FreeType Fonts and Rendering

FreeType Fonts and Rendering — Functions for shape engines to manipulate FreeType fonts

Synopsis

                    PangoFT2FontMap;
#define             PANGO_RENDER_TYPE_FT2
PangoFontMap*       pango_ft2_font_map_new              (void);
void                pango_ft2_font_map_set_resolution   (PangoFT2FontMap *fontmap,
                                                         double dpi_x,
                                                         double dpi_y);
PangoContext*       pango_ft2_font_map_create_context   (PangoFT2FontMap *fontmap);
void                (*PangoFT2SubstituteFunc)           (FcPattern *pattern,
                                                         gpointer data);
void                pango_ft2_font_map_set_default_substitute
                                                        (PangoFT2FontMap *fontmap,
                                                         PangoFT2SubstituteFunc func,
                                                         gpointer data,
                                                         GDestroyNotify notify);
void                pango_ft2_font_map_substitute_changed
                                                        (PangoFT2FontMap *fontmap);
PangoContext*       pango_ft2_get_context               (double dpi_x,
                                                         double dpi_y);
void                pango_ft2_render                    (FT_Bitmap *bitmap,
                                                         PangoFont *font,
                                                         PangoGlyphString *glyphs,
                                                         gint x,
                                                         gint y);
void                pango_ft2_render_transformed        (FT_Bitmap *bitmap,
                                                         const PangoMatrix *matrix,
                                                         PangoFont *font,
                                                         PangoGlyphString *glyphs,
                                                         int x,
                                                         int y);
void                pango_ft2_render_layout_line        (FT_Bitmap *bitmap,
                                                         PangoLayoutLine *line,
                                                         int x,
                                                         int y);
void                pango_ft2_render_layout_line_subpixel
                                                        (FT_Bitmap *bitmap,
                                                         PangoLayoutLine *line,
                                                         int x,
                                                         int y);
void                pango_ft2_render_layout             (FT_Bitmap *bitmap,
                                                         PangoLayout *layout,
                                                         int x,
                                                         int y);
void                pango_ft2_render_layout_subpixel    (FT_Bitmap *bitmap,
                                                         PangoLayout *layout,
                                                         int x,
                                                         int y);
PangoGlyph          pango_ft2_get_unknown_glyph         (PangoFont *font);
int                 pango_ft2_font_get_kerning          (PangoFont *font,
                                                         PangoGlyph left,
                                                         PangoGlyph right);
FT_Face             pango_ft2_font_get_face             (PangoFont *font);
PangoCoverage*      pango_ft2_font_get_coverage         (PangoFont *font,
                                                         PangoLanguage *language);
PangoFontMap*       pango_ft2_font_map_for_display      (void);
void                pango_ft2_shutdown_display          (void);

Object Hierarchy

  GObject
   +----PangoFontMap
         +----PangoFcFontMap
               +----PangoFT2FontMap

Description

The macros and functions in this section are used to access fonts and render text to bitmaps using the FreeType 2 library.

Details

PangoFT2FontMap

typedef struct _PangoFT2FontMap PangoFT2FontMap;

The PangoFT2FontMap is the PangoFontMap implementation for FreeType fonts.


PANGO_RENDER_TYPE_FT2

#define PANGO_RENDER_TYPE_FT2 "PangoRenderFT2"

Warning

PANGO_RENDER_TYPE_FT2 is deprecated and should not be used in newly-written code.

A string constant that was used to identify shape engines that work with the FreeType backend. See PANGO_RENDER_TYPE_FC for the replacement.


pango_ft2_font_map_new ()

PangoFontMap*       pango_ft2_font_map_new              (void);

Create a new PangoFT2FontMap object; a fontmap is used to cache information about available fonts, and holds certain global parameters such as the resolution and the default substitute function (see pango_ft2_font_map_set_default_substitute()).

Returns :

the newly created fontmap object. Unref with g_object_unref() when you are finished with it.

Since 1.2


pango_ft2_font_map_set_resolution ()

void                pango_ft2_font_map_set_resolution   (PangoFT2FontMap *fontmap,
                                                         double dpi_x,
                                                         double dpi_y);

Sets the horizontal and vertical resolutions for the fontmap.

fontmap :

a PangoFT2Fontmap

dpi_x :

dots per inch in the X direction

dpi_y :

dots per inch in the Y direction

Since 1.2


pango_ft2_font_map_create_context ()

PangoContext*       pango_ft2_font_map_create_context   (PangoFT2FontMap *fontmap);

Create a PangoContext for the given fontmap.

fontmap :

a PangoFT2Fontmap

Returns :

the newly created context; free with g_object_unref().

