ref: fb7dd4b3a868cb8987049c95bb32e6425a73c8b9
dir: /libfreetype/ttsbit.c/
/***************************************************************************/
/* */
/* ttsbit.c */
/* */
/* TrueType and OpenType embedded bitmap support (body). */
/* */
/* Copyright 1996-2001, 2002 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 <ft2build.h>
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_STREAM_H
#include FT_TRUETYPE_TAGS_H
#include "ttsbit.h"
#include "sferrors.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 trace_ttsbit
/*************************************************************************/
/* */
/* <Function> */
/* blit_sbit */
/* */
/* <Description> */
/* Blits a bitmap from an input stream into a given target. Supports */
/* x and y offsets as well as byte padded lines. */
/* */
/* <Input> */
/* target :: The target bitmap/pixmap. */
/* */
/* source :: The input packed bitmap data. */
/* */
/* line_bits :: The number of bits per line. */
/* */
/* byte_padded :: A flag which is true if lines are byte-padded. */
/* */
/* x_offset :: The horizontal offset. */
/* */
/* y_offset :: The vertical offset. */
/* */
/* <Note> */
/* IMPORTANT: The x and y offsets are relative to the top corner of */
/* the target bitmap (unlike the normal TrueType */
/* convention). A positive y offset indicates a downwards */
/* direction! */
/* */
static void
blit_sbit( FT_Bitmap* target,
FT_Byte* source,
FT_Int line_bits,
FT_Bool byte_padded,
FT_Int x_offset,
FT_Int y_offset )
{
FT_Byte* line_buff;
FT_Int line_incr;
FT_Int height;
FT_UShort acc;
FT_UInt loaded;
/* first of all, compute starting write position */
line_incr = target->pitch;
line_buff = target->buffer;
if ( line_incr < 0 )
line_buff -= line_incr * ( target->rows - 1 );
line_buff += ( x_offset >> 3 ) + y_offset * line_incr;
/***********************************************************************/
/* */
/* We use the extra-classic `accumulator' trick to extract the bits */
/* from the source byte stream. */
/* */
/* Namely, the variable `acc' is a 16-bit accumulator containing the */
/* last `loaded' bits from the input stream. The bits are shifted to */
/* the upmost position in `acc'. */
/* */
/***********************************************************************/
acc = 0; /* clear accumulator */
loaded = 0; /* no bits were loaded */
for ( height = target->rows; height > 0; height-- )
{
FT_Byte* cur = line_buff; /* current write cursor */
FT_Int count = line_bits; /* # of bits to extract per line */
FT_Byte shift = (FT_Byte)( x_offset & 7 ); /* current write shift */
FT_Byte space = (FT_Byte)( 8 - shift );
/* first of all, read individual source bytes */
if ( count >= 8 )
{
count -= 8;
{
do
{
FT_Byte val;
/* ensure that there are at least 8 bits in the accumulator */
if ( loaded < 8 )
{
acc |= (FT_UShort)((FT_UShort)*source++ << ( 8 - loaded ));
loaded += 8;
}
/* now write one byte */
val = (FT_Byte)( acc >> 8 );
if ( shift )
{
cur[0] |= (FT_Byte)( val >> shift );
cur[1] |= (FT_Byte)( val << space );
}
else
cur[0] |= val;
cur++;
acc <<= 8; /* remove bits from accumulator */
loaded -= 8;
count -= 8;
} while ( count >= 0 );
}
/* restore `count' to correct value */
count += 8;
}
/* now write remaining bits (count < 8) */
if ( count > 0 )
{
FT_Byte val;
/* ensure that there are at least `count' bits in the accumulator */
if ( (FT_Int)loaded < count )
{
acc |= (FT_UShort)((FT_UShort)*source++ << ( 8 - loaded ));
loaded += 8;
}
/* now write remaining bits */
val = (FT_Byte)( ( (FT_Byte)( acc >> 8 ) ) & ~( 0xFF >> count ) );
cur[0] |= (FT_Byte)( val >> shift );
if ( count > space )
