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freetype2/src/sfnt/ttsbit.c

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Initial revision
1999-12-17 00:11:37 +01:00
/***************************************************************************/
/* */
/* ttsbit.c */
/* */
/* TrueType and OpenType embedded bitmap support (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. */
/* */
/* */
/* WARNING: This file should not be compiled directly, it is meant to be */
/* included in the source of several font drivers (i.e., the TTF */
/* and OTF drivers). */
/* */
/***************************************************************************/
major re-organisation of the FreeType 2 directory hierarchy
2000-05-11 20:23:52 +02:00
#include <freetype/internal/ftdebug.h>
#include <freetype/internal/tterrors.h>
#include <freetype/tttags.h>
Initial revision
1999-12-17 00:11:37 +01:00
#include <ttsbit.h>
/*************************************************************************/
/* */
/* <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,
char* 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_Byte 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 = x_offset & 7; /* current write shift */
FT_Byte space = 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)*source++) << (8 - loaded);
loaded += 8;
}
/* now write one byte */
val = (FT_Byte)(acc >> 8);
if (shift)
{
cur[0] |= val >> shift;
cur[1] |= 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 ( loaded < count )
{
acc |= ((FT_UShort)*source++) << (8 - loaded);
loaded += 8;
}
/* now write remaining bits */
val = ((FT_Byte)(acc >> 8)) & ~(0xFF >> count);
cur[0] |= val >> shift;
if ( count > space )
cur[1] |= val << space;
acc <<= count;
loaded -= count;
}
/* now, skip to next line */
if ( byte_padded )
acc = loaded = 0; /* clear accumulator on byte-padded lines */
line_buff += line_incr;
}
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_Load_Small_SBit_Metrics */
/* */
/* <Description> */
/* Loads a small bitmap metrics record. */
/* */
/* <Input> */
/* stream :: The input stream. */
/* */
/* <Output> */
/* metrics :: A small metrics structure. */
/* */
static
void TT_Load_Small_SBit_Metrics( TT_SBit_Small_Metrics* metrics,
FT_Stream stream )
{
metrics->height = GET_Byte();
metrics->width = GET_Byte();
metrics->bearingX = GET_Char();
metrics->bearingY = GET_Char();
metrics->advance = GET_Byte();
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_Load_SBit_Metrics */
/* */
/* <Description> */
/* Loads a bitmap metrics record. */
/* */
/* <Input> */
/* stream :: The input stream. */
/* */
/* <Output> */
/* metrics :: A metrics structure. */
/* */
static
void TT_Load_SBit_Metrics( TT_SBit_Metrics* metrics,
FT_Stream stream )
{
metrics->height = GET_Byte();
metrics->width = GET_Byte();
metrics->horiBearingX = GET_Char();
metrics->horiBearingY = GET_Char();
metrics->horiAdvance = GET_Byte();
metrics->vertBearingX = GET_Char();
metrics->vertBearingY = GET_Char();
metrics->vertAdvance = GET_Byte();
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_Load_SBit_Line_Metrics */
/* */
/* <Description> */
/* Loads a bitmap line metrics record. */
/* */
/* <Input> */
/* stream :: The input stream. */
/* */
/* <Output> */
/* metrics :: A line metrics structure. */
/* */
static
void TT_Load_SBit_Line_Metrics( TT_SBit_Line_Metrics* metrics,
FT_Stream stream )
{
metrics->ascender = GET_Char();
metrics->descender = GET_Char();
metrics->max_width = GET_Byte();
metrics->caret_slope_numerator = GET_Char();
metrics->caret_slope_denominator = GET_Char();
metrics->caret_offset = GET_Char();
metrics->min_origin_SB = GET_Char();
metrics->min_advance_SB = GET_Char();
metrics->max_before_BL = GET_Char();
metrics->min_after_BL = GET_Char();
