git.zerfleddert.de Git - micropolis/blame_incremental - src/tk/tkcanvas.h

/*
 * tkCanvas.h --
 *
 *	Declarations shared among all the files that implement
 *	canvas widgets.
 *
 * Copyright 1991-1992 Regents of the University of California.
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies.  The University of California
 * makes no representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 *
 * $Header: /user6/ouster/wish/RCS/tkCanvas.h,v 1.14 92/08/19 08:34:16 ouster Exp $ SPRITE (Berkeley)
 */

#ifndef _TKCANVAS
#define _TKCANVAS

#ifndef _TK
#include "tk.h"
#endif

/*
 * For each item in a canvas widget there exists one record with
 * the following structure.  Each actual item is represented by
 * a record with the following stuff at its beginning, plus additional
 * type-specific stuff after that.
 */

#define TK_TAG_SPACE 3

typedef struct Tk_Item  {
    int id;				/* Unique identifier for this item
					 * (also serves as first tag for
					 * item). */
    struct Tk_Item *nextPtr;		/* Next in display list of all
					 * items in this canvas.  Later items
					 * in list are drawn on top of earlier
					 * ones. */
    Tk_Uid staticTagSpace[TK_TAG_SPACE];/* Built-in space for limited # of
					 * tags. */
    Tk_Uid *tagPtr;			/* Pointer to array of tags.  Usually
					 * points to staticTagSpace, but
					 * may point to malloc-ed space if
					 * there are lots of tags. */
    int tagSpace;			/* Total amount of tag space available
					 * at tagPtr. */
    int numTags;			/* Number of tag slots actually used
					 * at *tagPtr. */
    struct Tk_ItemType *typePtr;	/* Table of procedures that implement
					 * this type of item. */
    int x1, y1, x2, y2;			/* Bounding box for item, in integer
					 * canvas units. Set by item-specific
					 * code and guaranteed to contain every
					 * pixel drawn in item.  Item area
					 * includes x1 and y1 but not x2
					 * and y2. */

    /*
     *------------------------------------------------------------------
     * Starting here is additional type-specific stuff;  see the
     * declarations for individual types to see what is part of
     * each type.  The actual space below is determined by the
     * "itemInfoSize" of the type's Tk_ItemType record.
     *------------------------------------------------------------------
     */
} Tk_Item;

/*
 * The record below describes a canvas widget.  It is made available
 * to the item procedures so they can access certain shared fields such
 * as the overall displacement and scale factor for the canvas.
 */

typedef struct {
    Tk_Window tkwin;		/* Window that embodies the canvas.  NULL
				 * means that the window has been destroyed
				 * but the data structures haven't yet been
				 * cleaned up.*/
    Tcl_Interp *interp;		/* Interpreter associated with canvas. */
    Tk_Item *firstItemPtr;	/* First in list of all items in canvas,
				 * or NULL if canvas empty. */
    Tk_Item *lastItemPtr;	/* Last in list of all items in canvas,
				 * or NULL if canvas empty. */

    /*
     * Information used when displaying widget:
     */

    int borderWidth;		/* Width of 3-D border around window. */
    Tk_3DBorder bgBorder;	/* Used for canvas background. */
    XColor *bgColor;		/* Color used for clearing to background. */
    int relief;			/* Indicates whether window as a whole is
				 * raised, sunken, or flat. */
    GC pixmapGC;		/* Used to copy bits from a pixmap to the
				 * screen and also to clear the pixmap. */
    int width, height;		/* Dimensions to request for canvas window,
				 * specified in pixels. */
    int redrawX1, redrawY1;	/* Upper left corner of area to redraw,
				 * in pixel coordinates.  Border pixels
				 * are included.  Only valid if
				 * REDRAW_PENDING flag is set. */
    int redrawX2, redrawY2;	/* Lower right corner of area to redraw,
				 * in pixel coordinates.  Border pixels
				 * will *not* be redrawn. */
    int confine;		/* Non-zero means constrain view to keep
				 * as much of canvas visible as possible. */