cur[1] |= (FT_Byte)( val << space );
acc <<= count;
loaded -= count;
}
/* now, skip to next line */
if ( byte_padded )
{
acc = 0;
loaded = 0; /* clear accumulator on byte-padded lines */
}
line_buff += line_incr;
}
}
const FT_Frame_Field sbit_metrics_fields[] =
{
#undef FT_STRUCTURE
#define FT_STRUCTURE TT_SBit_MetricsRec
FT_FRAME_START( 8 ),
FT_FRAME_BYTE( height ),
FT_FRAME_BYTE( width ),
FT_FRAME_CHAR( horiBearingX ),
FT_FRAME_CHAR( horiBearingY ),
FT_FRAME_BYTE( horiAdvance ),
FT_FRAME_CHAR( vertBearingX ),
FT_FRAME_CHAR( vertBearingY ),
FT_FRAME_BYTE( vertAdvance ),
FT_FRAME_END
};
/*************************************************************************/
/* */
/* <Function> */
/* TT_Load_SBit_Const_Metrics */
/* */
/* <Description> */
/* Loads the metrics for `EBLC' index tables format 2 and 5. */
/* */
/* <Input> */
/* range :: The target range. */
/* */
/* stream :: The input stream. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
static FT_Error
Load_SBit_Const_Metrics( TT_SBit_Range range,
FT_Stream stream )
{
FT_Error error;
if ( FT_READ_ULONG( range->image_size ) )
return error;
return FT_STREAM_READ_FIELDS( sbit_metrics_fields, &range->metrics );
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_Load_SBit_Range_Codes */
/* */
/* <Description> */
/* Loads the range codes for `EBLC' index tables format 4 and 5. */
/* */
/* <Input> */
/* range :: The target range. */
/* */
/* stream :: The input stream. */
/* */
/* load_offsets :: A flag whether to load the glyph offset table. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
static FT_Error
Load_SBit_Range_Codes( TT_SBit_Range range,
FT_Stream stream,
FT_Bool load_offsets )
{
FT_Error error;
FT_ULong count, n, size;
FT_Memory memory = stream->memory;
if ( FT_READ_ULONG( count ) )
goto Exit;
range->num_glyphs = count;
/* Allocate glyph offsets table if needed */
if ( load_offsets )
{
if ( FT_NEW_ARRAY( range->glyph_offsets, count ) )
goto Exit;
size = count * 4L;
}
else
size = count * 2L;
/* Allocate glyph codes table and access frame */
if ( FT_NEW_ARRAY ( range->glyph_codes, count ) ||
FT_FRAME_ENTER( size ) )
goto Exit;
for ( n = 0; n < count; n++ )
{
range->glyph_codes[n] = FT_GET_USHORT();
if ( load_offsets )
range->glyph_offsets[n] = (FT_ULong)range->image_offset +
FT_GET_USHORT();
}
FT_FRAME_EXIT();
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_Load_SBit_Range */
/* */
/* <Description> */
/* Loads a given `EBLC' index/range table. */
/* */
/* <Input> */
/* range :: The target range. */
/* */
/* stream :: The input stream. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
static FT_Error
Load_SBit_Range( TT_SBit_Range range,
FT_Stream stream )
{
FT_Error error;
FT_Memory memory = stream->memory;
switch( range->index_format )
{
case 1: /* variable metrics with 4-byte offsets */
case 3: /* variable metrics with 2-byte offsets */
{
FT_ULong num_glyphs, n;
FT_Int size_elem;
FT_Bool large = FT_BOOL( range->index_format == 1 );
num_glyphs = range->last_glyph - range->first_glyph + 1L;
range->num_glyphs = num_glyphs;
num_glyphs++; /* XXX: BEWARE - see spec */
size_elem = large ? 4 : 2;
if ( FT_NEW_ARRAY( range->glyph_offsets, num_glyphs ) ||
FT_FRAME_ENTER( num_glyphs * size_elem ) )
goto Exit;
for ( n = 0; n < num_glyphs; n++ )
range->glyph_offsets[n] = (FT_ULong)( range->image_offset +
( large ? FT_GET_ULONG()
: FT_GET_USHORT() ) );
FT_FRAME_EXIT();
}
break;
case 2: /* all glyphs have identical metrics */
error = Load_SBit_Const_Metrics( range, stream );
break;
case 4:
error = Load_SBit_Range_Codes( range, stream, 1 );
break;
case 5:
error = Load_SBit_Const_Metrics( range, stream ) ||
