libvips/libvips/foreign/pdfload_pdfium.c

/* load PDF with PDFium
 *
 * 5/4/18
 * 	- from pdfload.c
 */

/*

    This file is part of VIPS.
    
    VIPS is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301  USA

 */

/*

    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk

 */

/* TODO 
 *
 * - more code sharing with pdfload.c, eg. vips_foreign_load_pdf_is_a_buffer()
 *   and get_flags etc.
 * - could share the page layout code too
 * - make pdf.c with base stuff in?
 * - FPDF_GetMetaText() results needs mapping from utf16 to utf8
 * - what about filename encodings
 * - do we need to clear the background to white in generate()?
 * - I guess we must write RGBA to match poppler output
 * - new_from_buffer stuff
 *
 */

/*
#define DEBUG
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

/* Just until we get rid of the final bits of poppler
 */
#include <cairo.h>

#include <vips/vips.h>
#include <vips/buf.h>
#include <vips/internal.h>

#ifdef HAVE_PDFIUM

#include <fpdfview.h>
#include <fpdf_doc.h>

typedef struct _VipsForeignLoadPdf {
	VipsForeignLoad parent_object;

	/* Load this page.
	 */
	int page_no;

	/* Load this many pages.
	 */
	int n; 

	/* Render at this DPI.
	 */
	double dpi;

	/* Calculate this from DPI. At 72 DPI, we render 1:1.
	 */
	double scale;

	FPDF_DOCUMENT *doc;
	FPDF_PAGE *page;
	int current_page;

	/* Doc has this many pages. 
	 */
	int n_pages;

	/* We need to read out the side of each page we will render, and lay
	 * them out in the final image.
	 */
	VipsRect image;
	VipsRect *pages;

} VipsForeignLoadPdf;

typedef VipsForeignLoadClass VipsForeignLoadPdfClass;

G_DEFINE_ABSTRACT_TYPE( VipsForeignLoadPdf, vips_foreign_load_pdf, 
	VIPS_TYPE_FOREIGN_LOAD );

static char *vips_pdfium_errors[] = {
	"no error",
	"unknown error",
	"file not found or could not be opened",
	"file not in PDF format or corrupted",
	"password required or incorrect password",
	"unsupported security scheme",
	"page not found or content error"
};

static void
vips_pdfium_error( void )
{
	int err = FPDF_GetLastError();

	if( err >= 0 && 
		err < VIPS_NUMBER( vips_pdfium_errors ) )
		vips_error( "pdfload", "%s", _( vips_pdfium_errors[err] ) );
	else
		vips_error( "pdfload", "%s", _( "unknown error" ) ); 
}

static void
vips_foreign_load_pdf_dispose( GObject *gobject )
{
	VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) gobject;

	VIPS_FREEF( FPDF_CloseDocument, pdf->doc ); 
	VIPS_FREEF( FPDF_ClosePage, pdf->page ); 

	G_OBJECT_CLASS( vips_foreign_load_pdf_parent_class )->dispose( gobject );
}

static void *
vips_pdfium_init_cb( void *dummy )
{
	FPDF_LIBRARY_CONFIG config;

	config.version = 2;
	config.m_pUserFontPaths = NULL;
	config.m_pIsolate = NULL;
	config.m_v8EmbedderSlot = 0;

	FPDF_InitLibraryWithConfig( &config );

	return( NULL );
}

static void
vips_pdfium_init( void )
{
	static GOnce once = G_ONCE_INIT;

	VIPS_ONCE( &once, vips_pdfium_init_cb, NULL );
}

static int
vips_foreign_load_pdf_build( VipsObject *object )
{
	VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) object;

	vips_pdfium_init();

	if( !vips_object_argument_isset( object, "scale" ) )
		pdf->scale = pdf->dpi / 72.0;

	if( VIPS_OBJECT_CLASS( vips_foreign_load_pdf_parent_class )->
		build( object ) )
		return( -1 );

	return( 0 );
}

static VipsForeignFlags
vips_foreign_load_pdf_get_flags_filename( const char *filename )
{
	/* We can render any part of the page on demand.
	 */
	return( VIPS_FOREIGN_PARTIAL );
}