metrics->pads[0] = GET_Char();
metrics->pads[1] = GET_Char();
}
/*************************************************************************/
/* */
/* <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> */
/* TrueType error code. 0 means success. */
/* */
static
TT_Error Load_SBit_Const_Metrics( TT_SBit_Range* range,
FT_Stream stream )
{
TT_Error error;
if ( !ACCESS_Frame( 12L ) )
{
range->image_size = GET_ULong();
TT_Load_SBit_Metrics( &range->metrics, stream );
FORGET_Frame();
}
return error;
}
/*************************************************************************/
/* */
/* <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> */
/* TrueType error code. 0 means success. */
/* */
static
TT_Error Load_SBit_Range_Codes( TT_SBit_Range* range,
FT_Stream stream,
TT_Bool load_offsets )
{
TT_Error error;
TT_ULong count, n, size;
FT_Memory memory = stream->memory;
if ( READ_ULong( count ) )
goto Exit;
range->num_glyphs = count;
/* Allocate glyph offsets table if needed */
if ( load_offsets )
{
if ( ALLOC_ARRAY( range->glyph_offsets, count, TT_ULong ) )
goto Exit;
size = count * 4L;
}
else
size = count * 2L;
/* Allocate glyph codes table and access frame */
if ( ALLOC_ARRAY ( range->glyph_codes, count, TT_UShort ) ||
ACCESS_Frame( size ) )
goto Exit;
for ( n = 0; n < count; n++ )
{
range->glyph_codes[n] = GET_UShort();
if (load_offsets)
range->glyph_offsets[n] = (TT_ULong)range->image_offset +
GET_UShort();
}
FORGET_Frame();
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> */
/* TrueType error code. 0 means success. */
/* */
static
TT_Error Load_SBit_Range( TT_SBit_Range* range,
FT_Stream stream )
{
TT_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 */
{
TT_ULong num_glyphs, n;
TT_Int size_elem;
TT_Bool large = (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 ( ALLOC_ARRAY( range->glyph_offsets,
num_glyphs, TT_ULong ) ||
ACCESS_Frame( num_glyphs * size_elem ) )
goto Exit;
for ( n = 0; n < num_glyphs; n++ )
range->glyph_offsets[n] = (TT_ULong)( range->image_offset +
(large ? GET_ULong() : GET_UShort()) );
FORGET_Frame();
}
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 = TT_Err_Invalid_File_Format;
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_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> */
/* TrueType error code. 0 means success. */
/* */
LOCAL_FUNC
TT_Error TT_Load_SBit_Strikes( TT_Face face,
FT_Stream stream )
{
TT_Error error = 0;
FT_Memory memory = stream->memory;
TT_Fixed version;
TT_ULong num_strikes;
TT_ULong table_base;
/* this table is optional */
error = face->goto_table( face, TTAG_EBLC, stream, 0 );
{
error = 0;
goto Exit;
}
table_base = FILE_Pos();
if ( ACCESS_Frame( 8L ) )
goto Exit;
version = GET_Long();
num_strikes = GET_ULong();
FORGET_Frame();
/* check version number and strike count */
if ( version != 0x00020000 ||
num_strikes >= 0x10000 )
{
FT_ERROR(( "TT_Load_SBit_Strikes: invalid table version!\n" ));
error = TT_Err_Invalid_File_Format;
goto Exit;
}
/* allocate the strikes table */
if ( ALLOC_ARRAY( face->sbit_strikes, num_strikes, TT_SBit_Strike ) )
goto Exit;
face->num_sbit_strikes = num_strikes;
/* now read each strike table separately */
{
TT_SBit_Strike* strike = face->sbit_strikes;
TT_ULong count = num_strikes;
if ( ACCESS_Frame( 48L * num_strikes ) )
goto Exit;
while ( count > 0 )
{
TT_ULong indexTablesSize;
strike->ranges_offset = GET_ULong();
indexTablesSize = GET_ULong(); /* don't save */
strike->num_ranges = GET_ULong();
strike->color_ref = GET_ULong();
TT_Load_SBit_Line_Metrics( &strike->hori, stream );
TT_Load_SBit_Line_Metrics( &strike->vert, stream );
strike->start_glyph = GET_UShort();
strike->end_glyph = GET_UShort();
strike->x_ppem = GET_Byte();
strike->y_ppem = GET_Byte();
strike->bit_depth = GET_Byte();
