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/*
* Any bit blitters are not included in FreeType 1.x.
* Because bitmap glyph is visible for client aplictions and
* FreeType is not provide any text renderers.
*/
#include "xttblit.h"
/*
* SBit blitter
* Derived from ttsbit.c of FreeType 2 (with modifications)
*/
/***************************************************************************/
/* */
/* 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). */
/* */
/***************************************************************************/
static
void blit_stream( TT_Raster_Map* target,
TT_Byte* source,
TT_Int line_bits,
TT_Int height,
TT_Bool align,
TT_Int x_offset,
TT_Int y_offset,
TT_Bool inverted )
{
TT_Byte* line_buff;
TT_Int line_incr;
TT_Int start_incr;
TT_Int cursor_sign;
TT_UInt acc;
TT_Byte loaded;
TT_Int y;
/* first of all, compute starting write position */
if ( target->flow == TT_Flow_Down )
{
line_buff = (TT_Byte*)target->bitmap;
start_incr = target->cols;
}
else
{
line_buff = (TT_Byte*)target->bitmap + (target->rows-1)*target->cols;
start_incr = -target->cols;
}
/* We must set height when inverted is true */
if (inverted)
{
if (height < 0)
return;
line_incr = -target->cols;
}
else
line_incr = target->cols;
cursor_sign = (( target->flow == TT_Flow_Down ) ^ inverted ) ? 1 : -1;
/* preperation for clipping */
if ( x_offset > 0 )
line_buff += x_offset / 8;
if ( y_offset > 0 )
line_buff += y_offset * start_incr;
if ( height < 0 )
height = target->rows;
/*********************************************************************/
/* */
/* 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 */
/* clip */
if ( y_offset < 0 )
{
switch ( align )
{
TT_Int step;
case -1:
source -= ((TT_Int)( line_bits + 7 ) / 8 ) * y_offset;
break;
case 0:
step = ( - line_bits * y_offset ) & 7;
source += ( - line_bits * y_offset ) / 8;
if (step)
{
acc = ((TT_UShort)*source++) << (step+8);
loaded = 8 - step;
}
break;
default:
source += - align * y_offset;
break;
}
}
/* y axis */
for ( y = 0 ; y < height ; y++ )
{
TT_Byte* cur = line_buff; /* current write cursor */
TT_Int count = line_bits; /* number of bits to extract per line */
TT_Byte shift = x_offset & 7; /* current write shift */
TT_Byte space = 8 - shift;
TT_Byte* source_position = source;
TT_Int byte_count;
if ( x_offset >= 0 )
byte_count = x_offset / 8;
else
byte_count = ( x_offset - 7 ) / 8 ;
if (( y_offset + cursor_sign * y ) >= target->rows )
break;
/* x axis */
if ( byte_count < 0 )
{
TT_Int skip_byte = - byte_count - 1;
if (!skip_byte)
acc = loaded = 0;
source += skip_byte;
if (loaded < 8)
{
acc |= ((TT_UShort)*source++) << (8-loaded);
loaded += 8;
}
acc <<= space;
loaded -= space;
count += x_offset;
/* In this case, start cursor is always left-sided */
byte_count = 0;
shift = 0;
space = 8;
}
/* first of all, read individual source bytes */
if ( count >= 8 )
{
count -= 8;
#if 0
/* This part is not modified yet */
/* small speedups for trivial cases */
if ( loaded == 0 )
{
/* super trivial case :-) */
if ( shift == 0 )
{
do
{
*cur++ |= *source++;
count -= 8;
}
while (count >= 0);
}
/* otherwise .... */
else
{
TT_Byte cache = cur[0];
do
{
TT_Byte val = *source++;
cur[0] = cache | (val >> shift);
cache = val << space;
cur++;
count -= 8;
}
while (count >= 0);
cur[0] |= cache;
}
}
else /* normal cases */
#endif /* 0 */
{
do
{
TT_Byte val;
/* ensure that there are at least 8 bits in the accumulator */
if (loaded < 8)
{
acc |= ((TT_UShort)*source++) << (8-loaded);
loaded += 8;
}
/* now write one byte */
val = (TT_Byte)(acc >> 8);
if ( byte_count < target->cols )
{
cur[0] |= val >> shift;
if ( byte_count < target->cols - 1 )
cur[1] |= val << space;
}
cur++;
byte_count++;
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 )
{
TT_Byte val;
/* ensure that there are at least 'count' bits in the accumulator */
if (loaded < count)
{
acc |= ((TT_UShort)*source++) << (8-loaded);
loaded += 8;
}
/* now write remaining bits */
val = ((TT_Byte)(acc >> 8)) & ~(0xFF >> count);
if ( byte_count < target->cols )
{
cur[0] |= val >> shift;
if ((count > space) && (byte_count < target->cols - 1))
cur[1] |= val << space;
}
acc <<= count;
loaded -= count;
}
/* now, skip to next line */
if ( align )
{
acc = loaded = 0; /* clear accumulator on byte-padded lines */
if ( align > 0 )
{
source_position += align;
source = source_position;
}
}
line_buff += line_incr;
}
}
/* */
/*
* This function is not included in FreeType 1 engine.
* Because SBit_Image is able to access from any applications directory.
*/
TT_Error XTT_Get_SBit_Bitmap( TT_Raster_Map* target,
TT_SBit_Image* source_sbit,
TT_Int x_offset,
TT_Int y_offset )
{
TT_Raster_Map* source = &source_sbit->map;
TT_Int inverted = 0;
TT_Int line_bits;
TT_Int height;
if ((target->flow != TT_Flow_Up) && (target->flow != TT_Flow_Down))
return TT_Err_Invalid_Argument;
/* calculate offset */
x_offset += ( source_sbit->metrics.bbox.xMin & -64 ) / 64;
x_offset *= source_sbit->bit_depth;
y_offset = target->rows
- ( y_offset + (( source_sbit->metrics.bbox.yMax + 63 ) & -64 ) / 64 );
inverted = (( source->flow * target->flow ) == -1 );
/* correct??? */
line_bits = source->width * source_sbit->bit_depth;
/* return if offsets are obvious mismatched */
if (( x_offset + line_bits < 0 ) ||
( x_offset >= target->width ) ||
( y_offset >= target->rows ) ||
( y_offset + source->rows < 0 ))
return TT_Err_Invalid_Argument;
/* return if the size of source is invalid */
if (( source->cols <= 0 ) ||
( source->rows <= 0 ) ||
( source->size <= 0 ))
return TT_Err_Invalid_Argument;
height = ( y_offset >= 0 ) ? source->rows : ( source->rows + y_offset );
blit_stream( target, source->bitmap, line_bits, height,
source->cols, x_offset, y_offset, inverted );
return TT_Err_Ok;
}
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