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/****************************************************************************
*
* hvfdrv.c
*
* HVF font driver implementation (body).
*
* Copyright (C) 2025-2026 by
* Apple Inc.
* written by Deborah Goldsmith <goldsmit@apple.com>
*
* 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.
*
*/
#include <freetype/internal/ftdebug.h>
#include <freetype/internal/ftstream.h>
#include <freetype/internal/sfnt.h>
#include <freetype/tttags.h>
#include <freetype/internal/tttypes.h> /* For TT_Face */
#include <freetype/internal/services/svfntfmt.h>
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
#include <freetype/ftmm.h>
#include <freetype/internal/services/svmm.h>
#include <freetype/internal/services/svmetric.h>
#endif
#include "hvfdrv.h"
#include "hvfobjs.h"
#include "hvfload.h"
#include "hvferror.h"
/**************************************************************************
*
* The macro FT_COMPONENT is used in trace mode. It is an implicit
* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
* messages during execution.
*/
#undef FT_COMPONENT
#define FT_COMPONENT hvfdrv
#ifdef FT_CONFIG_OPTION_HVF
/**************************************************************************
*
* FACE MANAGEMENT
*
*/
/**************************************************************************
*
* @Function:
* hvf_get_kerning
*
* @Description:
* Get kerning vector between two glyphs. Delegates to SFNT service
* since HVF fonts are TrueType/OpenType fonts.
*
* @Input:
* face ::
* A handle to the source face object.
*
* left_glyph ::
* The index of the left glyph in the kern pair.
*
* right_glyph ::
* The index of the right glyph in the kern pair.
*
* @Output:
* kerning ::
* The kerning vector in font units.
*
* @Return:
* FreeType error code. 0 means success.
*/
static FT_Error
hvf_get_kerning( FT_Face face,
FT_UInt left_glyph,
FT_UInt right_glyph,
FT_Vector* kerning )
{
TT_Face tt_face = (TT_Face)face;
SFNT_Service sfnt = (SFNT_Service)tt_face->sfnt;
kerning->x = 0;
kerning->y = 0;
if ( sfnt )
{
/* Use 'kern' table if available since that can be faster; otherwise */
/* use GPOS kerning pairs if available. */
if ( tt_face->kern_avail_bits )
kerning->x = sfnt->get_kerning( tt_face,
left_glyph,
right_glyph );
#ifdef TT_CONFIG_OPTION_GPOS_KERNING
else if ( tt_face->num_gpos_lookups_kerning )
kerning->x = sfnt->get_gpos_kerning( tt_face,
left_glyph,
right_glyph );
#endif
}
return FT_Err_Ok;
}
/**************************************************************************
*
* @Function:
* hvf_get_advances
*
* @Description:
* Get advance widths/heights for a range of glyphs. Delegates to
* TrueType infrastructure since HVF fonts are TrueType/OpenType fonts.
*
* @Input:
* face ::
* A handle to the source face object.
*
* start ::
* The first glyph index.
*
* count ::
* The number of advance values to retrieve.
*
* flags ::
* Loading flags (vertical/horizontal layout).
*
* @Output:
* advances ::
* The advance values in 16.16 format.
*
* @Return:
* FreeType error code. 0 means success.
*/
static FT_Error
hvf_get_advances( FT_Face face,
FT_UInt start,
FT_UInt count,
FT_Int32 flags,
FT_Fixed *advances )
{
TT_Face tt_face = (TT_Face)face;
FT_Bool horz;
FT_UInt nn;
if ( !FT_IS_SFNT( face ) )
return FT_THROW( Unimplemented_Feature );
horz = !( flags & FT_LOAD_VERTICAL_LAYOUT );
if ( horz )
{
/* Check availability of horizontal metrics. */
if ( !tt_face->horizontal.number_Of_HMetrics )
return FT_THROW( Unimplemented_Feature );
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
/* No fast retrieval for blended MM fonts without 'HVAR' table. */
if ( ( FT_IS_NAMED_INSTANCE( face ) || FT_IS_VARIATION( face ) ) &&
!( tt_face->variation_support & TT_FACE_FLAG_VAR_HADVANCE ) )
return FT_THROW( Unimplemented_Feature );
#endif
}
else /* vertical */
{
/* Check whether we have data from the 'vmtx' table at all. */