Load_SBit_Range_Codes( range, stream, 0 );
break;
default:
error = SFNT_Err_Invalid_File_Format;
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* tt_face_load_sbit_strikes */
/* */
/* <Description> */
/* Loads the table of embedded bitmap sizes for this face. */
/* */
/* <Input> */
/* face :: The target face object. */
/* */
/* stream :: The input stream. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
FT_LOCAL_DEF( FT_Error )
tt_face_load_sbit_strikes( TT_Face face,
FT_Stream stream )
{
FT_Error error = 0;
FT_Memory memory = stream->memory;
FT_Fixed version;
FT_ULong num_strikes;
FT_ULong table_base;
const FT_Frame_Field sbit_line_metrics_fields[] =
{
#undef FT_STRUCTURE
#define FT_STRUCTURE TT_SBit_LineMetricsRec
/* no FT_FRAME_START */
FT_FRAME_CHAR( ascender ),
FT_FRAME_CHAR( descender ),
FT_FRAME_BYTE( max_width ),
FT_FRAME_CHAR( caret_slope_numerator ),
FT_FRAME_CHAR( caret_slope_denominator ),
FT_FRAME_CHAR( caret_offset ),
FT_FRAME_CHAR( min_origin_SB ),
FT_FRAME_CHAR( min_advance_SB ),
FT_FRAME_CHAR( max_before_BL ),
FT_FRAME_CHAR( min_after_BL ),
FT_FRAME_CHAR( pads[0] ),
FT_FRAME_CHAR( pads[1] ),
FT_FRAME_END
};
const FT_Frame_Field strike_start_fields[] =
{
#undef FT_STRUCTURE
#define FT_STRUCTURE TT_SBit_StrikeRec
/* no FT_FRAME_START */
FT_FRAME_ULONG( ranges_offset ),
FT_FRAME_SKIP_LONG,
FT_FRAME_ULONG( num_ranges ),
FT_FRAME_ULONG( color_ref ),
FT_FRAME_END
};
const FT_Frame_Field strike_end_fields[] =
{
/* no FT_FRAME_START */
FT_FRAME_USHORT( start_glyph ),
FT_FRAME_USHORT( end_glyph ),
FT_FRAME_BYTE ( x_ppem ),
FT_FRAME_BYTE ( y_ppem ),
FT_FRAME_BYTE ( bit_depth ),
FT_FRAME_CHAR ( flags ),
FT_FRAME_END
};
face->num_sbit_strikes = 0;
/* this table is optional */
error = face->goto_table( face, TTAG_EBLC, stream, 0 );
if ( error )
error = face->goto_table( face, TTAG_bloc, stream, 0 );
if ( error )
goto Exit;
table_base = FT_STREAM_POS();
if ( FT_FRAME_ENTER( 8L ) )
goto Exit;
version = FT_GET_LONG();
num_strikes = FT_GET_ULONG();
FT_FRAME_EXIT();
/* check version number and strike count */
if ( version != 0x00020000L ||
num_strikes >= 0x10000L )
{
FT_ERROR(( "tt_face_load_sbit_strikes: invalid table version!\n" ));
error = SFNT_Err_Invalid_File_Format;
goto Exit;
}
/* allocate the strikes table */
if ( FT_NEW_ARRAY( face->sbit_strikes, num_strikes ) )
goto Exit;
face->num_sbit_strikes = num_strikes;
/* now read each strike table separately */
{
TT_SBit_Strike strike = face->sbit_strikes;
FT_ULong count = num_strikes;
if ( FT_FRAME_ENTER( 48L * num_strikes ) )
goto Exit;
while ( count > 0 )
{
if ( FT_STREAM_READ_FIELDS( strike_start_fields, strike ) ||
FT_STREAM_READ_FIELDS( sbit_line_metrics_fields, &strike->hori ) ||
FT_STREAM_READ_FIELDS( sbit_line_metrics_fields, &strike->vert ) ||
FT_STREAM_READ_FIELDS( strike_end_fields, strike ) )
break;
count--;
strike++;
}
FT_FRAME_EXIT();
}
/* allocate the index ranges for each strike table */
{
TT_SBit_Strike strike = face->sbit_strikes;
FT_ULong count = num_strikes;
while ( count > 0 )
{
TT_SBit_Range range;
FT_ULong count2 = strike->num_ranges;
if ( FT_NEW_ARRAY( strike->sbit_ranges, strike->num_ranges ) )
goto Exit;
/* read each range */
if ( FT_STREAM_SEEK( table_base + strike->ranges_offset ) ||
FT_FRAME_ENTER( strike->num_ranges * 8L ) )
goto Exit;
range = strike->sbit_ranges;
while ( count2 > 0 )
{
range->first_glyph = FT_GET_USHORT();
range->last_glyph = FT_GET_USHORT();
range->table_offset = table_base + strike->ranges_offset +
FT_GET_ULONG();
count2--;
range++;
}
FT_FRAME_EXIT();
/* Now, read each index table */
count2 = strike->num_ranges;
range = strike->sbit_ranges;
