/*
 * tkFont.h --
 *
 *	Declarations for interfaces between the generic and platform-
 *	specific parts of the font package.  This information is not
 *	visible outside of the font package.
 *
 * Copyright (c) 1996-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#ifndef _TKFONT
#define _TKFONT

#ifdef BUILD_tk
# undef TCL_STORAGE_CLASS
# define TCL_STORAGE_CLASS DLLEXPORT
#endif

/*
 * The following structure keeps track of the attributes of a font.  It can
 * be used to keep track of either the desired attributes or the actual
 * attributes gotten when the font was instantiated.
 */

typedef struct TkFontAttributes {
    Tk_Uid family;		/* Font family, or NULL to represent
				 * plaform-specific default system font. */
    int size;			/* Pointsize of font, 0 for default size, or
				 * negative number meaning pixel size. */
    int weight;			/* Weight flag; see below for def'n. */
    int slant;			/* Slant flag; see below for def'n. */
    int underline;		/* Non-zero for underline font. */
    int overstrike;		/* Non-zero for overstrike font. */
} TkFontAttributes;

/*
 * Possible values for the "weight" field in a TkFontAttributes structure.
 * Weight is a subjective term and depends on what the company that created
 * the font considers bold.
 */

#define TK_FW_NORMAL	0
#define TK_FW_BOLD	1

#define TK_FW_UNKNOWN	-1	/* Unknown weight.  This value is used for
				 * error checking and is never actually stored
				 * in the weight field. */

/*
 * Possible values for the "slant" field in a TkFontAttributes structure.
 */

#define TK_FS_ROMAN	0	
#define TK_FS_ITALIC	1
#define TK_FS_OBLIQUE	2	/* This value is only used when parsing X
				 * font names to determine the closest
				 * match.  It is only stored in the
				 * XLFDAttributes structure, never in the
				 * slant field of the TkFontAttributes. */

#define TK_FS_UNKNOWN	-1	/* Unknown slant.  This value is used for
				 * error checking and is never actually stored
				 * in the slant field. */

/*
 * The following structure keeps track of the metrics for an instantiated
 * font.  The metrics are the physical properties of the font itself.
 */

typedef struct TkFontMetrics {
    int	ascent;			/* From baseline to top of font. */
    int	descent;		/* From baseline to bottom of font. */
    int maxWidth;		/* Width of widest character in font. */
    int fixed;			/* Non-zero if this is a fixed-width font,
				 * 0 otherwise. */
} TkFontMetrics;

/*
 * The following structure is used to keep track of the generic information
 * about a font.  Each platform-specific font is represented by a structure
 * with the following structure at its beginning, plus any platform-
 * specific stuff after that.
 */

typedef struct TkFont {
    /*
     * Fields used and maintained exclusively by generic code.
     */

    int resourceRefCount;	/* Number of active uses of this font (each
				 * active use corresponds to a call to
				 * Tk_AllocFontFromTable or Tk_GetFont).
				 * If this count is 0, then this TkFont
				 * structure is no longer valid and it isn't
				 * present in a hash table: it is being
				 * kept around only because there are objects
				 * referring to it.  The structure is freed
				 * when resourceRefCount and objRefCount
				 * are both 0. */
    int objRefCount;		/* The number of Tcl objects that reference
				 * this structure. */
    Tcl_HashEntry *cacheHashPtr;/* Entry in font cache for this structure,
				 * used when deleting it. */
    Tcl_HashEntry *namedHashPtr;/* Pointer to hash table entry that
				 * corresponds to the named font that the
				 * tkfont was based on, or NULL if the tkfont
				 * was not based on a named font. */
    Screen *screen;		/* The screen where this font is valid. */
    int tabWidth;		/* Width of tabs in this font (pixels). */
    int	underlinePos;		/* Offset from baseline to origin of
				 * underline bar (used for drawing underlines
				 * on a non-underlined font). */
    int underlineHeight;	/* Height of underline bar (used for drawing
				 * underlines on a non-underlined font). */

    /*
     * Fields used in the generic code that are filled in by
     * platform-specific code.
     */

