as your compiled application, then binding to it dynamically at runtime is as simple as:
use pdfium_render::prelude::*;
let pdfium = Pdfium::new(
Pdfium::bind_to_library(Pdfium::pdfium_platform_library_name_at_path("./")).unwrap()
);
A common pattern used in the examples at https://github.com/ajrcarey/pdfium-render/tree/master/examples is to first attempt to bind to a Pdfium library in the same folder as the compiled example, and attempt to fall back to a system-provided library if that fails:
use pdfium_render::prelude::*;
let pdfium = Pdfium::new(
Pdfium::bind_to_library(Pdfium::pdfium_platform_library_name_at_path("./"))
.or_else(|_| Pdfium::bind_to_system_library())
.unwrap() // Or use the ? unwrapping operator to pass any error up to the caller
);
At the time of writing, the WASM builds at https://github.com/bblanchon/pdfium-binaries/releases are compiled with a non-growable WASM heap memory allocator. This means that attempting to open a PDF document longer than just a few pages will result in an unrecoverable out of memory error. The WASM builds at https://github.com/paulocoutinhox/pdfium-lib/releases are recommended as they do not have this problem.
If you prefer to link Pdfium directly into your executable at compile time, use the optional static
crate feature. This enables the Pdfium::bind_to_statically_linked_library()
function which binds
directly to the Pdfium functions included in your executable:
use pdfium_render::prelude::*;
let pdfium = Pdfium::new(Pdfium::bind_to_statically_linked_library().unwrap());
As a convenience, pdfium-render
can instruct cargo
to link a statically-built Pdfium
library for you. Set the path to the directory containing your pre-built library using
the PDFIUM_STATIC_LIB_PATH
environment variable when you run cargo build
, like so:
PDFIUM_STATIC_LIB_PATH="/path/containing/your/static/pdfium/library" cargo build
pdfium-render
will pass the following flags to cargo
:
cargo:rustc-link-lib=static=pdfium
cargo:rustc-link-search=native=$PDFIUM_STATIC_LIB_PATH
This saves you writing a custom build.rs
yourself. If you have your own build pipeline
that links Pdfium statically into your executable, simply leave the PDFIUM_STATIC_LIB_PATH
environment variable unset.
Note that the path you set in PDFIUM_STATIC_LIB_PATH
should not include the filename of the
library itself; it should just be the path of the containing directory. You must make sure your
statically-built library is named in the appropriate way for your target platform
(libpdfium.a
on Linux and macOS, for example) in order for the Rust compiler to locate it.
pdfium-render
will not build Pdfium for you; you must build Pdfium yourself, or source a
pre-built static archive from elsewhere.
See https://github.com/ajrcarey/pdfium-render/tree/master/examples for a full example that shows
how to bundle a Rust application using pdfium-render
alongside a pre-built Pdfium WASM module for
inspection and rendering of PDF files in a web browser.
The Pdfium::load_pdf_from_file()
and Pdfium::load_pdf_from_reader()
functions are not available
when running in the browser. The Pdfium::load_pdf_from_bytes()
function is available, and
the following additional functions are provided:
- The
Pdfium::load_pdf_from_fetch()
function uses the browser's built-infetch()
API to download a URL over the network and open it as a PDF document. - The
Pdfium::load_pdf_from_blob()
function opens a PDF document from the byte data in a JavascriptBlob
orFile
object, includingFile
objects returned from an<input type="file">
element.
The PdfDocument::save_to_file()
function is not available when running in the browser.
The PdfDocument::save_to_bytes()
and PdfDocument::save_to_writer()
functions are
available, and the following additional function is provided:
- The
PdfDocument::save_to_blob()
function returns the byte data for the document as a JavascriptBlob
object.
The following additional functions are provided during rendering:
- The
PdfBitmap::as_image_data()
function renders directly to a JavascriptImageData
object, ready to display in an HTML<canvas>
element. - The
PdfBitmap::as_array()
function renders directly to a JavascriptUint8Array
object. This function avoids a memory allocation and copy required by bothPdfBitmap::as_bytes()
andPdfBitmap::as_image_data()
, making it preferable for applications where performance is paramount.
