[freetype2] GSoC-2019-moazin 25250a3 25/26: Add `start_glyph_id' and `end_glyph_id'.

[Moazin Khatti]

branch: GSoC-2019-moazin
commit 25250a347808f547210c083f920481615849fb33
Author: Moazin Khatti <address@hidden>
Commit: Moazin Khatti <address@hidden>

    Add `start_glyph_id' and `end_glyph_id'.
    
    These two fields are added to `FT_SvgGlyphRec' and
    `FT_SVG_DocumentRec'. This is to allow the rendering port to create
    a caching mechanism.
---
 include/freetype/ftglyph.h     |  8 ++++++++
 include/freetype/svgrenderer.h | 10 ++++++++++
 src/base/ftglyph.c             |  7 +++++++
 src/sfnt/ttsvg.c               | 15 +++++++++++++--
 4 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/include/freetype/ftglyph.h b/include/freetype/ftglyph.h
index 6f8fdb8..fc503f9 100644
--- a/include/freetype/ftglyph.h
+++ b/include/freetype/ftglyph.h
@@ -263,6 +263,12 @@ FT_BEGIN_HEADER
    *   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 objects. However, the Glyph Management API
@@ -282,6 +288,8 @@ FT_BEGIN_HEADER
     FT_UInt             glyph_index;
     FT_Size_Metrics     metrics;
     FT_UShort           units_per_EM;
+    FT_UShort           start_glyph_id;
+    FT_UShort           end_glyph_id;
     /* TODO: (OT-SVG) Maybe put a transformation matrix here */
   } FT_SvgGlyphRec;
 
diff --git a/include/freetype/svgrenderer.h b/include/freetype/svgrenderer.h
index 449a443..b33e423 100644
--- a/include/freetype/svgrenderer.h
+++ b/include/freetype/svgrenderer.h
@@ -169,6 +169,12 @@ FT_BEGIN_HEADER
    *   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 objects. However, the Glyph Management API
@@ -187,6 +193,10 @@ FT_BEGIN_HEADER
     FT_ULong         svg_document_length;
     FT_Size_Metrics  metrics;
     FT_UShort        units_per_EM;
+    FT_UShort        start_glyph_id;
+    FT_UShort        end_glyph_id;
+    /* TODO: (OT-SVG) Not storing glyph_index here for now. Might need to
+     * at some point. Review this! */
   } FT_SVG_DocumentRec;
 
   /**************************************************************************
diff --git a/src/base/ftglyph.c b/src/base/ftglyph.c
index 22cf25b..f558476 100644
--- a/src/base/ftglyph.c
+++ b/src/base/ftglyph.c
@@ -328,6 +328,8 @@
     glyph->glyph_index         = slot->glyph_index;
     glyph->metrics             = document->metrics;
     glyph->units_per_EM        = document->units_per_EM;
+    glyph->start_glyph_id      = document->start_glyph_id;
+    glyph->end_glyph_id        = document->end_glyph_id;
 
     /* copy the document into glyph */
     FT_MEM_COPY( glyph->svg_document, document->svg_document, doc_length );
@@ -378,6 +380,8 @@
     target->svg_document_length = source->svg_document_length;
     target->metrics             = source->metrics;
     target->units_per_EM        = source->units_per_EM;
+    target->start_glyph_id      = source->start_glyph_id;
+    target->end_glyph_id        = source->end_glyph_id;
 
     /* allocate space for the svg document */
     target->svg_document = memory->alloc( memory,
@@ -413,6 +417,9 @@
     document->svg_document_length = glyph->svg_document_length;
     document->metrics             = glyph->metrics;
     document->units_per_EM        = glyph->units_per_EM;
+    document->start_glyph_id      = glyph->start_glyph_id;
+    document->end_glyph_id        = glyph->end_glyph_id;
+
     slot->format = FT_GLYPH_FORMAT_SVG;
 
     slot->other = document;
diff --git a/src/sfnt/ttsvg.c b/src/sfnt/ttsvg.c
index 798c907..41c0e16 100644
--- a/src/sfnt/ttsvg.c
+++ b/src/sfnt/ttsvg.c
@@ -126,7 +126,9 @@
             FT_UShort  num_entries,
             FT_UInt    glyph_index,
             FT_ULong   *doc_offset,
-            FT_ULong   *doc_length  )
+            FT_ULong   *doc_length,
+            FT_UShort  *start_glyph,
+            FT_UShort  *end_glyph )
   {
     FT_Error   error;
     FT_UShort  start_glyph_id;
@@ -158,7 +160,11 @@
     if ( found != TRUE )
       error = FT_THROW( Invalid_Glyph_Index );
     else
+    {
+      *start_glyph = start_glyph_id;
+      *end_glyph   = end_glyph_id;
       error = FT_Err_Ok;
+    }
     return error;
   }
 
@@ -174,6 +180,8 @@
 
     FT_ULong   doc_offset;
     FT_ULong   doc_length;
+    FT_UShort  start_glyph_id;
+    FT_UShort  end_glyph_id;
 
     FT_ULong   uncomp_size;
     FT_Byte*   uncomp_buffer;
@@ -192,7 +200,8 @@
     num_entries  = FT_NEXT_USHORT( doc_list );
 
     error = find_doc( doc_list, num_entries, glyph_index,
-                                &doc_offset, &doc_length );
+                                &doc_offset, &doc_length,
+                                &start_glyph_id, &end_glyph_id );
     if ( error != FT_Err_Ok )
       return error;
 
@@ -233,6 +242,8 @@
     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;
 
     glyph->other = svg_document;
     glyph->metrics.horiAdvance *= 
((float)glyph->face->size->metrics.x_ppem)/((float)glyph->face->units_per_EM) * 
64.0;