ref: a3cfed5e87232c933bdc64f43e8ebebcfd18b41b
dir: /src/base/ftbitmap.c/
/***************************************************************************/
/* */
/* ftbitmap.c */
/* */
/* FreeType utility functions for bitmaps (body). */
/* */
/* Copyright 2004-2018 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_BITMAP_H
#include FT_IMAGE_H
#include FT_INTERNAL_OBJECTS_H
static
const FT_Bitmap null_bitmap = { 0, 0, 0, 0, 0, 0, 0, 0 };
/* documentation is in ftbitmap.h */
FT_EXPORT_DEF( void )
FT_Bitmap_Init( FT_Bitmap *abitmap )
{
if ( abitmap )
*abitmap = null_bitmap;
}
/* deprecated function name; retained for ABI compatibility */
FT_EXPORT_DEF( void )
FT_Bitmap_New( FT_Bitmap *abitmap )
{
if ( abitmap )
*abitmap = null_bitmap;
}
/* documentation is in ftbitmap.h */
FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Copy( FT_Library library,
const FT_Bitmap *source,
FT_Bitmap *target)
{
FT_Memory memory;
FT_Error error = FT_Err_Ok;
FT_Int pitch;
FT_ULong size;
FT_Int source_pitch_sign, target_pitch_sign;
if ( !library )
return FT_THROW( Invalid_Library_Handle );
if ( !source || !target )
return FT_THROW( Invalid_Argument );
if ( source == target )
return FT_Err_Ok;
source_pitch_sign = source->pitch < 0 ? -1 : 1;
target_pitch_sign = target->pitch < 0 ? -1 : 1;
if ( !source->buffer )
{
*target = *source;
if ( source_pitch_sign != target_pitch_sign )
target->pitch = -target->pitch;
return FT_Err_Ok;
}
memory = library->memory;
pitch = source->pitch;
if ( pitch < 0 )
pitch = -pitch;
size = (FT_ULong)pitch * source->rows;
if ( target->buffer )
{
FT_Int target_pitch = target->pitch;
FT_ULong target_size;
if ( target_pitch < 0 )
target_pitch = -target_pitch;
target_size = (FT_ULong)target_pitch * target->rows;
if ( target_size != size )
(void)FT_QREALLOC( target->buffer, target_size, size );
}
else
(void)FT_QALLOC( target->buffer, size );
if ( !error )
{
unsigned char *p;
p = target->buffer;
*target = *source;
target->buffer = p;
if ( source_pitch_sign == target_pitch_sign )
FT_MEM_COPY( target->buffer, source->buffer, size );
else
{
/* take care of bitmap flow */
FT_UInt i;
FT_Byte* s = source->buffer;
FT_Byte* t = target->buffer;
t += (FT_ULong)pitch * ( target->rows - 1 );
for ( i = target->rows; i > 0; i-- )
{
FT_ARRAY_COPY( t, s, pitch );
s += pitch;
t -= pitch;
}
}
}
return error;
}
/* Enlarge `bitmap' horizontally and vertically by `xpixels' */
/* and `ypixels', respectively. */
static FT_Error
ft_bitmap_assure_buffer( FT_Memory memory,
FT_Bitmap* bitmap,
FT_UInt xpixels,
FT_UInt ypixels )
{
FT_Error error;
unsigned int pitch;
unsigned int new_pitch;
FT_UInt bpp;
FT_UInt width, height;
unsigned char* buffer = NULL;
width = bitmap->width;
height = bitmap->rows;
pitch = (unsigned int)FT_ABS( bitmap->pitch );
switch ( bitmap->pixel_mode )
{
case FT_PIXEL_MODE_MONO:
bpp = 1;
new_pitch = ( width + xpixels + 7 ) >> 3;
break;
