ref: 0360168a4d0decdeb2f9dfde9a3be887dcea3892
dir: /src/truetype/ttdriver.c/
/***************************************************************************/
/* */
/* ttdriver.c */
/* */
/* TrueType font driver implementation (body). */
/* */
/* Copyright 1996-1999 by */
/* David Turner, Robert Wilhelm, and Werner Lemberg. */
/* */
/* 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 <ftdebug.h>
#include <ftstream.h>
#include <ttnameid.h>
#include <sfnt.h>
#include <ttdriver.h>
#include <ttgload.h>
#undef FT_COMPONENT
#define FT_COMPONENT trace_ttdriver
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/**** ****/
/**** ****/
/**** F A C E S ****/
/**** ****/
/**** ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/******************************************************************
*
* <Function>
* find_encoding
*
* <Description>
* return the FT_Encoding corresponding to a given
* (platform_id,encoding_id) pair, as found in TrueType charmaps
*
* <Input>
* platform_id ::
* encoding_id ::
*
* <Return>
* the corresponding FT_Encoding tag. ft_encoding_none by default
*
*****************************************************************/
static
FT_Encoding find_encoding( int platform_id,
int encoding_id )
{
typedef struct TEncoding
{
int platform_id;
int encoding_id;
FT_Encoding encoding;
} TEncoding;
static
const TEncoding tt_encodings[] =
{
{ TT_PLATFORM_ISO, -1, ft_encoding_unicode },
{ TT_PLATFORM_APPLE_UNICODE, -1, ft_encoding_unicode },
{ TT_PLATFORM_MACINTOSH, TT_MAC_ID_ROMAN, ft_encoding_apple_roman },
{ TT_PLATFORM_MICROSOFT, TT_MS_ID_UNICODE_CS, ft_encoding_unicode },
{ TT_PLATFORM_MICROSOFT, TT_MS_ID_SJIS, ft_encoding_sjis },
{ TT_PLATFORM_MICROSOFT, TT_MS_ID_BIG_5, ft_encoding_big5 }
};
const TEncoding *cur, *limit;
cur = tt_encodings;
limit = cur + sizeof(tt_encodings)/sizeof(tt_encodings[0]);
for ( ; cur < limit; cur++ )
{
if (cur->platform_id == platform_id)
{
if (cur->encoding_id == encoding_id ||
cur->encoding_id == -1 )
return cur->encoding;
}
}
return ft_encoding_none;
}
/*************************************************************************/
/* */
/* <Function> */
/* Init_Face */
/* */
/* <Description> */
/* A driver method used to initialize a new TrueType face object. */
/* */
/* <Input> */
/* resource :: A handle to the source resource. */
/* */
/* typeface_index :: An index of the face in the font resource. Used */
/* to access individual faces in font collections. */
/* */
/* <InOut> */
/* face :: A handle to the face object. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* The `typeface_index' parameter field will be set to -1 if the */
/* engine only wants to test the format of the resource. This means */
/* that font drivers should simply check the font format, then return */
/* immediately with an error code of 0 (meaning success). The field */
/* `num_faces' should be set. */
/* */
/* Done_Face() will be called subsequently, whatever the result was. */
/* */
static
TT_Error Init_Face( FT_Stream stream,
TT_Long typeface_index,
TT_Face face )
{
TT_Error error;
/* initialize the TrueType face object */
error = TT_Init_Face( stream, typeface_index, face );
/* now set up root fields */
if ( !error && typeface_index >= 0 )
{
FT_Face root = &face->root;
FT_Int flags;
TT_CharMap charmap;
TT_Int n;
FT_Memory memory;
memory = root->memory;
/*****************************************************************/
/* */
/* Compute face flags. */
/* */
flags = FT_FACE_FLAG_SCALABLE | /* scalable outlines */
FT_FACE_FLAG_SFNT | /* SFNT file format */
FT_FACE_FLAG_HORIZONTAL; /* horizontal data */
/* fixed width font ? */
if ( face->postscript.isFixedPitch )
flags |= FT_FACE_FLAG_FIXED_WIDTH;
/* vertical information ? */
if ( face->vertical_info )
flags |= FT_FACE_FLAG_VERTICAL;
/* kerning available ? */
if ( face->kern_pairs )
flags |= FT_FACE_FLAG_KERNING;
root->face_flags = flags;
/*****************************************************************/