Since 1.2


PangoFT2SubstituteFunc ()

void                (*PangoFT2SubstituteFunc)           (FcPattern *pattern,
                                                         gpointer data);

Function type for doing final config tweaking on prepared FcPatterns.

pattern :

the FcPattern to tweak.

data :

user data.

pango_ft2_font_map_set_default_substitute ()

void                pango_ft2_font_map_set_default_substitute
                                                        (PangoFT2FontMap *fontmap,
                                                         PangoFT2SubstituteFunc func,
                                                         gpointer data,
                                                         GDestroyNotify notify);

Sets a function that will be called to do final configuration substitution on a FcPattern before it is used to load the font. This function can be used to do things like set hinting and antialiasing options.

fontmap :

a PangoFT2FontMap

func :

function to call to to do final config tweaking on FcPattern objects.

data :

data to pass to func

notify :

function to call when data is no longer used.

Since 1.2


pango_ft2_font_map_substitute_changed ()

void                pango_ft2_font_map_substitute_changed
                                                        (PangoFT2FontMap *fontmap);

Call this function any time the results of the default substitution function set with pango_ft2_font_map_set_default_substitute() change. That is, if your substitution function will return different results for the same input pattern, you must call this function.

fontmap :

a PangoFT2Fontmap

Since 1.2


pango_ft2_get_context ()

PangoContext*       pango_ft2_get_context               (double dpi_x,
                                                         double dpi_y);

Warning

pango_ft2_get_context is deprecated and should not be used in newly-written code.

Retrieves a PangoContext for the default PangoFT2 fontmap (see pango_ft2_fontmap_get_for_display()) and sets the resolution for the default fontmap to dpi_x by dpi_y.

Use of this function is deprecated; see pango_ft2_fontmap_create_context() instead.

dpi_x :

the horizontal DPI of the target device

dpi_y :

the vertical DPI of the target device

Returns :

the new PangoContext

pango_ft2_render ()

void                pango_ft2_render                    (FT_Bitmap *bitmap,
                                                         PangoFont *font,
                                                         PangoGlyphString *glyphs,
                                                         gint x,
                                                         gint y);

Renders a PangoGlyphString onto a FreeType2 bitmap.

bitmap :

the FreeType2 bitmap onto which to draw the string

font :

the font in which to draw the string

glyphs :

the glyph string to draw

x :

the x position of the start of the string (in pixels)

y :

the y position of the baseline (in pixels)

pango_ft2_render_transformed ()

void                pango_ft2_render_transformed        (FT_Bitmap *bitmap,
                                                         const PangoMatrix *matrix,
                                                         PangoFont *font,
                                                         PangoGlyphString *glyphs,
                                                         int x,
                                                         int y);

Renders a PangoGlyphString onto a FreeType2 bitmap, possibly transforming the layed-out coordinates through a transformation matrix. Note that the transformation matrix for font is not changed, so to produce correct rendering results, the font must have been loaded using a PangoContext with an identical transformation matrix to that passed in to this function.

bitmap :

the FreeType2 bitmap onto which to draw the string

matrix :

a PangoMatrix, or NULL to use an identity transformation

font :

the font in which to draw the string

glyphs :

the glyph string to draw

x :

the x position of the start of the string (in Pango units in user space coordinates)

y :

the y position of the baseline (in Pango units in user space coordinates)

Since 1.6


pango_ft2_render_layout_line ()

void                pango_ft2_render_layout_line        (FT_Bitmap *bitmap,
                                                         PangoLayoutLine *line,
                                                         int x,
                                                         int y);

Render a PangoLayoutLine onto a FreeType2 bitmap

bitmap :

a FT_Bitmap to render the line onto

line :

a PangoLayoutLine

x :

the x position of start of string (in pixels)

y :

the y position of baseline (in pixels)

pango_ft2_render_layout_line_subpixel ()

void                pango_ft2_render_layout_line_subpixel
                                                        (FT_Bitmap *bitmap,
                                                         PangoLayoutLine *line,
                                                         int x,
                                                         int y);

Render a PangoLayoutLine onto a FreeType2 bitmap, with he location specified in fixed-point Pango units rather than pixels. (Using this will avoid extra inaccuracies from rounding to integer pixels multiple times, even if the final glyph positions are integers.)

