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Al-Qurtas-Islamic-bank-The-.../src/sdf/ftbsdf.c

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#include <freetype/internal/ftobjs.h>
#include <freetype/internal/ftdebug.h>
#include <freetype/internal/ftmemory.h>
#include <freetype/fttrigon.h>
#include "ftsdf.h"
#include "ftsdferrs.h"
/**************************************************************************
*
* useful macros
*
*/
/* Convenient macro which calls the function */
/* and returns if any error occurs. */
#define FT_CALL( x ) do \
{ \
error = ( x ); \
if ( error != FT_Err_Ok ) \
goto Exit; \
} while ( 0 )
#define ONE 65536 /* 1 in 16.16 */
/**************************************************************************
*
* typedefs
*
*/
typedef FT_Vector FT_16D16_Vec; /* with 16.16 fixed point components */
typedef FT_Short FT_6D10; /* 6.10 fixed point representation */
typedef FT_Fixed FT_16D16; /* 16.16 fixed point representation */
/**************************************************************************
*
* structs
*
*/
typedef struct BSDF_TRaster_
{
FT_Memory memory; /* used internally to allocate memory */
} BSDF_TRaster;
/* Euclidean distance used for euclidean distance transform */
/* can also be interpreted as edge distance. */
typedef struct ED_
{
FT_16D16 dist; /* distance at `near' */
FT_16D16_Vec near; /* nearest point */
FT_Char sign; /* outside or inside */
} ED;
typedef struct BSDF_Worker_
{
ED* distance_map;
FT_Int width;
FT_Int rows;
SDF_Raster_Params params;
} BSDF_Worker;
/**************************************************************************
*
* initializer
*
*/
static
const ED zero_ed = { 0, { 0, 0 }, 0 };
/**************************************************************************
*
* rasterizer functions
*
*/
#ifdef CHECK_NEIGHBOR
#undef CHECK_NEIGHBOR
#endif
/* Use the macro only in `bsdf_is_edge' function. */
#define CHECK_NEIGHBOR( x_offset, y_offset ) \
if ( x + x_offset >= 0 && x + x_offset < w && \
y + y_offset >= 0 && y + y_offset < r ) \
{ \
num_neighbour++; \
to_check = s + y_offset * w + x_offset; \
if ( *to_check == 0 ) \
{ \
is_edge = 1; \
goto Done; \
} \
}
/**************************************************************************
*
* @Function:
* bsdf_is_edge
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static FT_Bool
bsdf_is_edge( FT_Byte* s, /* source bitmap */
FT_Int x, /* x index of point to check */
FT_Int y, /* y index of point to check */
FT_Int w, /* width */
FT_Int r ) /* rows */
{
FT_Bool is_edge = 0;
FT_Byte* to_check = NULL;
FT_Int num_neighbour = 0;
if ( *s == 0 )
goto Done;
if ( *s > 0 && *s < 255 )
{
is_edge = 1;
goto Done;
}
/* up */
CHECK_NEIGHBOR( 0, -1 );
/* down */
CHECK_NEIGHBOR( 0, 1 );
/* left */
CHECK_NEIGHBOR( -1, 0 );
/* right */
CHECK_NEIGHBOR( 1, 0 );
/* up left */
CHECK_NEIGHBOR( -1, -1 );
/* up right */
CHECK_NEIGHBOR( 1, -1 );
/* down left */
CHECK_NEIGHBOR( -1, 1 );
/* down right */
CHECK_NEIGHBOR( 1, 1 );
if ( num_neighbour != 8 )
is_edge = 1;
Done:
return is_edge;
}
#undef CHECK_NEIGHBOR
/**************************************************************************
*
* @Function:
* compute_gradient
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static FT_16D16_Vec
compute_gradient( ED* current,
FT_Int x,
FT_Int y,
FT_Int w,
FT_Int r )
{
/* [TODO]: Write proper explanation. */
FT_16D16_Vec g = { 0, 0 };
if ( x <= 0 || x >= w - 1 ||
y <= 0 || y >= r - 1 )
return g;
g.x = - current[-w - 1].dist -
