Idiomatic Rust bindings for Pdfium

pdfium-render provides an idiomatic high-level Rust interface around the low-level bindings to Pdfium exposed by the excellent pdfium-sys crate.

``` // Exports each page in the given test PDF file as a separate JPEG image.

use pdfium_render::{pdfium::Pdfium, bitmap::PdfBitmapRotation, bitmap_config::PdfBitmapConfig};
use image::ImageFormat;

// Bind to the system-provided Pdfium library.

let pdfium = Pdfium::new(Pdfium::bind_to_system_library().unwrap());

// Load a PDF file.

let document = pdfium.load_pdf_from_file("test.pdf", None).unwrap();

// Set our desired bitmap rendering options.

let bitmap_render_config = PdfBitmapConfig::new()
    .set_target_width(2000)
    .set_maximum_height(2000)
    .rotate_if_landscape(PdfBitmapRotation::Degrees90, true);

// Render each page to a bitmap, saving each as a JPEG.

document.pages().iter().for_each(|page| {
    page.get_bitmap_with_config(&bitmap_render_config).unwrap()
        .as_image() // Renders this page to an Image::DynamicImage
        .as_rgba8().unwrap()
        .save_with_format(format!("test-page-{}.jpg", page.index()), ImageFormat::Jpeg).unwrap();
});

```

In addition to providing a more natural interface to Pdfium, pdfium-render differs from pdfium-sys in several other important ways:

More examples, demonstrating page rendering, text extraction, page object introspection, and compiling to WASM are available at https://github.com/ajrcarey/pdfium-render/tree/master/examples.

What's new

Version 0.5.3 adds bindings to Pdfium's FPDFBookmark_*(), FPDFPageObj_*(), FPDFText_*(), and FPDFFont_*() functions and adds the PdfPageObjects, PdfPageText, and PdfBookmarks collections to the pdfium-render high-level interface. These additions make it possible to extract the text from PDF pages and page objects.

Porting existing Pdfium code from other languages

The high-level idiomatic Rust interface provided by the Pdfium struct is entirely optional; the Pdfium struct wraps around raw FFI bindings defined in the PdfiumLibraryBindings trait, and it is completely feasible to simply use the FFI bindings directly instead of the high level interface. This makes 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::bindtosystem_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();

```

External Pdfium builds

pdfium-render does not include Pdfium itself. You can either bind to a system-provided library or package an external build of Pdfium alongside your Rust application. When compiling to WASM, packaging an external build of Pdfium as a separate WASM module is essential.

Compiling to WASM

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.

Development status

The initial focus of this crate has been on rendering pages in a PDF file; consequently, FPDF* functions related to bitmaps and rendering have been 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.

If you need a function that is not currently exposed, just raise an issue.

Version history