if ( !tt_face->vertical_info )
return FT_THROW( Unimplemented_Feature );
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
/* No fast retrieval for blended MM fonts without 'VVAR' table. */
if ( ( FT_IS_NAMED_INSTANCE( face ) || FT_IS_VARIATION( face ) ) &&
!( tt_face->variation_support & TT_FACE_FLAG_VAR_VADVANCE ) )
return FT_THROW( Unimplemented_Feature );
#endif
}
/* Proceed to fast advances. */
for ( nn = 0; nn < count; nn++ )
{
FT_UShort aw;
FT_Short dummy;
( (SFNT_Service)tt_face->sfnt )->get_metrics( tt_face,
!horz,
start + nn,
&dummy,
&aw );
FT_TRACE5(( " idx %u: advance %s %d font unit%s\n",
start + nn,
horz ? "width" : "height",
aw,
aw == 1 ? "" : "s" ));
advances[nn] = aw;
}
return FT_Err_Ok;
}
/**************************************************************************
*
* SERVICE DEFINITIONS
*
*/
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
/* Service delegation functions following CFF module pattern. */
FT_CALLBACK_DEF( FT_Error )
hvf_set_mm_blend( FT_Face face, /* HVF_Face */
FT_UInt num_coords,
FT_Fixed* coords )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
HVF_Face hvf_face = (HVF_Face)face;
FT_Error error;
/* Call the underlying service. */
error = mm->set_mm_blend( face, num_coords, coords );
/* error == -1 means "no change"; early exit. */
if ( error == -1 )
return FT_Err_Ok;
/* If successful, refresh our cached HVF coordinates. */
if ( !error )
{
FT_Error refresh_error = hvf_refresh_axis_coordinates( hvf_face );
#ifdef FT_DEBUG_LEVEL_TRACE
if ( refresh_error )
{
/* Don't fail the entire operation, just log the issue. */
FT_TRACE3(( "hvf_set_mm_blend:"
" failed to refresh HVF coordinates (error %d)\n",
refresh_error ));
}
#else
FT_UNUSED( refresh_error );
#endif
}
return error;
}
FT_CALLBACK_DEF( FT_Error )
hvf_get_mm_blend( FT_Face face, /* HVF_Face */
FT_UInt num_coords,
FT_Fixed* coords )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->get_mm_blend( face, num_coords, coords );
}
FT_CALLBACK_DEF( FT_Error )
hvf_get_mm_var( FT_Face face, /* HVF_Face */
FT_MM_Var** master )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->get_mm_var( face, master );
}
FT_CALLBACK_DEF( FT_Error )
hvf_set_var_design( FT_Face face, /* HVF_Face */
FT_UInt num_coords,
FT_Fixed* coords )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
HVF_Face hvf_face = (HVF_Face)face;
FT_Error error;
/* Call the underlying service. */
error = mm->set_var_design( face, num_coords, coords );
/* error == -1 means "no change"; early exit. */
if ( error == -1 )
return FT_Err_Ok;
/* If successful, refresh our cached HVF coordinates. */
if ( !error || error == -2 )
{
FT_Error refresh_error = hvf_refresh_axis_coordinates( hvf_face );
#ifdef FT_DEBUG_LEVEL_TRACE
if ( refresh_error )
{
/* Don't fail the entire operation, just log the issue. */
FT_TRACE3(( "hvf_set_var_design:"
" failed to refresh HVF coordinates (error %d)\n",
refresh_error ));
}
#else
FT_UNUSED( refresh_error );
#endif
}
return error;
}
FT_CALLBACK_DEF( FT_Error )
hvf_get_var_design( FT_Face face, /* HVF_Face */
FT_UInt num_coords,
FT_Fixed* coords )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->get_var_design( face, num_coords, coords );
}
FT_CALLBACK_DEF( FT_Error )
hvf_set_named_instance( FT_Face face, /* HVF_Face */
FT_UInt instance_index )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
HVF_Face hvf_face = (HVF_Face)face;
FT_Error error;
/* Call the underlying service. */
error = mm->set_named_instance( face, instance_index );
/* error == -1 means "no change"; early exit. */
if ( error == -1 )
return FT_Err_Ok;
/* If successful, refresh our cached HVF coordinates. */
if ( !error )
{
FT_Error refresh_error = hvf_refresh_axis_coordinates( hvf_face );
#ifdef FT_DEBUG_LEVEL_TRACE
if ( refresh_error )
{
/* Don't fail the entire operation, just log the issue. */
FT_TRACE3(( "hvf_set_named_instance:"
" failed to refresh HVF coordinates (error %d)\n",
