cairo-renderer: set metadata in output

- metadata is taken from the SVG document;
- fields that are compatible with the target format
  (and also supported by cairo) are set accordingly

4 files changed, 139 insertions, 35 deletions

diff --git a/src/extension/internal/cairo-render-context.cpp b/src/extension/internal/cairo-render-context.cpp
index ab9f9e82f..2b4072336 100644
--- a/src/extension/internal/cairo-render-context.cpp
+++ b/src/extension/internal/cairo-render-context.cpp
@@ -885,6 +885,8 @@ CairoRenderContext::setupSurface(double width, double height)
             break;
     }
 
+    _setSurfaceMetadata(surface);
+
     return _finishSurfaceSetup (surface, &ctm);
 }
 
@@ -934,6 +936,42 @@ CairoRenderContext::_finishSurfaceSetup(cairo_surface_t *surface, cairo_matrix_t
     return true;
 }
 
+void
+CairoRenderContext::_setSurfaceMetadata(cairo_surface_t *surface)
+{
+    switch (_target) {
+#if defined CAIRO_HAS_PDF_SURFACE && CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 15, 4)
+        case CAIRO_SURFACE_TYPE_PDF:
+            if (!_metadata.title.empty()) {
+                cairo_pdf_surface_set_metadata(surface, CAIRO_PDF_METADATA_TITLE, _metadata.title.c_str());
+            }
+            if (!_metadata.author.empty()) {
+                cairo_pdf_surface_set_metadata(surface, CAIRO_PDF_METADATA_AUTHOR, _metadata.author.c_str());
+            }
+            if (!_metadata.subject.empty()) {
+                cairo_pdf_surface_set_metadata(surface, CAIRO_PDF_METADATA_SUBJECT, _metadata.subject.c_str());
+            }
+            if (!_metadata.keywords.empty()) {
+                cairo_pdf_surface_set_metadata(surface, CAIRO_PDF_METADATA_KEYWORDS, _metadata.keywords.c_str());
+            }
+            if (!_metadata.creator.empty()) {
+                cairo_pdf_surface_set_metadata(surface, CAIRO_PDF_METADATA_CREATOR, _metadata.creator.c_str());
+            }
+            break;
+#endif
+#if defined CAIRO_HAS_PS_SURFACE
+        case CAIRO_SURFACE_TYPE_PS:
+            if (!_metadata.title.empty()) {
+                cairo_ps_surface_dsc_comment(surface, (Glib::ustring("%%Title: ") + _metadata.title).c_str());
+            }
+            if (!_metadata.copyright.empty()) {
+                cairo_ps_surface_dsc_comment(surface, (Glib::ustring("%%Copyright: ") + _metadata.copyright).c_str());
+            }
+            break;
+#endif
+    }
+}
+
 bool
 CairoRenderContext::finish(bool finish_surface)
 {
diff --git a/src/extension/internal/cairo-render-context.h b/src/extension/internal/cairo-render-context.h
index 12cdb522d..1ff5ddeec 100644
--- a/src/extension/internal/cairo-render-context.h
+++ b/src/extension/internal/cairo-render-context.h
@@ -64,6 +64,18 @@ struct CairoRenderState {
     Geom::Affine transform;     // the CTM
 };
 
+// Metadata to set on the cairo surface (if the surface supports it)
+struct CairoRenderContextMetadata {
+    Glib::ustring title = "";
+    Glib::ustring author = "";
+    Glib::ustring subject = "";
+    Glib::ustring keywords = "";
+    Glib::ustring copyright = "";
+    Glib::ustring creator = "";
+    Glib::ustring cdate = ""; // currently unused
+    Glib::ustring mdate = ""; // currently unused
+};
+
 class CairoRenderContext {
     friend class CairoRenderer;
 public:
@@ -105,7 +117,7 @@ public:
 
     /** Creates the cairo_surface_t for the context with the
     given width, height and with the currently set target
-    surface type. */
+    surface type. Also sets supported metadata on the surface. */
     bool setupSurface(double width, double height);
 
     cairo_surface_t *getSurface();
@@ -208,6 +220,8 @@ protected:
 
     CairoOmitTextPageState _omittext_state;
 
+    CairoRenderContextMetadata _metadata;
+
     cairo_pattern_t *_createPatternForPaintServer(SPPaintServer const *const paintserver,
                                                   Geom::OptRect const &pbox, float alpha);
     cairo_pattern_t *_createPatternPainter(SPPaintServer const *const paintserver, Geom::OptRect const &pbox);
@@ -216,6 +230,8 @@ protected:
     unsigned int _showGlyphs(cairo_t *cr, PangoFont *font, std::vector<CairoGlyphInfo> const &glyphtext, bool is_stroke);
 
     bool _finishSurfaceSetup(cairo_surface_t *surface, cairo_matrix_t *ctm = nullptr);
+    void _setSurfaceMetadata(cairo_surface_t *surface);
+
     void _setFillStyle(SPStyle const *style, Geom::OptRect const &pbox);
     void _setStrokeStyle(SPStyle const *style, Geom::OptRect const &pbox);
 
diff --git a/src/extension/internal/cairo-renderer.cpp b/src/extension/internal/cairo-renderer.cpp
index 27f024ca1..35531cb04 100644
--- a/src/extension/internal/cairo-renderer.cpp
+++ b/src/extension/internal/cairo-renderer.cpp
@@ -29,54 +29,59 @@
 #include <csignal>
 #include <cerrno>
 
