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[bpt/emacs.git] / src / font.h

/* font.h -- Interface definition for font handling.
   Copyright (C) 2006 Free Software Foundation, Inc.
   Copyright (C) 2006
     National Institute of Advanced Industrial Science and Technology (AIST)
     Registration Number H13PRO009

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

#ifndef EMACS_FONT_H
#define EMACS_FONT_H

#include "ccl.h"

/* We have three types of Lisp objects related to font.

   FONT-SPEC

	Vector (length FONT_SPEC_MAX) of font properties.  Some
	properties can be left unspecified (i.e. nil).  Emacs asks
	font-drivers to find a font by FONT-SPEC.  A fontset entry
	specifies requisite properties whereas a face specifies just
	preferable properties.  This object is fully modifiable by
	Lisp.

   FONT-ENTITY

	Vector (length FONT_ENTITY_MAX) of fully specified font
	properties that a font-driver returns upon a request of
	FONT-SPEC.

	Note: Only the method `list' of a font-driver can create this
	object, and should never be modified by Lisp.  In that sense,
	it may be cleaner to implement it as a Lisp object of a new
	type (e.g. struct Lisp_Font).

   FONT-OBJECT

	Lisp object of type Lisp_Misc_Save_Value encapsulating a
	pointer to "struct font".  This corresponds to an opened font.

	Note: The note for FONT-ENTITY also applies to this.
*/


struct font_driver;
struct font;

/* An enumerator for each font property.  This is used as an index to
   the vector of FONT-SPEC and FONT-ENTITY.

   Note: The order is important and should not be changed.  */

enum font_property_index
  {
    /* FONT-TYPE is a symbol indicating a font backend; currently `x',
       `xft', `ftx', `freetype' are available.  For windows, we need
       `bdf' and `windows'.  For Mac OS X, we need `atm'.  */
    FONT_TYPE_INDEX,

    /* FONT-FOUNDRY is a foundry name (symbol).  */
    FONT_FOUNDRY_INDEX,

    /* FONT-FAMILY is a family name (symbol).  */
    FONT_FAMILY_INDEX,

    /* FONT-ADSTYLE is an additional style name (symbol).  */
    FONT_ADSTYLE_INDEX,

    /* FONT-REGISTRY is a combination of a charset-registry and
       charset0encoding name (symbol).  */
    FONT_REGISTRY_INDEX,

    /* FONT-WEIGHT is a numeric value of weight (e.g. medium, bold) of
       the font.  The value is what defined by FC_WEIGHT_* in
       fontconfig. */
    FONT_WEIGHT_INDEX,

    /* FONT-SLANT is a numeric value of slant (e.g. r, i, o) of the
       font.  The value is what defined by FC_SLANT_* in
       fontconfig plus 100. */
    FONT_SLANT_INDEX,

    /* FONT-WIDTH is a numeric value of setwidth (e.g. normal,
       condensed) of the font.  The value is what defined by
       FC_WIDTH_* in fontconfig. */
    FONT_WIDTH_INDEX,

    /* FONT-SIZE is a size of the font.  If integer, it is a pixel
       size.  For a font-spec, the value can be float specifying a
       point size.  For a font-entity, the value can be zero meaning
       that the font is scalable.  */
    FONT_SIZE_INDEX,

    /* In a font-spec, the value is an alist of extra information of a
       font such as name, OpenType features, and language coverage.
       In a font-entity, the value is an extra infomation for
       identifying a font (font-driver dependent).  */
    FONT_EXTRA_INDEX,		/* alist		alist */

    /* This value is the length of font-spec vector.  */
    FONT_SPEC_MAX,

    /* The followings are used only for a font-entity.  */

    /* Frame on which the font is found.  The value is nil if the font
       can be opend on any frame.  */
    FONT_FRAME_INDEX = FONT_SPEC_MAX,