while ( count2 > 0 )
{
/* Read the header */
if ( FT_STREAM_SEEK( range->table_offset ) ||
FT_FRAME_ENTER( 8L ) )
goto Exit;
range->index_format = FT_GET_USHORT();
range->image_format = FT_GET_USHORT();
range->image_offset = FT_GET_ULONG();
FT_FRAME_EXIT();
error = Load_SBit_Range( range, stream );
if ( error )
goto Exit;
count2--;
range++;
}
count--;
strike++;
}
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* tt_face_free_sbit_strikes */
/* */
/* <Description> */
/* Releases the embedded bitmap tables. */
/* */
/* <Input> */
/* face :: The target face object. */
/* */
FT_LOCAL_DEF( void )
tt_face_free_sbit_strikes( TT_Face face )
{
FT_Memory memory = face->root.memory;
TT_SBit_Strike strike = face->sbit_strikes;
TT_SBit_Strike strike_limit = strike + face->num_sbit_strikes;
if ( strike )
{
for ( ; strike < strike_limit; strike++ )
{
TT_SBit_Range range = strike->sbit_ranges;
TT_SBit_Range range_limit = range + strike->num_ranges;
if ( range )
{
for ( ; range < range_limit; range++ )
{
/* release the glyph offsets and codes tables */
/* where appropriate */
FT_FREE( range->glyph_offsets );
FT_FREE( range->glyph_codes );
}
}
FT_FREE( strike->sbit_ranges );
strike->num_ranges = 0;
}
FT_FREE( face->sbit_strikes );
}
face->num_sbit_strikes = 0;
}
FT_LOCAL_DEF( FT_Error )
tt_face_set_sbit_strike( TT_Face face,
FT_Int x_ppem,
FT_Int y_ppem,
FT_ULong *astrike_index )
{
FT_ULong i;
if ( x_ppem < 0 || x_ppem > 255 ||
y_ppem < 1 || y_ppem > 255 )
return SFNT_Err_Invalid_PPem;
for ( i = 0; i < face->num_sbit_strikes; i++ )
{
if ( ( face->sbit_strikes[i].y_ppem == y_ppem ) &&
( ( x_ppem == 0 ) ||
( face->sbit_strikes[i].x_ppem == x_ppem ) ) )
{
*astrike_index = i;
return SFNT_Err_Ok;
}
}
return SFNT_Err_Invalid_PPem;
}
/*************************************************************************/
/* */
/* <Function> */
/* find_sbit_range */
/* */
/* <Description> */
/* Scans a given strike's ranges and return, for a given glyph */
/* index, the corresponding sbit range, and `EBDT' offset. */
/* */
/* <Input> */
/* glyph_index :: The glyph index. */
/* */
/* strike :: The source/current sbit strike. */
/* */
/* <Output> */
/* arange :: The sbit range containing the glyph index. */
/* */
/* aglyph_offset :: The offset of the glyph data in `EBDT' table. */
/* */
/* <Return> */
/* FreeType error code. 0 means the glyph index was found. */
/* */
static FT_Error
find_sbit_range( FT_UInt glyph_index,
TT_SBit_Strike strike,
TT_SBit_Range *arange,
FT_ULong *aglyph_offset )
{
TT_SBit_RangeRec *range, *range_limit;
/* check whether the glyph index is within this strike's */
/* glyph range */
if ( glyph_index < (FT_UInt)strike->start_glyph ||
glyph_index > (FT_UInt)strike->end_glyph )
goto Fail;
/* scan all ranges in strike */
range = strike->sbit_ranges;
range_limit = range + strike->num_ranges;
if ( !range )
goto Fail;
for ( ; range < range_limit; range++ )
{
if ( glyph_index >= (FT_UInt)range->first_glyph &&
glyph_index <= (FT_UInt)range->last_glyph )
{
FT_UShort delta = (FT_UShort)( glyph_index - range->first_glyph );
switch ( range->index_format )
{
case 1:
case 3:
*aglyph_offset = range->glyph_offsets[delta];
break;
case 2:
*aglyph_offset = range->image_offset +
range->image_size * delta;
break;
case 4:
case 5:
{
FT_ULong n;
for ( n = 0; n < range->num_glyphs; n++ )
{
if ( (FT_UInt)range->glyph_codes[n] == glyph_index )
{
if ( range->index_format == 4 )
*aglyph_offset = range->glyph_offsets[n];
else
*aglyph_offset = range->image_offset +
n * range->image_size;
goto Found;
}
}
}
/* fall-through */
default:
goto Fail;
}
Found:
/* return successfully! */
*arange = range;
