Add code to load OT-SVG glyph documents.

* include/freetype/config/ftheader.h (FT_OTSVG_H): New macro.
* include/freetype/freetype.h (FT_FACE_FLAG_SVG, FT_HAS_SVG): New macros.
(FT_LOAD_SVG_ONLY): New internal macro.
* include/freetype/ftimage.h (FT_Glyph_Format): New enumeration value
`FT_GLYPH_FORMAT_SVG`.
* include/freetype/internal/ftobjs.h (FT_GLYPH_OWN_GZIP_SVG): New macro.
* include/freetype/internal/fttrace.h: Add `ttsvg` for `ttsvg.c`.
* include/freetype/internal/sfnt.h(load_svg, free_svg, load_svg_doc): New
functions.
* include/freetype/internal/tttypes.h (TT_FaceRec): Add `svg` for
the SVG table.
* include/freetype/otsvg.h (FT_SVG_DocumentRec): New structure to hold the
SVG document and other necessary information of an OT-SVG glyph in a glyph
slot.
* include/freetype/tttags.h (TTAG_SVG): New macro.

* src/base/ftobjs.c: Include `otsvg.h`.
(ft_glyphslot_init): Allocate `FT_SVG_DocumentRec` in `slot->other`
if the SVG table exists.
(ft_glyphslot_clear): Free it upon clean-up if it is a GZIP compressed
glyph.
(ft_glyphslot_done): Free the document data if it is a GZIP compressed
glyph.
(FT_Load_Glyph): Don't auto-hint SVG documents.

* src/cache/ftcbasic.c (ftc_basic_family_load_glyph): Add support for
FT_GLYPH_FORMAT_SVG.

* src/sfnt/rules.mk (SFNT_DRV_SRC): Add `ttsvg.c`.
* src/sfnt/sfdriver.c: Include `ttsvg.h`.
(sfnt_interface): Add `tt_face_load_svg`, `tt_face_free_svg` and
`tt_face_load_svg_doc`.
* src/sfnt/sfnt.c: Include `ttsvg.c`.
* src/sfnt/sfobjs.c (sfnt_load_face, sfnt_done_face): Add code to load and
free data of the the SVG table.
* src/sfnt/ttsvg.c: New file, implementing `tt_face_load_svg`,
`tt_face_free_svg` and `tt_face_load_svg_doc`.
* src/sfnt/ttsvg.h: Declarations of the SVG functions in
`ttsvg.c`.

18 files changed, 741 insertions, 24 deletions

diff --git a/include/freetype/config/ftheader.h b/include/freetype/config/ftheader.h
index f3ba39396..a8c6833df 100644
--- a/include/freetype/config/ftheader.h
+++ b/include/freetype/config/ftheader.h
@@ -777,6 +777,18 @@
 #define FT_COLOR_H  <freetype/ftcolor.h>
 
 
+  /**************************************************************************
+   *
+   * @macro:
+   *   FT_OTSVG_H
+   *
+   * @description:
+   *   A macro used in `#include` statements to name the file containing the
+   *   FreeType~2 API which handles the OpenType 'SVG~' glyphs.
+   */
+#define FT_OTSVG_H  <freetype/otsvg.h>
+
+
   /* */
 
   /* These header files don't need to be included by the user. */
diff --git a/include/freetype/freetype.h b/include/freetype/freetype.h
index 101863659..69beb7c7b 100644
--- a/include/freetype/freetype.h
+++ b/include/freetype/freetype.h
@@ -153,6 +153,7 @@ FT_BEGIN_HEADER
    *   FT_FACE_FLAG_GLYPH_NAMES
    *   FT_FACE_FLAG_EXTERNAL_STREAM
    *   FT_FACE_FLAG_HINTER
+   *   FT_FACE_FLAG_SVG
    *
    *   FT_HAS_HORIZONTAL
    *   FT_HAS_VERTICAL
@@ -161,6 +162,7 @@ FT_BEGIN_HEADER
    *   FT_HAS_GLYPH_NAMES
    *   FT_HAS_COLOR
    *   FT_HAS_MULTIPLE_MASTERS
+   *   FT_HAS_SVG
    *
    *   FT_IS_SFNT
    *   FT_IS_SCALABLE
@@ -1230,6 +1232,9 @@ FT_BEGIN_HEADER
    *     altered with @FT_Set_MM_Design_Coordinates,
    *     @FT_Set_Var_Design_Coordinates, or @FT_Set_Var_Blend_Coordinates.
    *     This flag is unset by a call to @FT_Set_Named_Instance.
+   *
+   *   FT_FACE_FLAG_SVG ::
+   *     [Since 2.12] The face has an 'SVG~' OpenType table.
    */
 #define FT_FACE_FLAG_SCALABLE          ( 1L <<  0 )
 #define FT_FACE_FLAG_FIXED_SIZES       ( 1L <<  1 )
@@ -1247,6 +1252,7 @@ FT_BEGIN_HEADER
 #define FT_FACE_FLAG_TRICKY            ( 1L << 13 )
 #define FT_FACE_FLAG_COLOR             ( 1L << 14 )
 #define FT_FACE_FLAG_VARIATION         ( 1L << 15 )
+#define FT_FACE_FLAG_SVG               ( 1L << 16 )
 