    /* List of font-objects opened from the font-entity.  */
    FONT_OBJLIST_INDEX,

    /* This value is the length of font-entity vector.  */
    FONT_ENTITY_MAX
  };

extern Lisp_Object QCotf, QClanguage, QCscript;

extern Lisp_Object null_string;
extern Lisp_Object null_vector;

/* Structure for an opened font.  We can safely cast this structure to
   "struft font_info".  */

struct font
{
  struct font_info font;

  /* From which font-entity the font is opened.  */
  Lisp_Object entity;

  /* By which pixel size the font is opened.  */
  int pixel_size;

  /* Font-driver for the font.  */
  struct font_driver *driver;

  /* File name of the font, or NULL if the font is not associated with
     a file.  */
  char *file_name;

  /* Charset to encode a character code into a glyph code of the
     font.  */
  int encoding_charset;

  /* Charset to check if a character code is supported by the font.
     -1 means that the contents of the font must be looked up to
     determine it.
   */
  int repertory_charet;

  /* Minimum glyph width (in pixels).  */
  int min_width;

  /* Ascent and descent of the font (in pixels).  */
  int ascent, descent;

  /* There will be more to this structure, but they are private to a
     font-driver.  */
};

struct font_metrics
{
  short lbearing, rbearing, width, ascent, descent;
};

struct font_bitmap
{
  int rows;
  int width;
  int pitch;
  unsigned char *buffer;
  int left;
  int top;
  int advance;
  void *extra;
};

/* Predicates to check various font-related objects.  */

#define FONTP(x)	\
  (VECTORP (x) && (ASIZE (x) == FONT_SPEC_MAX || ASIZE (x) == FONT_ENTITY_MAX))
#define FONT_SPEC_P(x)	\
  (VECTORP (x) && ASIZE (x) == FONT_SPEC_MAX)
#define FONT_ENTITY_P(x)	\
  (VECTORP (x) && ASIZE (x) == FONT_ENTITY_MAX)
#define FONT_OBJECT_P(x)	\
  (XTYPE (x) == Lisp_Misc && XMISCTYPE (x) == Lisp_Misc_Save_Value)


/* Check macros for various font-related objects.  */

#define CHECK_FONT(x)	\
  do { if (! FONTP (x)) x = wrong_type_argument (Qfont, x); } while (0)
#define CHECK_FONT_SPEC(x)	\
  do { if (! FONT_SPEC_P (x)) x = wrong_type_argument (Qfont, x); } while (0)
#define CHECK_FONT_ENTITY(x)	\
  do { if (! FONT_ENTITY_P (x)) x = wrong_type_argument (Qfont, x); } while (0)
#define CHECK_FONT_OBJECT(x)	\
  do { if (! FONT_OBJECT_P (x)) x = wrong_type_argument (Qfont, x); } while (0)

#define CHECK_FONT_GET_OBJECT(x, font)					\
  do {									\
    if (! FONT_OBJECT_P (x)) x = wrong_type_argument (Qfont, x);	\
    if (! XSAVE_VALUE (x)->pointer) error ("Font already closed");	\
    font = XSAVE_VALUE (x)->pointer;					\
  } while (0)

struct face;
struct composition;

/* Macros for lispy glyph-string.  */
#define LGSTRING_FONT(lgs) AREF (AREF ((lgs), 0), 0)
#define LGSTRING_LBEARING(lgs) AREF (AREF ((lgs), 0), 1)
#define LGSTRING_RBEARING(lgs) AREF (AREF ((lgs), 0), 2)
#define LGSTRING_WIDTH(lgs) AREF (AREF ((lgs), 0), 3)
#define LGSTRING_ASCENT(lgs) AREF (AREF ((lgs), 0), 4)
#define LGSTRING_DESCENT(lgs) AREF (AREF ((lgs), 0), 5)
#define LGSTRING_SET_FONT(lgs, val) ASET (AREF ((lgs), 0), 0, (val))
#define LGSTRING_SET_LBEARING(lgs, val) ASET (AREF ((lgs), 0), 1, (val))
#define LGSTRING_SET_RBEARING(lgs, val)	ASET (AREF ((lgs), 0), 2, (val))
#define LGSTRING_SET_WIDTH(lgs, val) ASET (AREF ((lgs), 0), 3, (val))
#define LGSTRING_SET_ASCENT(lgs, val) ASET (AREF ((lgs), 0), 4, (val))
#define LGSTRING_SET_DESCENT(lgs, val) ASET (AREF ((lgs), 0), 5, (val))

