Tk_CanvasTextInfo(3)					       Tk Library Procedures					      Tk_CanvasTextInfo(3)

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NAME

       Tk_CanvasTextInfo - additional information for managing text items in canvases

SYNOPSIS

       #include <tk.h>

       Tk_CanvasTextInfo *
       Tk_CanvasGetTextInfo(canvas)

ARGUMENTS

       Tk_Canvas canvas (in)	      A token that identifies a particular canvas widget.
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DESCRIPTION

       Textual	canvas	items  are  somewhat  more  complicated  to manage than other items, due to things like the selection and the input focus.
       Tk_CanvasGetTextInfo may be invoked by a type manager to obtain additional information needed for items	that  display  text.   The  return
       value  from  Tk_CanvasGetTextInfo is a pointer to a structure that is shared between Tk and all the items that display text.  The structure
       has the following form:
	      typedef struct Tk_CanvasTextInfo {
		  Tk_3DBorder selBorder;
		  int selBorderWidth;
		  XColor *selFgColorPtr;
		  Tk_Item *selItemPtr;
		  int selectFirst;
		  int selectLast;
		  Tk_Item *anchorItemPtr;
		  int selectAnchor;
		  Tk_3DBorder insertBorder;
		  int insertWidth;
		  int insertBorderWidth;
		  Tk_Item *focusItemPtr;
		  int gotFocus;
		  int cursorOn;
	      } Tk_CanvasTextInfo;
       The selBorder field identifies a Tk_3DBorder that should be used for drawing the background under selected text.  selBorderWidth gives  the
       width  of  the  raised border around selected text, in pixels.  selFgColorPtr points to an XColor that describes the foreground color to be
       used when drawing selected text.  selItemPtr points to the item that is currently selected, or NULL if there is no item selected or if  the
       canvas  does  not have the selection.  selectFirst and selectLast give the indices of the first and last selected characters in selItemPtr,
       as returned by the indexProc for that item.  anchorItemPtr points to the item that currently has the selection anchor;  this is not  neces-
       sarily the same as selItemPtr.  selectAnchor is an index that identifies the anchor position within anchorItemPtr.  insertBorder contains a
       Tk_3DBorder to use when drawing the insertion cursor;  insertWidth gives the total width of the insertion cursor in pixels, and	insertBor-
       derWidth  gives the width of the raised	border around the insertion cursor.  focusItemPtr identifies the item that currently has the input
       focus, or NULL if there is no such item.  gotFocus is 1 if the canvas widget has the input focus and 0 otherwise.  cursorOn  is	1  if  the
       insertion  cursor should be drawn in focusItemPtr and 0 if it should not be drawn;  this field is toggled on and off by Tk to make the cur-
       sor blink.

       The structure returned by Tk_CanvasGetTextInfo is shared between Tk and the type managers;  typically the type manager calls  Tk_CanvasGet-
       TextInfo  once  when  an  item is created and then saves the pointer in the item's record.  Tk will update information in the Tk_CanvasTex-
       tInfo;  for example, a configure widget command might change the selBorder field, or a select widget command might change  the  selectFirst
       field, or Tk might change cursorOn in order to make the insertion cursor flash on and off during successive redisplays.

       Type  managers  should treat all of the fields of the Tk_CanvasTextInfo structure as read-only, except for selItemPtr, selectFirst, select-
       Last, and selectAnchor.	Type managers may change selectFirst, selectLast, and selectAnchor to adjust for insertions and deletions  in  the
       item  (but  only if the item is the current owner of the selection or anchor, as determined by selItemPtr or anchorItemPtr).  If all of the
       selected text in the item is deleted, the item should set selItemPtr to NULL to indicate that there is no longer a selection.

KEYWORDS

       canvas, focus, insertion cursor, selection, selection anchor, text

Tk									4.0						      Tk_CanvasTextInfo(3)