Adds the functionality to load SVG documents.

SVG document corresponding to a glyphID is fetched and stored
in an `FT_SVG_Document' structure which is referenced in the
glyphslot.

* include/freetype/config/ftheader.h: Adds `FT_OTSVG_H'.

* include/freetype/ftimage.h: Adds `FT_GLYPH_FORMAT_SVG'.

* include/freetype/internal/ftobjs.h: Adds `FT_GLYPH_OWN_GZIP_SVG'.

* include/freetype/internal/sfnt.h: Adds `load_svg_doc' and its
function type `TT_Load_Svg_Doc_Func'.

* include/freetype/otsvg.h: Adds `FT_SVG_Document' and its struct.

* src/base/ftobjs.c: Adds code to allocate and free memory for
`FT_SVG_Document' in `slot->other'.

* src/cff/cffgload.c: Adds code to load SVG glyph if it's present.

* src/truetype/ttgload.c: Ditto.

* src/sfnt/sfdriver.c: Adds `tt_face_load_svg_doc'.

* src/sfnt/ttsvg.h: Ditto.

* src/sfnt/ttsvg.c: Adds implementation of `tt_face_load_svg_doc'
and its helper functions.

5 files changed, 142 insertions, 4 deletions

diff --git a/include/freetype/config/ftheader.h b/include/freetype/config/ftheader.h
index 696d6ba90..55716c2e5 100644
--- a/include/freetype/config/ftheader.h
+++ b/include/freetype/config/ftheader.h
@@ -550,6 +550,19 @@
   /**************************************************************************
    *
    * @macro:
+   *   FT_OTSVG_H
+   *
+   * @description:
+   *   A macro used in `#include` statements to name the file containing the
+   *   API of OT-SVG support related things.
+   *
+   */
+#define FT_OTSVG_H  <freetype/otsvg.h>
+
+
+  /**************************************************************************
+   *
+   * @macro:
    *   FT_BBOX_H
    *
    * @description:
diff --git a/include/freetype/ftimage.h b/include/freetype/ftimage.h
index face34fe4..86fb04065 100644
--- a/include/freetype/ftimage.h
+++ b/include/freetype/ftimage.h
@@ -732,6 +732,9 @@ FT_BEGIN_HEADER
    *     contours.  Some Type~1 fonts, like those in the Hershey family,
    *     contain glyphs in this format.  These are described as @FT_Outline,
    *     but FreeType isn't currently capable of rendering them correctly.
+   *
+   *   FT_GLYPH_FORMAT_SVG ::
+   *     The glyph is represented by an SVG document in the SVG table.
    */
   typedef enum  FT_Glyph_Format_
   {
@@ -740,7 +743,8 @@ FT_BEGIN_HEADER
     FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
     FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP,    'b', 'i', 't', 's' ),
     FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE,   'o', 'u', 't', 'l' ),
-    FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER,   'p', 'l', 'o', 't' )
+    FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER,   'p', 'l', 'o', 't' ),
+    FT_IMAGE_TAG( FT_GLYPH_FORMAT_SVG,       's', 'v', 'g', ' ' )
 
   } FT_Glyph_Format;
 
@@ -752,6 +756,7 @@ FT_BEGIN_HEADER
 #define ft_glyph_format_bitmap     FT_GLYPH_FORMAT_BITMAP
 #define ft_glyph_format_outline    FT_GLYPH_FORMAT_OUTLINE
 #define ft_glyph_format_plotter    FT_GLYPH_FORMAT_PLOTTER
+#define ft_glyph_format_svg        FT_GLYPH_FORMAT_SVG
 
 
   /*************************************************************************/
diff --git a/include/freetype/internal/ftobjs.h b/include/freetype/internal/ftobjs.h
index 0c1d3e5bf..2f2050921 100644
--- a/include/freetype/internal/ftobjs.h
+++ b/include/freetype/internal/ftobjs.h
@@ -418,7 +418,8 @@ FT_BEGIN_HEADER
    *     initializing the glyph slot.
    */
 
-#define FT_GLYPH_OWN_BITMAP  0x1U
+#define FT_GLYPH_OWN_BITMAP    0x1U
+#define FT_GLYPH_OWN_GZIP_SVG  0x2U
 