#define LGSTRING_LENGTH(lgs) (ASIZE ((lgs)) - 1)
#define LGSTRING_GLYPH(lgs, idx) AREF ((lgs), (idx) + 1)

#define LGLYPH_CHAR(g) AREF ((g), 2)
#define LGLYPH_CODE(g) AREF ((g), 3)
#define LGLYPH_XOFF(g) AREF ((g), 4)
#define LGLYPH_YOFF(g) AREF ((g), 5)
#define LGLYPH_WIDTH(g) AREF ((g), 6)
#define LGLYPH_WADJUST(g) AREF ((g), 7)
#define LGLYPH_SET_CHAR(g, val) ASET ((g), 2, (val))
#define LGLYPH_SET_CODE(g, val) ASET ((g), 3, (val))
#define LGLYPH_SET_XOFF(g, val) ASET ((g), 4, (val))
#define LGLYPH_SET_YOFF(g, val) ASET ((g), 5, (val))
#define LGLYPH_SET_WIDTH(g, val) ASET ((g), 6, (val))
#define LGLYPH_SET_WADJUST(g, val) ASET ((g), 7, (val))

#define FONT_INVALID_CODE 0xFFFFFFFF

struct font_driver
{
  /* Symbol indicating the type of the font-driver.  */
  Lisp_Object type;

  /* Return a cache of font-entities on FRAME.  The cache must be a
     cons whose cdr part is the actual cache area.  */
  Lisp_Object (*get_cache) P_ ((Lisp_Object frame));

  /* Parse font name NAME, store the font properties in SPEC, and
     return 0.  If the font-driver can't parse NAME, return -1.  */
  int (*parse_name) P_ ((FRAME_PTR f, char *name, Lisp_Object spec));

  /* List fonts matching with FONT_SPEC on FRAME.  The value is a
     vector of font-entities.  This is the sole API that allocates
     font-entities.  */
  Lisp_Object (*list) P_ ((Lisp_Object frame, Lisp_Object font_spec));

  /* List available families.  The value is a list of family names
     (symbols).  The method can be NULL if the driver doesn't support
     this facility. */
  Lisp_Object (*list_family) P_ ((Lisp_Object frame));

  /* Free FONT_EXTRA_INDEX field of FONT_ENTITY.  This method can be
     NULL if FONT_EXTRA_INDEX of FONT_ENTITY is a normal Lisp object
     (i.e. not Lisp_Save_Value).  */
  void (*free_entity) P_ ((Lisp_Object font_entity));

  /* Open a font specified by FONT_ENTITY on frame F.  If the font is
     scalable, open it with PIXEL_SIZE.  */
  struct font *(*open) P_ ((FRAME_PTR f, Lisp_Object font_entity,
			    int pixel_size));

  /* Close FONT on frame F.  */
  void (*close) P_ ((FRAME_PTR f, struct font *font));

  /* Prepare FACE for displaying characters by FONT on frame F.  If
     successful, return 0.  Otherwise, return -1.  This method can be
     NULL if there's nothing to do.  */
  int (*prepare_face) P_ ((FRAME_PTR f, struct face *face));

  /* Done FACE for displaying characters by FACE->font on frame F.
     This method can be NULL if there's nothing to do.  */
  void (*done_face) P_ ((FRAME_PTR f, struct face *face));

  /* If FONT_ENTITY has a glyph for character C, return 1.  If not,
     return 0.  If a font must be opened to check it, return -1.  This
     method can be NULL if the driver always requires a font to be
     opened for this check.  In that case, we must open a font and use
     `encode_char' method.  */
  int (*has_char) P_ ((Lisp_Object entity, int c));