refresh_error ));
}
#else
FT_UNUSED( refresh_error );
#endif
}
return error;
}
FT_CALLBACK_DEF( FT_Error )
hvf_get_default_named_instance( FT_Face face, /* HVF_Face */
FT_UInt *instance_index )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->get_default_named_instance( face, instance_index );
}
FT_CALLBACK_DEF( void )
hvf_construct_ps_name( FT_Face face ) /* HVF_Face */
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
mm->construct_ps_name( face );
}
FT_CALLBACK_DEF( FT_Error )
hvf_load_delta_set_index_mapping( FT_Face face, /* HVF_Face */
FT_ULong offset,
GX_DeltaSetIdxMap map,
GX_ItemVarStore itemStore,
FT_ULong table_len )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->load_delta_set_idx_map( face, offset, map,
itemStore, table_len );
}
FT_CALLBACK_DEF( FT_Error )
hvf_load_item_variation_store( FT_Face face, /* HVF_Face */
FT_ULong offset,
GX_ItemVarStore itemStore )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->load_item_var_store( face, offset, itemStore );
}
FT_CALLBACK_DEF( FT_ItemVarDelta )
hvf_get_item_delta( FT_Face face, /* HVF_Face */
GX_ItemVarStore itemStore,
FT_UInt outerIndex,
FT_UInt innerIndex )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->get_item_delta( face, itemStore, outerIndex, innerIndex );
}
FT_CALLBACK_DEF( void )
hvf_done_item_variation_store( FT_Face face, /* HVF_Face */
GX_ItemVarStore itemStore )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
mm->done_item_var_store( face, itemStore );
}
FT_CALLBACK_DEF( void )
hvf_done_delta_set_index_map( FT_Face face, /* HVF_Face */
GX_DeltaSetIdxMap deltaSetIdxMap )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
mm->done_delta_set_idx_map( face, deltaSetIdxMap );
}
FT_CALLBACK_DEF( FT_Error )
hvf_get_var_blend( FT_Face face, /* HVF_Face */
FT_UInt* num_coords,
FT_Fixed** coords,
FT_Fixed** normalizedcoords,
FT_MM_Var** mm_var )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
return mm->get_var_blend( face, num_coords, coords,
normalizedcoords, mm_var );
}
FT_CALLBACK_DEF( void )
hvf_done_blend( FT_Face face ) /* HVF_Face */
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MultiMasters mm = (FT_Service_MultiMasters)tt_face->mm;
mm->done_blend( face );
}
FT_CALLBACK_DEF( FT_Error )
hvf_hadvance_adjust( FT_Face face, /* HVF_Face */
FT_UInt gindex,
FT_Int *avalue )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MetricsVariations var = (FT_Service_MetricsVariations)
tt_face->tt_var;
return var->hadvance_adjust( face, gindex, avalue );
}
FT_CALLBACK_DEF( FT_Error )
hvf_vadvance_adjust( FT_Face face, /* HVF_Face */
FT_UInt gindex,
FT_Int *avalue )
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MetricsVariations var = (FT_Service_MetricsVariations)
tt_face->tt_var;
return var->vadvance_adjust( face, gindex, avalue );
}
FT_CALLBACK_DEF( void )
hvf_apply_mvar( FT_Face face ) /* HVF_Face */
{
TT_Face tt_face = (TT_Face)face;
FT_Service_MetricsVariations var = (FT_Service_MetricsVariations)
tt_face->tt_var;
var->metrics_adjust( face );
}
FT_CALLBACK_DEF( void )
hvf_size_reset_height( FT_Size size )
{
/* Delegate to size's face services. */
TT_Face tt_face = (TT_Face)size->face;
FT_Service_MetricsVariations var = (FT_Service_MetricsVariations)
tt_face->tt_var;
if ( var->size_reset )
var->size_reset( size );
}
FT_DEFINE_SERVICE_MULTIMASTERSREC(
hvf_service_gx_multi_masters,
NULL, /* FT_Get_MM_Func get_mm */
NULL, /* FT_Set_MM_Design_Func set_mm_design */
hvf_set_mm_blend, /* FT_Set_MM_Blend_Func set_mm_blend */
hvf_get_mm_blend, /* FT_Get_MM_Blend_Func get_mm_blend */
hvf_get_mm_var, /* FT_Get_MM_Var_Func get_mm_var */
hvf_set_var_design, /* FT_Set_Var_Design_Func set_var_design */
hvf_get_var_design, /* FT_Get_Var_Design_Func get_var_design */
hvf_set_named_instance,
/* FT_Set_Named_Instance_Func set_named_instance */
hvf_get_default_named_instance,
/* FT_Get_Default_Named_Instance_Func get_default_named_instance */
