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# Basic Data Types

## Synopsis

This section contains the basic data types defined by FreeType 2, ranging from simple scalar types to bitmap descriptors. More font-specific structures are defined in a different section.

## FT_Byte

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef unsigned char  FT_Byte;

A simple typedef for the unsigned char type.

## FT_Bytes

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef const FT_Byte*  FT_Bytes;

A typedef for constant memory areas.

## FT_Char

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed char  FT_Char;

A simple typedef for the signed char type.

## FT_Int

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed int  FT_Int;

A typedef for the int type.

## FT_UInt

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef unsigned int  FT_UInt;

A typedef for the unsigned int type.

## FT_Int16

Defined in FT_CONFIG_CONFIG_H (freetype/config/ftconfig.h).

      typedef signed short  FT_Int16;

A typedef for a 16bit signed integer type.

## FT_UInt16

Defined in FT_CONFIG_CONFIG_H (freetype/config/ftconfig.h).

      typedef unsigned short  FT_UInt16;

A typedef for a 16bit unsigned integer type.

## FT_Int32

Defined in FT_CONFIG_CONFIG_H (freetype/config/ftconfig.h).

      typedef signed XXX  FT_Int32;

A typedef for a 32bit signed integer type. The size depends on the configuration.

## FT_UInt32

Defined in FT_CONFIG_CONFIG_H (freetype/config/ftconfig.h).

      typedef unsigned XXX  FT_UInt32;

## FT_Int64

Defined in FT_CONFIG_CONFIG_H (freetype/config/ftconfig.h).

      typedef signed XXX  FT_Int64;

## FT_UInt64

Defined in FT_CONFIG_CONFIG_H (freetype/config/ftconfig.h).

      typedef unsigned XXX  FT_UInt64;

## FT_Short

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed short  FT_Short;

A typedef for signed short.

## FT_UShort

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef unsigned short  FT_UShort;

A typedef for unsigned short.

## FT_Long

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed long  FT_Long;

A typedef for signed long.

## FT_ULong

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef unsigned long  FT_ULong;

A typedef for unsigned long.

## FT_Bool

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef unsigned char  FT_Bool;

A typedef of unsigned char, used for simple booleans. As usual, values 1 and 0 represent true and false, respectively.

## FT_Offset

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef size_t  FT_Offset;

This is equivalent to the ANSI C `size_t` type, i.e., the largest unsigned integer type used to express a file size or position, or a memory block size.

## FT_PtrDist

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef ft_ptrdiff_t  FT_PtrDist;

This is equivalent to the ANSI C `ptrdiff_t` type, i.e., the largest signed integer type used to express the distance between two pointers.

## FT_String

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef char  FT_String;

A simple typedef for the char type, usually used for strings.

## FT_Tag

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef FT_UInt32  FT_Tag;

A typedef for 32-bit tags (as used in the SFNT format).

## FT_Error

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef int  FT_Error;

The FreeType error code type. A value of 0 is always interpreted as a successful operation.

## FT_Fixed

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed long  FT_Fixed;

This type is used to store 16.16 fixed-point values, like scaling values or matrix coefficients.

## FT_Pointer

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef void*  FT_Pointer;

A simple typedef for a typeless pointer.

## FT_Pos

Defined in FT_IMAGE_H (freetype/ftimage.h).

      typedef signed long  FT_Pos;

The type FT_Pos is used to store vectorial coordinates. Depending on the context, these can represent distances in integer font units, or 16.16, or 26.6 fixed-point pixel coordinates.

## FT_Vector

Defined in FT_IMAGE_H (freetype/ftimage.h).

      typedef struct  FT_Vector_
      {
        FT_Pos  x;
        FT_Pos  y;

      } FT_Vector;

A simple structure used to store a 2D vector; coordinates are of the FT_Pos type.

#### fields

x | The horizontal coordinate.
y | The vertical coordinate.

## FT_BBox

Defined in FT_IMAGE_H (freetype/ftimage.h).

      typedef struct  FT_BBox_
      {
        FT_Pos  xMin, yMin;
        FT_Pos  xMax, yMax;

      } FT_BBox;

A structure used to hold an outline's bounding box, i.e., the coordinates of its extrema in the horizontal and vertical directions.