The PdfFont::load_type1_from_file()
and PdfFont::load_true_type_from_file()
functions are
not available when running in the browser. The following additional functions are provided:
- The
PdfFont::load_type1_from_fetch()
function uses the browser's built-infetch()
API to download a URL over the network and load it as a Type 1 font. - The
PdfFont::load_true_type_from_fetch()
function uses the browser's built-infetch()
API to download a URL over the network and load it as a TrueType font. - The
PdfFont::load_type1_from_blob()
function loads a Type 1 font from the byte data in a JavascriptBlob
orFile
object, includingFile
objects returned from an<input type="file">
element. - The
PdfFont::load_true_type_from_blob()
function loads a TrueType font from the byte data in a JavascriptBlob
orFile
object, includingFile
objects returned from an<input type="file">
element.
Pdfium makes no guarantees about thread safety and should be assumed not to be thread safe. The Pdfium authors specifically recommend that parallel processing, not multi-threading, be used to process multiple documents simultaneously.
pdfium-render
achieves thread safety by locking access to Pdfium behind a mutex;
each thread must acquire exclusive access to this mutex in order to make any call to Pdfium.
This has the effect of sequencing all calls to Pdfium as if they were single-threaded,
even when using pdfium-render
from multiple threads. This approach offers no performance benefit,
but it ensures that Pdfium will not crash when running as part of a multi-threaded application.
An example of safely using pdfium-render
as part of a multithreaded parallel iterator is
available at https://github.com/ajrcarey/pdfium-render/tree/master/examples.
This crate provides the following optional features:
bindings
: usescbindgen
to generate Rust bindings to the Pdfium functions defined in theinclude/*.h
files each timecargo build
is run. Ifcbindgen
or any of its dependencies are not available then the build will fail.static
: enables binding to a statically-linked build of Pdfium. See the "Static linking" section above.thread_safe
: wraps access to Pdfium behind a mutex to ensure thread-safe access to Pdfium. See the "Multithreading" section above.
The thread_safe
feature is enabled by default. All other features are disabled by default.
The high-level idiomatic Rust interface provided by pdfium-render
is built on top of
raw FFI bindings defined in the PdfiumLibraryBindings
trait. It is completely feasible to use
these raw FFI bindings directly if you wish, making porting existing code that calls FPDF_*
functions
trivial while still gaining the benefits of late binding and WASM compatibility.
For instance, the following code snippet (taken from a C++ sample):
string test_doc = "test.pdf";
FPDF_InitLibrary();
FPDF_DOCUMENT doc = FPDF_LoadDocument(test_doc, NULL);
// ... do something with doc
FPDF_CloseDocument(doc);
FPDF_DestroyLibrary();
would translate to the following Rust code:
let bindings = Pdfium::bind_to_system_library().unwrap();
let test_doc = "test.pdf";
bindings.FPDF_InitLibrary();
let doc = bindings.FPDF_LoadDocument(test_doc, None);
// ... do something with doc
bindings.FPDF_CloseDocument(doc);
bindings.FPDF_DestroyLibrary();
Pdfium's API uses three different string types: classic C-style null-terminated char arrays,
UTF-8 byte arrays, and a UTF-16LE byte array type named FPDF_WIDESTRING
. For functions that take a
C-style string or a UTF-8 byte array, pdfium-render
's binding will take the standard Rust &str
type.
For functions that take an FPDF_WIDESTRING
, pdfium-render
exposes two functions: the vanilla
FPDF_*()
function that takes an FPDF_WIDESTRING
, and an additional FPDF_*_str()
helper function
that takes a standard Rust &str
and converts it internally to an FPDF_WIDESTRING
before calling
Pdfium. Examples of functions with additional _str()
helpers include FPDFBookmark_Find()
,
FPDFAnnot_SetStringValue()
, and FPDFText_SetText()
.
The PdfiumLibraryBindings::get_pdfium_utf16le_bytes_from_str()
and
PdfiumLibraryBindings::get_string_from_pdfium_utf16le_bytes()
utility functions are provided
for converting to and from FPDF_WIDESTRING
in your own code.