2 * current[ -1 ].dist -
current[ w - 1].dist +
current[-w + 1].dist +
2 * current[ 1 ].dist +
current[ w + 1].dist;
g.y = - current[-w - 1].dist -
2 * current[ -w ].dist -
current[-w + 1].dist +
current[ w - 1].dist +
2 * current[ w ].dist +
current[ w + 1].dist;
FT_Vector_NormLen( &g );
g.x = FT_MulFix( g.x, ONE / 2 - current->dist );
g.y = FT_MulFix( g.y, ONE / 2 - current->dist );
return g;
}
/**************************************************************************
*
* @Function:
* bsdf_approximate_edge
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static FT_Error
bsdf_approximate_edge( BSDF_Worker* worker )
{
/* [TODO]: Write proper explanation. */
FT_Error error = FT_Err_Ok;
FT_Int i, j;
FT_Int index;
ED* ed;
if ( !worker || !worker->distance_map )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
ed = worker->distance_map;
for ( j = 0; j < worker->rows; j++ )
{
for ( i = 0; i < worker->width; i++ )
{
index = j * worker->width + i;
if ( ed[index].dist != 0 )
ed[index].near = compute_gradient( ed + index, i, j,
worker->width, worker->rows );
}
}
for ( j = 0; j < worker->rows; j++ )
{
for ( i = 0; i < worker->width; i++ )
{
index = j * worker->width + i;
if ( ed[index].dist == 0 )
{
ed[index].dist = 200 * ONE;
ed[index].near.x = 100 * ONE;
ed[index].near.y = 100 * ONE;
}
else
ed[index].dist = FT_Vector_Length( &ed[index].near );
}
}
Exit:
return error;
}
/**************************************************************************
*
* @Function:
* bsdf_init_distance_map
*
* @Description:
* This function initialize the distance map according to
* algorithm '8-point sequential Euclidean distance mapping' (8SED).
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static FT_Error
bsdf_init_distance_map( const FT_Bitmap* source,
BSDF_Worker* worker )
{
FT_Error error = FT_Err_Ok;
FT_Bool is_monochrome = 0;
FT_Int x_diff, y_diff;
FT_Int num_channels;
FT_Int t_i, t_j, s_i, s_j;
FT_Byte* s;
ED* t;
/* again check the parameters (probably unnecessary) */
if ( !source || !worker )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* Because of the way we convert bitmap to SDF */
/* i.e. aligning the source to the center of the */
/* target, the target's width/rows must be checked */
/* before copying. */
if ( worker->width < source->width ||
worker->rows < source->rows )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* check pixel mode */
if ( source->pixel_mode == FT_PIXEL_MODE_NONE )
{
FT_ERROR(( "[bsdf] bsdf_copy_source_to_target: "
"Invalid pixel mode of source bitmap" ));
error = FT_THROW( Invalid_Argument );
goto Exit;
}
#ifdef FT_DEBUG_LEVEL_TRACE
if ( source->pixel_mode == FT_PIXEL_MODE_MONO )
{
FT_TRACE0(( "[bsdf] bsdf_copy_source_to_target:\n"
"The `bsdf' renderer can convert monochrome bitmap\n"
"to SDF, but the results are not perfect because there\n"
"is no way to approximate actual outline from monochrome\n"
"bitmap. Consider using anti-aliased bitmap instead.\n" ));
}
#endif
/* Calculate the difference in width and rows */
/* of the target and source. */
x_diff = worker->width - source->width;
y_diff = worker->rows - source->rows;
x_diff /= 2;
y_diff /= 2;
t = (ED*)worker->distance_map;
s = source->buffer;
/* For now we only support pixel mode `FT_PIXEL_MODE_MONO' */
/* and `FT_PIXEL_MODE_GRAY'. More will be added later. */
/* [NOTE]: We can also use `FT_Bitmap_Convert' to convert */
/* bitmap to 8bpp. To avoid extra allocation and */