#### fields

xMin | The horizontal minimum (left-most).
yMin | The vertical minimum (bottom-most).
xMax | The horizontal maximum (right-most).
yMax | The vertical maximum (top-most).

#### note

The bounding box is specified with the coordinates of the lower left and the upper right corner. In PostScript, those values are often called (llx,lly) and (urx,ury), respectively.

If `yMin` is negative, this value gives the glyph's descender. Otherwise, the glyph doesn't descend below the baseline. Similarly, if `ymax` is positive, this value gives the glyph's ascender.

`xMin` gives the horizontal distance from the glyph's origin to the left edge of the glyph's bounding box. If `xMin` is negative, the glyph extends to the left of the origin.

## FT_Matrix

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef struct  FT_Matrix_
      {
        FT_Fixed  xx, xy;
        FT_Fixed  yx, yy;

      } FT_Matrix;

A simple structure used to store a 2x2 matrix. Coefficients are in 16.16 fixed-point format. The computation performed is:

      x' = x*xx + y*xy
      y' = x*yx + y*yy

#### fields

xx | Matrix coefficient.
xy | Matrix coefficient.
yx | Matrix coefficient.
yy | Matrix coefficient.

## FT_FWord

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed short  FT_FWord;   /* distance in FUnits */

A signed 16-bit integer used to store a distance in original font units.

## FT_UFWord

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef unsigned short  FT_UFWord;  /* unsigned distance */

An unsigned 16-bit integer used to store a distance in original font units.

## FT_F2Dot14

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed short  FT_F2Dot14;

A signed 2.14 fixed-point type used for unit vectors.

## FT_UnitVector

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef struct  FT_UnitVector_
      {
        FT_F2Dot14  x;
        FT_F2Dot14  y;

      } FT_UnitVector;

A simple structure used to store a 2D vector unit vector. Uses FT_F2Dot14 types.

#### fields

x | Horizontal coordinate.
y | Vertical coordinate.

## FT_F26Dot6

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef signed long  FT_F26Dot6;

A signed 26.6 fixed-point type used for vectorial pixel coordinates.

## FT_Data

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef struct  FT_Data_
      {
        const FT_Byte*  pointer;
        FT_Int          length;

      } FT_Data;

Read-only binary data represented as a pointer and a length.

#### fields

pointer | The data.
length | The length of the data in bytes.

## FT_MAKE_TAG

Defined in FT_TYPES_H (freetype/fttypes.h).

    #define FT_MAKE_TAG( _x1, _x2, _x3, _x4 ) \
              (FT_Tag)                        \
              ( ( (FT_ULong)_x1 << 24 ) |     \
                ( (FT_ULong)_x2 << 16 ) |     \
                ( (FT_ULong)_x3 <<  8 ) |     \
                  (FT_ULong)_x4         )

This macro converts four-letter tags that are used to label TrueType tables into an unsigned long, to be used within FreeType.

#### note

The produced values must be 32-bit integers. Don't redefine this macro.

## FT_Generic

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef struct  FT_Generic_
      {
        void*                 data;
        FT_Generic_Finalizer  finalizer;

      } FT_Generic;

Client applications often need to associate their own data to a variety of FreeType core objects. For example, a text layout API might want to associate a glyph cache to a given size object.

Some FreeType object contains a `generic` field, of type `FT_Generic`, which usage is left to client applications and font servers.

It can be used to store a pointer to client-specific data, as well as the address of a ‘finalizer’ function, which will be called by FreeType when the object is destroyed (for example, the previous client example would put the address of the glyph cache destructor in the `finalizer` field).

#### fields

data | A typeless pointer to any client-specified data. This field is completely ignored by the FreeType library.
finalizer | A pointer to a ‘generic finalizer’ function, which will be called when the object is destroyed. If this field is set to `NULL`, no code will be called.