bitmap :

a FT_Bitmap to render the line onto

line :

a PangoLayoutLine

x :

the x position of start of string (in Pango units)

y :

the y position of baseline (in Pango units)

Since 1.6


pango_ft2_render_layout ()

void                pango_ft2_render_layout             (FT_Bitmap *bitmap,
                                                         PangoLayout *layout,
                                                         int x,
                                                         int y);

Render a PangoLayout onto a FreeType2 bitmap

bitmap :

a FT_Bitmap to render the layout onto

layout :

a PangoLayout

x :

the X position of the left of the layout (in pixels)

y :

the Y position of the top of the layout (in pixels)

pango_ft2_render_layout_subpixel ()

void                pango_ft2_render_layout_subpixel    (FT_Bitmap *bitmap,
                                                         PangoLayout *layout,
                                                         int x,
                                                         int y);

Render a PangoLayout onto a FreeType2 bitmap, with he location specified in fixed-point Pango units rather than pixels. (Using this will avoid extra inaccuracies from rounding to integer pixels multiple times, even if the final glyph positions are integers.)

bitmap :

a FT_Bitmap to render the layout onto

layout :

a PangoLayout

x :

the X position of the left of the layout (in Pango units)

y :

the Y position of the top of the layout (in Pango units)

Since 1.6


pango_ft2_get_unknown_glyph ()

PangoGlyph          pango_ft2_get_unknown_glyph         (PangoFont *font);

Warning

pango_ft2_get_unknown_glyph is deprecated and should not be used in newly-written code.

Return the index of a glyph suitable for drawing unknown characters with font, or PANGO_GLYPH_EMPTY if no suitable glyph found.

If you want to draw an unknown-box for a character that is not covered by the font, use PANGO_GET_UNKNOWN_GLYPH() instead.

font :

a PangoFont

Returns :

a glyph index into font, or PANGO_GLYPH_EMPTY

pango_ft2_font_get_kerning ()

int                 pango_ft2_font_get_kerning          (PangoFont *font,
                                                         PangoGlyph left,
                                                         PangoGlyph right);

Warning

pango_ft2_font_get_kerning is deprecated and should not be used in newly-written code.

Retrieves kerning information for a combination of two glyphs.

Use pango_fc_font_kern_glyphs() instead.

font :

a PangoFont

left :

the left PangoGlyph

right :

the right PangoGlyph

Returns :

The amount of kerning (in Pango units) to apply for the given combination of glyphs.

pango_ft2_font_get_face ()

FT_Face             pango_ft2_font_get_face             (PangoFont *font);

Warning

pango_ft2_font_get_face is deprecated and should not be used in newly-written code.

Returns the native FreeType2 FT_Face structure used for this PangoFont. This may be useful if you want to use FreeType2 functions directly.

Use pango_fc_font_lock_face() instead; when you are done with a face from pango_fc_font_lock_face() you must call pango_fc_font_unlock_face().

font :

a PangoFont

Returns :

a pointer to a FT_Face structure, with the size set correctly, or NULL if font is NULL.

pango_ft2_font_get_coverage ()

PangoCoverage*      pango_ft2_font_get_coverage         (PangoFont *font,
                                                         PangoLanguage *language);

Warning

pango_ft2_font_get_coverage is deprecated and should not be used in newly-written code.

Gets the PangoCoverage for a PangoFT2Font. Use pango_font_get_coverage() instead.

font :

a PangoFT2Font.

language :

a language tag.

Returns :

a PangoCoverage.

pango_ft2_font_map_for_display ()

PangoFontMap*       pango_ft2_font_map_for_display      (void);

Warning

pango_ft2_font_map_for_display is deprecated and should not be used in newly-written code.

Returns a PangoFT2FontMap. This font map is cached and should not be freed. If the font map is no longer needed, it can be released with pango_ft2_shutdown_display(). Use of the global PangoFT2 fontmap is deprecated; use pango_ft2_font_map_new() instead.

Returns :

a PangoFT2FontMap.

pango_ft2_shutdown_display ()

void                pango_ft2_shutdown_display          (void);

Warning

pango_ft2_shutdown_display is deprecated and should not be used in newly-written code.

Free the global fontmap. (See pango_ft2_font_map_for_display()) Use of the global PangoFT2 fontmap is deprecated.