    /*
     * Information used to manage and display selection:
     */

    Tk_3DBorder selBorder;	/* Border and background for selected
				 * characters. */
    int selBorderWidth;		/* Width of border around selection. */
    XColor *selFgColorPtr;	/* Foreground color for selected text. */
    Tk_Item *selItemPtr;	/* Pointer to selected item.  NULL means
				 * selection isn't in this canvas. */
    int selectFirst;		/* Index of first selected character. */
    int selectLast;		/* Index of last selected character. */
    Tk_Item *anchorItemPtr;	/* Item corresponding to "selectAnchor":
				 * not necessarily selItemPtr. */
    int selectAnchor;		/* Fixed end of selection (i.e. "select to"
				 * operation will use this as one end of the
				 * selection). */

    /*
     * Information for display insertion cursor in text:
     */

    Tk_3DBorder cursorBorder;	/* Used to draw vertical bar for insertion
				 * cursor. */
    int cursorWidth;		/* Total width of insertion cursor. */
    int cursorBorderWidth;	/* Width of 3-D border around insert cursor. */
    int cursorOnTime;		/* Number of milliseconds cursor should spend
				 * in "on" state for each blink. */
    int cursorOffTime;		/* Number of milliseconds cursor should spend
				 * in "off" state for each blink. */
    Tk_TimerToken cursorBlinkHandler;
				/* Timer handler used to blink cursor on and
				 * off. */
    Tk_Item *focusItemPtr;	/* Item that currently has the input focus,
				 * or NULL if no such item. */

    /*
     * Transformation applied to canvas as a whole:  to compute screen
     * coordinates (X,Y) from canvas coordinates (x,y), do the following:
     *
     * X = x - xOrigin;
     * Y = y - yOrigin;
     */

    int xOrigin, yOrigin;	/* Canvas coordinates corresponding to
				 * upper-left corner of window, given in
				 * canvas pixel units. */
    int drawableXOrigin, drawableYOrigin;
				/* During redisplay, these fields give the
				 * canvas coordinates corresponding to
				 * the upper-left corner of the drawable
				 * where items are actually being drawn
				 * (typically a pixmap smaller than the
				 * whole window). */

    /*
     * Information used for event bindings associated with items.
     */

    Tk_BindingTable bindingTable;
				/* Table of all bindings currently defined
				 * for this canvas.  NULL means that no
				 * bindings exist, so the table hasn't been
				 * created.  Each "object" used for this
				 * table is either a Tk_Uid for a tag or
				 * the address of an item named by id. */
    Tk_Item *currentItemPtr;	/* The item currently containing the mouse
				 * pointer, or NULL if none. */
    double closeEnough;		/* The mouse is assumed to be inside an
				 * item if it is this close to it. */
    XEvent pickEvent;		/* The event upon which the current choice
				 * of currentItem is based.  Must be saved
				 * so that if the currentItem is deleted,
				 * can pick another. */

    /*
     * Information used for managing scrollbars:
     */

    char *xScrollCmd;		/* Command prefix for communicating with
				 * horizontal scrollbar.  NULL means no
				 * horizontal scrollbar.  Malloc'ed*/
    char *yScrollCmd;		/* Command prefix for communicating with
				 * vertical scrollbar.  NULL means no
				 * vertical scrollbar.  Malloc'ed*/
    int scrollX1, scrollY1, scrollX2, scrollY2;
				/* These four coordinates define the region
				 * that is the 100% area for scrolling (i.e.
				 * these numbers determine the size and
				 * location of the sliders on scrollbars).
				 * Units are pixels in canvas coords. */
    char *regionString;		/* The option string from which scrollX1
				 * etc. are derived.  Malloc'ed. */
    int scrollIncrement;	/* The number of canvas units that the
				 * picture shifts when a scrollbar up or
				 * down arrow is pressed. */

    /*
     * Information used for scanning:
     */

    int scanX;			/* X-position at which scan started (e.g.
				 * button was pressed here). */
    int scanXOrigin;		/* Value of xOrigin field when scan started. */
    int scanY;			/* Y-position at which scan started (e.g.
				 * button was pressed here). */
    int scanYOrigin;		/* Value of yOrigin field when scan started. */