/* */
/* Compute style flags. */
/* */
flags = 0;
if ( face->os2.version != 0xFFFF )
{
/* We have an OS/2 table, use the `fsSelection' field */
if ( face->os2.fsSelection & 1 )
flags |= FT_STYLE_FLAG_ITALIC;
if ( face->os2.fsSelection & 32 )
flags |= FT_STYLE_FLAG_BOLD;
}
else
{
/* This is an old Mac font, use the header field */
if ( face->header.Mac_Style & 1 )
flags |= FT_STYLE_FLAG_BOLD;
if ( face->header.Mac_Style & 2 )
flags |= FT_STYLE_FLAG_ITALIC;
}
face->root.style_flags = flags;
/*****************************************************************/
/* */
/* Polish the charmaps. */
/* */
/* Try to set the charmap encoding according to the platform & */
/* encoding ID of each charmap. */
/* */
charmap = face->charmaps;
root->num_charmaps = face->num_charmaps;
/* allocate table of pointers */
if ( ALLOC_ARRAY( root->charmaps, root->num_charmaps, FT_CharMap ) )
return error;
for ( n = 0; n < root->num_charmaps; n++, charmap++ )
{
FT_Int platform = charmap->cmap.platformID;
FT_Int encoding = charmap->cmap.platformEncodingID;
charmap->root.face = (FT_Face)face;
charmap->root.platform_id = platform;
charmap->root.encoding_id = encoding;
charmap->root.encoding = find_encoding(platform,encoding);
/* now, set root->charmap with a unicode charmap wherever available */
if (!root->charmap && charmap->root.encoding == ft_encoding_unicode)
root->charmap = (FT_CharMap)charmap;
root->charmaps[n] = (FT_CharMap)charmap;
}
root->num_fixed_sizes = 0;
root->available_sizes = 0;
/*****************************************************************/
/* */
/* Set up metrics. */
/* */
root->bbox.xMin = face->header.xMin;
root->bbox.yMin = face->header.yMin;
root->bbox.xMax = face->header.xMax;
root->bbox.yMax = face->header.yMax;
root->units_per_EM = face->header.Units_Per_EM;
/* The ascender/descender/height are computed from the OS/2 table */
/* when found. Otherwise, they're taken from the horizontal header */
if ( face->os2.version != 0xFFFF )
{
root->ascender = face->os2.sTypoAscender;
root->descender = -face->os2.sTypoDescender;
root->height = root->ascender + root->descender +
face->os2.sTypoLineGap;
}
else
{
root->ascender = face->horizontal.Ascender;
root->descender = face->horizontal.Descender;
root->height = root->ascender + root->descender +
face->horizontal.Line_Gap;
}
root->max_advance_width = face->horizontal.advance_Width_Max;
root->max_advance_height = root->height;
if ( face->vertical_info )
root->max_advance_height = face->vertical.advance_Height_Max;
root->underline_position = face->postscript.underlinePosition;
root->underline_thickness = face->postscript.underlineThickness;
/* root->max_points - already set up */
/* root->max_contours - already set up */
}
return error;
}
#undef PAIR_TAG
#define PAIR_TAG( left, right ) ( ((TT_ULong)left << 16) | (TT_ULong)right )
/*************************************************************************/
/* */
/* <Function> */
/* Get_Kerning */
/* */
/* <Description> */
/* A driver method used to return the kerning vector between two */
/* glyphs of the same face. */
/* */
/* <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. This is in font units for */
/* scalable formats, and in pixels for fixed-sizes */
/* formats. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* Only horizontal layouts (left-to-right & right-to-left) are */
/* supported by this function. Other layouts, or more sophisticated */
/* kernings are out of scope of this method (the basic driver */
/* interface is meant to be simple). */
/* */
/* They can be implemented by format-specific interfaces. */
/* */
static
TT_Error Get_Kerning( TT_Face face,
TT_UShort left_glyph,
TT_UShort right_glyph,
TT_Vector* kerning )
{
TT_Kern_0_Pair* pair;
if ( !face )
return TT_Err_Invalid_Face_Handle;
kerning->x = 0;
kerning->y = 0;
if ( face->kern_pairs )
{
/* there are some kerning pairs in this font file! */
