@database "bullet"
@master "AMIDEV:NDK/Autodocs/bullet.doc"

@Node Main "bullet.doc"
@toc "Autodocs/AG/INDEX/Main"
    @{" --background-- " Link "--background--"}
    @{" CloseEngine() " Link "CloseEngine()"}
    @{" ObtainInfoA() " Link "ObtainInfoA()"}
    @{" OpenEngine() " Link "OpenEngine()"}
    @{" ReleaseInfoA() " Link "ReleaseInfoA()"}
    @{" SetInfoA() " Link "SetInfoA()"}
@EndNode

@Node "--background--" "bullet.library/--background--"

@{b}   AMIGA FONTS@{ub}
	The existence of a disk font is indicated by the existence of
	its associated font contents file, whose name has the suffix
	".font".  It is this name that is used in the actual font
	open call of the application.  Amiga fonts are collected in
	the directory path(s) associated with the FONTS: assign.  It
	is this assign that is searched if no explicit path name is
	provided in the font open call: use of an explicit path is
	generally discouraged.  The actual bitmaps of traditional
	Amiga fonts are stored in a directory with the name of the
	font contents file stripped of its ".font" suffix.  This
	directory is usually in the same directory as the font
	contents file.  This traditional arrangement is supported by
	the FixFonts system application.

	For example:
	    o   FONTS: is assigned to Sys:Fonts/
	    o   Sys:Fonts/garnet.font exists and describes that the
		font "garnet.font" exists
	    o   Sys:Fonts/garnet/ contains the bitmap images for
		sizes 9 and 16

	Other variations of file placement may exist, but they
	require custom tools to maintain -- tools available not from
	Commodore, but from other sources such as Fish disks.

	Font contents files are flagged with magic numbers that not
	only verify that they are a font contents files but also what
	variation of file structure they contain.

@{b}   OUTLINE TYPEFACES@{ub}
	The existence of an outline typeface is indicated by a magic
	number in the font contents file.  They are further described
	in the associated outline typeface tag file, whose name is
	the that of the font contents file with the suffix ".otag"
	substituted for ".font".  This tag file contains a tag list
	that is to be processed and passed to the outline engine
	(i.e.  bullet.library) in order to select the associated
	typeface.  It also contains information applications may use
	to guide their use of the typeface.

@{b}   OTAG SPECIFICATION EXAMPLE@{ub}
	Here are the steps necessary to go from an arbitrary font
	name into an environment where glyphs from that font
	can be accessed:
	1.  @{"Read" Link "dos/Read()"} the header from the font contents (.font) file and
	    verify that the magic cookie fch_ID is OFCH_ID.
	    If it is not, then this is an Amiga bitmap font,
	    not an outline font.
	2.  @{"Read" Link "dos/Read()"} the associated outline tag (.otag) file into memory:
	    a.  Validate that the OT_FileIdent exists and matches the
		file size.
	    b.  @{"Allocate" Link "exec/Allocate()"} a memory buffer and read the file into it.
	    c.  Resolve addresses: for each tag with the OT_Indirect
		bit set, add the memory buffer origin to the
		associated data.
	3.  Find the OT_Engine tag and ensure that you have the
	    proper engine open:
	    a.  If you already have an engine handle for this engine
		name, you skip these steps.
	    b.  append the suffix ".library" to the engine name.
		(e.g. "bullet" becomes "bullet.library").
	    c.  use exec's @{"OpenLibrary()" Link "exec/OpenLibrary()"} to open the library.
	    d.  use the engine's @{"OpenEngine()" Link "OpenEngine()"} to acquire an engine
		handle.
	4.  Pass the full path name of the .otag file to the engine
	    with the OT_OTagPath tag using SetInfo().
	5.  Pass the memory copy of the .otag file to the engine with
	    the OT_OTagList tag using SetInfo().  This step may be
	    combined with step 4, passing first the path then the
	    list in one call.
	The library is now ready to accept glyph metric information
	(e.g. size and glyph code) and produce glyph bitmaps.

@{b}   DISKFONT USE OF OTAG ENTRIES@{ub}
	The diskfont library uses other entries from the outline tag
	(.otag) file.  The following are used both during inquiry of
	what typefaces exist (AvailFonts) and during creation of an
	Amiga @{"TextFont" Link "INCLUDE:graphics/text.h/Main" 87} (OpenDiskFont):
	o   OT_IsFixed is used to determine whether these outlines
	    describe a PROPORTIONAL flagged font.
	o   OT_StemWeight is used to determine whether these outlines
	    describe a BOLD style font.
	o   OT_SlantStyle is used to determine whether these outlines
	    describe an ITALIC style font.
	o   OT_HorizStyle is used to determine whether these outlines
	    describe an EXTENDED style font.
	The following are used only during OpenDiskFont:
	o   OT_YSizeFactor is used to convert the Amiga pixel height
	    specification, which describes the distance from the
	    lowest decender to the highest ascender, into a point
	    size specification, which is related (via YSizeFactor)
	    to a nominal character height.
	o   OT_SpaceWidth is used as the width of the space character.
	The following is used only during AvailFonts:
	o   OT_AvailSizes is used to generate a list of sizes
	    available for the font.