 
   /**************************************************************************
@@ -1489,6 +1495,22 @@ FT_BEGIN_HEADER
 
   /**************************************************************************
    *
+   * @macro:
+   *   FT_HAS_SVG
+   *
+   * @description:
+   *   A macro that returns true whenever a face object contains an 'SVG~'
+   *   OpenType table.
+   *
+   * @since:
+   *   2.12
+   */
+#define FT_HAS_SVG( face ) \
+          ( !!( (face)->face_flags & FT_FACE_FLAG_SVG ) )
+
+
+  /**************************************************************************
+   *
    * @enum:
    *   FT_STYLE_FLAG_XXX
    *
@@ -3075,15 +3097,15 @@ FT_BEGIN_HEADER
    *
    */
 #define FT_LOAD_DEFAULT                      0x0
-#define FT_LOAD_NO_SCALE                     ( 1L << 0 )
-#define FT_LOAD_NO_HINTING                   ( 1L << 1 )
-#define FT_LOAD_RENDER                       ( 1L << 2 )
-#define FT_LOAD_NO_BITMAP                    ( 1L << 3 )
-#define FT_LOAD_VERTICAL_LAYOUT              ( 1L << 4 )
-#define FT_LOAD_FORCE_AUTOHINT               ( 1L << 5 )
-#define FT_LOAD_CROP_BITMAP                  ( 1L << 6 )
-#define FT_LOAD_PEDANTIC                     ( 1L << 7 )
-#define FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH  ( 1L << 9 )
+#define FT_LOAD_NO_SCALE                     ( 1L << 0  )
+#define FT_LOAD_NO_HINTING                   ( 1L << 1  )
+#define FT_LOAD_RENDER                       ( 1L << 2  )
+#define FT_LOAD_NO_BITMAP                    ( 1L << 3  )
+#define FT_LOAD_VERTICAL_LAYOUT              ( 1L << 4  )
+#define FT_LOAD_FORCE_AUTOHINT               ( 1L << 5  )
+#define FT_LOAD_CROP_BITMAP                  ( 1L << 6  )
+#define FT_LOAD_PEDANTIC                     ( 1L << 7  )
+#define FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH  ( 1L << 9  )
 #define FT_LOAD_NO_RECURSE                   ( 1L << 10 )
 #define FT_LOAD_IGNORE_TRANSFORM             ( 1L << 11 )
 #define FT_LOAD_MONOCHROME                   ( 1L << 12 )
@@ -3097,8 +3119,9 @@ FT_BEGIN_HEADER
   /* */
 
   /* used internally only by certain font drivers */
-#define FT_LOAD_ADVANCE_ONLY                 ( 1L << 8 )
+#define FT_LOAD_ADVANCE_ONLY                 ( 1L << 8  )
 #define FT_LOAD_SBITS_ONLY                   ( 1L << 14 )
+#define FT_LOAD_SVG_ONLY                     ( 1L << 23 )
 
 
   /**************************************************************************
diff --git a/include/freetype/ftglyph.h b/include/freetype/ftglyph.h
index 1e62abed9..c934fd55c 100644
--- a/include/freetype/ftglyph.h
+++ b/include/freetype/ftglyph.h
@@ -181,7 +181,7 @@ FT_BEGIN_HEADER
    *
    * @description:
    *   A handle to an object used to model an outline glyph image.  This is a
-   *   sub-class of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec.
+   *   'sub-class' of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec.
    */
   typedef struct FT_OutlineGlyphRec_*  FT_OutlineGlyph;
 
diff --git a/include/freetype/ftimage.h b/include/freetype/ftimage.h
index af5855b6d..582b2c0f7 100644
--- a/include/freetype/ftimage.h
+++ b/include/freetype/ftimage.h
@@ -741,6 +741,10 @@ 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 ::
+   *     [Since 2.12] The glyph is represented by an SVG document in the
+   *     'SVG~' table.
    */
   typedef enum  FT_Glyph_Format_
   {
@@ -749,7 +753,8 @@ 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;
 
