Rich HyperText Object

/*
**	(c) COPYRIGHT CERN 1994.
**	Please first read the full copyright statement in the file COPYRIGH.
*/
This is the C interface to the Objective-C (or whatever) Style-oriented HyperText class. It is used when a style-oriented text object is available or craeted in order to display hypertext.

This module is a part of the Library of Common Code. However, it is NOT implemented anywhere in the library, as it is client (and often platform) specific code. Hence these functions must be implemented in the client. The Line Mode Browser has the implementation in the GridText module. 

#ifndef HTEXT_H
#define HTEXT_H

#include "HTAnchor.h"
#include "HTStyle.h"
#include "HTStream.h"

#ifndef THINK_C
#ifndef HyperText		/* Objective C version defined HyperText */
typedef struct _HText HText;	/* Normal Library */
#else
@class HText;			/* Objective C version for NeXTStep */
#endif
#else
class CHyperText;		/* Mac Think-C browser hook */
typedef CHyperText HText;
#endif

extern HText * HTMainText;		/* Pointer to current main text */
extern HTParentAnchor * HTMainAnchor;	/* Pointer to current text's anchor */

Creation and deletion

HText_new: Create hypertext object

There are several methods depending on how much you want to specify. The output stream is used with objects which need to output the hypertext to a stream. The structure is for objects which need to refer to the structure which is kep by the creating stream. 
 extern HText *	HText_new PARAMS((HTParentAnchor * 	anchor));

 extern HText *	HText_new2 PARAMS((HTParentAnchor * 	anchor,
 				HTStream * 		output_stream));

 extern HText *	HText_new3 PARAMS((HTRequest *		request,
 				HTStream * 		output_stream,
				HTStructured * 		structure));

Free hypertext object

extern void 	HText_free PARAMS((HText * me));

Object Building methods

These are used by a parser to build the text in an object HText_beginAppend must be called, then any combination of other append calls, then HText_endAppend. This allows optimised handling using buffers and caches which are flushed at the end. 
extern void HText_beginAppend PARAMS((HText * text));

extern void HText_endAppend PARAMS((HText * text));

Set the style for future text

extern void HText_setStyle PARAMS((HText * text, HTStyle * style));

Add one character

extern void HText_appendCharacter PARAMS((HText * text, char ch));

Add a zero-terminated string

extern void HText_appendText PARAMS((HText * text, CONST char * str));

New Paragraph

and similar things 
extern void HText_appendParagraph PARAMS((HText * text));

extern void HText_appendLineBreak PARAMS((HText * text));

extern void HText_appendHorizontalRule PARAMS((HText * text));

Start/end sensitive text

The anchor object is created and
passed to HText_beginAnchor. The
senstive text is added to the text
object, and then HText_endAnchor
is called. Anchors may not be nested.

extern void HText_beginAnchor PARAMS((HText * text, HTChildAnchor * anc));
extern void HText_endAnchor PARAMS((HText * text));





Set the next free identifier

The string must be of the form aaannnnn where aaa is the prefix
for automatically generated ids, normally "z", and nnnn is the
next unused number.  If not present, defaults to z0.  An
editor should pick up both the a and n bits, and increment n
when generating ids. This ensures that old ids are not reused,
even if the elements using them have been deleted from the document.

extern void HText_setNextId PARAMS((
	HText *		text,
	CONST char *    s));




Append an inline image
The image is handled by the creation
of an anchor whose destination is
the image document to be included.
The semantics is the intended inline
display of the image.

An alternative implementation could
be, for example, to begin an anchor,
append the alternative text or "IMAGE",
then end the anchor. This would simply
generate some text linked to the
image itself as a separate document.



extern void HText_appendImage PARAMS((
	HText * 	text,
	HTChildAnchor * anc,
	CONST char * 	alternative_text,
	CONST char *	alignment,
	BOOL		isMap));




HText_appendObject:  Append an object
which does its own work
The SGML parameters are passed untouched.
Currently this is only used for empty
elements.  Extensions could be (1)
to pass CDATA contents as well as
any attributes and (2) to pass the
whole structured stream until the
compound object has parsed itself.

extern void HText_appendObject PARAMS((
	HText * 		text,
	int			element_number,
	CONST BOOL *		present,
	CONST char * CONST * 	value));




HText_unimplemented: Warn that object
is not completely rendered.
If the parser realises that it has
incompletely parsed an object, then
it can call this to flag it to the
object.  This will for example prevent
editing or writing back.

extern void HText_unimplemented PARAMS((
	HText *		text));





Utilities


Dump diagnostics to stderr


extern void HText_dump PARAMS((HText * me));	




Return the anchor associated with
this node


extern HTParentAnchor * HText_nodeAnchor PARAMS((HText * me));





Browsing functions






Bring to front and highlight it



extern BOOL HText_select PARAMS((HText * text)); 
extern BOOL HText_selectAnchor PARAMS((HText * text, HTChildAnchor* anchor)); 




Editing functions
These are called from the application.
There are many more functions not
included here from the orginal text
object. These functions NEED NOT
BE IMPLEMENTED in a browser which
cannot edit.

/*	Style handling:
*/
/*	Apply this style to the selection
*/
extern void HText_applyStyle PARAMS((HText * me, HTStyle *style));

/*	Update all text with changed style.
*/
extern void HText_updateStyle PARAMS((HText * me, HTStyle *style));

/*	Return style of  selection
*/
extern HTStyle * HText_selectionStyle PARAMS((
	HText * me,
	HTStyleSheet* sheet));

/*	Paste in styled text
*/
extern void HText_replaceSel PARAMS((HText * me,
	CONST char *aString, 
	HTStyle* aStyle));

/*	Apply this style to the selection and all similarly formatted text
**	(style recovery only)
*/
extern void HTextApplyToSimilar PARAMS((HText * me, HTStyle *style));
 
/*	Select the first unstyled run.
**	(style recovery only)
*/
extern void HTextSelectUnstyled PARAMS((HText * me, HTStyleSheet *sheet));


/*	Anchor handling:
*/
extern void		HText_unlinkSelection PARAMS((HText * me));
extern HTAnchor *	HText_referenceSelected PARAMS((HText * me));
extern HTAnchor *	HText_linkSelTo PARAMS((HText * me, HTAnchor* anchor));


#endif /* HTEXT_H */

end