static VipsForeignFlags
vips_foreign_load_pdf_get_flags( VipsForeignLoad *load )
{
	return( VIPS_FOREIGN_PARTIAL );
}

static gboolean
vips_foreign_load_pdf_is_a_buffer( const void *buf, size_t len )
{
	const guchar *str = (const guchar *) buf;

	if( len >= 4 &&
		str[0] == '%' && 
		str[1] == 'P' &&
		str[2] == 'D' &&
		str[3] == 'F' )
		return( 1 );

	return( 0 );
}

static gboolean
vips_foreign_load_pdf_is_a( const char *filename )
{
	unsigned char buf[4];

	if( vips__get_bytes( filename, buf, 4 ) == 4 &&
		vips_foreign_load_pdf_is_a_buffer( buf, 4 ) )
		return( 1 );

	return( 0 );
}

static int
vips_foreign_load_pdf_get_page( VipsForeignLoadPdf *pdf, int page_no )
{
	if( pdf->current_page != page_no ) { 
		VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( pdf );

		VIPS_FREEF( FPDF_ClosePage, pdf->page ); 
		pdf->current_page = -1;

#ifdef DEBUG
		printf( "vips_foreign_load_pdf_get_page: %d\n", page_no );
#endif /*DEBUG*/

		if( !(pdf->page = FPDF_LoadPage( pdf->doc, page_no )) ) {
			vips_pdfium_error();
			vips_error( class->nickname, 
				_( "unable to load page %d" ), page_no );
			return( -1 ); 
		}
		pdf->current_page = page_no;
	}

	return( 0 );
}

/* String-based metadata fields we extract.
 */
typedef struct _VipsForeignLoadPdfMetadata {
	char *tag;		// as understood by PDFium
	char *field;		// as understood by libvips
} VipsForeignLoadPdfMetadata;

static VipsForeignLoadPdfMetadata vips_foreign_load_pdf_metadata[] = {
	{ "Title", "pdf-title" },
	{ "Author", "pdf-author" },
	{ "Subject", "pdf-subject" },
	{ "Keywords", "pdf-keywords" },
	{ "Creator", "pdf-creator" },
	{ "Producer", "pdf-producer" },
	// poppler has "metadata" as well, but pdfium does not support this
};
static int n_metadata = VIPS_NUMBER( vips_foreign_load_pdf_metadata );

static int
vips_foreign_load_pdf_set_image( VipsForeignLoadPdf *pdf, VipsImage *out )
{
	int i;
	double res;

#ifdef DEBUG
	printf( "vips_foreign_load_pdf_set_image: %p\n", pdf );
#endif /*DEBUG*/

	/* We render to a linecache, so fat strips work well.
	 */
        vips_image_pipelinev( out, VIPS_DEMAND_STYLE_FATSTRIP, NULL );

	/* Extract and attach metadata.
	 */
	vips_image_set_int( out, "pdf-n_pages", pdf->n_pages ); 

	for( i = 0; i < n_metadata; i++ ) {
		VipsForeignLoadPdfMetadata *metadata = 
			&vips_foreign_load_pdf_metadata[i];

		char text[1024];

		if( FPDF_GetMetaText( pdf->doc, metadata->tag, text, 1024 ) ) {
			// FPDF is utf16, we must swap to utf8
			vips_image_set_string( out, metadata->field, text ); 
		}
	}

	/* We need pixels/mm for vips.
	 */
	res = pdf->dpi / 25.4;

	vips_image_init_fields( out, 
		pdf->image.width, pdf->image.height, 
		4, VIPS_FORMAT_UCHAR,
		VIPS_CODING_NONE, VIPS_INTERPRETATION_sRGB, res, res );

	return( 0 );
}

static int
vips_foreign_load_pdf_header( VipsForeignLoad *load )
{
	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( load );
	VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) load;

	int top;
	int i;

#ifdef DEBUG
	printf( "vips_foreign_load_pdf_header: %p\n", pdf );
#endif /*DEBUG*/

	pdf->n_pages = FPDF_GetPageCount( pdf->doc );

