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`.
This commit is contained in:
Moazin Khatti 2021-12-25 19:20:44 -08:00 committed by Werner Lemberg
parent 06c1a25e63
commit f93a897afe
18 changed files with 741 additions and 24 deletions

View File

@ -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. */

View File

@ -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 )
/**************************************************************************
@ -1487,6 +1493,22 @@ FT_BEGIN_HEADER
( !!( (face)->face_flags & FT_FACE_FLAG_COLOR ) )
/**************************************************************************
*
* @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:
@ -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 )
/**************************************************************************

View File

@ -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;

View File

@ -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;

View File

@ -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_
{

View File

@ -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) */

View File

@ -311,6 +311,33 @@ FT_BEGIN_HEADER
TT_SBit_MetricsRec *ametrics );
/**************************************************************************
*
* @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:
@ -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_ \
};

View File

@ -1644,6 +1644,9 @@ FT_BEGIN_HEADER
void* cpal;
void* colr;
/* since 2.12 */
void* svg;
} TT_FaceRec;

114
include/freetype/otsvg.h Normal file
View File

@ -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 */

View File

@ -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', ' ' )

View File

@ -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 )
{

View File

@ -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;

View File

@ -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 \

View File

@ -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 */
)

View File

@ -27,6 +27,7 @@
#include "ttcmap.c"
#include "ttcolr.c"
#include "ttcpal.c"
#include "ttsvg.c"
#include "ttkern.c"
#include "ttload.c"

View File

@ -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

386
src/sfnt/ttsvg.c Normal file
View File

@ -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 */

43
src/sfnt/ttsvg.h Normal file
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@ -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 */