@EndNode

@Node "CloseEngine()" "bullet.library/CloseEngine"

@{b}    NAME@{ub}
	CloseEngine -- Release an engine handle

@{b}    SYNOPSIS@{ub}
	CloseEngine(engineHandle)
	            A0

	void CloseEngine(struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *);

@{b}    FUNCTION@{ub}
	This function releases the engine handle acquired with
	@{"OpenEngine" Link "bullet/OpenEngine()"}.  It first releases any data acquired with
	@{"ObtainInfoA" Link "bullet/ObtainInfoA()"} associated with the engineHandle that has not yet
	been released.

@{b}    INPUTS@{ub}
	engineHandle -- the handle acquired via @{"OpenEngine" Link "bullet/OpenEngine()"}.  If zero,
		no operation is performed.

@{b}    RESULT@{ub}
	This function has no result.  The only error that can occur is
	when the when an invalid engineHandle is supplied: the
	application is assumed not to do that.

@{b}    EXAMPLE@{ub}
	EndGame(code, arg1, arg2, arg3, arg3)
	{
	    ...
	    CloseEngine(EngineHandle);
	    ...
	}

@{b}    SEE ALSO@{ub}
	@{"OpenEngine()" Link "OpenEngine()"}

@EndNode

@Node "ObtainInfoA()" "bullet.library/ObtainInfoA"

@{b}    NAME@{ub}
	ObtainInfoA -- Inquire tagged font and/or glyph metrics
	ObtainInfo -- varargs form of ObtainInfoA

@{b}    SYNOPSIS@{ub}
	error = ObtainInfoA(engineHandle, tagList)
	                    A0            A1

	ULONG ObtainInfoA(struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *, struct @{"TagItem" Link "INCLUDE:utility/tagitem.h/Main" 30} *);

	error = ObtainInfo(engineHandle, firstTag, ...)

	ULONG ObtainInfo(struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *, @{"Tag" Link "INCLUDE:utility/tagitem.h/Main" 28}, ...);

@{b}    FUNCTION@{ub}
	This function accepts a tagList whose tag field elements are
	valid for inquiry, and whose associated data fields are
	pointers to the destination in which to place the requested
	data.

	@{"Tag" Link "INCLUDE:utility/tagitem.h/Main" 28} items that refer to data indirectly (OT_Indirect is set)
	return pointers that may be allocated or cached by the
	library.  This data must be treated as read-only data.  When
	the application is done with the data acquired via ObtainInfoA,
	it must perform a @{"ReleaseInfoA" Link "bullet/ReleaseInfoA()"} to allow the library to release
	the data.

@{b}    INPUTS@{ub}
	engineHandle -- the handle acquired via @{"OpenEngine" Link "bullet/OpenEngine()"}.
	tagList -- a tagList containing OT_ tags valid for inquiry
		paired with the destination pointers for the inquiry
		results.  All destinations are longwords, whether they
		are pointers or values, and regardless of whether the
		value could fit in a smaller variable.

@{b}    RESULT@{ub}
	This function returns a zero success indication, or a non-zero
	error code.

@{b}    EXAMPLE@{ub}
	    ULONG pointSize;
	    struct @{"GlyphMap" Link "INCLUDE:diskfont/glyph.h/Main" 29} *glyph;
	    ...
	    if (!ObtainInfo(EngineHandle, OT_Glyph, &glyph, TAG_DONE)) {
		...
		ReleaseInfo(EngineHandle, OT_Glyph, glyph, TAG_DONE);
	    }

@{b}    SEE ALSO@{ub}
	@{"ReleaseInfoA()" Link "ReleaseInfoA()"}, @{"diskfont/diskfonttag.h" Link "INCLUDE:diskfont/diskfonttag.h/Main" 0}, @{"diskfont/oterrors.h" Link "INCLUDE:diskfont/oterrors.h/Main" 0}

@EndNode

@Node "OpenEngine()" "bullet.library/OpenEngine"

@{b}    NAME@{ub}
	OpenEngine -- Acquire engine handle

@{b}    SYNOPSIS@{ub}
	engineHandle = OpenEngine()

	struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *OpenEngine(void)

@{b}    FUNCTION@{ub}
	This function establishes a context for access to the bullet
	library.  This context remains valid until it is closed via
	@{"CloseEngine" Link "bullet/CloseEngine()"}.  Each specific context isolates the specification
	of the various font attributes from other contexts concurrently
	accessing the bullet library.  A context can be shared among
	different tasks.

@{b}    RESULT@{ub}
	This function returns an engineHandle, or @{"NULL" Link "rexxsupport/NULL"} if for some
	reason no engineHandle can be created.