diff --git a/include/freetype/internal/ftobjs.h b/include/freetype/internal/ftobjs.h
index 1e86fc2e3..1c779ceae 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/fttrace.h b/include/freetype/internal/fttrace.h
index e2c214ca0..425101434 100644
--- a/include/freetype/internal/fttrace.h
+++ b/include/freetype/internal/fttrace.h
@@ -61,6 +61,7 @@ FT_TRACE_DEF( ttbdf )     /* TrueType embedded BDF   (ttbdf.c)    */
 FT_TRACE_DEF( ttcmap )    /* charmap handler         (ttcmap.c)   */
 FT_TRACE_DEF( ttcolr )    /* glyph layer table       (ttcolr.c)   */
 FT_TRACE_DEF( ttcpal )    /* color palette table     (ttcpal.c)   */
+FT_TRACE_DEF( ttsvg )     /* OpenType SVG table      (ttsvg.c)    */
 FT_TRACE_DEF( ttkern )    /* kerning handler         (ttkern.c)   */
 FT_TRACE_DEF( ttload )    /* basic TrueType tables   (ttload.c)   */
 FT_TRACE_DEF( ttmtx )     /* metrics-related tables  (ttmtx.c)    */
diff --git a/include/freetype/internal/sfnt.h b/include/freetype/internal/sfnt.h
index d985a9942..c67b47e86 100644
--- a/include/freetype/internal/sfnt.h
+++ b/include/freetype/internal/sfnt.h
@@ -314,6 +314,33 @@ FT_BEGIN_HEADER
   /**************************************************************************
    *
    * @functype:
+   *   TT_Load_Svg_Doc_Func
+   *
+   * @description:
+   *   Scan the SVG document list to find the document containing the glyph
+   *   that has the ID 'glyph*XXX*', where *XXX* is the value of
+   *   `glyph_index` as a decimal integer.
+   *
+   * @inout:
+   *   glyph ::
+   *     The glyph slot from which pointers to the SVG document list is to be
+   *     grabbed.  The results are stored back in the slot.
+   *
+   * @input:
+   *   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:
@@ -946,6 +973,11 @@ FT_BEGIN_HEADER
     TT_Get_Name_Func     get_name;
     TT_Get_Name_ID_Func  get_name_id;
 
+    /* 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;
 
 
@@ -997,7 +1029,10 @@ FT_BEGIN_HEADER
           colr_blend_,                   \
           get_metrics_,                  \
           get_name_,                     \
-          get_name_id_ )                 \
+          get_name_id_,                  \
+          load_svg_,                     \
+          free_svg_,                     \
+          load_svg_doc_ )                \
   static const SFNT_Interface  class_ =  \
   {                                      \
     goto_table_,                         \
@@ -1042,7 +1077,10 @@ FT_BEGIN_HEADER
     colr_blend_,                         \
     get_metrics_,                        \
     get_name_,                           \
-    get_name_id_                         \
+    get_name_id_,                        \
+    load_svg_,                           \
+    free_svg_,                           \
+    load_svg_doc_                        \
   };
 
 
diff --git a/include/freetype/internal/tttypes.h b/include/freetype/internal/tttypes.h
index a1ff0532f..df719387b 100644
--- a/include/freetype/internal/tttypes.h
+++ b/include/freetype/internal/tttypes.h
@@ -1644,6 +1644,9 @@ FT_BEGIN_HEADER
     void*                 cpal;
     void*                 colr;
 
+    /* since 2.12 */
+    void*                 svg;
+
   } TT_FaceRec;
 