    /*
     * Information used to speed up searches by remembering the last item
     * created or found with an item id search.
     */

    Tk_Item *hotPtr;		/* Pointer to "hot" item (one that's been
				 * recently used.  NULL means there's no
				 * hot item. */
    Tk_Item *hotPrevPtr;	/* Pointer to predecessor to hotPtr (NULL
				 * means item is first in list).  This is
				 * only a hint and may not really be hotPtr's
				 * predecessor. */

    /*
     * Miscellaneous information:
     */

    Cursor cursor;		/* Current cursor for window, or None. */
    double pixelsPerMM;		/* Scale factor between MM and pixels;
				 * used when converting coordinates. */
    int flags;			/* Various flags;  see below for
				 * definitions. */
    int nextId;			/* Number to use as id for next item
				 * created in widget. */
    Tk_TimerToken updateTimerToken; /* Added by Don to optimize rapid
				     * updates. */
} Tk_Canvas;

/*
 * Flag bits for canvases:
 *
 * REDRAW_PENDING -		1 means a DoWhenIdle handler has already
 *				been created to redraw some or all of the
 *				canvas.
 * REPICK_NEEDED -		1 means DisplayCanvas should pick a new
 *				current item before redrawing the canvas.
 * GOT_FOCUS -			1 means the focus is currently in this
 *				widget, so should draw the insertion cursor.
 * CURSOR_ON -			1 means the insertion cursor is in the "on"
 *				phase of its blink cycle.  0 means either
 *				we don't have the focus or the cursor is in
 *				the "off" phase of its cycle.
 * BUTTON_DOWN -		1 means that a button is currently down;
 *				this is used to implement grabs for the
 *				duration of button presses.
 * UPDATE_SCROLLBARS -		1 means the scrollbars should get updated
 *				as part of the next display operation.
 */

#define REDRAW_PENDING		1
#define REPICK_NEEDED		2
#define GOT_FOCUS		4
#define CURSOR_ON		8
#define BUTTON_DOWN		0x10
#define UPDATE_SCROLLBARS	0x20

/*
 * Records of the following type are used to describe a type of
 * item (e.g.  lines, circles, etc.) that can form part of a
 * canvas widget.
 */

typedef int	Tk_ItemCreateProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, int argc, char **argv));
typedef int	Tk_ItemConfigureProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, int argc, char **argv, int flags));
typedef int	Tk_ItemCoordProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, int argc, char **argv));
typedef void	Tk_ItemDeleteProc _ANSI_ARGS_((Tk_Item *itemPtr));
typedef void	Tk_ItemDisplayProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, Drawable dst));
typedef double	Tk_ItemPointProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, double *pointPtr));
typedef int	Tk_ItemAreaProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, double *rectPtr));
typedef void	Tk_ItemPostscriptProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr));
typedef void	Tk_ItemScaleProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, double originX, double originY,
		    double scaleX, double scaleY));
typedef void	Tk_ItemTranslateProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, double deltaX, double deltaY));
typedef int	Tk_ItemIndexProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, char *indexString,
		    int *indexPtr));
typedef void	Tk_ItemCursorProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, int index));
typedef int	Tk_ItemSelectionProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, int offset, char *buffer,
		    int maxBytes));
typedef int	Tk_ItemInsertProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, int beforeThis, char *string));
typedef int	Tk_ItemDCharsProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
		    Tk_Item *itemPtr, int first, int last));