    Font fid;			/* For backwards compatibility with XGCValues
				 * structures.  Remove when TkGCValues is
				 * implemented.  */
    TkFontAttributes fa;	/* Actual font attributes obtained when the
				 * the font was created, as opposed to the
				 * desired attributes passed in to
				 * TkpGetFontFromAttributes().  The desired
				 * metrics can be determined from the string
				 * that was used to create this font. */
    TkFontMetrics fm;		/* Font metrics determined when font was
				 * created. */
    struct TkFont *nextPtr;	/* Points to the next TkFont structure with
				 * the same name.  All fonts with the
				 * same name (but different displays) are
				 * chained together off a single entry in
				 * a hash table. */
} TkFont;

/*
 * The following structure is used to return attributes when parsing an
 * XLFD.  The extra information is of interest to the Unix-specific code
 * when attempting to find the closest matching font.
 */

typedef struct TkXLFDAttributes {
    Tk_Uid foundry;		/* The foundry of the font. */
    int slant;			/* The tristate value for the slant, which
				 * is significant under X. */
    int setwidth;		/* The proportionate width, see below for
				 * definition. */
    Tk_Uid charset;		/* The actual charset string. */
} TkXLFDAttributes;

/*
 * Possible values for the "setwidth" field in a TkXLFDAttributes structure.
 * The setwidth is whether characters are considered wider or narrower than
 * normal.
 */

#define TK_SW_NORMAL	0
#define TK_SW_CONDENSE	1
#define TK_SW_EXPAND	2
#define TK_SW_UNKNOWN	3	/* Unknown setwidth.  This value may be
				 * stored in the setwidth field. */

/*
 * The following defines specify the meaning of the fields in a fully
 * qualified XLFD.
 */

#define XLFD_FOUNDRY	    0
#define XLFD_FAMILY	    1
#define XLFD_WEIGHT	    2
#define XLFD_SLANT	    3
#define XLFD_SETWIDTH	    4
#define XLFD_ADD_STYLE	    5
#define XLFD_PIXEL_SIZE	    6
#define XLFD_POINT_SIZE	    7
#define XLFD_RESOLUTION_X   8
#define XLFD_RESOLUTION_Y   9
#define XLFD_SPACING	    10
#define XLFD_AVERAGE_WIDTH  11
#define XLFD_CHARSET	    12
#define XLFD_NUMFIELDS	    13	/* Number of fields in XLFD. */

/*
 * Low-level API exported by generic code to platform-specific code.
 */

#define TkInitFontAttributes(fa)   memset((fa), 0, sizeof(TkFontAttributes));
#define TkInitXLFDAttributes(xa)   memset((xa), 0, sizeof(TkXLFDAttributes));

EXTERN int		TkFontParseXLFD _ANSI_ARGS_((CONST char *string,
			    TkFontAttributes *faPtr, TkXLFDAttributes *xaPtr));
EXTERN char **		TkFontGetAliasList _ANSI_ARGS_((CONST char *faceName));
EXTERN char ***		TkFontGetFallbacks _ANSI_ARGS_((void));
EXTERN int		TkFontGetPixels _ANSI_ARGS_((Tk_Window tkwin, 
			    int size));
EXTERN int		TkFontGetPoints _ANSI_ARGS_((Tk_Window tkwin, 
			    int size));
EXTERN char **		TkFontGetGlobalClass _ANSI_ARGS_((void));
EXTERN char **		TkFontGetSymbolClass _ANSI_ARGS_((void));
EXTERN int		TkFontGetFirstTextLayout _ANSI_ARGS_((
			    Tk_TextLayout layout, Tk_Font *font, char *dst));

/*
 * Low-level API exported by platform-specific code to generic code. 
 */

EXTERN void		TkpDeleteFont _ANSI_ARGS_((TkFont *tkFontPtr));
EXTERN void		TkpFontPkgInit _ANSI_ARGS_((TkMainInfo *mainPtr));
EXTERN TkFont *		TkpGetFontFromAttributes _ANSI_ARGS_((
			    TkFont *tkFontPtr, Tk_Window tkwin,
			    CONST TkFontAttributes *faPtr));
EXTERN void		TkpGetFontFamilies _ANSI_ARGS_((Tcl_Interp *interp,
			    Tk_Window tkwin));
EXTERN TkFont *		TkpGetNativeFont _ANSI_ARGS_((Tk_Window tkwin,
			    CONST char *name));

# undef TCL_STORAGE_CLASS
# define TCL_STORAGE_CLASS DLLIMPORT

#endif	/* _TKFONT */