-#include "libnrtype/Layout-TNG.h"
+
 #include <2geom/transforms.h>
 #include <2geom/pathvector.h>
-
+#include <cairo.h>
 #include <glib.h>
-
 #include <glibmm/i18n.h>
-#include "display/curve.h"
-#include "display/canvas-bpath.h"
+
+// include support for only the compiled-in surface types
+#ifdef CAIRO_HAS_PDF_SURFACE
+#include <cairo-pdf.h>
+#endif
+#ifdef CAIRO_HAS_PS_SURFACE
+#include <cairo-ps.h>
+#endif
+
+#include "cairo-render-context.h"
+#include "cairo-renderer.h"
+#include "document.h"
+#include "inkscape-version.h"
+#include "rdf.h"
+
 #include "display/cairo-utils.h"
+#include "display/canvas-bpath.h"
+#include "display/curve.h"
+
+#include "extension/system.h"
+
+#include "helper/pixbuf-ops.h"
+#include "helper/png-write.h"
+
+#include "io/sys.h"
+
+#include "libnrtype/Layout-TNG.h"
+
 #include "object/sp-anchor.h"
-#include "object/sp-item.h"
+#include "object/sp-clippath.h"
+#include "object/sp-flowtext.h"
+#include "object/sp-hatch-path.h"
+#include "object/sp-image.h"
 #include "object/sp-item-group.h"
-#include "object/sp-marker.h"
+#include "object/sp-item.h"
 #include "object/sp-linear-gradient.h"
+#include "object/sp-marker.h"
+#include "object/sp-mask.h"
+#include "object/sp-pattern.h"
 #include "object/sp-radial-gradient.h"
 #include "object/sp-root.h"
 #include "object/sp-shape.h"
-#include "object/sp-use.h"
-#include "object/sp-text.h"
-#include "object/sp-flowtext.h"
-#include "object/sp-hatch-path.h"
-#include "object/sp-image.h"
 #include "object/sp-symbol.h"
-#include "object/sp-pattern.h"
-#include "object/sp-mask.h"
-#include "object/sp-clippath.h"
+#include "object/sp-text.h"
+#include "object/sp-use.h"
 
 #include "util/units.h"
-#include "helper/png-write.h"
-#include "helper/pixbuf-ops.h"
-
-#include "cairo-renderer.h"
-#include "cairo-render-context.h"
-#include "extension/system.h"
-
-#include "io/sys.h"
-
-#include <cairo.h>
-#include "document.h"
-
-// include support for only the compiled-in surface types
-#ifdef CAIRO_HAS_PDF_SURFACE
-#include <cairo-pdf.h>
-#endif
-#ifdef CAIRO_HAS_PS_SURFACE
-#include <cairo-ps.h>
-#endif
 
 //#define TRACE(_args) g_printf _args
 #define TRACE(_args)
@@ -657,6 +662,45 @@ void CairoRenderer::renderHatchPath(CairoRenderContext *ctx, SPHatchPath const &
     ctx->popState();
 }
 
+void CairoRenderer::setMetadata(CairoRenderContext *ctx, SPDocument *doc) {
+    // title
+    const gchar *title = rdf_get_work_entity(doc, rdf_find_entity("title"));
+    if (title) {
+        ctx->_metadata.title = title;
+    }
+
+    // author
+    const gchar *author = rdf_get_work_entity(doc, rdf_find_entity("creator"));
+    if (author) {
+        ctx->_metadata.author = author;
+    }
+
+    // subject
+    const gchar *subject = rdf_get_work_entity(doc, rdf_find_entity("description"));
+    if (subject) {
+        ctx->_metadata.subject = subject;
+    }
+
+    // keywords
+    const gchar *keywords = rdf_get_work_entity(doc, rdf_find_entity("subject"));
+    if (keywords) {
+        ctx->_metadata.keywords = keywords;
+    }
+
+    // copyright
+    const gchar *copyright = rdf_get_work_entity(doc, rdf_find_entity("rights"));
+    if (copyright) {
+        ctx->_metadata.copyright = copyright;
+    }
+
+    // creator
+    ctx->_metadata.creator = Glib::ustring::compose("Inkscape %1 (https://inkscape.org)",
+                                                    Inkscape::version_string_without_revision);
+
+   // cdate / mdate
+   // (currently unused)
+}
+
 bool
 CairoRenderer::setupDocument(CairoRenderContext *ctx, SPDocument *doc, bool pageBoundingBox, float bleedmargin_px, SPItem *base)
 {
@@ -692,6 +736,8 @@ CairoRenderer::setupDocument(CairoRenderContext *ctx, SPDocument *doc, bool page
 
     TRACE(("setupDocument: %f x %f\n", ctx->_width, ctx->_height));
 
+    setMetadata(ctx, doc);
+
     bool ret = ctx->setupSurface(ctx->_width, ctx->_height);
 
     if (ret) {
diff --git a/src/extension/internal/cairo-renderer.h b/src/extension/internal/cairo-renderer.h
index a8eab52a8..26f2f414a 100644
--- a/src/extension/internal/cairo-renderer.h
+++ b/src/extension/internal/cairo-renderer.h
@@ -55,6 +55,10 @@ public:
     /** Traverses the object tree and invokes the render methods. */
     void renderItem(CairoRenderContext *ctx, SPItem *item);
     void renderHatchPath(CairoRenderContext *ctx, SPHatchPath const &hatchPath, unsigned key);
+
+private:
+    /** Extract metadata from doc and set it on ctx. */
+    void setMetadata(CairoRenderContext *ctx, SPDocument *doc);
 };
 
 // FIXME: this should be a static method of CairoRenderer