  /* Return a glyph code of FONT for characer C.  If FONT doesn't have
     such a glyph, return FONT_INVALID_CODE.  */
  unsigned (*encode_char) P_ ((struct font *font, int c));

  /* Perform the size computation of glyphs of FONT and fillin members
     of METRICS.  The glyphs are specified by their glyph codes in
     CODE (length NGLYPHS).  */
  int (*text_extents) P_ ((struct font *font,
			   unsigned *code, int nglyphs,
			   struct font_metrics *metrics));

  /* Draw glyphs between FROM and TO of S->char2b at (X Y) pixel
     position of frame F with S->FACE and S->GC.  If WITH_BACKGROUND
     is nonzero, fill the background in advance.  It is assured that
     WITH_BACKGROUND is zero when (FROM > 0 || TO < S->nchars).  */
  int (*draw) P_ ((struct glyph_string *s, int from, int to,
		   int x, int y, int with_background));

  /* Store bitmap data for glyph-code CODE of FONT in BITMAP.  This
     method can be NULL if the driver doesn't support this facility.
     It is intended that this method is callled from the other
     font-driver for actual drawing.  */
  int (*get_bitmap) P_ ((struct font *font, unsigned code,
			 struct font_bitmap *bitmap,
			 int bits_per_pixel));

  /* Free bitmap data in BITMAP.  This method can be NULL if no data
     have to be freed.  */
  void (*free_bitmap) P_ ((struct font *font, struct font_bitmap *bitmap));

  /* Return an outline data for glyph-code CODE of FONT.  The format
     of the outline data depends on the font-driver.  This method can
     be NULL if the driver doesn't support this facility.  */
  void *(*get_outline) P_ ((struct font *font, unsigned code));

  /* Free OUTLINE (that is obtained by the above method).  */
  void (*free_outline) P_ ((struct font *font, void *outline));

  /* Get coordinates of the INDEXth anchor point of the glyph whose
     code is CODE.  Store the coordinates in *X and *Y.  Return 0 if
     the operations was successfull.  Otherwise return -1.  This
     method can be NULL if the driver doesn't support this
     facility.  */
  int (*anchor_point) P_ ((struct font *font, unsigned code, int index,
			   int *x, int *y));

  /* Return a list describing which scripts/languages FONT
     supports by which GSUB/GPOS features of OpenType tables.  */
  Lisp_Object (*otf_capability) P_ ((struct font *font));

  /* Drive FONT's OTF GSUB features according to GSUB_SPEC.

     GSUB_SPEC is in this format (all elements are symbols):
	(SCRIPT LANGSYS GSUB-FEATURE ...)
     If one of GSUB-FEATURE is nil, apply all gsub features except for
     already applied and listed later.  For instance, if the font has
     GSUB features nukt, haln, rphf, blwf, and half,
	(deva nil nukt haln nil rphf)
     applies nukt and haln in this order, then applies blwf and half
     in the order apearing in the font.  The features are of the
     default langsys of `deva' script.

     This method applies the specified features to the codes in the
     elements of GSTRING-IN (between FROMth and TOth).  The output
     codes are stored in GSTRING-OUT at the IDXth element and the
     following elements.

     Return the number of output codes.  If none of the features are
     applicable to the input data, return 0.  If GSTRING-OUT is too
     short, return -1.  */
  int (*otf_gsub) P_ ((struct font *font, Lisp_Object gsub_spec,
		       Lisp_Object gstring_in, int from, int to,
		       Lisp_Object gstring_out, int idx));

  /* Drive FONT's OTF GPOS features according to GPOS_SPEC.

     GPOS_SPEC is in this format (all elements are symbols):
	(SCRIPT LANGSYS GPOS-FEATURE ...)
     The meaning is the same as GSUB_SPEC above. 