The initial focus of this crate was on rendering pages in a PDF file; consequently, FPDF_*
functions related to page rendering were prioritised. By 1.0, the functionality of all
FPDF_*
functions exported by all Pdfium modules will be available, with the exception of certain
functions specific to interactive scripting, user interaction, and printing.
- Releases numbered 0.4.x added support for all page rendering Pdfium functions to
pdfium-render
. - Releases numbered 0.5.x-0.6.x added support for most read-only Pdfium functions to
pdfium-render
. - Releases numbered 0.7.x aim to progressively add support for all Pdfium page object creation and editing functions to
pdfium-render
. - Releases numbered 0.8.x aim to progressively add support for all other Pdfium editing functions to
pdfium-render
. - Releases numbered 0.9.x aim to fill any remaining gaps in the high-level interface prior to 1.0.
By version 0.8.0, pdfium-render
should provide useful coverage for the vast majority of common
use cases, whether rendering existing documents or creating new ones.
There are 368 FPDF_*
functions in the Pdfium API. As of version 0.7.14, 270 (73%) have
bindings available in pdfium-render
, with the functionality of roughly three-quarters of these
available via the pdfium-render
high-level interface.
Some functions and type definitions in the high-level interface have been renamed or revised since their initial implementation. The initial implementations are still available but are marked as deprecated. These deprecated items will be removed in release 0.9.0.
If you need a binding to a Pdfium function that is not currently available, just raise an issue.
- 0.7.15: adds
PdfPageAnnotationCommon::name()
,PdfPageAnnotationCommon::contents()
,PdfPageAnnotationCommon::author()
,PdfPageAnnotationCommon::creation_date()
, andPdfPageAnnotationCommon::modification_date()
functions for working with annotations; addsPdfPageText::for_annotation()
andPdfPageText::chars_for_annotation()
for more easily extracting text and characters associated with annotations; addsexamples/annotations.rs
andexamples/image_extract.rs
; renamesexamples/text.rs
toexamples/text_extract.rs
. - 0.7.14: fixes a bug in the WASM implementation of
FPDF_StructElement_GetStringAttribute()
; pins required version ofimage
crate to at least 0.24.0 or later to avoid incompatibility between theimage::DynamicImage
trait definitions in 0.23.x and 0.24.x; adds compatibility with web workers to the WASM implementation, thanks to an excellent contribution from https://github.com/NyxCode. - 0.7.13: adds transformation and clipping functions to
PdfRenderConfig
; adds bindings forFPDF_RenderPageBitmapWithMatrix()
; deprecatesPdfRenderConfig::rotate_if_portait()
in favour of the correctly-spelledPdfRenderConfig::rotate_if_portrait()
. Deprecated items will be removed in release 0.9.0. - 0.7.12: adds
PdfPage::render_into_bitmap()
andPdfPage::render_into_bitmap_with_config()
functions for higher performance; deprecatesPdfPage::get_bitmap()
in favour ofPdfPage::render()
; deprecatesPdfPage::get_bitmap_with_config()
in favour ofPdfPage::render_with_config()
; deprecatesPdfBitmapConfig
in favour ofPdfRenderConfig
; deprecatesPdfBitmap::render()
as the function is no longer necessary. Deprecated items will be removed in release 0.9.0. - 0.7.11: adds the new WASM-specific
PdfBitmap::as_array()
function as a higher performance alternative to the cross-platformPdfBitmap::as_bytes()
function, thanks to an excellent contribution from https://github.com/NyxCode. - 0.7.10: corrects some typos in documentation; adds additional constructors to
PdfPageImageObject
that apply a specified width and/or height at object creation time. - 0.7.9: adds retrieval of the list of image filters applied to a
PdfPageImageObject
; adds thePdfColorSpace
enum; adds bindings for theFPDF_*Signature*()
,FPDFSignatureObj_*()
, andFPDF_StructTree_*()
functions. - 0.7.8: adds image support to the
PdfPageImageObject
struct, thePdfPageObjects::add_image_object()
andPdfPageObjects::create_image_object()
functions, additional convenience functions for loading fonts from files and readers toPdfFont
, and bindings forFPDF_VIEWERREF_Get*()
functions. - 0.7.7: adds the
thread_safe
crate feature and the accompanying example inexamples/thread_safe.rs
. - 0.7.6: adds retrieval of text settings on a character-by-character basis to the
PdfPageText
andPdfPageTextObject
objects; addsPdfPageTextSegment
andPdfPageTextChar
structs to the high-level interface; adds retrieval of current transformation settings to all page objects; adds thePdfPageTextObject::scaled_font_size()
function and renamesPdfPageTextObject::font_size()
toPdfPageTextObject::unscaled_font_size()
as these names make clearer the differences between scaled and unscaled font sizes in text objects; adds bindings for all remainingFPDFText_*()
functions. - 0.7.5: corrects a bug in error handling on Windows. See ajrcarey#24 for more information.