case FT_PIXEL_MODE_GRAY2:
bpp = 2;
new_pitch = ( width + xpixels + 3 ) >> 2;
break;
case FT_PIXEL_MODE_GRAY4:
bpp = 4;
new_pitch = ( width + xpixels + 1 ) >> 1;
break;
case FT_PIXEL_MODE_GRAY:
case FT_PIXEL_MODE_LCD:
case FT_PIXEL_MODE_LCD_V:
bpp = 8;
new_pitch = width + xpixels;
break;
default:
return FT_THROW( Invalid_Glyph_Format );
}
/* if no need to allocate memory */
if ( ypixels == 0 && new_pitch <= pitch )
{
/* zero the padding */
FT_UInt bit_width = pitch * 8;
FT_UInt bit_last = ( width + xpixels ) * bpp;
if ( bit_last < bit_width )
{
FT_Byte* line = bitmap->buffer + ( bit_last >> 3 );
FT_Byte* end = bitmap->buffer + pitch;
FT_UInt shift = bit_last & 7;
FT_UInt mask = 0xFF00U >> shift;
FT_UInt count = height;
for ( ; count > 0; count--, line += pitch, end += pitch )
{
FT_Byte* write = line;
if ( shift > 0 )
{
write[0] = (FT_Byte)( write[0] & mask );
write++;
}
if ( write < end )
FT_MEM_ZERO( write, end - write );
}
}
return FT_Err_Ok;
}
/* otherwise allocate new buffer */
if ( FT_QALLOC_MULT( buffer, bitmap->rows + ypixels, new_pitch ) )
return error;
/* new rows get added at the top of the bitmap, */
/* thus take care of the flow direction */
if ( bitmap->pitch > 0 )
{
FT_UInt len = ( width * bpp + 7 ) >> 3;
unsigned char* in = bitmap->buffer;
unsigned char* out = buffer;
unsigned char* limit = bitmap->buffer + pitch * bitmap->rows;
unsigned int delta = new_pitch - len;
FT_MEM_ZERO( out, new_pitch * ypixels );
out += new_pitch * ypixels;
while ( in < limit )
{
FT_MEM_COPY( out, in, len );
in += pitch;
out += len;
/* we use FT_QALLOC_MULT, which doesn't zero out the buffer; */
/* consequently, we have to manually zero out the remaining bytes */
FT_MEM_ZERO( out, delta );
out += delta;
}
}
else
{
FT_UInt len = ( width * bpp + 7 ) >> 3;
unsigned char* in = bitmap->buffer;
unsigned char* out = buffer;
unsigned char* limit = bitmap->buffer + pitch * bitmap->rows;
unsigned int delta = new_pitch - len;
while ( in < limit )
{
FT_MEM_COPY( out, in, len );
in += pitch;
out += len;
FT_MEM_ZERO( out, delta );
out += delta;
}
FT_MEM_ZERO( out, new_pitch * ypixels );
}
FT_FREE( bitmap->buffer );
bitmap->buffer = buffer;
/* set pitch only, width and height are left untouched */
if ( bitmap->pitch < 0 )
bitmap->pitch = -(int)new_pitch;
else
bitmap->pitch = (int)new_pitch;
return FT_Err_Ok;
}
/* documentation is in ftbitmap.h */
FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Embolden( FT_Library library,
FT_Bitmap* bitmap,
FT_Pos xStrength,
FT_Pos yStrength )
{
FT_Error error;
unsigned char* p;
FT_Int i, x, pitch;
FT_UInt y;
FT_Int xstr, ystr;
if ( !library )
return FT_THROW( Invalid_Library_Handle );
if ( !bitmap || !bitmap->buffer )
return FT_THROW( Invalid_Argument );
if ( ( ( FT_PIX_ROUND( xStrength ) >> 6 ) > FT_INT_MAX ) ||
( ( FT_PIX_ROUND( yStrength ) >> 6 ) > FT_INT_MAX ) )
return FT_THROW( Invalid_Argument );
