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freetype2
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Code Issues 9 Releases Wiki Activity

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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
include/freetype/config/ftheader.h
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. */

43
include/freetype/freetype.h
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 )
/**************************************************************************

2
include/freetype/ftglyph.h
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;

7
include/freetype/ftimage.h
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;

3
include/freetype/internal/ftobjs.h
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_
{

1
include/freetype/internal/fttrace.h
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) */

42
include/freetype/internal/sfnt.h
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_ \
};

3
include/freetype/internal/tttypes.h
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 */

1
include/freetype/tttags.h
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', ' ' )

74
src/base/ftobjs.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 )
{

3
src/cache/ftcbasic.c vendored
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;

1
src/sfnt/rules.mk
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 \

19
src/sfnt/sfdriver.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 */
)

1
src/sfnt/sfnt.c
View File

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

10
src/sfnt/sfobjs.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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/****************************************************************************
*
* 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 */