strike->flags = GET_Char();
count--;
strike++;
}
FORGET_Frame();
}
/* allocate the index ranges for each strike table */
{
TT_SBit_Strike* strike = face->sbit_strikes;
TT_ULong count = num_strikes;
while ( count > 0 )
{
TT_SBit_Range* range;
TT_ULong count2 = strike->num_ranges;
if ( ALLOC_ARRAY( strike->sbit_ranges,
strike->num_ranges,
TT_SBit_Range ) )
goto Exit;
/* read each range */
if ( FILE_Seek( table_base + strike->ranges_offset ) ||
ACCESS_Frame( strike->num_ranges * 8L ) )
goto Exit;
range = strike->sbit_ranges;
while ( count2 > 0 )
{
range->first_glyph = GET_UShort();
range->last_glyph = GET_UShort();
range->table_offset = table_base + strike->ranges_offset
+ GET_ULong();
count2--;
range++;
}
FORGET_Frame();
/* Now, read each index table */
count2 = strike->num_ranges;
range = strike->sbit_ranges;
while ( count2 > 0 )
{
/* Read the header */
if ( FILE_Seek( range->table_offset ) ||
ACCESS_Frame( 8L ) )
goto Exit;
range->index_format = GET_UShort();
range->image_format = GET_UShort();
range->image_offset = GET_ULong();
FORGET_Frame();
error = Load_SBit_Range( range, stream );
if ( error )
goto Exit;
count2--;
range++;
}
count--;
strike++;
}
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_Free_SBit_Strikes */
/* */
/* <Description> */
/* Releases the embedded bitmap tables. */
/* */
/* <Input> */
/* face :: The target face object. */
/* */
LOCAL_FUNC
void TT_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 */
FREE( range->glyph_offsets );
FREE( range->glyph_codes );
}
}
FREE( strike->sbit_ranges );
strike->num_ranges = 0;
}
FREE( face->sbit_strikes );
}
face->num_sbit_strikes = 0;
}
/*************************************************************************/
/* */
/* <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> */
/* TrueType error code. 0 means the glyph index was found. */
/* */
static
TT_Error Find_SBit_Range( TT_UInt glyph_index,
TT_SBit_Strike* strike,
TT_SBit_Range** arange,
TT_ULong* aglyph_offset )
{
TT_SBit_Range *range, *range_limit;
/* check whether the glyph index is within this strike's */
/* glyph range */
if ( glyph_index < strike->start_glyph ||
glyph_index > 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 >= range->first_glyph &&
glyph_index <= range->last_glyph )
{
TT_UShort delta = 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:
{
TT_ULong n;
for ( n = 0; n < range->num_glyphs; n++ )
{
if ( 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;
break;
}
}
}
/* fall-through */
default:
goto Fail;
}
/* return successfully! */
*arange = range;
return 0;
}
}
Fail:
*arange = 0;
*aglyph_offset = 0;
return TT_Err_Invalid_Argument;
}
/*************************************************************************/
/* */
/* <Function> */
/* Find_SBit_Image */
/* */
/* <Description> */
/* Checks whether an embedded bitmap (an `sbit') exists for a given */
/* glyph, at given x and y ppems. */
/* */
/* <Input> */
/* face :: The target face object. */
/* glyph_index :: The glyph index. */
/* x_ppem :: The horizontal resolution in points per EM. */
/* y_ppem :: The vertical resolution in points per EM. */
/* */
/* <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> */
/* TrueType error code. 0 means success. Returns */
/* TT_Err_Invalid_Argument if no sbit exist for the requested glyph. */
/* */
static
TT_Error Find_SBit_Image( TT_Face face,
TT_UInt glyph_index,
TT_Int x_ppem,
TT_Int y_ppem,
TT_SBit_Range** arange,
TT_SBit_Strike** astrike,
TT_ULong* aglyph_offset )
{
TT_SBit_Strike* strike = face->sbit_strikes;
TT_SBit_Strike* strike_limit = strike + face->num_sbit_strikes;
if ( !strike)
goto Fail;
for ( ; strike < strike_limit; strike++ )
{
if ( strike->x_ppem == x_ppem && strike->y_ppem == y_ppem )
{
TT_Error error;
