Pango Reference Manual |
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Xft Fonts and RenderingXft Fonts and Rendering — Font handling and rendering with the Xft backend |
PangoXftFont; PangoXftFontMap; #define PANGO_RENDER_TYPE_XFT PangoContext* pango_xft_get_context (Display *display, int screen); PangoFontMap* pango_xft_get_font_map (Display *display, int screen); void pango_xft_set_default_substitute (Display *display, int screen, PangoXftSubstituteFunc func, gpointer data, GDestroyNotify notify); void (*PangoXftSubstituteFunc) (FcPattern *pattern, gpointer data); void pango_xft_substitute_changed (Display *display, int screen); void pango_xft_shutdown_display (Display *display, int screen); XftFont* pango_xft_font_get_font (PangoFont *font); Display* pango_xft_font_get_display (PangoFont *font); gboolean pango_xft_font_has_char (PangoFont *font, gunichar wc); FT_Face pango_xft_font_lock_face (PangoFont *font); void pango_xft_font_unlock_face (PangoFont *font); guint pango_xft_font_get_glyph (PangoFont *font, gunichar wc); PangoGlyph pango_xft_font_get_unknown_glyph (PangoFont *font, gunichar wc); PangoXftRenderer; PangoXftRendererClass; PangoRenderer* pango_xft_renderer_new (Display *display, int screen); void pango_xft_renderer_set_draw (PangoXftRenderer *xftrenderer, XftDraw *draw); void pango_xft_renderer_set_default_color (PangoXftRenderer *xftrenderer, PangoColor *default_color); void pango_xft_render (XftDraw *draw, XftColor *color, PangoFont *font, PangoGlyphString *glyphs, gint x, gint y); void pango_xft_picture_render (Display *display, Picture src_picture, Picture dest_picture, PangoFont *font, PangoGlyphString *glyphs, gint x, gint y); void pango_xft_render_transformed (XftDraw *draw, XftColor *color, PangoMatrix *matrix, PangoFont *font, PangoGlyphString *glyphs, int x, int y); void pango_xft_render_layout_line (XftDraw *draw, XftColor *color, PangoLayoutLine *line, int x, int y); void pango_xft_render_layout (XftDraw *draw, XftColor *color, PangoLayout *layout, int x, int y);
The Xft library is a library for displaying fonts on the X window system; internally it uses the fontconfig library to locate font files, and the FreeType library to load and render fonts. The Xft backend is the recommended Pango font backend for screen display with X.
Using the Xft backend is generally straightforward; pango_xft_get_context() creates a context for a specified display and screen. You can then create a PangoLayout with that context and render it with pango_xft_render_layout(). At a more advanced level, the lowlevel fontconfig options used for rendering fonts can be affected using pango_xft_set_default_substitute(), and pango_xft_substitute_changed().
A range of functions for drawing pieces of a layout, such as individual layout lines and glyphs strings are provided. You can also directly create a PangoXftRenderer. Finally, in some advanced cases, it is useful to derive from PangoXftRenderer. Deriving from PangoXftRenderer is useful for two reasons. One reason is be to support custom attributes by overriding PangoRendererClass virtual functions like 'prepare_run' or 'draw_shape'. The reason is to customize exactly how the final bits are drawn to the destination by overring the PangoXftRendererClass virtual functions 'composite_glyphs' and 'composite_trapezoids'.
#define PANGO_RENDER_TYPE_XFT "PangoRenderXft"
PANGO_RENDER_TYPE_XFT 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 Xft backend. See PANGO_RENDER_TYPE_FC for the replacement.
PangoContext* pango_xft_get_context (Display *display, int screen);
Retrieves a PangoContext appropriate for rendering with Xft fonts on the given screen of the given display.
display : | an X display. |
screen : | an X screen. |
Returns : | the new PangoContext. |
PangoFontMap* pango_xft_get_font_map (Display *display, int screen);
Returns the PangoXftFontmap for the given display and screen. The fontmap is owned by Pango and will be valid until the display is closed.
display : | an X display |
screen : | the screen number of a screen within display |
Returns : | a PangoFontMap object, owned by Pango. |
Since 1.2
void pango_xft_set_default_substitute (Display *display, int screen, PangoXftSubstituteFunc 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.
display : | an X Display |
screen : | the screen number of a screen within display |
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
void (*PangoXftSubstituteFunc) (FcPattern *pattern, gpointer data);
Function type for doing final config tweaking on prepared FcPatterns.
pattern : | the FcPattern to tweak. |
data : | user data. |
void pango_xft_substitute_changed (Display *display, int screen);
Call this function any time the results of the default substitution function set with pango_xft_set_default_substitute() change. That is, if your subsitution function will return different results for the same input pattern, you must call this function.
display : | an X Display |
screen : | the screen number of a screen within display |
Since 1.2
void pango_xft_shutdown_display (Display *display, int screen);
Release any resources that have been cached for the combination of display and screen. Note that when the X display is closed, resources are released automatically, without needing to call this function.
display : | an X display |
screen : | the screen number of a screen within display |
Since 1.2
XftFont* pango_xft_font_get_font (PangoFont *font);
Returns the XftFont of a font.
font : | a PangoFont. |
Returns : | the XftFont associated to font. |
Display* pango_xft_font_get_display (PangoFont *font);
Returns the X display of the XftFont of a font.
font : | a PangoFont. |
Returns : | the X display of the XftFont associated to font. |
gboolean pango_xft_font_has_char (PangoFont *font, gunichar wc);
pango_xft_font_has_char is deprecated and should not be used in newly-written code.
Determines whether font has a glyph for the codepoint wc.