     This method applies the specified features to the codes in the
     elements of GSTRING (between FROMth and TOth).  The resulting
     positioning information (x-offset and y-offset) is stored in the
     slots of the elements.

     Return 1 if at least one glyph has nonzero x-offset or y-offset.
     Otherwise return 0.  */
  int (*otf_gpos) P_ ((struct font *font, Lisp_Object gpos_spec,
		       Lisp_Object gstring, int from, int to));
};


struct font_driver_list
{
  struct font_driver *driver;
  struct font_driver_list *next;
};

extern int enable_font_backend;

EXFUN (Ffont_spec, MANY);

extern Lisp_Object font_symbolic_weight P_ ((Lisp_Object font));
extern Lisp_Object font_symbolic_slant P_ ((Lisp_Object font));
extern Lisp_Object font_symbolic_width P_ ((Lisp_Object font));

extern Lisp_Object font_find_object P_ ((struct font *font));
extern char *font_get_name P_ ((Lisp_Object));
extern Lisp_Object font_get_frame P_ ((Lisp_Object font));
extern int font_has_char P_ ((FRAME_PTR, Lisp_Object, int));
extern unsigned font_encode_char P_ ((Lisp_Object, int));

extern int font_set_lface_from_name P_ ((FRAME_PTR f,
					 Lisp_Object lface,
					 Lisp_Object fontname,
					 int force_p, int may_fail_p));
extern Lisp_Object font_find_for_lface P_ ((FRAME_PTR f, Lisp_Object *lface,
					    Lisp_Object spec));
extern Lisp_Object font_open_for_lface P_ ((FRAME_PTR f, Lisp_Object *lface,
					    Lisp_Object entity));
extern void font_load_for_face P_ ((FRAME_PTR f, struct face *face));
extern void font_prepare_for_face P_ ((FRAME_PTR f, struct face *face));
extern Lisp_Object font_open_by_name P_ ((FRAME_PTR f, char *name));

extern Lisp_Object intern_downcase P_ ((char *str, int len));
extern void font_update_sort_order P_ ((int *order));

extern void font_parse_old_font_spec P_ ((Lisp_Object, Lisp_Object,
					  Lisp_Object, Lisp_Object));


extern int font_parse_xlfd P_ ((char *name, Lisp_Object font, int merge));
extern int font_unparse_xlfd P_ ((Lisp_Object font, int pixel_size,
				  char *name, int bytes));
extern void register_font_driver P_ ((struct font_driver *driver, FRAME_PTR f));
extern void free_font_driver_list P_ ((FRAME_PTR f));

extern struct font *font_prepare_composition P_ ((struct composition *cmp));


#ifdef HAVE_LIBOTF
/* This can be used as `otf_capability' method of a font-driver.  */
extern Lisp_Object font_otf_capability P_ ((struct font *font));
/* This can be used as `otf_gsub' method of a font-driver.  */
extern int font_otf_gsub P_ ((struct font *font, Lisp_Object gsub_spec,
			      Lisp_Object gstring_in, int from, int to,
			      Lisp_Object gstring_out, int idx));
/* This can be used as `otf_gpos' method of a font-driver.  */
extern int font_otf_gpos P_ ((struct font *font, Lisp_Object gpos_spec,
			      Lisp_Object gstring, int from, int to));
#endif	/* HAVE_LIBOTF */

#ifdef HAVE_FREETYPE
extern struct font_driver ftfont_driver;
#endif	/* HAVE_FREETYPE */
#ifdef HAVE_X_WINDOWS
extern struct font_driver xfont_driver;
extern struct font_driver ftxfont_driver;
#ifdef HAVE_XFT
extern struct font_driver xftfont_driver;
#endif	/* HAVE_XFT */
#endif	/* HAVE_X_WINDOWS */
#ifdef WINDOWSNT
extern struct font_driver w32font_driver;
#endif	/* WINDOWSNT */
#ifdef MAC_OS
extern struct font_driver atmfont_driver;
#endif	/* MAC_OS */

#endif	/* not EMACS_FONT_H */