/* since the target bitmap can be 16bpp we manually */
/* convert the source bitmap to desired bpp. */
switch ( source->pixel_mode ) {
case FT_PIXEL_MODE_GRAY2:
case FT_PIXEL_MODE_GRAY4:
case FT_PIXEL_MODE_GRAY16:
case FT_PIXEL_MODE_LCD:
case FT_PIXEL_MODE_LCD_V:
case FT_PIXEL_MODE_MONO:
/* [TODO] */
FT_ERROR(( "[bsdf] bsdf_copy_source_to_target: "
"support for pixel mode not yet added\n" ));
error = FT_THROW( Unimplemented_Feature );
break;
case FT_PIXEL_MODE_GRAY:
{
FT_Int t_width = worker->width;
FT_Int t_rows = worker->rows;
FT_Int s_width = source->width;
FT_Int s_rows = source->rows;
/* loop through all the pixels and */
/* assign pixel values from source */
for ( t_j = 0; t_j < t_rows; t_j++ )
{
for ( t_i = 0; t_i < t_width; t_i++ )
{
FT_Int t_index = t_j * t_width + t_i;
FT_Int s_index;
FT_Int pixel_value;
t[t_index] = zero_ed;
s_i = t_i - x_diff;
s_j = t_j - y_diff;
/* Assign 0 to padding similar to */
/* the source bitmap. */
if ( s_i < 0 || s_i >= s_width ||
s_j < 0 || s_j >= s_rows )
{
t[t_index].sign = -1;
continue;
}
if ( worker->params.flip_y )
s_index = ( s_rows - s_j - 1 ) * s_width + s_i;
else
s_index = s_j * s_width + s_i;
pixel_value = (FT_Int)s[s_index];
/* clamp the pixel value to [0, 256] */
if ( pixel_value == 255 )
pixel_value = 256;
/* only assign values to the edge pixels */
if ( bsdf_is_edge( s + s_index , s_i, s_j, s_width, s_rows ) )
t[t_index].dist = 256 * pixel_value;
/* We assume that if the pixel is inside a contour */
/* then it's coverage value must be > 127. */
if ( pixel_value > 127 )
t[t_index].sign = 1;
else
t[t_index].sign = -1;
}
}
break;
}
default:
FT_ERROR(( "[bsdf] bsdf_copy_source_to_target: "
"unsopported pixel mode of source bitmap\n" ));
error = FT_THROW( Unimplemented_Feature );
break;
}
Exit:
return error;
}
/**************************************************************************
*
* @Function:
* compare_neighbor
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static void
compare_neighbor( ED* current,
FT_Int x_offset,
FT_Int y_offset,
FT_Int width )
{
ED* to_check;
FT_16D16 dist;
FT_16D16_Vec dist_vec;
to_check = current + ( y_offset * width ) + x_offset;
/* While checking for nearest point we first */
/* approximate the dist of the `current' point */
/* by adding the deviation ( which will be root */
/* 2 max ). And if the new value is lesser than */
/* the current value then only we calculate the */
/* actual distances using `FT_Vector_Length'. */
/* Of course this will be eliminated while using */
/* squared distances. */
/* approximate the distance */
dist = to_check->dist + ( FT_ABS( x_offset ) + FT_ABS( y_offset ) ) * ONE;
if ( dist < current->dist )
{
dist_vec = to_check->near;
dist_vec.x += x_offset * ONE;
dist_vec.y += y_offset * ONE;
dist = FT_Vector_Length( &dist_vec );
if ( dist < current->dist )
{
current->dist = dist;
current->near = dist_vec;
}
}
}
/**************************************************************************
*
* @Function:
* first_pass
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static void
first_pass( BSDF_Worker* worker )
{
FT_Int i, j; /* iterators */
FT_Int w, r; /* width, rows */
ED* dm; /* distance map */
dm = worker->distance_map;
w = worker->width;
r = worker->rows;
/* Start scanning from top to bottom and sweep each */
/* row back and forth comparing the distances of the */
/* neighborhood. Leave the first row as it has no top */
/* neighbor, it will be covered in the 2nd scan of */