## FT_Generic_Finalizer

Defined in FT_TYPES_H (freetype/fttypes.h).

      typedef void  (*FT_Generic_Finalizer)( void*  object );

Describe a function used to destroy the ‘client’ data of any FreeType object. See the description of the `FT_Generic` type for details of usage.

#### input

The address of the FreeType object that is under finalization. Its client data is accessed through its `generic` field.

## FT_Bitmap

Defined in FT_IMAGE_H (freetype/ftimage.h).

      typedef struct  FT_Bitmap_
      {
        unsigned int    rows;
        unsigned int    width;
        int             pitch;
        unsigned char*  buffer;
        unsigned short  num_grays;
        unsigned char   pixel_mode;
        unsigned char   palette_mode;
        void*           palette;

      } FT_Bitmap;

A structure used to describe a bitmap or pixmap to the raster. Note that we now manage pixmaps of various depths through the `pixel_mode` field.

#### fields

rows | The number of bitmap rows.
width | The number of pixels in bitmap row.

pitch

The pitch's absolute value is the number of bytes taken by one bitmap row, including padding. However, the pitch is positive when the bitmap has a ‘down’ flow, and negative when it has an ‘up’ flow. In all cases, the pitch is an offset to add to a bitmap pointer in order to go down one row.

Note that ‘padding’ means the alignment of a bitmap to a byte border, and FreeType functions normally align to the smallest possible integer value.

For the B/W rasterizer, `pitch` is always an even number.

To change the pitch of a bitmap (say, to make it a multiple of 4), use `FT_Bitmap_Convert`. Alternatively, you might use callback functions to directly render to the application's surface; see the file `example2.cpp` in the tutorial for a demonstration.

buffer | A typeless pointer to the bitmap buffer. This value should be aligned on 32-bit boundaries in most cases.
num_grays | This field is only used with `FT_PIXEL_MODE_GRAY`; it gives the number of gray levels used in the bitmap.
pixel_mode | The pixel mode, i.e., how pixel bits are stored. See `FT_Pixel_Mode` for possible values.
palette_mode | This field is intended for paletted pixel modes; it indicates how the palette is stored. Not used currently.
palette | A typeless pointer to the bitmap palette; this field is intended for paletted pixel modes. Not used currently.

## FT_Pixel_Mode

Defined in FT_IMAGE_H (freetype/ftimage.h).

      typedef enum  FT_Pixel_Mode_
      {
        FT_PIXEL_MODE_NONE = 0,
        FT_PIXEL_MODE_MONO,
        FT_PIXEL_MODE_GRAY,
        FT_PIXEL_MODE_GRAY2,
        FT_PIXEL_MODE_GRAY4,
        FT_PIXEL_MODE_LCD,
        FT_PIXEL_MODE_LCD_V,
        FT_PIXEL_MODE_BGRA,

        FT_PIXEL_MODE_MAX      /* do not remove */

      } FT_Pixel_Mode;

      /* these constants are deprecated; use the corresponding `FT_Pixel_Mode` */
      /* values instead.                                                       */
    #define ft_pixel_mode_none   FT_PIXEL_MODE_NONE
    #define ft_pixel_mode_mono   FT_PIXEL_MODE_MONO
    #define ft_pixel_mode_grays  FT_PIXEL_MODE_GRAY
    #define ft_pixel_mode_pal2   FT_PIXEL_MODE_GRAY2
    #define ft_pixel_mode_pal4   FT_PIXEL_MODE_GRAY4

An enumeration type used to describe the format of pixels in a given bitmap. Note that additional formats may be added in the future.