TT_ULong search_tag = PAIR_TAG( left_glyph, right_glyph );
TT_Long left, right;
left = 0;
right = face->num_kern_pairs - 1;
while ( left + 1 < right )
{
TT_Int middle = (left + right) >> 1;
TT_ULong cur_pair;
pair = face->kern_pairs + middle;
cur_pair = PAIR_TAG( pair->left, pair->right );
if ( cur_pair == search_tag )
goto Found;
if ( cur_pair < search_tag )
left = middle;
else
right = middle;
}
pair = face->kern_pairs + left;
if ( PAIR_TAG( pair->left, pair->right ) == search_tag )
goto Found;
pair = face->kern_pairs + right;
if ( PAIR_TAG( pair->left, pair->right ) == search_tag )
goto Found;
}
Exit:
return TT_Err_Ok;
Found:
kerning->x = pair->value;
goto Exit;
}
#undef PAIR_TAG
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/**** ****/
/**** ****/
/**** S I Z E S ****/
/**** ****/
/**** ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* Set_Char_Sizes */
/* */
/* <Description> */
/* A driver method used to reset a size's character sizes (horizontal */
/* and vertical) expressed in fractional points. */
/* */
/* <Input> */
/* char_width :: The character width expressed in 26.6 fractional */
/* points. */
/* char_height :: The character height expressed in 26.6 fractional */
/* points. */
/* */
/* <InOut> */
/* size :: A handle to the target size object. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
static
TT_Error Set_Char_Sizes( TT_Size size,
TT_F26Dot6 char_width,
TT_F26Dot6 char_height,
TT_UInt horz_resolution,
TT_UInt vert_resolution )
{
FT_Size_Metrics* metrics = &size->root.metrics;
TT_Face face = (TT_Face)size->root.face;
TT_Long dim_x, dim_y;
/* This bit flag, when set, indicates that the pixel size must be */
/* truncated to an integer. Nearly all TrueType fonts have this */
/* bit set, as hinting won't work really well otherwise. */
/* */
/* However, for those rare fonts who do not set it, we override */
/* the default computations performed by the base layer. I really */
/* don't know if this is useful, but hey, that's the spec :-) */
/* */
if ( (face->header.Flags & 8) == 0 )
{
/* Compute pixel sizes in 26.6 units */
dim_x = (char_width * horz_resolution) / 72;
dim_y = (char_height * vert_resolution) / 72;
metrics->x_scale = FT_DivFix( dim_x, face->root.units_per_EM );
metrics->y_scale = FT_DivFix( dim_y, face->root.units_per_EM );
metrics->x_ppem = (TT_UShort)(dim_x >> 6);
metrics->y_ppem = (TT_UShort)(dim_y >> 6);
}
size->ttmetrics.valid = FALSE;
return TT_Reset_Size( size );
}
/*************************************************************************/
/* */
/* <Function> */
/* Set_Pixel_Sizes */
/* */
/* <Description> */
/* A driver method used to reset a size's character sizes (horizontal */
/* and vertical) expressed in integer pixels. */
/* */
/* <Input> */
/* pixel_width :: The character width expressed in integer pixels. */
/* */
/* pixel_height :: The character height expressed in integer pixels. */
/* */
/* <InOut> */
/* size :: A handle to the target size object. */
/* */
/* <Return> */
/* FreeType error code. 0 means success */
/* */
static
TT_Error Set_Pixel_Sizes( TT_Size size,
TT_UInt pixel_width,
TT_UInt pixel_height )
{
(void) pixel_width;
(void) pixel_height;
/* many things were pre-computed by the base layer */
size->ttmetrics.valid = FALSE;
return TT_Reset_Size( size );
}
/*************************************************************************/
/* */
/* <Function> */
/* Load_Glyph */
/* */
/* <Description> */
/* A driver method used to load a glyph within a given glyph slot. */
/* */
/* <Input> */
/* slot :: A handle to the target slot object where the glyph */
/* will be loaded. */
/* */
/* size :: A handle to the source face size at which the glyph */
/* must be scaled/loaded/etc. */
/* */
/* glyph_index :: The index of the glyph in the font file. */
/* */
/* load_flags :: A flag indicating what to load for this glyph. The */
/* FTLOAD_??? constants can be used to control the */
/* glyph loading process (e.g., whether the outline */