   typedef struct  FT_Slot_InternalRec_
   {
diff --git a/include/freetype/internal/sfnt.h b/include/freetype/internal/sfnt.h
index fbc29d3a2..d09b190aa 100644
--- a/include/freetype/internal/sfnt.h
+++ b/include/freetype/internal/sfnt.h
@@ -315,6 +315,31 @@ FT_BEGIN_HEADER
   /**************************************************************************
    *
    * @functype:
+   *   TT_Load_Svg_Doc_Func
+   *
+   * @description:
+   *   Scans the SVG documents list to find the document containing the glyph
+   *   that has the id "glyph<glyph_index>".
+   *
+   * @input:
+   *   glyph ::
+   *     The glyph slot from which pointers to SVG documents list will be
+   *     grabbed.  The results will be stored back in the slot too.
+   *
+   *   glyph_index ::
+   *     The index of the glyph that is to be looked up.
+   *
+   * @return:
+   *   FreeType error code.  0 means success.
+   */
+  typedef FT_Error
+  (*TT_Load_Svg_Doc_Func)( FT_GlyphSlot  glyph,
+                           FT_UInt       glyph_index );
+
+
+  /**************************************************************************
+   *
+   * @functype:
    *   TT_Set_SBit_Strike_Func
    *
    * @description:
@@ -781,6 +806,7 @@ FT_BEGIN_HEADER
     /* OpenType SVG support */
     TT_Load_Table_Func           load_svg;
     TT_Free_Table_Func           free_svg;
+    TT_Load_Svg_Doc_Func         load_svg_doc;
 
   } SFNT_Interface;
 
@@ -830,7 +856,8 @@ FT_BEGIN_HEADER
           get_name_,                     \
           get_name_id_,                  \
           load_svg_,                     \
-          free_svg_ )                    \
+          free_svg_,                     \
+          load_svg_doc_ )                \
   static const SFNT_Interface  class_ =  \
   {                                      \
     goto_table_,                         \
@@ -872,7 +899,8 @@ FT_BEGIN_HEADER
     get_name_,                           \
     get_name_id_,                        \
     load_svg_,                           \
-    free_svg_                            \
+    free_svg_,                           \
+    load_svg_doc_                        \
   };
 
 
diff --git a/include/freetype/otsvg.h b/include/freetype/otsvg.h
new file mode 100644
index 000000000..5569ce4d6
--- /dev/null
+++ b/include/freetype/otsvg.h
@@ -0,0 +1,91 @@
+/****************************************************************************
+ *
+ * otsvg.h
+ *
+ *   Interface for OT-SVG support related things (specification).
+ *
+ * Copyright (C) 2004-2019 by
+ * David Turner, Robert Wilhelm, Werner Lemberg and Moazin Khatti.
+ *
+ * This file is part of the FreeType project, and may only be used,
+ * modified, and distributed under the terms of the FreeType project
+ * license, LICENSE.TXT.  By continuing to use, modify, or distribute
+ * this file you indicate that you have read the license and
+ * understand and accept it fully.
+ *
+ */
+
+
+#ifndef FTSVG_RENDERER_H_
+#define FTSVG_RENDERER_H_
+
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
+#ifdef FREETYPE_H
+#error "freetype.h of FreeType 1 has been loaded!"
+#error "Please fix the directory search order for header files"
+#error "so that freetype.h of FreeType 2 is found first."
+#endif
+
+FT_BEGIN_HEADER
+
+  /**************************************************************************
+   *
+   * @struct:
+   *   FT_SVG_DocumentRec_
+   *
+   * @description:
+   *   A structure that models one SVG document.
+   *
+   * @fields:
+   *   svg_document ::
+   *     A pointer to the SVG document string.
+   *
+   *   svg_document_length ::
+   *     The length of the SVG document string.
+   *
+   *   metrics ::
+   *     A metrics object storing the size information.
+   *
+   *   units_per_EM ::
+   *     The size of the EM square.
+   *
+   *   start_glyph_id ::
+   *     The starting glyph ID for the glyph range that this document has.
+   *
+   *   end_glyph_id ::
+   *     The ending glyph ID for the glyph range that this document has.
+   *
+   * @note:
+   *   `metrics` and `units_per_EM` might look like repetitions since both
+   *   fields are stored in face object, but they are not; When the slot is
+   *   passed down to a renderer, the renderer can only access the `metrics`
+   *   and `units_per_EM` by `slot->face`. However, when `FT_Glyph_To_Bitmap`
+   *   sets up a dummy object, it has no way to set a `face` object. Thus,
+   *   metrics information and units_per_EM (which is necessary for OT-SVG)
+   *   has to be stored separately.
+   */
+
+  typedef struct FT_SVG_DocumentRec_
+  {
+    FT_Byte*         svg_document;
+    FT_ULong         svg_document_length;
+    FT_Size_Metrics  metrics;
+    FT_UShort        units_per_EM;
+    FT_UShort        start_glyph_id;
+    FT_UShort        end_glyph_id;
+  } FT_SVG_DocumentRec;
+
+  /**************************************************************************
+   *
+   * @type:
+   *   FT_SVG_Document
+   *
+   * @description:
+   *   A handle to a FT_SVG_DocumentRec object.
+   */
+  typedef struct FT_SVG_DocumentRec_*  FT_SVG_Document;
+
+FT_END_HEADER
+#endif