@{b}    EXAMPLE@{ub}
	    BulletBase = OpenLibrary("bullet.library", 0);
	    if (!BulletBase)
		EndGame(ERROR_LibOpen, "bullet.library", 0);
	    EngineHandle = OpenEngine();
	    if (!EngineHandle)
		EndGame(ERROR_InternalCall, "OpenEngine");

@{b}    SEE ALSO@{ub}
	@{"CloseEngine()" Link "CloseEngine()"}

@EndNode

@Node "ReleaseInfoA()" "bullet.library/ReleaseInfoA"

@{b}    NAME@{ub}
	ReleaseInfoA -- Release data obtained with @{"ObtainInfoA" Link "bullet/ObtainInfoA()"}
	ReleaseInfo -- varargs form of ReleaseInfoA

@{b}    SYNOPSIS@{ub}
	error = ReleaseInfoA(engineHandle, tagList)
	                     A0            A1

	ULONG ReleaseInfoA(struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *, struct @{"TagItem" Link "INCLUDE:utility/tagitem.h/Main" 30} *);

	error = ReleaseInfo(engineHandle, firstTag, ...)

	ULONG ReleaseInfo(struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *, @{"Tag" Link "INCLUDE:utility/tagitem.h/Main" 28}, ...);

@{b}    FUNCTION@{ub}
	This function releases the data obtained with @{"ObtainInfoA" Link "bullet/ObtainInfoA()"}.
	Data associated with tags that are not indirect, i.e. for which
	OT_Indirect is not set, need not be released, but it is not an
	error to do so.  Released data may be immediately freed or may
	become a candidate to be expunged from memory when the system
	reaches a low memory condition, depending on the library's
	internal implementation.

	Each ReleaseInfoA tag item must be associated with a prior
	@{"ObtainInfoA" Link "bullet/ObtainInfoA()"}.

@{b}    INPUTS@{ub}
	engineHandle -- the handle acquired via @{"OpenEngine" Link "bullet/OpenEngine()"}.
	tagList -- a tagList containing OT_ tags valid for inquiry
		paired with the data previously acquired for them with
		@{"ObtainInfoA" Link "bullet/ObtainInfoA()"}.  Null pointers quietly accepted and
		ignored for indirect data.

@{b}    RESULT@{ub}
	This function has no result.  The only error that can occur is
	when the Obtain and Release pairs are mismatched: the
	application is assumed not to do that.

@{b}    EXAMPLE@{ub}
	    ULONG pointSize;
	    struct @{"GlyphMap" Link "INCLUDE:diskfont/glyph.h/Main" 29} *glyph;
	    ...
	    error = ObtainInfo(EngineHandle, OT_Glyph, &glyph, TAG_DONE);
	    ...
	    ReleaseInfo(EngineHandle, OT_Glyph, glyph, TAG_DONE);

@{b}    SEE ALSO@{ub}
	ReleaseInfoA(), @{"diskfont/diskfonttag.h" Link "INCLUDE:diskfont/diskfonttag.h/Main" 0}, @{"diskfont/oterrors.h" Link "INCLUDE:diskfont/oterrors.h/Main" 0}

@EndNode

@Node "SetInfoA()" "bullet.library/SetInfoA"

@{b}    NAME@{ub}
	SetInfoA -- Set font and/or glyph metrics
	SetInfo -- varargs form of SetInfoA

@{b}    SYNOPSIS@{ub}
	error = SetInfoA(engineHandle, tagList)
	                 A0            A1

	ULONG SetInfoA(struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *, struct @{"TagItem" Link "INCLUDE:utility/tagitem.h/Main" 30} *);

	error = SetInfo(engineHandle, firstTag, ...)

	ULONG SetInfo(struct @{"GlyphEngine" Link "INCLUDE:diskfont/glyph.h/Main" 21} *, @{"Tag" Link "INCLUDE:utility/tagitem.h/Main" 28}, ...);

@{b}    FUNCTION@{ub}
	This function accepts a tagList whose tag field elements are
	valid for specification, and whose associated data fields are
	used to supply the specified data.

	Data that is supplied via an indirect pointer (OT_Indirect) to
	an array or structure is copied from that array or structure
	into the internal memory of the library.  Changes to the data
	after this call do not affect the engine.

@{b}    INPUTS@{ub}
	engineHandle -- the handle acquired via @{"OpenEngine" Link "bullet/OpenEngine()"}.
	tagList -- a tagList containing OT_ tags valid for
		specification paired with the specification data.

@{b}    RESULT@{ub}
	This function returns a zero success indication, or a non-zero
	error code.

@{b}    EXAMPLE@{ub}
	    if (!(error = SetInfo(EngineHandle, OT_PointHeight, fpoints,
		    OT_GlyphCode, GC_daggerdbl, TAG_DONE)) {
		error = ObtainInfo(EngineHandle, OT_Glyph, &glyph);
		...
		ReleaseInfo(EngineHandle, OT_Glyph, glyph);
	    }

@{b}    SEE ALSO@{ub}
	@{"diskfont/diskfonttag.h" Link "INCLUDE:diskfont/diskfonttag.h/Main" 0}, @{"diskfont/oterrors.h" Link "INCLUDE:diskfont/oterrors.h/Main" 0},

@EndNode