/* the image, that is from bottom to top. */
for ( j = 1; j < r; j++ )
{
FT_Int index;
FT_16D16 dist;
FT_16D16_Vec dist_vec;
ED* to_check;
ED* current;
/* Forward pass of rows (left -> right), leave, the */
/* first column, will be covered in backward pass. */
for ( i = 1; i < w; i++ )
{
index = j * w + i;
current = dm + index;
/* left-up */
compare_neighbor( current, -1, -1, w );
/* up */
compare_neighbor( current, 0, -1, w );
/* up-right */
compare_neighbor( current, 1, -1, w );
/* left */
compare_neighbor( current, -1, 0, w );
}
/* Backward pass of rows (right -> left), leave, the */
/* last column, already covered in the forward pass. */
for ( i = w - 2; i >= 0; i-- )
{
index = j * w + i;
current = dm + index;
/* right */
compare_neighbor( current, 1, 0, w );
}
}
}
/**************************************************************************
*
* @Function:
* second_pass
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static void
second_pass( BSDF_Worker* worker )
{
FT_Int i, j; /* iterators */
FT_Int w, r; /* width, rows */
ED* dm; /* distance map */
dm = worker->distance_map;
w = worker->width;
r = worker->rows;
/* Start scanning from bottom to top and sweep each */
/* row back and forth comparing the distances of the */
/* neighborhood. Leave the last row as it has no down */
/* neighbor, it is already covered in the 1stscan of */
/* the image, that is from top to bottom. */
for ( j = r - 2; j >= 0; j-- )
{
FT_Int index;
FT_16D16 dist;
FT_16D16_Vec dist_vec;
ED* to_check;
ED* current;
/* Forward pass of rows (left -> right), leave, the */
/* first column, will be covered in backward pass. */
for ( i = 1; i < w; i++ )
{
index = j * w + i;
current = dm + index;
/* left-up */
compare_neighbor( current, -1, 1, w );
/* up */
compare_neighbor( current, 0, 1, w );
/* up-right */
compare_neighbor( current, 1, 1, w );
/* left */
compare_neighbor( current, -1, 0, w );
}
/* Backward pass of rows (right -> left), leave, the */
/* last column, already covered in the forward pass. */
for ( i = w - 2; i >= 0; i-- )
{
index = j * w + i;
current = dm + index;
/* right */
compare_neighbor( current, 1, 0, w );
}
}
}
/**************************************************************************
*
* @Function:
* edt8
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static FT_Error
edt8( BSDF_Worker* worker )
{
FT_Error error = FT_Err_Ok;
if ( !worker || !worker->distance_map )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* first scan of the image */
first_pass( worker );
/* second scan of the image */
second_pass( worker );
Exit:
return error;
}
/**************************************************************************
*
* @Function:
* finalize_sdf
*
* @Description:
* [TODO]
*
* @Input:
* [TODO]
*
* @Return:
* [TODO]
*/
static FT_Error
finalize_sdf( BSDF_Worker* worker,
FT_Bitmap* target )
{
FT_Error error = FT_Err_Ok;
FT_Int w, r;
FT_Int i, j;
FT_6D10* t_buffer;
if ( !worker || !target )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
w = target->width;
r = target->rows;
t_buffer = (FT_6D10*)target->buffer;
if ( w != worker->width ||
r != worker->rows )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
for ( j = 0; j < r; j++ )
{
for ( i = 0; i < w; i++ )
{
FT_Int index;
FT_16D16 dist;
FT_6D10 final_dist;
index = j * w + i;
dist = worker->distance_map[index].dist;
/* convert from 16.16 to 6.10 */
dist /= 64;
final_dist = (FT_6D10)(dist & 0x0000FFFF);
/* [TODO]: Assing the sign properly. */
