ref: 9bbb3611b35b5619cca9b1eba5b6297597beccfa
dir: /src/sdf/ftbsdf.c/
#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"
#include "ftsdfcommon.h"
/**************************************************************************
*
* useful macros
*
*/
#define ONE 65536 /* 1 in 16.16 */
/**************************************************************************
*
* structs
*
*/
/**************************************************************************
*
* @Struct:
* BSDF_TRaster
*
* @Description:
* This struct is used in place of @FT_Raster and is stored within the
* internal FreeType renderer struct. While rasterizing this is passed
* to the @FT_Raster_RenderFunc function, which then can be used however
* we want.
*
* @Fields:
* memory ::
* Used internally to allocate intermediate memory while raterizing.
*
*/
typedef struct BSDF_TRaster_
{
FT_Memory memory;
} BSDF_TRaster;
/**************************************************************************
*
* @Struct:
* ED
*
* @Description:
* Euclidean distance. It gets used for Euclidean distance transforms;
* it can also be interpreted as an edge distance.
*
* @Fields:
* dist ::
* Vector length of the `near` parameter. Can be squared or absolute
* depending on the `USE_SQUARED_DISTANCES` macro defined in file
* `ftsdfcommon.h`.
*
* near ::
* Vector to the nearest edge. Can also be interpreted as shortest
* distance of a point.
*
* alpha ::
* Alpha value of the original bitmap from which we generate SDF.
* Needed for computing the gradient and determining the proper sign
* of a pixel.
*
*/
typedef struct ED_
{
FT_16D16 dist;
FT_16D16_Vec near;
FT_Byte alpha;
} ED;
/**************************************************************************
*
* @Struct:
* BSDF_Worker
*
* @Description:
* A convenience struct that is passed to functions while generating
* SDF; most of those functions require the same parameters.
*
* @Fields:
* distance_map ::
* A one-dimensional array that gets interpreted as two-dimensional
* one. It contains the Euclidean distances of all points of the
* bitmap.
*
* width ::
* Width of the above `distance_map`.
*
* rows ::
* Number of rows in the above `distance_map`.
*
* params ::
* Internal parameters and properties required by the rasterizer. See
* file `ftsdf.h` for more.
*
*/
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 };
/* END */