	/* @n == -1 means until the end of the doc.
	 */
	if( pdf->n == -1 )
		pdf->n = pdf->n_pages - pdf->page_no;

	if( pdf->page_no + pdf->n > pdf->n_pages ||
		pdf->page_no < 0 ||
		pdf->n <= 0 ) {
		vips_error( class->nickname, "%s", _( "pages out of range" ) );
		return( -1 ); 
	}

	/* Lay out the pages in our output image.
	 */
	if( !(pdf->pages = VIPS_ARRAY( pdf, pdf->n, VipsRect )) )
		return( -1 ); 

	top = 0;
	pdf->image.left = 0;
	pdf->image.top = 0;
	pdf->image.width = 0;
	pdf->image.height = 0;
	for( i = 0; i < pdf->n; i++ ) {
		if( vips_foreign_load_pdf_get_page( pdf, pdf->page_no + i ) )
			return( -1 );
		pdf->pages[i].left = 0;
		pdf->pages[i].top = top;
		pdf->pages[i].width = 
			FPDF_GetPageWidth( pdf->page ) * pdf->scale;
		pdf->pages[i].height = 
			FPDF_GetPageHeight( pdf->page ) * pdf->scale;

		if( pdf->pages[i].width > pdf->image.width )
			pdf->image.width = pdf->pages[i].width;
		pdf->image.height += pdf->pages[i].height;

		top += pdf->pages[i].height;
	}

	/* If all pages are the same size, we can tag this as a toilet roll
	 * image and tiffsave will be able to save it as a multipage tiff.
	 */
	for( i = 1; i < pdf->n; i++ ) 
		if( pdf->pages[i].width != pdf->pages[0].width ||
			pdf->pages[i].height != pdf->pages[0].height )
			break;
	if( i == pdf->n ) 
		vips_image_set_int( load->out, 
			VIPS_META_PAGE_HEIGHT, pdf->pages[0].height );

	vips_foreign_load_pdf_set_image( pdf, load->out ); 

	return( 0 );
}

static int
vips_foreign_load_pdf_generate( VipsRegion *or, 
	void *seq, void *a, void *b, gboolean *stop )
{
	VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) a;
	VipsRect *r = &or->valid;

	int top;
	int i;
	int y;

	/*
	printf( "vips_foreign_load_pdf_generate: "
		"left = %d, top = %d, width = %d, height = %d\n", 
		r->left, r->top, r->width, r->height ); 
	 */

	/* Poppler won't always paint the background. Use 255 (white) for the
	 * bg, PDFs generally assume a paper background colour.
	 */
	vips_region_paint( or, r, 255 ); 

	/* Search through the pages we are drawing for the first containing
	 * this rect. This could be quicker, perhaps a binary search, but who 
	 * cares.
	 */
	for( i = 0; i < pdf->n; i++ )
		if( VIPS_RECT_BOTTOM( &pdf->pages[i] ) > r->top )
			break;

	top = r->top; 
	while( top < VIPS_RECT_BOTTOM( r ) ) {
		VipsRect rect;
		cairo_surface_t *surface;
		cairo_t *cr;

		vips_rect_intersectrect( r, &pdf->pages[i], &rect );

		surface = cairo_image_surface_create_for_data( 
			VIPS_REGION_ADDR( or, rect.left, rect.top ), 
			CAIRO_FORMAT_ARGB32, 
			rect.width, rect.height, 
			VIPS_REGION_LSKIP( or ) );
		cr = cairo_create( surface );
		cairo_surface_destroy( surface );

		cairo_scale( cr, pdf->scale, pdf->scale );
		cairo_translate( cr, 
			(pdf->pages[i].left - rect.left) / pdf->scale, 
			(pdf->pages[i].top - rect.top) / pdf->scale );

		/* poppler is single-threaded, but we don't need to lock since 
		 * we're running inside a non-threaded tilecache.
		 */
		if( vips_foreign_load_pdf_get_page( pdf, pdf->page_no + i ) )
			return( -1 ); 
		//poppler_page_render( pdf->page, cr );

		cairo_destroy( cr );

		top += rect.height;
		i += 1;
	}

	/* Cairo makes pre-multipled BRGA, we must byteswap and unpremultiply.
	 */
	for( y = 0; y < r->height; y++ ) 
		vips__cairo2rgba( 
			(guint32 *) VIPS_REGION_ADDR( or, r->left, r->top + y ), 
			r->width ); 

	return( 0 ); 
}

static int
vips_foreign_load_pdf_load( VipsForeignLoad *load )
{
	VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) load;
	VipsImage **t = (VipsImage **) 
		vips_object_local_array( (VipsObject *) load, 2 );