if ( final_dist > worker->params.spread * 1024 )
final_dist = worker->params.spread * 1024;
t_buffer[index] = final_dist * worker->distance_map[index].sign;
}
}
Exit:
return error;
}
/**************************************************************************
*
* interface functions
*
*/
static FT_Error
bsdf_raster_new( FT_Memory memory,
FT_Raster* araster)
{
FT_Error error = FT_Err_Ok;
BSDF_TRaster* raster = NULL;
*araster = 0;
if ( !FT_ALLOC( raster, sizeof( BSDF_TRaster ) ) )
{
raster->memory = memory;
*araster = (FT_Raster)raster;
}
return error;
}
static void
bsdf_raster_reset( FT_Raster raster,
unsigned char* pool_base,
unsigned long pool_size )
{
/* no use of this function */
FT_UNUSED( raster );
FT_UNUSED( pool_base );
FT_UNUSED( pool_size );
}
static FT_Error
bsdf_raster_set_mode( FT_Raster raster,
unsigned long mode,
void* args )
{
FT_UNUSED( raster );
FT_UNUSED( mode );
FT_UNUSED( args );
return FT_Err_Ok;
}
static FT_Error
bsdf_raster_render( FT_Raster raster,
const FT_Raster_Params* params )
{
FT_Error error = FT_Err_Ok;
FT_Bitmap* source = NULL;
FT_Bitmap* target = NULL;
FT_Memory memory = NULL;
BSDF_TRaster* bsdf_raster = (BSDF_TRaster*)raster;
BSDF_Worker worker;
const SDF_Raster_Params* sdf_params = (const SDF_Raster_Params*)params;
FT_UNUSED( raster );
/* check for valid parameters */
if ( !raster || !params )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* check if the flag is set */
if ( sdf_params->root.flags != FT_RASTER_FLAG_SDF )
{
error = FT_THROW( Raster_Corrupted );
goto Exit;
}
source = sdf_params->root.source;
target = sdf_params->root.target;
/* check the source and target bitmap */
if ( !source || !target )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
memory = bsdf_raster->memory;
if ( !memory )
{
FT_TRACE0(( "[bsdf] bsdf_raster_render:\n"
" Raster not setup properly, "
"unable to find memory handle.\n" ));
error = FT_THROW( Invalid_Handle );
goto Exit;
}
/* check if spread is set properly */
if ( sdf_params->spread > MAX_SPREAD ||
sdf_params->spread < MIN_SPREAD )
{
FT_TRACE0((
"[bsdf] bsdf_raster_render:\n"
" The `spread' field of `SDF_Raster_Params' is invalid,\n"
" the value of this field must be within [%d, %d].\n"
" Also, you must pass `SDF_Raster_Params' instead of the\n"
" default `FT_Raster_Params' while calling this function\n"
" and set the fields properly.\n"
, MIN_SPREAD, MAX_SPREAD ));
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* setup the worker */
/* allocate the distance map */
if ( FT_QALLOC_MULT( worker.distance_map, target->rows,
target->width * sizeof( *worker.distance_map ) ) )
goto Exit;
worker.width = target->width;
worker.rows = target->rows;
worker.params = *sdf_params;
FT_CALL( bsdf_init_distance_map( source, &worker ) );
FT_CALL( bsdf_approximate_edge( &worker ) );
FT_CALL( edt8( &worker ) );
FT_CALL( finalize_sdf( &worker, target ) );
Exit:
return error;
}
static void
bsdf_raster_done( FT_Raster raster )
{
FT_Memory memory = (FT_Memory)((BSDF_TRaster*)raster)->memory;
FT_FREE( raster );
}
FT_DEFINE_RASTER_FUNCS(
ft_bitmap_sdf_raster,
FT_GLYPH_FORMAT_BITMAP,
(FT_Raster_New_Func) bsdf_raster_new, /* raster_new */
(FT_Raster_Reset_Func) bsdf_raster_reset, /* raster_reset */
(FT_Raster_Set_Mode_Func) bsdf_raster_set_mode, /* raster_set_mode */
(FT_Raster_Render_Func) bsdf_raster_render, /* raster_render */
(FT_Raster_Done_Func) bsdf_raster_done /* raster_done */
)
/* END */
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