return 0;
}
}
Fail:
*arange = 0;
*aglyph_offset = 0;
return SFNT_Err_Invalid_Argument;
}
/*************************************************************************/
/* */
/* <Function> */
/* find_sbit_image */
/* */
/* <Description> */
/* Checks whether an embedded bitmap (an `sbit') exists for a given */
/* glyph, at a given strike. */
/* */
/* <Input> */
/* face :: The target face object. */
/* */
/* glyph_index :: The glyph index. */
/* */
/* strike_index :: The current strike index. */
/* */
/* <Output> */
/* arange :: The SBit range containing the glyph index. */
/* */
/* astrike :: The SBit strike containing the glyph index. */
/* */
/* aglyph_offset :: The offset of the glyph data in `EBDT' table. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. Returns */
/* SFNT_Err_Invalid_Argument if no sbit exists for the requested */
/* glyph. */
/* */
static FT_Error
find_sbit_image( TT_Face face,
FT_UInt glyph_index,
FT_ULong strike_index,
TT_SBit_Range *arange,
TT_SBit_Strike *astrike,
FT_ULong *aglyph_offset )
{
FT_Error error;
TT_SBit_Strike strike;
if ( !face->sbit_strikes ||
( face->num_sbit_strikes <= strike_index ) )
goto Fail;
strike = &face->sbit_strikes[strike_index];
error = find_sbit_range( glyph_index, strike,
arange, aglyph_offset );
if ( error )
goto Fail;
*astrike = strike;
return SFNT_Err_Ok;
Fail:
/* no embedded bitmap for this glyph in face */
*arange = 0;
*astrike = 0;
*aglyph_offset = 0;
return SFNT_Err_Invalid_Argument;
}
/*************************************************************************/
/* */
/* <Function> */
/* load_sbit_metrics */
/* */
/* <Description> */
/* Gets the big metrics for a given SBit. */
/* */
/* <Input> */
/* stream :: The input stream. */
/* */
/* range :: The SBit range containing the glyph. */
/* */
/* <Output> */
/* big_metrics :: A big SBit metrics structure for the glyph. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* The stream cursor must be positioned at the glyph's offset within */
/* the `EBDT' table before the call. */
/* */
/* If the image format uses variable metrics, the stream cursor is */
/* positioned just after the metrics header in the `EBDT' table on */
/* function exit. */
/* */
static FT_Error
load_sbit_metrics( FT_Stream stream,
TT_SBit_Range range,
TT_SBit_Metrics metrics )
{
FT_Error error = SFNT_Err_Ok;
switch ( range->image_format )
{
case 1:
case 2:
case 8:
/* variable small metrics */
{
TT_SBit_SmallMetricsRec smetrics;
const FT_Frame_Field sbit_small_metrics_fields[] =
{
#undef FT_STRUCTURE
#define FT_STRUCTURE TT_SBit_SmallMetricsRec
FT_FRAME_START( 5 ),
FT_FRAME_BYTE( height ),
FT_FRAME_BYTE( width ),
FT_FRAME_CHAR( bearingX ),
FT_FRAME_CHAR( bearingY ),
FT_FRAME_BYTE( advance ),
FT_FRAME_END
};
/* read small metrics */
if ( FT_STREAM_READ_FIELDS( sbit_small_metrics_fields, &smetrics ) )
goto Exit;
/* convert it to a big metrics */
metrics->height = smetrics.height;
metrics->width = smetrics.width;
metrics->horiBearingX = smetrics.bearingX;
metrics->horiBearingY = smetrics.bearingY;
metrics->horiAdvance = smetrics.advance;
/* these metrics are made up at a higher level when */
/* needed. */
metrics->vertBearingX = 0;
metrics->vertBearingY = 0;
metrics->vertAdvance = 0;
}
break;
case 6:
case 7:
case 9:
/* variable big metrics */
if ( FT_STREAM_READ_FIELDS( sbit_metrics_fields, metrics ) )
goto Exit;
break;
case 5:
default: /* constant metrics */
if ( range->index_format == 2 || range->index_format == 5 )
*metrics = range->metrics;
else
return SFNT_Err_Invalid_File_Format;
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* crop_bitmap */
/* */
/* <Description> */