 
diff --git a/include/freetype/otsvg.h b/include/freetype/otsvg.h
new file mode 100644
index 000000000..b8ff84f7b
--- /dev/null
+++ b/include/freetype/otsvg.h
@@ -0,0 +1,114 @@
+/****************************************************************************
+ *
+ * otsvg.h
+ *
+ *   Interface for OT-SVG support related things (specification).
+ *
+ * Copyright (C) 2022 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 OTSVG_H_
+#define OTSVG_H_
+
+#include <freetype/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.
+   *
+   *   svg_document_length ::
+   *     The length of `svg_document`.
+   *
+   *   metrics ::
+   *     A metrics object storing the size information.
+   *
+   *   units_per_EM ::
+   *     The size of the EM square.
+   *
+   *   start_glyph_id ::
+   *     The first glyph ID in the glyph range covered by this document.
+   *
+   *   end_glyph_id ::
+   *     The last glyph ID in the glyph range covered by this document.
+   *
+   *   transform ::
+   *     A 2x2 transformation matrix to apply to the glyph while rendering
+   *     it.
+   *
+   *   delta ::
+   *     The translation to apply to the glyph while rendering.
+   *
+   * @note:
+   *   When the slot is passed down to a renderer, the renderer can only
+   *   access the `metrics` and `units_per_EM` fields via `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.
+   *
+   * @since:
+   *   2.12
+   */
+  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_Matrix  transform;
+    FT_Vector  delta;
+
+  } FT_SVG_DocumentRec;
+
+
+  /**************************************************************************
+   *
+   * @type:
+   *   FT_SVG_Document
+   *
+   * @description:
+   *   A handle to an @FT_SVG_DocumentRec object.
+   *
+   * @since:
+   *   2.12
+   */
+  typedef struct FT_SVG_DocumentRec_*  FT_SVG_Document;
+
+
+FT_END_HEADER
+
+#endif /* OTSVG_H_ */
+
+
+/* END */
diff --git a/include/freetype/tttags.h b/include/freetype/tttags.h
index 290bd71d7..8b807641b 100644
--- a/include/freetype/tttags.h
+++ b/include/freetype/tttags.h
@@ -95,6 +95,7 @@ FT_BEGIN_HEADER
 #define TTAG_sbix  FT_MAKE_TAG( 's', 'b', 'i', 'x' )
 #define TTAG_sfnt  FT_MAKE_TAG( 's', 'f', 'n', 't' )
 #define TTAG_SING  FT_MAKE_TAG( 'S', 'I', 'N', 'G' )
+#define TTAG_SVG   FT_MAKE_TAG( 'S', 'V', 'G', ' ' )
 #define TTAG_trak  FT_MAKE_TAG( 't', 'r', 'a', 'k' )
 #define TTAG_true  FT_MAKE_TAG( 't', 'r', 'u', 'e' )
 #define TTAG_ttc   FT_MAKE_TAG( 't', 't', 'c', ' ' )
diff --git a/src/base/ftobjs.c b/src/base/ftobjs.c
index 4f5e7d439..391f46c7e 100644
--- a/src/base/ftobjs.c
+++ b/src/base/ftobjs.c
@@ -19,6 +19,7 @@
 #include <freetype/ftlist.h>
 #include <freetype/ftoutln.h>
 #include <freetype/ftfntfmt.h>
+#include <freetype/otsvg.h>
 
 #include <freetype/internal/ftvalid.h>
 #include <freetype/internal/ftobjs.h>
@@ -328,6 +329,19 @@
     if ( !error && clazz->init_slot )
       error = clazz->init_slot( slot );
 
+#ifdef FT_CONFIG_OPTION_SVG
+    /* if SVG table exists, allocate the space in `slot->other` */
+    if ( slot->face->face_flags & FT_FACE_FLAG_SVG )
+    {
+      FT_SVG_Document  document;
+
+
+      if ( FT_NEW( document ) )
+        goto Exit;
+      slot->other = document;
+    }
+#endif
+
   Exit:
     return error;
   }
@@ -564,8 +578,27 @@
     slot->subglyphs     = NULL;
     slot->control_data  = NULL;
     slot->control_len   = 0;
-    slot->other         = NULL;
-    slot->format        = FT_GLYPH_FORMAT_NONE;
+
+#ifndef FT_CONFIG_OPTION_SVG
+    slot->other = NULL;
+#else
+    if ( !( slot->face->face_flags & FT_FACE_FLAG_SVG ) )
+      slot->other = NULL;
+    else
+    {
+      if ( slot->internal->flags & FT_GLYPH_OWN_GZIP_SVG )
+      {
+        FT_Memory        memory = slot->face->memory;
+        FT_SVG_Document  doc    = (FT_SVG_Document)slot->other;
+
+
+        FT_FREE( doc->svg_document );
+        slot->internal->load_flags &= ~FT_GLYPH_OWN_GZIP_SVG;
+      }
+    }
+#endif
+
+    slot->format = FT_GLYPH_FORMAT_NONE;
 
     slot->linearHoriAdvance = 0;
     slot->linearVertAdvance = 0;
@@ -583,6 +616,23 @@
     FT_Driver_Class  clazz  = driver->clazz;
     FT_Memory        memory = driver->root.memory;
 
+#ifdef FT_CONFIG_OPTION_SVG
+    if ( slot->face->face_flags & FT_FACE_FLAG_SVG )
+    {
+      /* free memory in case SVG was there */
+      if ( slot->internal->flags & FT_GLYPH_OWN_GZIP_SVG )
+      {
+        FT_SVG_Document  doc = (FT_SVG_Document)slot->other;
+
+
+        FT_FREE( doc->svg_document );
+
+        slot->internal->flags &= ~FT_GLYPH_OWN_GZIP_SVG;
+      }
+
+      FT_FREE( slot->other );
+    }
+#endif
 
     if ( clazz->done_slot )
       clazz->done_slot( slot );
@@ -952,11 +1002,21 @@
       FT_AutoHinter_Interface  hinting;
 
