[cairo] [PATCH] Allow users to set custom producer in PDF metadata

[Guillaume Ayoub]

External libraries using cairo may want	to edit	the Producer metadata tag
in generated PDF files.

This patch allows users	to edit	this tag as any other tag, and keeps the
previous cairo string as a fallback when no custom string is set.

---
 src/cairo-pdf-interchange.c     | 18 +++++++++++++++---
 src/cairo-pdf-surface-private.h |  1 +
 src/cairo-pdf.h                 |  2 ++
 test/pdf-tagged-text.c          |  1 +
 4 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/cairo-pdf-interchange.c b/src/cairo-pdf-interchange.c
index 9aa6934dc..35b91dfba 100644
--- a/src/cairo-pdf-interchange.c
+++ b/src/cairo-pdf-interchange.c
@@ -1047,9 +1047,17 @@ cairo_pdf_interchange_write_docinfo (cairo_pdf_surface_t *surface)
 
     _cairo_output_stream_printf (surface->output,
 				 "%d 0 obj\n"
-				 "<< /Producer (cairo %s (http://cairographics.org))\n",
-				 surface->docinfo_res.id,
-				 cairo_version_string ());
+				 "<<",
+				 surface->docinfo_res.id);
+
+    if (ic->docinfo.producer)
+	_cairo_output_stream_printf (surface->output,
+				     " /Producer %s\n",
+				     ic->docinfo.producer);
+    else
+	_cairo_output_stream_printf (surface->output,
+				     " /Producer (cairo %s (http://cairographics.org))\n",
+				     cairo_version_string ());
 
     if (ic->docinfo.title)
 	_cairo_output_stream_printf (surface->output, "   /Title %s\n", ic->docinfo.title);
@@ -1722,6 +1730,10 @@ _cairo_pdf_interchange_set_metadata (cairo_pdf_surface_t  *surface,
 	    free (ic->docinfo.mod_date);
 	    ic->docinfo.mod_date = s;
 	    break;
+	case CAIRO_PDF_METADATA_PRODUCER:
+	    free (ic->docinfo.producer);
+	    ic->docinfo.producer = s;
+	    break;
     }
 
     return CAIRO_STATUS_SUCCESS;
diff --git a/src/cairo-pdf-surface-private.h b/src/cairo-pdf-surface-private.h
index 3793332ce..51d7047b5 100644
--- a/src/cairo-pdf-surface-private.h
+++ b/src/cairo-pdf-surface-private.h
@@ -216,6 +216,7 @@ struct docinfo {
     char *creator;
     char *create_date;
     char *mod_date;
+    char *producer;
 };
 
 typedef struct _cairo_pdf_interchange {
diff --git a/src/cairo-pdf.h b/src/cairo-pdf.h
index 5be0b3f1b..ee8fb3dd4 100644
--- a/src/cairo-pdf.h
+++ b/src/cairo-pdf.h
@@ -122,6 +122,7 @@ cairo_pdf_surface_add_outline (cairo_surface_t	          *surface,
  * @CAIRO_PDF_METADATA_CREATOR: The document creator (Since 1.16)
  * @CAIRO_PDF_METADATA_CREATE_DATE: The document creation date (Since 1.16)
  * @CAIRO_PDF_METADATA_MOD_DATE: The document modification date (Since 1.16)
+ * @CAIRO_PDF_METADATA_PRODUCER: The document producer (Since 1.16)
  *
  * #cairo_pdf_metadata_t is used by the
  * cairo_pdf_surface_set_metadata() function specify the metadata to set.
@@ -136,6 +137,7 @@ typedef enum _cairo_pdf_metadata {
     CAIRO_PDF_METADATA_CREATOR,
     CAIRO_PDF_METADATA_CREATE_DATE,
     CAIRO_PDF_METADATA_MOD_DATE,
+    CAIRO_PDF_METADATA_PRODUCER,
 } cairo_pdf_metadata_t;
 
 cairo_public void
diff --git a/test/pdf-tagged-text.c b/test/pdf-tagged-text.c
index 5c1b82bc2..6f3f4e54f 100644
--- a/test/pdf-tagged-text.c
+++ b/test/pdf-tagged-text.c
@@ -325,6 +325,7 @@ create_document (cairo_surface_t *surface, cairo_t *cr)
     cairo_pdf_surface_set_metadata (surface, CAIRO_PDF_METADATA_CREATOR, "pdf-features");
     cairo_pdf_surface_set_metadata (surface, CAIRO_PDF_METADATA_CREATE_DATE, "2016-01-01T12:34:56+10:30");
     cairo_pdf_surface_set_metadata (surface, CAIRO_PDF_METADATA_MOD_DATE, "2016-06-21T05:43:21Z");
+    cairo_pdf_surface_set_metadata (surface, CAIRO_PDF_METADATA_PRODUCER, "cairo producer");
 
     cairo_tag_begin (cr, "Document", NULL);
 
-- 
2.18.0