/* should be scaled, whether to load bitmaps or not, */
/* whether to hint the outline, etc). */
/* <Output> */
/* result :: A set of bit flags indicating the type of data that */
/* was loaded in the glyph slot (outline, bitmap, */
/* pixmap, etc). */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
static
TT_Error Load_Glyph( TT_GlyphSlot slot,
TT_Size size,
TT_UShort glyph_index,
TT_UInt load_flags )
{
TT_Error error;
if ( !slot )
return TT_Err_Invalid_Glyph_Handle;
/* check that we want a scaled outline or bitmap */
if ( !size )
load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING;
if ( load_flags & FT_LOAD_NO_SCALE )
size = NULL;
/* reset the size object if necessary */
if ( size )
{
/* these two object must have the same parent */
if ( size->root.face != slot->face )
return TT_Err_Invalid_Face_Handle;
if ( !size->ttmetrics.valid )
{
if ( FT_SET_ERROR( TT_Reset_Size( size ) ) )
return error;
}
}
/* now load the glyph outline if necessary */
error = TT_Load_Glyph( size, slot, glyph_index, load_flags );
/* force drop-out mode to 2 */
slot->outline.dropout_mode = 2;
return error;
}
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/**** ****/
/**** ****/
/**** C H A R A C T E R M A P P I N G S ****/
/**** ****/
/**** ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* Get_Char_Index */
/* */
/* <Description> */
/* Uses a charmap to return a given character code's glyph index. */
/* */
/* <Input> */
/* charmap :: A handle to the source charmap object. */
/* charcode :: The character code. */
/* */
/* <Return> */
/* Glyph index. 0 means `undefined character code'. */
/* */
static
FT_UInt Get_Char_Index( TT_CharMap charmap,
TT_Long charcode )
{
TT_Error error;
TT_Face face;
TT_CMapTable* cmap;
cmap = &charmap->cmap;
face = (TT_Face)charmap->root.face;
/* Load table if needed */
if ( !cmap->loaded )
{
SFNT_Interface* sfnt = (SFNT_Interface*)face->sfnt;
error = sfnt->load_charmap( face, cmap, face->root.stream );
if (error)
return error;
cmap->loaded = TRUE;
}
if ( cmap->get_index )
return cmap->get_index( cmap, charcode );
else
return 0;
}
/* The FT_DriverInterface structure is defined in ftdriver.h. */
const FT_DriverInterface tt_driver_interface =
{
sizeof ( TT_DriverRec ),
sizeof ( TT_FaceRec ),
sizeof ( TT_SizeRec ),
sizeof ( FT_GlyphSlotRec ),
"truetype", /* driver name */
100, /* driver version == 1.0 */
200, /* driver requires FreeType 2.0 or above */
(void*)0,
(FTDriver_initDriver) TT_Init_Driver,
(FTDriver_doneDriver) TT_Done_Driver,
(FTDriver_getInterface) 0, /* now extra interface for now */
(FTDriver_initFace) Init_Face,
(FTDriver_doneFace) TT_Done_Face,
(FTDriver_getKerning) Get_Kerning,
(FTDriver_initSize) TT_Init_Size,
(FTDriver_doneSize) TT_Done_Size,
(FTDriver_setCharSizes) Set_Char_Sizes,
(FTDriver_setPixelSizes) Set_Pixel_Sizes,
(FTDriver_initGlyphSlot) TT_Init_GlyphSlot,
(FTDriver_doneGlyphSlot) TT_Done_GlyphSlot,
(FTDriver_loadGlyph) Load_Glyph,
(FTDriver_getCharIndex) Get_Char_Index,
};
/*************************************************************************/
/* */
/* <Function> */
/* getDriverInterface */
/* */
/* <Description> */
/* This function is used when compiling the TrueType driver as a */
/* shared library (`.DLL' or `.so'). It will be used by the */
/* high-level library of FreeType to retrieve the address of the */
/* driver's generic interface. */
/* */
/* It shouldn't be implemented in a static build, as each driver must */
/* have the same function as an exported entry point. */
/* */
/* <Return> */
/* The address of the TrueType's driver generic interface. The */
/* format-specific interface can then be retrieved through the method */
/* interface->get_format_interface. */
/* */
#ifdef FT_CONFIG_OPTION_DYNAMIC_DRIVERS
EXPORT_FUNC
FT_DriverInterface* getDriverInterface( void )
{
return &truetype_driver_interface;
}
#endif /* CONFIG_OPTION_DYNAMIC_DRIVERS */
/* END */