Use pango_fc_font_has_char() instead.
font : | a PangoFont for the Xft backend |
wc : | Unicode codepoint to look up |
Returns : | TRUE if font has the requested codepoint. |
Since 1.2
FT_Face pango_xft_font_lock_face (PangoFont *font);
pango_xft_font_lock_face is deprecated and should not be used in newly-written code.
Gets the FreeType FT_Face associated with a font, This face will be kept around until you call pango_xft_font_unlock_face().
Use pango_fc_font_lock_face() instead.
font : | a PangoFont. |
Returns : | the FreeType FT_Face associated with font. |
Since 1.2
void pango_xft_font_unlock_face (PangoFont *font);
pango_xft_font_unlock_face is deprecated and should not be used in newly-written code.
Releases a font previously obtained with pango_xft_font_lock_face().
Use pango_fc_font_unlock_face() instead.
font : | a PangoFont. |
Since 1.2
guint pango_xft_font_get_glyph (PangoFont *font, gunichar wc);
pango_xft_font_get_glyph is deprecated and should not be used in newly-written code.
Gets the glyph index for a given unicode codepoint for font. If you only want to determine whether the font has the glyph, use pango_xft_font_has_char().
Use pango_fc_font_get_glyph() instead.
font : | a PangoFont for the Xft backend |
wc : | Unicode codepoint to look up |
Returns : | the glyph index, or 0, if the unicode codepoint doesn't exist in the font. |
Since 1.2
PangoGlyph pango_xft_font_get_unknown_glyph (PangoFont *font, gunichar wc);
pango_xft_font_get_unknown_glyph is deprecated and should not be used in newly-written code.
Returns the index of a glyph suitable for drawing wc as an unknown character.
Use pango_fc_font_get_unknown_glyph() instead.
font : | a PangoFont. |
wc : | the Unicode character for which a glyph is needed. |
Returns : | a glyph index into font. |
typedef struct { } PangoXftRenderer;
PangoXftRenderer is a subclass of PangoRenderer used for rendering with Pango's Xft backend. It can be used directly, or it can be further subclassed to modify exactly how drawing of individual elements occurs.
Since 1.8
typedef struct { void (*composite_trapezoids) (PangoXftRenderer *xftrenderer, PangoRenderPart part, XTrapezoid *trapezoids, int n_trapezoids); void (*composite_glyphs) (PangoXftRenderer *xftrenderer, XftFont *xft_font, XftGlyphSpec *glyphs, int n_glyphs); } PangoXftRendererClass;
The class structure for PangoXftRenderer
composite_trapezoids () | draw the specified trapezoids using the current color and other attributes for part |
composite_glyphs () | draw the specified glyphs using the current foreground color and other foreground attributes |
Since 1.8
PangoRenderer* pango_xft_renderer_new (Display *display, int screen);
Create a new PangoXftRenderer to allow rendering Pango objects with the Xft library. You must call pango_xft_renderer_set_draw() before using the renderer.
display : | an X display |
screen : | the index of the screen for display to which rendering will be done |
Returns : | the newly created PangoXftRenderer object. Unref with g_object_unref() when you are finished with it. |
Since 1.8
void pango_xft_renderer_set_draw (PangoXftRenderer *xftrenderer, XftDraw *draw);
Sets the XftDraw object that the renderer is drawing to. The renderer must not be currently active.
xftrenderer : | a PangoXftRenderer |
draw : | a XftDraw |
Since 1.8
void pango_xft_renderer_set_default_color (PangoXftRenderer *xftrenderer, PangoColor *default_color);
Sets the default foreground color for a XftRenderer.
xftrenderer : | a XftRenderer |
default_color : | the default foreground color |
Since 1.8
void pango_xft_render (XftDraw *draw, XftColor *color, PangoFont *font, PangoGlyphString *glyphs, gint x, gint y);
Renders a PangoGlyphString onto an XftDraw object wrapping an X drawable.
draw : | the XftDraw object. |
color : | the color in 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 start of string (in pixels) |
y : | the y position of baseline (in pixels) |
void pango_xft_picture_render (Display *display, Picture src_picture, Picture dest_picture, PangoFont *font, PangoGlyphString *glyphs, gint x, gint y);
Renders a PangoGlyphString onto an Xrender Picture object.
display : | an X display |
src_picture : | the source picture to draw the string with |
dest_picture : | the destination picture to draw the strign onto |
font : | the font in which to draw the string |
glyphs : | the glyph string to draw |
x : | the x position of start of string (in pixels) |
y : | the y position of baseline (in pixels) |
void pango_xft_render_transformed (XftDraw *draw, XftColor *color, PangoMatrix *matrix, PangoFont *font, PangoGlyphString *glyphs, int x, int y);
Renders a PangoGlyphString onto a XftDraw, 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.
draw : | an XftDraw |
color : | the color in which to draw the glyphs |
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 1.8
void pango_xft_render_layout_line (XftDraw *draw, XftColor *color, PangoLayoutLine *line, int x, int y);
Render a PangoLayoutLine onto a XftDraw
draw : | an XftDraw |
color : | the foreground color in which to draw the layout line (may be overriden by color attributes) |
line : | a PangoLayoutLine |
x : | the x position of start of string (in pango units) |
y : | the y position of baseline (in pango units) |
Since 1.8
void pango_xft_render_layout (XftDraw *draw, XftColor *color, PangoLayout *layout, int x, int y);
Render a PangoLayout onto a XftDraw
draw : | an XftDraw |
color : | the foreground color in which to draw the layout (may be overriden by color attributes) |
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 1.8
<< FreeType Fonts and Rendering | Deprecated X font backend >> |