- 0.7.4: adds the
PdfPageGroupObject::remove_objects_from_page()
function; renamedPdfPageObjects::delete_object()
andPdfPageObjects::delete_object_at_index()
functions toPdfPageObjects::remove_object()
andPdfPageObjects::remove_object_at_index()
as these names better reflect the underlying operation that occurs. - 0.7.3: corrects a bug in the implementation of
PdfPages::append()
introduced in 0.7.2. - 0.7.2: adds object groups for manipulating and transforming groups of page objects as if they
were a single object, and the
PdfPages::watermark()
function for applying individualized watermarks to any or all pages in a document. Fixes a potential double-free bug inPdfFont::drop()
. - 0.7.1: adds path segment creation to the
PdfPagePathObject
object, convenience functions for quickly creating rectangles, ellipses, and circles, and thePdfPageObjects::add_path_object()
function. - 0.7.0: adds
PdfPermissions
collection, adds document loading and saving support, adds initial creation and editing support for documents, pages, and text objects, and improves WASM document file handling. - 0.6.0: fixes some typos in documentation, updates upstream Pdfium WASM package source repository name.
- 0.5.9: corrects a bug in the statically linked bindings implementation. Adjusted tests to cover both dynamic and statically linked bindings implementations.
- 0.5.8: corrects a bug in the WASM implementation of certain
FPDFAnnot_*()
functions. Resolves a potential memory leak affecting the WASM implementation of variousFPDF_*()
functions. - 0.5.7: adds support for binding to a statically-linked build of Pdfium, adds
bindgen
andstatic
crate features. - 0.5.6: adds
pdfium_render::prelude
, adds bindings forFPDFAnnot_*()
andFPDFPage_*Annot*()
functions, addsPdfPageAnnotations
collection andPdfPageAnnotation
struct to the high-level interface. - 0.5.5: fixes two bugs in the WASM implementation, one to do with colors, one to do with text extraction. See ajrcarey#9 and ajrcarey#11 for more information.
- 0.5.4: changes default setting of
PdfBitmapConfig::set_reverse_byte_order()
totrue
to switch from Pdfium's default BGRA8 pixel format to RGBA8. This is necessary since theimage
crate dropped support for BGRA8 in version 0.24. See ajrcarey#9 for more information. - 0.5.3: adds bindings for
FPDFBookmark_*()
,FPDFPageObj_*()
,FPDFText_*()
, andFPDFFont_*()
functions, addsPdfPageObjects
,PdfPageText
, andPdfBookmarks
collections to the high-level interface. - 0.5.2: adds bindings for
FPDF_GetPageBoundingBox()
,FPDFDoc_GetPageMode()
,FPDFPage_Get*Box()
, andFPDFPage_Set*Box()
functions, addsPdfPageBoundaries
collection to the high-level interface. - 0.5.1: adds bindings for
FPDFPage_GetRotation()
andFPDFPage_SetRotation()
functions, addsPdfMetadata
collection to the high-level interface. - 0.5.0: adds rendering of annotations and form field elements, thanks to an excellent contribution from https://github.com/inzanez.
- 0.4.2: bug fixes in
PdfBitmapConfig
implementation. - 0.4.1: improvements to documentation and READMEs.
- 0.4.0: initial release of minimal page rendering functionality.