typedef struct Tk_ItemType {
    char *name;				/* The name of this type of item, such
					 * as "line". */
    int itemSize;			/* Total amount of space needed for
					 * item's record. */
    Tk_ItemCreateProc *createProc;	/* Procedure to create a new item of
					 * this type. */
    Tk_ConfigSpec *configSpecs;		/* Pointer to array of configuration
					 * specs for this type.  Used for
					 * returning configuration info. */
    Tk_ItemConfigureProc *configProc;	/* Procedure to call to change
					 * configuration options. */
    Tk_ItemCoordProc *coordProc;	/* Procedure to call to get and set
					 * the item's coordinates. */
    Tk_ItemDeleteProc *deleteProc;	/* Procedure to delete existing item of
					 * this type. */
    Tk_ItemDisplayProc *displayProc;	/* Procedure to display items of
					 * this type. */
    int alwaysRedraw;			/* Non-zero means displayProc should
					 * be called even when the item has
					 * been moved off-screen. */
    Tk_ItemPointProc *pointProc;	/* Computes distance from item to
					 * a given point. */
    Tk_ItemAreaProc *areaProc;		/* Computes whether item is inside,
					 * outside, or overlapping an area. */
    Tk_ItemPostscriptProc *postscriptProc;
					/* Procedure to write a Postscript
					 * description for items of this
					 * type. */
    Tk_ItemScaleProc *scaleProc;	/* Procedure to rescale items of
					 * this type. */
    Tk_ItemTranslateProc *translateProc;/* Procedure to translate items of
					 * this type. */
    Tk_ItemIndexProc *indexProc;	/* Procedure to determine index of
					 * indicated character.  NULL if
					 * item doesn't support indexing. */
    Tk_ItemCursorProc *cursorProc;	/* Procedure to set cursor position
					 * to just before a given position. */
    Tk_ItemSelectionProc *selectionProc;/* Procedure to return selection (in
					 * STRING format) when it is in this
					 * item. */
    Tk_ItemInsertProc *insertProc;	/* Procedure to insert something into
					 * an item. */
    Tk_ItemDCharsProc *dCharsProc;	/* Procedure to delete characters
					 * from an item. */
    struct Tk_ItemType *nextPtr;	/* Used to link types together into
					 * a list. */
} Tk_ItemType;

/*
 * Macros to transform a point from double-precision canvas coordinates
 * to integer pixel coordinates in the pixmap where redisplay is being
 * done.
 */

#define SCREEN_X(canvasPtr, x) \
	(((int) ((x) + 0.5)) - (canvasPtr)->drawableXOrigin)
#define SCREEN_Y(canvasPtr, y) \
	(((int) ((y) + 0.5)) - (canvasPtr)->drawableYOrigin)

/*
 * Canvas-related variables that are shared among Tk modules but not
 * exported to the outside world:
 */

extern Tk_CustomOption tkCanvasTagsOption;

/*
 * Canvas-related procedures that are shared among Tk modules but not
 * exported to the outside world:
 */

extern void		TkBezierScreenPoints _ANSI_ARGS_((Tk_Canvas *canvasPtr,
			    double control[], int numSteps,
			    XPoint *xPointPtr));
extern void		TkFillPolygon _ANSI_ARGS_((Tk_Canvas *canvasPtr,
			    double *coordPtr, int numPoints, Drawable drawable,
			    GC gc));
extern int		TkGetCanvasCoord _ANSI_ARGS_((Tk_Canvas *canvasPtr,
			    char *string, double *doublePtr));
extern void		TkIncludePoint _ANSI_ARGS_((Tk_Canvas *canvasPtr,
			    Tk_Item *itemPtr, double *pointPtr));
extern int		TkMakeBezierCurve _ANSI_ARGS_((Tk_Canvas *canvasPtr,
			    double *pointPtr, int numPoints, int numSteps,
			    XPoint xPoints[], double dblPoints[]));