 
-      /* try to load embedded bitmaps first if available            */
-      /*                                                            */
-      /* XXX: This is really a temporary hack that should disappear */
-      /*      promptly with FreeType 2.1!                           */
-      /*                                                            */
+      /* XXX: The use of the `FT_LOAD_XXX_ONLY` flags is not very */
+      /*      elegant.                                            */
+
+      /* try to load SVG documents if available */
+      if ( FT_HAS_SVG( face ) )
+      {
+        error = driver->clazz->load_glyph( slot, face->size,
+                                           glyph_index,
+                                           load_flags | FT_LOAD_SVG_ONLY );
+
+        if ( !error && slot->format == FT_GLYPH_FORMAT_SVG )
+          goto Load_Ok;
+      }
+
+      /* try to load embedded bitmaps if available */
       if ( FT_HAS_FIXED_SIZES( face )              &&
            ( load_flags & FT_LOAD_NO_BITMAP ) == 0 )
       {
diff --git a/src/cache/ftcbasic.c b/src/cache/ftcbasic.c
index 4aa3c6a07..635b17d07 100644
--- a/src/cache/ftcbasic.c
+++ b/src/cache/ftcbasic.c
@@ -183,7 +183,8 @@
       if ( !error )
       {
         if ( face->glyph->format == FT_GLYPH_FORMAT_BITMAP  ||
-             face->glyph->format == FT_GLYPH_FORMAT_OUTLINE )
+             face->glyph->format == FT_GLYPH_FORMAT_OUTLINE ||
+             face->glyph->format == FT_GLYPH_FORMAT_SVG     )
         {
           /* ok, copy it */
           FT_Glyph  glyph;
diff --git a/src/sfnt/rules.mk b/src/sfnt/rules.mk
index 6aca3781d..ac4b57122 100644
--- a/src/sfnt/rules.mk
+++ b/src/sfnt/rules.mk
@@ -36,6 +36,7 @@ SFNT_DRV_SRC := $(SFNT_DIR)/pngshim.c   \
                 $(SFNT_DIR)/ttbdf.c     \
                 $(SFNT_DIR)/ttcmap.c    \
                 $(SFNT_DIR)/ttcolr.c    \
+                $(SFNT_DIR)/ttsvg.c     \
                 $(SFNT_DIR)/ttcpal.c    \
                 $(SFNT_DIR)/ttkern.c    \
                 $(SFNT_DIR)/ttload.c    \
diff --git a/src/sfnt/sfdriver.c b/src/sfnt/sfdriver.c
index a1f761980..9115b6d3c 100644
--- a/src/sfnt/sfdriver.c
+++ b/src/sfnt/sfdriver.c
@@ -36,6 +36,10 @@
 #include "ttcpal.h"
 #endif
 
+#ifdef FT_CONFIG_OPTION_SVG
+#include "ttsvg.h"
+#endif
+
 #ifdef TT_CONFIG_OPTION_POSTSCRIPT_NAMES
 #include "ttpost.h"
 #endif
@@ -1214,6 +1218,12 @@
 #define PUT_COLOR_LAYERS( a )  NULL
 #endif
 
+#ifdef FT_CONFIG_OPTION_SVG
+#define PUT_SVG_SUPPORT( a )  a
+#else
+#define PUT_SVG_SUPPORT( a )  NULL
+#endif
+
 #define PUT_COLOR_LAYERS_V1( a )  PUT_COLOR_LAYERS( a )
 
 #ifdef TT_CONFIG_OPTION_POSTSCRIPT_NAMES
@@ -1308,7 +1318,14 @@
     tt_face_get_metrics,    /* TT_Get_Metrics_Func     get_metrics     */
 
     tt_face_get_name,       /* TT_Get_Name_Func        get_name        */
-    sfnt_get_name_id        /* TT_Get_Name_ID_Func     get_name_id     */
+    sfnt_get_name_id,       /* TT_Get_Name_ID_Func     get_name_id     */
+
+    PUT_SVG_SUPPORT( tt_face_load_svg ),
+                            /* TT_Load_Table_Func      load_svg        */
+    PUT_SVG_SUPPORT( tt_face_free_svg ),
+                            /* TT_Free_Table_Func      free_svg        */
+    PUT_SVG_SUPPORT( tt_face_load_svg_doc )
+                            /* TT_Load_Svg_Doc_Func    load_svg_doc    */
   )
 
 
diff --git a/src/sfnt/sfnt.c b/src/sfnt/sfnt.c
index d4378667c..9b3ceaedc 100644
--- a/src/sfnt/sfnt.c
+++ b/src/sfnt/sfnt.c
@@ -27,6 +27,7 @@
 #include "ttcmap.c"
 #include "ttcolr.c"
 #include "ttcpal.c"
+#include "ttsvg.c"
 
 #include "ttkern.c"
 #include "ttload.c"
diff --git a/src/sfnt/sfobjs.c b/src/sfnt/sfobjs.c
index 228364223..f9d4d3858 100644
--- a/src/sfnt/sfobjs.c
+++ b/src/sfnt/sfobjs.c
@@ -996,6 +996,10 @@
       LOAD_( colr );
     }
 