/* Crops a bitmap to its tightest bounding box, and adjusts its */
/* metrics. */
/* */
/* <InOut> */
/* map :: The bitmap. */
/* */
/* metrics :: The corresponding metrics structure. */
/* */
static void
crop_bitmap( FT_Bitmap* map,
TT_SBit_Metrics metrics )
{
/***********************************************************************/
/* */
/* In this situation, some bounding boxes of embedded bitmaps are too */
/* large. We need to crop it to a reasonable size. */
/* */
/* --------- */
/* | | ----- */
/* | *** | |***| */
/* | * | | * | */
/* | * | ------> | * | */
/* | * | | * | */
/* | * | | * | */
/* | *** | |***| */
/* --------- ----- */
/* */
/***********************************************************************/
FT_Int rows, count;
FT_Long line_len;
FT_Byte* line;
/***********************************************************************/
/* */
/* first of all, check the top-most lines of the bitmap, and remove */
/* them if they're empty. */
/* */
{
line = (FT_Byte*)map->buffer;
rows = map->rows;
line_len = map->pitch;
for ( count = 0; count < rows; count++ )
{
FT_Byte* cur = line;
FT_Byte* limit = line + line_len;
for ( ; cur < limit; cur++ )
if ( cur[0] )
goto Found_Top;
/* the current line was empty - skip to next one */
line = limit;
}
Found_Top:
/* check that we have at least one filled line */
if ( count >= rows )
goto Empty_Bitmap;
/* now, crop the empty upper lines */
if ( count > 0 )
{
line = (FT_Byte*)map->buffer;
FT_MEM_MOVE( line, line + count * line_len,
( rows - count ) * line_len );
metrics->height = (FT_Byte)( metrics->height - count );
metrics->horiBearingY = (FT_Char)( metrics->horiBearingY - count );
metrics->vertBearingY = (FT_Char)( metrics->vertBearingY - count );
map->rows -= count;
rows -= count;
}
}
/***********************************************************************/
/* */
/* second, crop the lower lines */
/* */
{
line = (FT_Byte*)map->buffer + ( rows - 1 ) * line_len;
for ( count = 0; count < rows; count++ )
{
FT_Byte* cur = line;
FT_Byte* limit = line + line_len;
for ( ; cur < limit; cur++ )
if ( cur[0] )
goto Found_Bottom;
/* the current line was empty - skip to previous one */
line -= line_len;
}
Found_Bottom:
if ( count > 0 )
{
metrics->height = (FT_Byte)( metrics->height - count );
rows -= count;
map->rows -= count;
}
}
/***********************************************************************/
/* */
/* third, get rid of the space on the left side of the glyph */
/* */
do
{
FT_Byte* limit;
line = (FT_Byte*)map->buffer;
limit = line + rows * line_len;
for ( ; line < limit; line += line_len )
if ( line[0] & 0x80 )
goto Found_Left;
/* shift the whole glyph one pixel to the left */
line = (FT_Byte*)map->buffer;
limit = line + rows * line_len;
for ( ; line < limit; line += line_len )
{
FT_Int n, width = map->width;
FT_Byte old;
FT_Byte* cur = line;
old = (FT_Byte)(cur[0] << 1);
for ( n = 8; n < width; n += 8 )
{
FT_Byte val;
val = cur[1];
cur[0] = (FT_Byte)( old | ( val >> 7 ) );
old = (FT_Byte)( val << 1 );
cur++;
}
cur[0] = old;
}
map->width--;
metrics->horiBearingX++;
metrics->vertBearingX++;
metrics->width--;
} while ( map->width > 0 );
Found_Left:
/***********************************************************************/
/* */
/* finally, crop the bitmap width to get rid of the space on the right */
/* side of the glyph. */
/* */
do
{
FT_Int right = map->width - 1;
FT_Byte* limit;
FT_Byte mask;
line = (FT_Byte*)map->buffer + ( right >> 3 );
limit = line + rows * line_len;
mask = (FT_Byte)( 0x80 >> ( right & 7 ) );
for ( ; line < limit; line += line_len )
if ( line[0] & mask )
goto Found_Right;