#ifdef DEBUG
	printf( "vips_foreign_load_pdf_load: %p\n", pdf );
#endif /*DEBUG*/

	/* Read to this image, then cache to out, see below.
	 */
	t[0] = vips_image_new(); 

	vips_foreign_load_pdf_set_image( pdf, t[0] ); 
	if( vips_image_generate( t[0], 
		NULL, vips_foreign_load_pdf_generate, NULL, pdf, NULL ) )
		return( -1 );

	/* Don't use tilecache to keep the number of calls to
	 * pdf_page_render() low. Don't thread the cache, we rely on
	 * locking to keep pdf single-threaded. Use a large strip size to
	 * (again) keep the number of calls to page_render low. 
	 */
	if( vips_linecache( t[0], &t[1],
		"tile_height", 5000,
		NULL ) ) 
		return( -1 );
	if( vips_image_write( t[1], load->real ) ) 
		return( -1 );

	return( 0 );
}

static void
vips_foreign_load_pdf_class_init( VipsForeignLoadPdfClass *class )
{
	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
	VipsObjectClass *object_class = (VipsObjectClass *) class;
	VipsForeignLoadClass *load_class = (VipsForeignLoadClass *) class;

	gobject_class->dispose = vips_foreign_load_pdf_dispose;
	gobject_class->set_property = vips_object_set_property;
	gobject_class->get_property = vips_object_get_property;

	object_class->nickname = "pdfload_base";
	object_class->description = _( "load PDF with libpoppler" );
	object_class->build = vips_foreign_load_pdf_build;

	load_class->get_flags_filename = 
		vips_foreign_load_pdf_get_flags_filename;
	load_class->get_flags = vips_foreign_load_pdf_get_flags;
	load_class->load = vips_foreign_load_pdf_load;

	VIPS_ARG_INT( class, "page", 10,
		_( "Page" ),
		_( "Load this page from the file" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignLoadPdf, page_no ),
		0, 100000, 0 );

	VIPS_ARG_INT( class, "n", 11,
		_( "n" ),
		_( "Load this many pages" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignLoadPdf, n ),
		-1, 100000, 1 );

	VIPS_ARG_DOUBLE( class, "dpi", 12,
		_( "DPI" ),
		_( "Render at this DPI" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignLoadPdf, dpi ),
		0.001, 100000.0, 72.0 );

	VIPS_ARG_DOUBLE( class, "scale", 13,
		_( "Scale" ),
		_( "Scale output by this factor" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignLoadPdf, scale ),
		0.001, 100000.0, 1.0 );

}

static void
vips_foreign_load_pdf_init( VipsForeignLoadPdf *pdf )
{
	pdf->dpi = 72.0;
	pdf->scale = 1.0;
	pdf->n = 1;
	pdf->current_page = -1;
}

typedef struct _VipsForeignLoadPdfFile {
	VipsForeignLoadPdf parent_object;

	/* Filename for load.
	 */
	char *filename; 

	char *uri;

} VipsForeignLoadPdfFile;

typedef VipsForeignLoadPdfClass VipsForeignLoadPdfFileClass;

G_DEFINE_TYPE( VipsForeignLoadPdfFile, vips_foreign_load_pdf_file, 
	vips_foreign_load_pdf_get_type() );

static void
vips_foreign_load_pdf_file_dispose( GObject *gobject )
{
	VipsForeignLoadPdfFile *file = 
		(VipsForeignLoadPdfFile *) gobject;

	VIPS_FREE( file->uri );

	G_OBJECT_CLASS( vips_foreign_load_pdf_file_parent_class )->
		dispose( gobject );
}

static int
vips_foreign_load_pdf_file_header( VipsForeignLoad *load )
{
	VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) load;
	VipsForeignLoadPdfFile *file = (VipsForeignLoadPdfFile *) load;

	char *path;
	GError *error = NULL; 

