src/sfnt/ttsvg.c - third_party/freetype2 - Git at Google

 /****************************************************************************
  *
  * ttsvg.c
  *
  *   OpenType SVG Color (specification).
  *
  * Copyright (C) 2018-2019 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.
  *
  */


   /**************************************************************************
    *
    * `SVG' table specification:
    *
    *    https://docs.microsoft.com/en-us/typography/opentype/spec/svg
    *
    */

 #include <ft2build.h>
 #include FT_INTERNAL_STREAM_H
 #include FT_INTERNAL_OBJECTS_H
 #include FT_INTERNAL_DEBUG_H
 #include FT_TRUETYPE_TAGS_H
 #include FT_GZIP_H
 #include FT_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       */
     /* Pointer to the starting of SVG Document List */
     FT_Byte*   svg_doc_list;
     /* Memory that backs up SVG */
     void*     table;
     FT_ULong  table_size;

   } Svg;

 #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 the 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(( "num entiries: %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 algo */
     if ( num_entries == 0 )
     {
       error = FT_THROW( Invalid_Table );
       return error;
     }

     FT_TRACE6(( "--- binary search glyph id: %d ---\n", glyph_index ));

     start_doc = extract_svg_doc( stream + start_index * 12 );
     end_doc   = extract_svg_doc( stream + end_index * 12 );

     FT_TRACE6(( "--- start glyph ---\n" ));
     FT_TRACE6(( "start_id: %d\n", start_doc.start_glyph_id ));
     FT_TRACE6(( "end_id: %d\n", start_doc.end_glyph_id ));
     FT_TRACE6(( "--- end glyph ---\n" ));
     FT_TRACE6(( "start_id: %d\n", end_doc.start_glyph_id ));
     FT_TRACE6(( "end_id: %d\n", end_doc.end_glyph_id ));
     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 );
       FT_TRACE6(( "--- current glyph ---\n" ));
       FT_TRACE6(( "start_id: %d\n", mid_doc.start_glyph_id ));
       FT_TRACE6(( "end_id: %d\n", mid_doc.end_glyph_id ));
       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 );
         FT_TRACE6(( "RIGHT\n" ));
       }
       else if ( comp_res == -1 )
       {
         end_index = i - 1;
         end_doc = extract_svg_doc( stream + end_index * 4 );
         FT_TRACE6(( "LEFT\n" ));
       }
       else
       {
         found = TRUE;
         FT_TRACE5(( "FOUND\n" ));
         break;
       }
     }

     FT_TRACE5(( "--- binary search end ---\n" ));
     /* search algo end */
     if ( found != TRUE )
     {
       FT_TRACE5(( "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 Document List */
     FT_UShort  num_entries;          /* Total no of entires in doc list  */
     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;

     FT_Error   error  = FT_Err_Ok;
     TT_Face    face   = (TT_Face)glyph->face;
     FT_Memory  memory = face->root.memory;
     Svg*       svg    = face->svg;

     FT_SVG_Document  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 to 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 ) )
     {
       /* get the size of the orignal document. This helps in alotting the
        * buffer to accomodate the uncompressed version. The last 4 bytes
        * of the compressed document are equal to orignal_size modulo 2^32.
        * Since SVG docs will be lesser in size then 2^32, we can use this
        * accurately. The four bytes are stored in little-endian format.
        */
       FT_TRACE4(( "SVG document found 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];

       uncomp_buffer = (FT_Byte*) memory->alloc( memory, uncomp_size );
       error = FT_Gzip_Uncompress( memory, uncomp_buffer, &uncomp_size,
                                           doc_list,      doc_length  );
       if ( error != FT_Err_Ok )
       {
         memory->free( memory, 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;
     }

     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%.*s\n", 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 */
	/****************************************************************************
	*
	* ttsvg.c
	*
	* OpenType SVG Color (specification).
	*
	* Copyright (C) 2018-2019 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.
	*
	*/


	/**************************************************************************
	*
	* `SVG' table specification:
	*
	* https://docs.microsoft.com/en-us/typography/opentype/spec/svg
	*
	*/

	#include <ft2build.h>
	#include FT_INTERNAL_STREAM_H
	#include FT_INTERNAL_OBJECTS_H
	#include FT_INTERNAL_DEBUG_H
	#include FT_TRUETYPE_TAGS_H
	#include FT_GZIP_H
	#include FT_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 */
	/* Pointer to the starting of SVG Document List */
	FT_Byte* svg_doc_list;
	/* Memory that backs up SVG */
	void* table;
	FT_ULong table_size;

	} Svg;

	#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 the 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(( "num entiries: %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 algo */
	if ( num_entries == 0 )
	{
	error = FT_THROW( Invalid_Table );
	return error;
	}

	FT_TRACE6(( "--- binary search glyph id: %d ---\n", glyph_index ));

	start_doc = extract_svg_doc( stream + start_index * 12 );
	end_doc = extract_svg_doc( stream + end_index * 12 );

	FT_TRACE6(( "--- start glyph ---\n" ));
	FT_TRACE6(( "start_id: %d\n", start_doc.start_glyph_id ));
	FT_TRACE6(( "end_id: %d\n", start_doc.end_glyph_id ));
	FT_TRACE6(( "--- end glyph ---\n" ));
	FT_TRACE6(( "start_id: %d\n", end_doc.start_glyph_id ));
	FT_TRACE6(( "end_id: %d\n", end_doc.end_glyph_id ));
	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 );
	FT_TRACE6(( "--- current glyph ---\n" ));
	FT_TRACE6(( "start_id: %d\n", mid_doc.start_glyph_id ));
	FT_TRACE6(( "end_id: %d\n", mid_doc.end_glyph_id ));
	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 );
	FT_TRACE6(( "RIGHT\n" ));
	}
	else if ( comp_res == -1 )
	{
	end_index = i - 1;
	end_doc = extract_svg_doc( stream + end_index * 4 );
	FT_TRACE6(( "LEFT\n" ));
	}
	else
	{
	found = TRUE;
	FT_TRACE5(( "FOUND\n" ));
	break;
	}
	}

	FT_TRACE5(( "--- binary search end ---\n" ));
	/* search algo end */
	if ( found != TRUE )
	{
	FT_TRACE5(( "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 Document List */
	FT_UShort num_entries; /* Total no of entires in doc list */
	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;

	FT_Error error = FT_Err_Ok;
	TT_Face face = (TT_Face)glyph->face;
	FT_Memory memory = face->root.memory;
	Svg* svg = face->svg;

	FT_SVG_Document 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 to 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 ) )
	{
	/* get the size of the orignal document. This helps in alotting the
	* buffer to accomodate the uncompressed version. The last 4 bytes
	* of the compressed document are equal to orignal_size modulo 2^32.
	* Since SVG docs will be lesser in size then 2^32, we can use this
	* accurately. The four bytes are stored in little-endian format.
	*/
	FT_TRACE4(( "SVG document found 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];

	uncomp_buffer = (FT_Byte*) memory->alloc( memory, uncomp_size );
	error = FT_Gzip_Uncompress( memory, uncomp_buffer, &uncomp_size,
	doc_list, doc_length );
	if ( error != FT_Err_Ok )
	{
	memory->free( memory, 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;
	}

	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%.*s\n", 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 */