+    /* OpenType-SVG glyph support */
+    if ( sfnt->load_svg )
+      LOAD_( svg );
+
     /* consider the pclt, kerning, and gasp tables as optional */
     LOAD_( pclt );
     LOAD_( gasp );
@@ -1416,6 +1420,12 @@
         sfnt->free_cpal( face );
         sfnt->free_colr( face );
       }
+
+#ifdef FT_CONFIG_OPTION_SVG
+      /* free SVG data */
+      if ( sfnt->free_svg )
+        sfnt->free_svg( face );
+#endif
     }
 
 #ifdef TT_CONFIG_OPTION_BDF
diff --git a/src/sfnt/ttsvg.c b/src/sfnt/ttsvg.c
new file mode 100644
index 000000000..a4c10b98c
--- /dev/null
+++ b/src/sfnt/ttsvg.c
@@ -0,0 +1,386 @@
+/****************************************************************************
+ *
+ * ttsvg.c
+ *
+ *   OpenType SVG Color (specification).
+ *
+ * Copyright (C) 2022 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.
+ *
+ */
+
+
+  /**************************************************************************
+   *
+   * 'SVG' table specification:
+   *
+   *    https://docs.microsoft.com/en-us/typography/opentype/spec/svg
+   *
+   */
+
+#include <ft2build.h>
+#include <freetype/internal/ftstream.h>
+#include <freetype/internal/ftobjs.h>
+#include <freetype/internal/ftdebug.h>
+#include <freetype/tttags.h>
+#include <freetype/ftgzip.h>
+#include <freetype/otsvg.h>
+
+
+#ifdef FT_CONFIG_OPTION_SVG
+
+#include "ttsvg.h"
+
+
+  typedef struct  Svg_
+  {
+    FT_UShort  version;                 /* table version (starting at 0)  */
+    FT_UShort  num_entries;             /* number of SVG document records */
+
+    FT_Byte*  svg_doc_list;  /* pointer to the start of SVG Document List */
+
+    void*     table;                          /* memory that backs up SVG */
+    FT_ULong  table_size;
+
+  } Svg;
+
+
+  /**************************************************************************
+   *
+   * The macro FT_COMPONENT is used in trace mode.  It is an implicit
+   * parameter of the FT_TRACE() and FT_ERROR() macros, usued to print/log
+   * messages during execution.
+   */
+#undef  FT_COMPONENT
+#define FT_COMPONENT  ttsvg
+
+
+  FT_LOCAL_DEF( FT_Error )
+  tt_face_load_svg( TT_Face    face,
+                    FT_Stream  stream )
+  {
+    FT_Error   error;
+    FT_Memory  memory = face->root.memory;
+
+    FT_ULong  table_size;
+    FT_Byte*  table = NULL;
+    FT_Byte*  p     = NULL;
+    Svg*      svg   = NULL;
+    FT_ULong  offsetToSVGDocumentList;
+
+
+    error = face->goto_table( face, TTAG_SVG, stream, &table_size );
+    if ( error )
+      goto NoSVG;
+
+    if ( FT_FRAME_EXTRACT( table_size, table ) )
+      goto NoSVG;
+
+    /* Allocate memory for the SVG object */
+    if ( FT_NEW( svg ) )
+      goto NoSVG;
+
+    p                       = table;
+    svg->version            = FT_NEXT_USHORT( p );
+    offsetToSVGDocumentList = FT_NEXT_ULONG( p );
+
+    if ( offsetToSVGDocumentList == 0 )
+      goto InvalidTable;
+
+    svg->svg_doc_list = (FT_Byte*)( table + offsetToSVGDocumentList );
+
+    p                = svg->svg_doc_list;
+    svg->num_entries = FT_NEXT_USHORT( p );
+
+    FT_TRACE3(( "version: %d\n", svg->version ));
+    FT_TRACE3(( "number of entries: %d\n", svg->num_entries ));
+
+    svg->table      = table;
+    svg->table_size = table_size;
+
+    face->svg              = svg;
+    face->root.face_flags |= FT_FACE_FLAG_SVG;
+
+    return FT_Err_Ok;
+
+  InvalidTable:
+    error = FT_THROW( Invalid_Table );
+
+  NoSVG:
+    FT_FRAME_RELEASE( table );
+    FT_FREE( svg );
+    face->svg = NULL;
+
+    return error;
+  }
+
+
+  FT_LOCAL_DEF( void )
+  tt_face_free_svg( TT_Face  face )
+  {
+    FT_Memory  memory = face->root.memory;
+    FT_Stream  stream = face->root.stream;
+
+    Svg*  svg = (Svg*)face->svg;
+
+
+    if ( svg )
+    {
+      FT_FRAME_RELEASE( svg->table );