/* crop the whole glyph to the right */
map->width--;
metrics->width--;
} while ( map->width > 0 );
Found_Right:
/* all right, the bitmap was cropped */
return;
Empty_Bitmap:
map->width = 0;
map->rows = 0;
map->pitch = 0;
map->pixel_mode = FT_PIXEL_MODE_MONO;
}
static FT_Error
Load_SBit_Single( FT_Bitmap* map,
FT_Int x_offset,
FT_Int y_offset,
FT_Int pix_bits,
FT_UShort image_format,
TT_SBit_Metrics metrics,
FT_Stream stream )
{
FT_Error error;
/* check that the source bitmap fits into the target pixmap */
if ( x_offset < 0 || x_offset + metrics->width > map->width ||
y_offset < 0 || y_offset + metrics->height > map->rows )
{
error = SFNT_Err_Invalid_Argument;
goto Exit;
}
{
FT_Int glyph_width = metrics->width;
FT_Int glyph_height = metrics->height;
FT_Int glyph_size;
FT_Int line_bits = pix_bits * glyph_width;
FT_Bool pad_bytes = 0;
/* compute size of glyph image */
switch ( image_format )
{
case 1: /* byte-padded formats */
case 6:
{
FT_Int line_length;
switch ( pix_bits )
{
case 1:
line_length = ( glyph_width + 7 ) >> 3;
break;
case 2:
line_length = ( glyph_width + 3 ) >> 2;
break;
case 4:
line_length = ( glyph_width + 1 ) >> 1;
break;
default:
line_length = glyph_width;
}
glyph_size = glyph_height * line_length;
pad_bytes = 1;
}
break;
case 2:
case 5:
case 7:
line_bits = glyph_width * pix_bits;
glyph_size = ( glyph_height * line_bits + 7 ) >> 3;
break;
default: /* invalid format */
return SFNT_Err_Invalid_File_Format;
}
/* Now read data and draw glyph into target pixmap */
if ( FT_FRAME_ENTER( glyph_size ) )
goto Exit;
/* don't forget to multiply `x_offset' by `map->pix_bits' as */
/* the sbit blitter doesn't make a difference between pixmap */
/* depths. */
blit_sbit( map, (FT_Byte*)stream->cursor, line_bits, pad_bytes,
x_offset * pix_bits, y_offset );
FT_FRAME_EXIT();
}
Exit:
return error;
}
static FT_Error
Load_SBit_Image( TT_SBit_Strike strike,
TT_SBit_Range range,
FT_ULong ebdt_pos,
FT_ULong glyph_offset,
FT_Bitmap* map,
FT_Int x_offset,
FT_Int y_offset,
FT_Stream stream,
TT_SBit_Metrics metrics )
{
FT_Memory memory = stream->memory;
FT_Error error;
/* place stream at beginning of glyph data and read metrics */
if ( FT_STREAM_SEEK( ebdt_pos + glyph_offset ) )
goto Exit;
error = load_sbit_metrics( stream, range, metrics );
if ( error )
goto Exit;
/* this function is recursive. At the top-level call, the */
/* field map.buffer is NULL. We thus begin by finding the */
/* dimensions of the higher-level glyph to allocate the */
/* final pixmap buffer */
if ( map->buffer == 0 )
{
FT_Long size;
map->width = metrics->width;
map->rows = metrics->height;
switch ( strike->bit_depth )
{
case 1:
map->pixel_mode = FT_PIXEL_MODE_MONO;
map->pitch = ( map->width + 7 ) >> 3;
break;
case 2:
map->pixel_mode = FT_PIXEL_MODE_GRAY2;
map->pitch = ( map->width + 3 ) >> 2;
break;
case 4:
map->pixel_mode = FT_PIXEL_MODE_GRAY4;
map->pitch = ( map->width + 1 ) >> 1;
break;
case 8:
map->pixel_mode = FT_PIXEL_MODE_GRAY;
map->pitch = map->width;
break;
default:
return SFNT_Err_Invalid_File_Format;
}
size = map->rows * map->pitch;
/* check that there is no empty image */
if ( size == 0 )
goto Exit; /* exit successfully! */
if ( FT_ALLOC( map->buffer, size ) )
goto Exit;
}
switch ( range->image_format )
{
case 1: /* single sbit image - load it */
case 2:
case 5:
case 6:
case 7:
return Load_SBit_Single( map, x_offset, y_offset, strike->bit_depth,
range->image_format, metrics, stream );
case 8: /* compound format */
FT_Stream_Skip( stream, 1L );
/* fallthrough */
case 9:
break;
default: /* invalid image format */
return SFNT_Err_Invalid_File_Format;
}
/* All right, we have a compound format. First of all, read */