xstr = (FT_Int)FT_PIX_ROUND( xStrength ) >> 6;
ystr = (FT_Int)FT_PIX_ROUND( yStrength ) >> 6;
if ( xstr == 0 && ystr == 0 )
return FT_Err_Ok;
else if ( xstr < 0 || ystr < 0 )
return FT_THROW( Invalid_Argument );
switch ( bitmap->pixel_mode )
{
case FT_PIXEL_MODE_GRAY2:
case FT_PIXEL_MODE_GRAY4:
{
FT_Bitmap tmp;
/* convert to 8bpp */
FT_Bitmap_Init( &tmp );
error = FT_Bitmap_Convert( library, bitmap, &tmp, 1 );
if ( error )
return error;
FT_Bitmap_Done( library, bitmap );
*bitmap = tmp;
}
break;
case FT_PIXEL_MODE_MONO:
if ( xstr > 8 )
xstr = 8;
break;
case FT_PIXEL_MODE_LCD:
xstr *= 3;
break;
case FT_PIXEL_MODE_LCD_V:
ystr *= 3;
break;
case FT_PIXEL_MODE_BGRA:
/* We don't embolden color glyphs. */
return FT_Err_Ok;
}
error = ft_bitmap_assure_buffer( library->memory, bitmap,
(FT_UInt)xstr, (FT_UInt)ystr );
if ( error )
return error;
/* take care of bitmap flow */
pitch = bitmap->pitch;
if ( pitch > 0 )
p = bitmap->buffer + pitch * ystr;
else
{
pitch = -pitch;
p = bitmap->buffer + (FT_UInt)pitch * ( bitmap->rows - 1 );
}
/* for each row */
for ( y = 0; y < bitmap->rows; y++ )
{
/*
* Horizontally:
*
* From the last pixel on, make each pixel or'ed with the
* `xstr' pixels before it.
*/
for ( x = pitch - 1; x >= 0; x-- )
{
unsigned char tmp;
tmp = p[x];
for ( i = 1; i <= xstr; i++ )
{
if ( bitmap->pixel_mode == FT_PIXEL_MODE_MONO )
{
p[x] |= tmp >> i;
/* the maximum value of 8 for `xstr' comes from here */
if ( x > 0 )
p[x] |= p[x - 1] << ( 8 - i );
#if 0
if ( p[x] == 0xFF )
break;
#endif
}
else
{
if ( x - i >= 0 )
{
if ( p[x] + p[x - i] > bitmap->num_grays - 1 )
{
p[x] = (unsigned char)( bitmap->num_grays - 1 );
break;
}
else
{
p[x] = (unsigned char)( p[x] + p[x - i] );
if ( p[x] == bitmap->num_grays - 1 )
break;
}
}
else
break;
}
}
}
/*
* Vertically:
*
* Make the above `ystr' rows or'ed with it.
*/
for ( x = 1; x <= ystr; x++ )
{
unsigned char* q;
q = p - bitmap->pitch * x;
for ( i = 0; i < pitch; i++ )
q[i] |= p[i];
}
p += bitmap->pitch;
}
bitmap->width += (FT_UInt)xstr;
bitmap->rows += (FT_UInt)ystr;
return FT_Err_Ok;
}
static FT_Byte
ft_gray_for_premultiplied_srgb_bgra( const FT_Byte* bgra )
{
FT_UInt a = bgra[3];
FT_UInt l;
/* Short-circuit transparent color to avoid division by zero. */
if ( !a )
return 0;
/*
* Luminosity for sRGB is defined using ~0.2126,0.7152,0.0722
* coefficients for RGB channels *on the linear colors*.
* A gamma of 2.2 is fair to assume. And then, we need to
* undo the premultiplication too.
*
* https://accessibility.kde.org/hsl-adjusted.php
*
* We do the computation with integers only, applying a gamma of 2.0.
* We guarantee 32-bit arithmetic to avoid overflow but the resulting
* luminosity fits into 16 bits.
*
*/
l = ( 4732UL /* 0.0722 * 65536 */ * bgra[0] * bgra[0] +
46871UL /* 0.7152 * 65536 */ * bgra[1] * bgra[1] +
13933UL /* 0.2126 * 65536 */ * bgra[2] * bgra[2] ) >> 16;
/*
* Final transparency can be determined as follows.
