From 5db2c64d90528f2552821e24199ec1e4da8a8b93 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Mon, 8 Feb 2016 16:57:37 +0000
Subject: [PATCH] add @scale option

and set xres/yres
---
 TODO                          |  2 --
 libvips/foreign/foreign.c     |  4 +++-
 libvips/foreign/popplerload.c | 38 ++++++++++++++++++++++++++++++-----
 3 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/TODO b/TODO
index aa2c2fea..bda32361 100644
--- a/TODO
+++ b/TODO
@@ -4,8 +4,6 @@
 
 - add file type sniffing .. "%PDF" should be enough
 
-- metadata: xres/yres
-
 - trim page edges? we often have black now
 
 - new vips_reduce:
diff --git a/libvips/foreign/foreign.c b/libvips/foreign/foreign.c
index b533a290..d2c75845 100644
--- a/libvips/foreign/foreign.c
+++ b/libvips/foreign/foreign.c
@@ -2857,12 +2857,14 @@ vips_matload( const char *filename, VipsImage **out, ... )
  *
  * @page: %gint, load this page, numbered from zero
  * @dpi: %gdouble, render at this DPI
+ * @scale: %gdouble, scale render by this factor
  *
  * Render a PDF file into a VIPS image. 
  *
  * Use @page to select a page to render, numbering from zero.
  *
- * Use @dpi to set the rendering resolution. The default is 72. 
+ * Use @dpi to set the rendering resolution. The default is 72. Alternatively
+ * you can scale the rendering by @scale.
  *
  * This function only reads the image header and does not render any pixel
  * data. Rendering only occurs when pixels are accessed.
diff --git a/libvips/foreign/popplerload.c b/libvips/foreign/popplerload.c
index 1c64dc56..debd2c0d 100644
--- a/libvips/foreign/popplerload.c
+++ b/libvips/foreign/popplerload.c
@@ -97,6 +97,21 @@ vips_foreign_load_poppler_dispose( GObject *gobject )
 		dispose( gobject );
 }
 
+static int
+vips_foreign_load_poppler_build( VipsObject *object )
+{
+	VipsForeignLoadPoppler *poppler = (VipsForeignLoadPoppler *) object;
+
+	if( !vips_object_argument_isset( object, "scale" ) )
+		poppler->scale = poppler->dpi / 72.0;
+
+	if( VIPS_OBJECT_CLASS( vips_foreign_load_poppler_parent_class )->
+		build( object ) )
+		return( -1 );
+
+	return( 0 );
+}
+
 static VipsForeignFlags
 vips_foreign_load_poppler_get_flags_filename( const char *filename )
 {
@@ -136,17 +151,21 @@ vips_foreign_load_poppler_parse( VipsForeignLoadPoppler *poppler,
 	PopplerRectangle crop_box;
 	double width;
 	double height;
+	double res;
 	int i;
-	char *str;
 
 	poppler_page_get_size( poppler->page, &width, &height ); 
 
 	poppler_page_get_crop_box( poppler->page, &crop_box ); 
 
+	/* We need pixels/mm for vips.
+	 */
+	res = poppler->dpi / 25.4;
+
 	vips_image_init_fields( out, 
 		width * poppler->scale, height * poppler->scale, 
 		4, VIPS_FORMAT_UCHAR,
-		VIPS_CODING_NONE, VIPS_INTERPRETATION_sRGB, 1.0, 1.0 );
+		VIPS_CODING_NONE, VIPS_INTERPRETATION_sRGB, res, res );
 
 	VIPS_SETSTR( out->filename, poppler->filename );
 
@@ -163,6 +182,8 @@ vips_foreign_load_poppler_parse( VipsForeignLoadPoppler *poppler,
 		VipsForeignLoadPopperMetadata *metadata = 
 			&vips_foreign_load_poppler_metadata[i];
 
+		char *str;
+
 		if( (str = metadata->poppler_fetch( poppler->doc )) ) { 
 			vips_image_set_string( out, metadata->field, str ); 
 			g_free( str );
@@ -179,8 +200,6 @@ vips_foreign_load_poppler_header( VipsForeignLoad *load )
 	char *path;
 	GError *error = NULL;
 
-	poppler->scale = poppler->dpi / 72.0;
-
 	/* We need an absolute path for a URI.
 	 */
 	path = vips_realpath( poppler->filename );
@@ -309,6 +328,7 @@ vips_foreign_load_poppler_class_init( VipsForeignLoadPopplerClass *class )
 
 	object_class->nickname = "popplerload";
 	object_class->description = _( "load PDF with poppler" );
+	object_class->build = vips_foreign_load_poppler_build;
 
 	foreign_class->suffs = vips_foreign_poppler_suffs;
 
@@ -332,19 +352,27 @@ vips_foreign_load_poppler_class_init( VipsForeignLoadPopplerClass *class )
 		G_STRUCT_OFFSET( VipsForeignLoadPoppler, page_no ),
 		0, 100000, 0 );
 
-	VIPS_ARG_DOUBLE( class, "dpi", 10,
+	VIPS_ARG_DOUBLE( class, "dpi", 11,
 		_( "DPI" ),
 		_( "Render at this DPI" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsForeignLoadPoppler, dpi ),
 		0.001, 100000.0, 72.0 );
 
+	VIPS_ARG_DOUBLE( class, "scale", 12,
+		_( "Scale" ),
+		_( "Scale output by this factor" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsForeignLoadPoppler, scale ),
+		0.001, 100000.0, 1.0 );
+
 }
 
 static void
 vips_foreign_load_poppler_init( VipsForeignLoadPoppler *poppler )
 {
 	poppler->dpi = 72.0;
+	poppler->scale = 1.0;
 }
 
 #endif /*HAVE_POPPLER*/