+      FT_FREE( svg );
+    }
+  }
+
+
+  typedef struct  Svg_doc_
+  {
+    FT_UShort  start_glyph_id;
+    FT_UShort  end_glyph_id;
+
+    FT_ULong  offset;
+    FT_ULong  length;
+
+  } Svg_doc;
+
+
+  static Svg_doc
+  extract_svg_doc( FT_Byte*  stream )
+  {
+    Svg_doc  doc;
+
+
+    doc.start_glyph_id = FT_NEXT_USHORT( stream );
+    doc.end_glyph_id   = FT_NEXT_USHORT( stream );
+
+    doc.offset = FT_NEXT_ULONG( stream );
+    doc.length = FT_NEXT_ULONG( stream );
+
+    return doc;
+  }
+
+
+  static FT_Int
+  compare_svg_doc( Svg_doc  doc,
+                   FT_UInt  glyph_index )
+  {
+    if ( glyph_index < doc.start_glyph_id )
+      return -1;
+    else if ( glyph_index > doc.end_glyph_id )
+      return 1;
+    else
+      return 0;
+  }
+
+
+  static FT_Error
+  find_doc( FT_Byte*    stream,
+            FT_UShort   num_entries,
+            FT_UInt     glyph_index,
+            FT_ULong   *doc_offset,
+            FT_ULong   *doc_length,
+            FT_UShort  *start_glyph,
+            FT_UShort  *end_glyph )
+  {
+    FT_Error  error;
+
+    Svg_doc  start_doc;
+    Svg_doc  mid_doc;
+    Svg_doc  end_doc;
+
+    FT_Bool  found = FALSE;
+    FT_UInt  i     = 0;
+
+    FT_UInt  start_index = 0;
+    FT_UInt  end_index   = num_entries - 1;
+    FT_Int   comp_res;
+
+
+    /* search algorithm */
+    if ( num_entries == 0 )
+    {
+      error = FT_THROW( Invalid_Table );
+      return error;
+    }
+
+    start_doc = extract_svg_doc( stream + start_index * 12 );
+    end_doc   = extract_svg_doc( stream + end_index * 12 );
+
+    if ( ( compare_svg_doc( start_doc, glyph_index ) == -1 ) ||
+         ( compare_svg_doc( end_doc, glyph_index ) == 1 )    )
+    {
+      error = FT_THROW( Invalid_Glyph_Index );
+      return error;
+    }
+
+    while ( start_index <= end_index )
+    {
+      i        = ( start_index + end_index ) / 2;
+      mid_doc  = extract_svg_doc( stream + i * 12 );
+      comp_res = compare_svg_doc( mid_doc, glyph_index );
+
+      if ( comp_res == 1 )
+      {
+        start_index = i + 1;
+        start_doc   = extract_svg_doc( stream + start_index * 4 );
+      }
+      else if ( comp_res == -1 )
+      {
+        end_index = i - 1;
+        end_doc   = extract_svg_doc( stream + end_index * 4 );
+      }
+      else
+      {
+        found = TRUE;
+        break;
+      }
+    }
+    /* search algorithm end */
+
+    if ( found != TRUE )
+    {
+      FT_TRACE5(( "SVG glyph not found\n" ));
+      error = FT_THROW( Invalid_Glyph_Index );
+    }
+    else
+    {
+      *doc_offset = mid_doc.offset;
+      *doc_length = mid_doc.length;
+
+      *start_glyph = mid_doc.start_glyph_id;
+      *end_glyph   = mid_doc.end_glyph_id;
+
+      error = FT_Err_Ok;
+    }
+
+    return error;
+  }
+
+
+  FT_LOCAL_DEF( FT_Error )
+  tt_face_load_svg_doc( FT_GlyphSlot  glyph,
+                        FT_UInt       glyph_index )
+  {
+    FT_Byte*   doc_list;        /* pointer to the SVG doc list         */
+    FT_UShort  num_entries;     /* total number of entries in doc list */
+    FT_ULong   doc_offset;
+    FT_ULong   doc_length;
+
+    FT_UShort  start_glyph_id;
+    FT_UShort  end_glyph_id;
+
+    FT_Error   error  = FT_Err_Ok;
+    TT_Face    face   = (TT_Face)glyph->face;
+    FT_Memory  memory = face->root.memory;
+    Svg*       svg    = (Svg*)face->svg;
+
+    FT_SVG_Document  svg_document = (FT_SVG_Document)glyph->other;
+
+
+    FT_ASSERT( !( svg == NULL ) );
+
+    doc_list    = svg->svg_doc_list;
+    num_entries = FT_NEXT_USHORT( doc_list );
+
+    error = find_doc( doc_list, num_entries, glyph_index,
+                                &doc_offset, &doc_length,
+                                &start_glyph_id, &end_glyph_id );