error = Find_SBit_Range( glyph_index, strike, arange, aglyph_offset );
if ( error )
goto Fail;
*astrike = strike;
return TT_Err_Ok;
}
}
Fail:
/* no embedded bitmap for this glyph in face */
*arange = 0;
*astrike = 0;
*aglyph_offset = 0;
return TT_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> */
/* TrueType 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
TT_Error Load_SBit_Metrics( FT_Stream stream,
TT_SBit_Range* range,
TT_SBit_Metrics* metrics )
{
TT_Error error = TT_Err_Ok;
switch ( range->index_format )
{
case 1: /* variable metrics */
case 3:
case 4:
{
switch ( range->image_format )
{
case 1: /* small metrics */
case 2:
case 8:
{
TT_SBit_Small_Metrics smetrics;
/* read small metrics */
if ( ACCESS_Frame( 5L ) )
goto Exit;
TT_Load_Small_SBit_Metrics( &smetrics, stream );
FORGET_Frame();
/* 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;
default: /* big metrics */
if ( ACCESS_Frame( 8L ) )
goto Exit;
TT_Load_SBit_Metrics( metrics, stream );
FORGET_Frame();
}
}
break;
default: /* constant metrics */
*metrics = range->metrics;
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* Crop_Bitmap */
/* */
/* <Description> */
/* Crops a bitmap to its tightest bounding box, and adjusts its */
/* metrics. */
/* */
/* <Input> */
/* image :: The input glyph slot. */
/* */
/* 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. */
/* */
/* --------- */
/* | | ----- */
/* | *** | |***| */
/* | * | | * | */
/* | * | ------> | * | */
/* | * | | * | */
/* | * | | * | */
/* | *** | |***| */
/* --------- ----- */
/* */
/***********************************************************************/
TT_Int rows, count;
TT_Long line_len;
TT_Byte* line;
/***********************************************************************/
/* */
/* first of all, checks the top-most lines of the bitmap, and removes */
/* them if they're empty. */
/* */
{
line = (TT_Byte*)map->buffer;
rows = map->rows;
line_len = map->pitch;
for ( count = 0; count < rows; count++ )
{
TT_Byte* cur = line;
TT_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 = (TT_Byte*)map->buffer;
MEM_Move( line, line + count * line_len, (rows - count) * line_len );
metrics->height -= count;
metrics->horiBearingY -= count;
metrics->vertBearingY -= count;
map->rows -= count;
rows -= count;
}
}
/***********************************************************************/
/* */
/* second, crop the lower lines */
/* */
{
line = (TT_Byte*)map->buffer + (rows - 1) * line_len;
for ( count = 0; count < rows; count++ )
{
TT_Byte* cur = line;
TT_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 -= count;
rows -= count;
map->rows -= count;
}
}
/***********************************************************************/
/* */
/* third, get rid of the space on the left side of the glyph */
/* */
do
{
TT_Byte* limit;
line = (TT_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 = (TT_Byte*)map->buffer;
limit = line + rows * line_len;
for ( ; line < limit; line += line_len )
{
TT_Int n, width = map->width;
TT_Byte old;
TT_Byte* cur = line;
old = cur[0] << 1;
for ( n = 8; n < width; n += 8 )
{
TT_Byte val;
val = cur[1];
cur[0] = old | (val >> 7);
old = 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
{
TT_Int right = map->width-1;
TT_Byte* limit;
TT_Byte mask;
line = (TT_Byte*)map->buffer + (right >> 3);
limit = line + rows*line_len;
mask = 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
TT_Error Load_SBit_Single( FT_Bitmap* map,
TT_Int x_offset,
TT_Int y_offset,
TT_Int pix_bits,
TT_UShort image_format,
TT_SBit_Metrics* metrics,
FT_Stream stream )
{
TT_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 = TT_Err_Invalid_Argument;
goto Exit;
}
{
TT_Int glyph_width = metrics->width;
TT_Int glyph_height = metrics->height;
TT_Int glyph_size;