/* the array of elements. */
{
TT_SBit_Component components;
TT_SBit_Component comp;
FT_UShort num_components, count;
if ( FT_READ_USHORT( num_components ) ||
FT_NEW_ARRAY( components, num_components ) )
goto Exit;
count = num_components;
if ( FT_FRAME_ENTER( 4L * num_components ) )
goto Fail_Memory;
for ( comp = components; count > 0; count--, comp++ )
{
comp->glyph_code = FT_GET_USHORT();
comp->x_offset = FT_GET_CHAR();
comp->y_offset = FT_GET_CHAR();
}
FT_FRAME_EXIT();
/* Now recursively load each element glyph */
count = num_components;
comp = components;
for ( ; count > 0; count--, comp++ )
{
TT_SBit_Range elem_range;
TT_SBit_MetricsRec elem_metrics;
FT_ULong elem_offset;
/* find the range for this element */
error = find_sbit_range( comp->glyph_code,
strike,
&elem_range,
&elem_offset );
if ( error )
goto Fail_Memory;
/* now load the element, recursively */
error = Load_SBit_Image( strike,
elem_range,
ebdt_pos,
elem_offset,
map,
x_offset + comp->x_offset,
y_offset + comp->y_offset,
stream,
&elem_metrics );
if ( error )
goto Fail_Memory;
}
Fail_Memory:
FT_FREE( components );
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* tt_face_load_sbit_image */
/* */
/* <Description> */
/* Loads a given glyph sbit image from the font resource. This also */
/* returns its metrics. */
/* */
/* <Input> */
/* face :: The target face object. */
/* */
/* strike_index :: The current strike index. */
/* */
/* glyph_index :: The current glyph index. */
/* */
/* load_flags :: The glyph load flags (the code checks for the flag */
/* FT_LOAD_CROP_BITMAP). */
/* */
/* stream :: The input stream. */
/* */
/* <Output> */
/* map :: The target pixmap. */
/* */
/* metrics :: A big sbit metrics structure for the glyph image. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. Returns an error if no */
/* glyph sbit exists for the index. */
/* */
/* <Note> */
/* The `map.buffer' field is always freed before the glyph is loaded. */
/* */
FT_LOCAL_DEF( FT_Error )
tt_face_load_sbit_image( TT_Face face,
FT_ULong strike_index,
FT_UInt glyph_index,
FT_UInt load_flags,
FT_Stream stream,
FT_Bitmap *map,
TT_SBit_MetricsRec *metrics )
{
FT_Error error;
FT_Memory memory = stream->memory;
FT_ULong ebdt_pos, glyph_offset;
TT_SBit_Strike strike;
TT_SBit_Range range;
/* Check whether there is a glyph sbit for the current index */
error = find_sbit_image( face, glyph_index, strike_index,
&range, &strike, &glyph_offset );
if ( error )
goto Exit;
/* now, find the location of the `EBDT' table in */
/* the font file */
error = face->goto_table( face, TTAG_EBDT, stream, 0 );
if ( error )
error = face->goto_table( face, TTAG_bdat, stream, 0 );
if (error)
goto Exit;
ebdt_pos = FT_STREAM_POS();
/* clear the bitmap & load the bitmap */
if ( face->root.glyph->flags & FT_GLYPH_OWN_BITMAP )
FT_FREE( map->buffer );
map->rows = map->pitch = map->width = 0;
error = Load_SBit_Image( strike, range, ebdt_pos, glyph_offset,
map, 0, 0, stream, metrics );
if ( error )
goto Exit;
/* the glyph slot owns this bitmap buffer */
face->root.glyph->flags |= FT_GLYPH_OWN_BITMAP;
/* setup vertical metrics if needed */
if ( strike->flags & 1 )
{
/* in case of a horizontal strike only */
FT_Int advance;
advance = strike->hori.ascender - strike->hori.descender;
/* some heuristic values */
metrics->vertBearingX = (FT_Char)(-metrics->width / 2 );
metrics->vertBearingY = (FT_Char)( advance / 10 );
metrics->vertAdvance = (FT_Char)( advance * 12 / 10 );
}
/* Crop the bitmap now, unless specified otherwise */
if ( load_flags & FT_LOAD_CROP_BITMAP )
crop_bitmap( map, metrics );
Exit:
return error;
}
/* END */