*
* - If alpha is zero, we want 0.
* - If alpha is zero and luminosity is zero, we want 255.
* - If alpha is zero and luminosity is one, we want 0.
*
* So the formula is a * (1 - l) = a - l * a.
*
* We still need to undo premultiplication by dividing l by a*a.
*
*/
return (FT_Byte)( a - l / a );
}
/* documentation is in ftbitmap.h */
FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Convert( FT_Library library,
const FT_Bitmap *source,
FT_Bitmap *target,
FT_Int alignment )
{
FT_Error error = FT_Err_Ok;
FT_Memory memory;
FT_Byte* s;
FT_Byte* t;
if ( !library )
return FT_THROW( Invalid_Library_Handle );
if ( !source || !target )
return FT_THROW( Invalid_Argument );
memory = library->memory;
switch ( source->pixel_mode )
{
case FT_PIXEL_MODE_MONO:
case FT_PIXEL_MODE_GRAY:
case FT_PIXEL_MODE_GRAY2:
case FT_PIXEL_MODE_GRAY4:
case FT_PIXEL_MODE_LCD:
case FT_PIXEL_MODE_LCD_V:
case FT_PIXEL_MODE_BGRA:
{
FT_Int pad, old_target_pitch, target_pitch;
FT_ULong old_size;
old_target_pitch = target->pitch;
if ( old_target_pitch < 0 )
old_target_pitch = -old_target_pitch;
old_size = target->rows * (FT_UInt)old_target_pitch;
target->pixel_mode = FT_PIXEL_MODE_GRAY;
target->rows = source->rows;
target->width = source->width;
pad = 0;
if ( alignment > 0 )
{
pad = (FT_Int)source->width % alignment;
if ( pad != 0 )
pad = alignment - pad;
}
target_pitch = (FT_Int)source->width + pad;
if ( target_pitch > 0 &&
(FT_ULong)target->rows > FT_ULONG_MAX / (FT_ULong)target_pitch )
return FT_THROW( Invalid_Argument );
if ( FT_QREALLOC( target->buffer,
old_size, target->rows * (FT_UInt)target_pitch ) )
return error;
target->pitch = target->pitch < 0 ? -target_pitch : target_pitch;
}
break;
default:
error = FT_THROW( Invalid_Argument );
}
s = source->buffer;
t = target->buffer;
/* take care of bitmap flow */
if ( source->pitch < 0 )
s -= source->pitch * (FT_Int)( source->rows - 1 );
if ( target->pitch < 0 )
t -= target->pitch * (FT_Int)( target->rows - 1 );
switch ( source->pixel_mode )
{
case FT_PIXEL_MODE_MONO:
{
FT_UInt i;
target->num_grays = 2;
for ( i = source->rows; i > 0; i-- )
{
FT_Byte* ss = s;
FT_Byte* tt = t;
FT_UInt j;
/* get the full bytes */
for ( j = source->width >> 3; j > 0; j-- )
{
FT_Int val = ss[0]; /* avoid a byte->int cast on each line */
tt[0] = (FT_Byte)( ( val & 0x80 ) >> 7 );
tt[1] = (FT_Byte)( ( val & 0x40 ) >> 6 );
tt[2] = (FT_Byte)( ( val & 0x20 ) >> 5 );
tt[3] = (FT_Byte)( ( val & 0x10 ) >> 4 );
tt[4] = (FT_Byte)( ( val & 0x08 ) >> 3 );
tt[5] = (FT_Byte)( ( val & 0x04 ) >> 2 );
tt[6] = (FT_Byte)( ( val & 0x02 ) >> 1 );
tt[7] = (FT_Byte)( val & 0x01 );
tt += 8;
ss += 1;
}
/* get remaining pixels (if any) */
j = source->width & 7;
if ( j > 0 )