TT_Int line_bits = pix_bits * glyph_width;
TT_Bool pad_bytes = 0;
/* compute size of glyph image */
switch ( image_format )
{
case 1: /* byte-padded formats */
case 6:
{
TT_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 TT_Err_Invalid_File_Format;
}
/* Now read data and draw glyph into target pixmap */
if ( ACCESS_Frame( 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, stream->cursor, line_bits, pad_bytes,
x_offset * pix_bits, y_offset );
FORGET_Frame();
}
Exit:
return error;
}
static
TT_Error Load_SBit_Image( TT_SBit_Strike* strike,
TT_SBit_Range* range,
TT_ULong ebdt_pos,
TT_ULong glyph_offset,
FT_Bitmap* map,
TT_Int x_offset,
TT_Int y_offset,
FT_Stream stream,
TT_SBit_Metrics* metrics )
{
FT_Memory memory = stream->memory;
TT_Error error;
/* place stream at beginning of glyph data and read metrics */
if ( FILE_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 )
{
TT_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_pal2;
map->pitch = (map->width+3) >> 2;
break;
case 4:
map->pixel_mode = ft_pixel_mode_pal4;
map->pitch = (map->width+1) >> 1;
break;
case 8:
map->pixel_mode = ft_pixel_mode_grays;
map->pitch = map->width;
break;
default:
return TT_Err_Invalid_File_Format;
}
size = map->rows * map->pitch;
/* check that there is no empty image */
if ( size == 0 )
goto Exit; /* exit successfully! */
if ( 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 */
case 9:
break;
default: /* invalid image format */
return TT_Err_Invalid_File_Format;
}
/* All right, we're in a compound format. First of all, read */
/* the array of elements */
{
TT_SBit_Component* components;
TT_SBit_Component* comp;
TT_UShort num_components, count;
if ( READ_UShort( num_components ) ||
ALLOC_ARRAY( components, num_components, TT_SBit_Component ) )
goto Exit;
count = num_components;
if ( ACCESS_Frame( 4L * num_components ) )
goto Fail_Memory;
for ( comp = components; count > 0; count--, comp++ )
{
comp->glyph_code = GET_UShort();
comp->x_offset = GET_Char();
comp->y_offset = GET_Char();
}
FORGET_Frame();
/* Now recursively load each element glyph */
count = num_components;
comp = components;
for ( ; count > 0; count--, comp++ )
{
TT_SBit_Range* elem_range;
TT_SBit_Metrics elem_metrics;
TT_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:
FREE( components );
}
Exit:
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* TT_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. */
/* */
/* x_ppem :: The horizontal resolution in points per EM. */
/* */
/* y_ppem :: The vertical resolution in points per EM. */
/* */
/* glyph_index :: The current glyph index. */
/* */
/* stream :: The input stream. */
/* */
/* <Output> */
/* map :: The target pixmap. */
/* metrics :: A big sbit metrics structure for the glyph image. */
/* */
/* <Return> */
/* TrueType 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. */
/* */
LOCAL_FUNC
TT_Error TT_Load_SBit_Image( TT_Face face,
TT_Int x_ppem,
TT_Int y_ppem,
TT_UInt glyph_index,
FT_Stream stream,
FT_Bitmap* map,
TT_SBit_Metrics* metrics )
{
TT_Error error;
FT_Memory memory = stream->memory;
TT_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, x_ppem, y_ppem,
&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) goto Exit;
ebdt_pos = FILE_Pos();
/* clear the bitmap & load the bitmap */
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;
/* setup vertical metrics if needed */
if ( strike->flags & 1 )
{
/* in case of a horizontal strike only */
FT_Int advance;
FT_Int top;
advance = strike->hori.ascender - strike->hori.descender;
top = advance / 10;
metrics->vertBearingX = -metrics->width / 2;
metrics->vertBearingY = advance / 10;
metrics->vertAdvance = advance * 12 / 10;
}
/* Crop the bitmap now */
Crop_Bitmap( map, metrics );
Exit:
return error;
}
/* END */