#### values

FT_PIXEL_MODE_NONE | Value 0 is reserved.
FT_PIXEL_MODE_MONO | A monochrome bitmap, using 1 bit per pixel. Note that pixels are stored in most-significant order (MSB), which means that the left-most pixel in a byte has value 128.
FT_PIXEL_MODE_GRAY | An 8-bit bitmap, generally used to represent anti-aliased glyph images. Each pixel is stored in one byte. Note that the number of ‘gray’ levels is stored in the `num_grays` field of the `FT_Bitmap` structure (it generally is 256).
FT_PIXEL_MODE_GRAY2 | A 2-bit per pixel bitmap, used to represent embedded anti-aliased bitmaps in font files according to the OpenType specification. We haven't found a single font using this format, however.
FT_PIXEL_MODE_GRAY4 | A 4-bit per pixel bitmap, representing embedded anti-aliased bitmaps in font files according to the OpenType specification. We haven't found a single font using this format, however.
FT_PIXEL_MODE_LCD | An 8-bit bitmap, representing RGB or BGR decimated glyph images used for display on LCD displays; the bitmap is three times wider than the original glyph image. See also `FT_RENDER_MODE_LCD`.
FT_PIXEL_MODE_LCD_V | An 8-bit bitmap, representing RGB or BGR decimated glyph images used for display on rotated LCD displays; the bitmap is three times taller than the original glyph image. See also `FT_RENDER_MODE_LCD_V`.

FT_PIXEL_MODE_BGRA

[Since 2.5] An image with four 8-bit channels per pixel, representing a color image (such as emoticons) with alpha channel. For each pixel, the format is BGRA, which means, the blue channel comes first in memory. The color channels are pre-multiplied and in the sRGB colorspace. For example, full red at half-translucent opacity will be represented as ‘00,00,80,80’, not ‘00,00,FF,80’. See also `FT_LOAD_COLOR`.

## FT_Glyph_Format

Defined in FT_IMAGE_H (freetype/ftimage.h).

      typedef enum  FT_Glyph_Format_
      {
        FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ),

        FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
        FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP,    'b', 'i', 't', 's' ),
        FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE,   'o', 'u', 't', 'l' ),
        FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER,   'p', 'l', 'o', 't' )

      } FT_Glyph_Format;

      /* these constants are deprecated; use the corresponding */
      /* `FT_Glyph_Format` values instead.                     */
    #define ft_glyph_format_none       FT_GLYPH_FORMAT_NONE
    #define ft_glyph_format_composite  FT_GLYPH_FORMAT_COMPOSITE
    #define ft_glyph_format_bitmap     FT_GLYPH_FORMAT_BITMAP
    #define ft_glyph_format_outline    FT_GLYPH_FORMAT_OUTLINE
    #define ft_glyph_format_plotter    FT_GLYPH_FORMAT_PLOTTER

An enumeration type used to describe the format of a given glyph image. Note that this version of FreeType only supports two image formats, even though future font drivers will be able to register their own format.

#### values

FT_GLYPH_FORMAT_NONE | The value 0 is reserved.
FT_GLYPH_FORMAT_COMPOSITE | The glyph image is a composite of several other images. This format is only used with `FT_LOAD_NO_RECURSE`, and is used to report compound glyphs (like accented characters).
FT_GLYPH_FORMAT_BITMAP | The glyph image is a bitmap, and can be described as an `FT_Bitmap`. You generally need to access the `bitmap` field of the `FT_GlyphSlotRec` structure to read it.
FT_GLYPH_FORMAT_OUTLINE | The glyph image is a vectorial outline made of line segments and Bezier arcs; it can be described as an `FT_Outline`; you generally want to access the `outline` field of the `FT_GlyphSlotRec` structure to read it.
FT_GLYPH_FORMAT_PLOTTER | The glyph image is a vectorial path with no inside and outside contours. Some Type 1 fonts, like those in the Hershey family, contain glyphs in this format. These are described as `FT_Outline`, but FreeType isn't currently capable of rendering them correctly.

## FT_IMAGE_TAG

Defined in FT_IMAGE_H (freetype/ftimage.h).

    #ifndef FT_IMAGE_TAG
    #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 )  \
              value = ( ( (unsigned long)_x1 << 24 ) | \
                        ( (unsigned long)_x2 << 16 ) | \
                        ( (unsigned long)_x3 << 8  ) | \
                          (unsigned long)_x4         )
    #endif /* FT_IMAGE_TAG */

This macro converts four-letter tags to an unsigned long type.

#### note

Since many 16-bit compilers don't like 32-bit enumerations, you should redefine this macro in case of problems to something like this:

      #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 )  value

to get a simple enumeration without assigning special numbers.