NULL, /* FT_Set_MM_WeightVector_Func set_mm_weightvector */
NULL, /* FT_Get_MM_WeightVector_Func get_mm_weightvector */
hvf_construct_ps_name,
/* FT_Construct_PS_Name_Func construct_ps_name */
hvf_load_delta_set_index_mapping,
/* FT_Var_Load_Delta_Set_Idx_Map_Func load_delta_set_idx_map */
hvf_load_item_variation_store,
/* FT_Var_Load_Item_Var_Store_Func load_item_variation_store */
hvf_get_item_delta,
/* FT_Var_Get_Item_Delta_Func get_item_delta */
hvf_done_item_variation_store,
/* FT_Var_Done_Item_Var_Store_Func done_item_variation_store */
hvf_done_delta_set_index_map,
/* FT_Var_Done_Delta_Set_Idx_Map_Func done_delta_set_index_map */
hvf_get_var_blend, /* FT_Get_Var_Blend_Func get_var_blend */
hvf_done_blend /* FT_Done_Blend_Func done_blend */
)
FT_DEFINE_SERVICE_METRICSVARIATIONSREC(
hvf_service_metrics_variations,
hvf_hadvance_adjust, /* FT_HAdvance_Adjust_Func hadvance_adjust */
NULL, /* FT_LSB_Adjust_Func lsb_adjust */
NULL, /* FT_RSB_Adjust_Func rsb_adjust */
hvf_vadvance_adjust, /* FT_VAdvance_Adjust_Func vadvance_adjust */
NULL, /* FT_TSB_Adjust_Func tsb_adjust */
NULL, /* FT_BSB_Adjust_Func bsb_adjust */
NULL, /* FT_VOrg_Adjust_Func vorg_adjust */
hvf_apply_mvar, /* FT_Metrics_Adjust_Func metrics_adjust */
hvf_size_reset_height /* FT_Size_Reset_Func size_reset */
)
#endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
FT_DEFINE_SERVICEDESCREC3(
hvf_services,
FT_SERVICE_ID_FONT_FORMAT, FT_FONT_FORMAT_HVF,
FT_SERVICE_ID_MULTI_MASTERS, &hvf_service_gx_multi_masters,
FT_SERVICE_ID_METRICS_VARIATIONS, &hvf_service_metrics_variations )
#else
FT_DEFINE_SERVICEDESCREC1(
hvf_services,
FT_SERVICE_ID_FONT_FORMAT, FT_FONT_FORMAT_HVF )
#endif
FT_CALLBACK_DEF( FT_Module_Interface )
hvf_get_interface( FT_Module driver, /* HVF_Driver */
const char* hvf_interface )
{
FT_Library library;
FT_Module_Interface result;
FT_Module sfntd;
SFNT_Service sfnt;
FT_TRACE5(( "hvf_get_interface: Looking up service %s\n",
hvf_interface ));
result = ft_service_list_lookup( hvf_services, hvf_interface );
if ( result )
return result;
FT_TRACE3(( "hvf_get_interface: Did not find service %s; falling back\n",
hvf_interface ));
if ( !driver )
return NULL;
library = driver->library;
if ( !library )
return NULL;
/* Only return the default interface from the SFNT module. */
sfntd = FT_Get_Module( library, "sfnt" );
if ( sfntd )
{
sfnt = (SFNT_Service)( sfntd->clazz->module_interface );
if ( sfnt )
return sfnt->get_interface( driver, hvf_interface );
}
return NULL;
}
#endif /* FT_CONFIG_OPTION_HVF */
/**************************************************************************
*
* DRIVER INTERFACE
*
*/
#ifdef FT_CONFIG_OPTION_HVF
#define PUT_HVF_MODULE( a ) a
#else
#define PUT_HVF_MODULE( a ) NULL
#endif
FT_DEFINE_DRIVER(
hvf_driver_class,
FT_MODULE_FONT_DRIVER |
FT_MODULE_DRIVER_SCALABLE |
FT_MODULE_DRIVER_HAS_HINTER,
sizeof ( FT_DriverRec ),
"hvf", /* driver name */
0x10000L, /* driver version == 1.0 */
0x20000L, /* driver requires FreeType 2.0 or above */
NULL, /* module-specific interface */
NULL, /* FT_Module_Constructor module_init */
NULL, /* FT_Module_Destructor module_done */
PUT_HVF_MODULE( hvf_get_interface ),
/* FT_Module_Requester get_interface */
sizeof ( HVF_FaceRec ),
sizeof ( FT_SizeRec ),
sizeof ( FT_GlyphSlotRec ),
hvf_face_init, /* FT_Face_InitFunc init_face */
PUT_HVF_MODULE( hvf_face_done ), /* FT_Face_DoneFunc done_face */
NULL, /* FT_Size_InitFunc init_size */
NULL, /* FT_Size_DoneFunc done_size */
NULL, /* FT_Slot_InitFunc init_slot */
NULL, /* FT_Slot_DoneFunc done_slot */
hvf_slot_load_glyph, /* FT_Slot_LoadFunc load_glyph */
PUT_HVF_MODULE( hvf_get_kerning ),
/* FT_Face_GetKerningFunc get_kerning */
NULL, /* FT_Face_AttachFunc attach_file */
PUT_HVF_MODULE( hvf_get_advances ),
/* FT_Face_GetAdvancesFunc get_advances */
NULL, /* FT_Size_RequestFunc request_size */
NULL /* FT_Size_SelectFunc select_size */
)
/* END */