	/* We need an absolute path for a URI.
	 */
	path = vips_realpath( file->filename );
	if( !(file->uri = g_filename_to_uri( path, NULL, &error )) ) { 
		g_free( path );
		vips_g_error( &error );
		return( -1 ); 
	}
	g_free( path );

	if( !(pdf->doc = FPDF_LoadDocument( file->uri, NULL )) ) { 
		vips_pdfium_error();
		vips_error( "pdfload", 
			_( "unable to load \"%s\"" ), file->uri ); 
		return( -1 ); 
	}

	VIPS_SETSTR( load->out->filename, file->filename );

	return( vips_foreign_load_pdf_header( load ) );
}

static const char *vips_foreign_pdf_suffs[] = {
	".pdf",
	NULL
};

static void
vips_foreign_load_pdf_file_class_init( 
	VipsForeignLoadPdfFileClass *class )
{
	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
	VipsObjectClass *object_class = (VipsObjectClass *) class;
	VipsForeignClass *foreign_class = (VipsForeignClass *) class;
	VipsForeignLoadClass *load_class = (VipsForeignLoadClass *) class;

	gobject_class->dispose = vips_foreign_load_pdf_file_dispose;
	gobject_class->set_property = vips_object_set_property;
	gobject_class->get_property = vips_object_get_property;

	object_class->nickname = "pdfload";

	foreign_class->suffs = vips_foreign_pdf_suffs;

	load_class->is_a = vips_foreign_load_pdf_is_a;
	load_class->header = vips_foreign_load_pdf_file_header;

	VIPS_ARG_STRING( class, "filename", 1, 
		_( "Filename" ),
		_( "Filename to load from" ),
		VIPS_ARGUMENT_REQUIRED_INPUT, 
		G_STRUCT_OFFSET( VipsForeignLoadPdfFile, filename ),
		NULL );

}

static void
vips_foreign_load_pdf_file_init( VipsForeignLoadPdfFile *file )
{
}

typedef struct _VipsForeignLoadPdfBuffer {
	VipsForeignLoadPdf parent_object;

	/* Load from a buffer.
	 */
	VipsArea *buf;

} VipsForeignLoadPdfBuffer;

typedef VipsForeignLoadPdfClass VipsForeignLoadPdfBufferClass;

G_DEFINE_TYPE( VipsForeignLoadPdfBuffer, vips_foreign_load_pdf_buffer, 
	vips_foreign_load_pdf_get_type() );

static int
vips_foreign_load_pdf_buffer_header( VipsForeignLoad *load )
{
	/*
	VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) load;
	VipsForeignLoadPdfBuffer *buffer = 
		(VipsForeignLoadPdfBuffer *) load;

	if( !(pdf->doc = poppler_document_new_from_data( 
		buffer->buf->data, buffer->buf->length, NULL, &error )) ) { 
		vips_g_error( &error );
		return( -1 ); 
	}
	 */

	return( vips_foreign_load_pdf_header( load ) );
}

static void
vips_foreign_load_pdf_buffer_class_init( 
	VipsForeignLoadPdfBufferClass *class )
{
	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
	VipsObjectClass *object_class = (VipsObjectClass *) class;
	VipsForeignLoadClass *load_class = (VipsForeignLoadClass *) class;

	gobject_class->set_property = vips_object_set_property;
	gobject_class->get_property = vips_object_get_property;

	object_class->nickname = "pdfload_buffer";

	load_class->is_a_buffer = vips_foreign_load_pdf_is_a_buffer;
	load_class->header = vips_foreign_load_pdf_buffer_header;

	VIPS_ARG_BOXED( class, "buffer", 1, 
		_( "Buffer" ),
		_( "Buffer to load from" ),
		VIPS_ARGUMENT_REQUIRED_INPUT, 
		G_STRUCT_OFFSET( VipsForeignLoadPdfBuffer, buf ),
		VIPS_TYPE_BLOB );

}

static void
vips_foreign_load_pdf_buffer_init( VipsForeignLoadPdfBuffer *buffer )
{
}

#endif /*HAVE_PDFIUM*/