+    if ( error != FT_Err_Ok )
+      goto Exit;
+
+    doc_list = svg->svg_doc_list;      /* reset, so we can use it again */
+    doc_list = (FT_Byte*)( doc_list + doc_offset );
+
+    if ( ( doc_list[0] == 0x1F ) && ( doc_list[1] == 0x8B )
+                                 && ( doc_list[2] == 0x08 ) )
+    {
+#ifdef FT_CONFIG_OPTION_SYSTEM_ZLIB
+
+      FT_ULong  uncomp_size;
+      FT_Byte*  uncomp_buffer;
+
+
+      /*
+       * Get the size of the original document.  This helps in allotting the
+       * buffer to accommodate the uncompressed version.  The last 4 bytes
+       * of the compressed document are equal to the original size modulo
+       * 2^32.  Since the size of SVG documents is less than 2^32 bytes we
+       * can use this accurately.  The four bytes are stored in
+       * little-endian format.
+       */
+      FT_TRACE4(( "SVG document is GZIP compressed\n" ));
+      uncomp_size = (FT_ULong)doc_list[doc_length - 1] << 24 |
+                    (FT_ULong)doc_list[doc_length - 2] << 16 |
+                    (FT_ULong)doc_list[doc_length - 3] << 8  |
+                    (FT_ULong)doc_list[doc_length - 4];
+
+      if ( FT_QALLOC( uncomp_buffer, uncomp_size ) )
+        goto Exit;
+
+      error = FT_Gzip_Uncompress( memory,
+                                  uncomp_buffer,
+                                  &uncomp_size,
+                                  doc_list,
+                                  doc_length );
+      if ( error )
+      {
+        FT_FREE( uncomp_buffer );
+        error = FT_THROW( Invalid_Table );
+        goto Exit;
+      }
+
+      glyph->internal->flags |= FT_GLYPH_OWN_GZIP_SVG;
+
+      doc_list   = uncomp_buffer;
+      doc_length = uncomp_size;
+
+#else /* !FT_CONFIG_OPTION_SYSTEM_ZLIB */
+
+      error = FT_THROW( Unimplemented_Feature );
+      goto Exit;
+
+#endif /* !FT_CONFIG_OPTION_SYSTEM_ZLIB */
+    }
+
+    svg_document->svg_document        = doc_list;
+    svg_document->svg_document_length = doc_length;
+
+    svg_document->metrics      = glyph->face->size->metrics;
+    svg_document->units_per_EM = glyph->face->units_per_EM;
+
+    svg_document->start_glyph_id = start_glyph_id;
+    svg_document->end_glyph_id   = end_glyph_id;
+
+    svg_document->transform.xx = 0x10000;
+    svg_document->transform.xy = 0;
+    svg_document->transform.yx = 0;
+    svg_document->transform.yy = 0x10000;
+
+    svg_document->delta.x = 0;
+    svg_document->delta.y = 0;
+
+    FT_TRACE5(( "start_glyph_id: %d\n", start_glyph_id ));
+    FT_TRACE5(( "end_glyph_id:   %d\n", end_glyph_id ));
+    FT_TRACE5(( "svg_document:\n" ));
+    FT_TRACE5(( " %.*s\n", (FT_UInt)doc_length, doc_list ));
+
+    glyph->other = svg_document;
+
+  Exit:
+    return error;
+  }
+
+#else /* !FT_CONFIG_OPTION_SVG */
+
+  /* ANSI C doesn't like empty source files */
+  typedef int  _tt_svg_dummy;
+
+#endif /* !FT_CONFIG_OPTION_SVG */
+
+
+/* END */
diff --git a/src/sfnt/ttsvg.h b/src/sfnt/ttsvg.h
new file mode 100644
index 000000000..7c234fd52
--- /dev/null
+++ b/src/sfnt/ttsvg.h
@@ -0,0 +1,43 @@
+/****************************************************************************
+ *
+ * ttsvg.h
+ *
+ *   OpenType SVG Color (specification).
+ *
+ * Copyright (C) 2022 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 TTSVG_H_
+#define TTSVG_H_
+
+#include <freetype/internal/ftstream.h>
+#include <freetype/internal/tttypes.h>
+
+
+FT_BEGIN_HEADER
+
+  FT_LOCAL( FT_Error )
+  tt_face_load_svg( TT_Face    face,
+                    FT_Stream  stream );
+
+  FT_LOCAL( void )
+  tt_face_free_svg( TT_Face  face );
+
+  FT_LOCAL( FT_Error )
+  tt_face_load_svg_doc( FT_GlyphSlot  glyph,
+                        FT_UInt       glyph_index );
+
+FT_END_HEADER
+
+#endif /* TTSVG_H_ */
+
+
+/* END */