{
FT_Int val = *ss;
for ( ; j > 0; j-- )
{
tt[0] = (FT_Byte)( ( val & 0x80 ) >> 7);
val <<= 1;
tt += 1;
}
}
s += source->pitch;
t += target->pitch;
}
}
break;
case FT_PIXEL_MODE_GRAY:
case FT_PIXEL_MODE_LCD:
case FT_PIXEL_MODE_LCD_V:
{
FT_UInt width = source->width;
FT_UInt i;
target->num_grays = 256;
for ( i = source->rows; i > 0; i-- )
{
FT_ARRAY_COPY( t, s, width );
s += source->pitch;
t += target->pitch;
}
}
break;
case FT_PIXEL_MODE_GRAY2:
{
FT_UInt i;
target->num_grays = 4;
for ( i = source->rows; i > 0; i-- )
{
FT_Byte* ss = s;
FT_Byte* tt = t;
FT_UInt j;
/* get the full bytes */
for ( j = source->width >> 2; j > 0; j-- )
{
FT_Int val = ss[0];
tt[0] = (FT_Byte)( ( val & 0xC0 ) >> 6 );
tt[1] = (FT_Byte)( ( val & 0x30 ) >> 4 );
tt[2] = (FT_Byte)( ( val & 0x0C ) >> 2 );
tt[3] = (FT_Byte)( ( val & 0x03 ) );
ss += 1;
tt += 4;
}
j = source->width & 3;
if ( j > 0 )
{
FT_Int val = ss[0];
for ( ; j > 0; j-- )
{
tt[0] = (FT_Byte)( ( val & 0xC0 ) >> 6 );
val <<= 2;
tt += 1;
}
}
s += source->pitch;
t += target->pitch;
}
}
break;
case FT_PIXEL_MODE_GRAY4:
{
FT_UInt i;
target->num_grays = 16;
for ( i = source->rows; i > 0; i-- )
{
FT_Byte* ss = s;
FT_Byte* tt = t;
FT_UInt j;
/* get the full bytes */
for ( j = source->width >> 1; j > 0; j-- )
{
FT_Int val = ss[0];
tt[0] = (FT_Byte)( ( val & 0xF0 ) >> 4 );
tt[1] = (FT_Byte)( ( val & 0x0F ) );
ss += 1;
tt += 2;
}
if ( source->width & 1 )
tt[0] = (FT_Byte)( ( ss[0] & 0xF0 ) >> 4 );
s += source->pitch;
t += target->pitch;
}
}
break;
case FT_PIXEL_MODE_BGRA:
{
FT_UInt i;
target->num_grays = 256;
for ( i = source->rows; i > 0; i-- )
{
FT_Byte* ss = s;
FT_Byte* tt = t;
FT_UInt j;
for ( j = source->width; j > 0; j-- )
{
tt[0] = ft_gray_for_premultiplied_srgb_bgra( ss );
ss += 4;
tt += 1;
}
s += source->pitch;
t += target->pitch;
}
}
break;
default:
;
}
return error;
}
/* documentation is in ftbitmap.h */
FT_EXPORT_DEF( FT_Error )
FT_GlyphSlot_Own_Bitmap( FT_GlyphSlot slot )
{
if ( slot && slot->format == FT_GLYPH_FORMAT_BITMAP &&
!( slot->internal->flags & FT_GLYPH_OWN_BITMAP ) )
{
FT_Bitmap bitmap;
FT_Error error;
FT_Bitmap_Init( &bitmap );
error = FT_Bitmap_Copy( slot->library, &slot->bitmap, &bitmap );
if ( error )
return error;
slot->bitmap = bitmap;
slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
}
return FT_Err_Ok;
}
/* documentation is in ftbitmap.h */
FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Done( FT_Library library,
FT_Bitmap *bitmap )
{
FT_Memory memory;
if ( !library )
return FT_THROW( Invalid_Library_Handle );
if ( !bitmap )
return FT_THROW( Invalid_Argument );
memory = library->memory;
FT_FREE( bitmap->buffer );
*bitmap = null_bitmap;
return FT_Err_Ok;
}
/* END */