#endif /* _TKCANVAS */
Commit	Line	Data
	1	/*
	2	* tkCanvas.h --
	3	*
	4	* Declarations shared among all the files that implement
	5	* canvas widgets.
	6	*
	7	* Copyright 1991-1992 Regents of the University of California.
	8	* Permission to use, copy, modify, and distribute this
	9	* software and its documentation for any purpose and without
	10	* fee is hereby granted, provided that the above copyright
	11	* notice appear in all copies. The University of California
	12	* makes no representations about the suitability of this
	13	* software for any purpose. It is provided "as is" without
	14	* express or implied warranty.
	15	*
	16	* $Header: /user6/ouster/wish/RCS/tkCanvas.h,v 1.14 92/08/19 08:34:16 ouster Exp $ SPRITE (Berkeley)
	17	*/
	18
	19	#ifndef _TKCANVAS
	20	#define _TKCANVAS
	21
	22	#ifndef _TK
	23	#include "tk.h"
	24	#endif
	25
	26	/*
	27	* For each item in a canvas widget there exists one record with
	28	* the following structure. Each actual item is represented by
	29	* a record with the following stuff at its beginning, plus additional
	30	* type-specific stuff after that.
	31	*/
	32
	33	#define TK_TAG_SPACE 3
	34
	35	typedef struct Tk_Item {
	36	int id; /* Unique identifier for this item
	37	* (also serves as first tag for
	38	* item). */
	39	struct Tk_Item nextPtr; / Next in display list of all
	40	* items in this canvas. Later items
	41	* in list are drawn on top of earlier
	42	* ones. */
	43	Tk_Uid staticTagSpace[TK_TAG_SPACE];/* Built-in space for limited # of
	44	* tags. */
	45	Tk_Uid tagPtr; / Pointer to array of tags. Usually
	46	* points to staticTagSpace, but
	47	* may point to malloc-ed space if
	48	* there are lots of tags. */
	49	int tagSpace; /* Total amount of tag space available
	50	* at tagPtr. */
	51	int numTags; /* Number of tag slots actually used
	52	* at tagPtr. /
	53	struct Tk_ItemType typePtr; / Table of procedures that implement
	54	* this type of item. */
	55	int x1, y1, x2, y2; /* Bounding box for item, in integer
	56	* canvas units. Set by item-specific
	57	* code and guaranteed to contain every
	58	* pixel drawn in item. Item area
	59	* includes x1 and y1 but not x2
	60	* and y2. */
	61
	62	/*
	63	*------------------------------------------------------------------
	64	* Starting here is additional type-specific stuff; see the
	65	* declarations for individual types to see what is part of
	66	* each type. The actual space below is determined by the
	67	* "itemInfoSize" of the type's Tk_ItemType record.
	68	*------------------------------------------------------------------
	69	*/
	70	} Tk_Item;
	71
	72	/*
	73	* The record below describes a canvas widget. It is made available
	74	* to the item procedures so they can access certain shared fields such
	75	* as the overall displacement and scale factor for the canvas.
	76	*/
	77
	78	typedef struct {
	79	Tk_Window tkwin; /* Window that embodies the canvas. NULL
	80	* means that the window has been destroyed
	81	* but the data structures haven't yet been
	82	* cleaned up.*/
	83	Tcl_Interp interp; / Interpreter associated with canvas. */
	84	Tk_Item firstItemPtr; / First in list of all items in canvas,
	85	* or NULL if canvas empty. */
	86	Tk_Item lastItemPtr; / Last in list of all items in canvas,
	87	* or NULL if canvas empty. */
	88
	89	/*
	90	* Information used when displaying widget:
	91	*/
	92
	93	int borderWidth; /* Width of 3-D border around window. */
	94	Tk_3DBorder bgBorder; /* Used for canvas background. */
	95	XColor bgColor; / Color used for clearing to background. */
	96	int relief; /* Indicates whether window as a whole is
	97	* raised, sunken, or flat. */
	98	GC pixmapGC; /* Used to copy bits from a pixmap to the
	99	* screen and also to clear the pixmap. */
	100	int width, height; /* Dimensions to request for canvas window,
	101	* specified in pixels. */
	102	int redrawX1, redrawY1; /* Upper left corner of area to redraw,
	103	* in pixel coordinates. Border pixels
	104	* are included. Only valid if
	105	* REDRAW_PENDING flag is set. */
	106	int redrawX2, redrawY2; /* Lower right corner of area to redraw,
	107	* in pixel coordinates. Border pixels
	108	* will not be redrawn. */
	109	int confine; /* Non-zero means constrain view to keep
	110	* as much of canvas visible as possible. */
	111
	112	/*
	113	* Information used to manage and display selection:
	114	*/
	115
	116	Tk_3DBorder selBorder; /* Border and background for selected
	117	* characters. */
	118	int selBorderWidth; /* Width of border around selection. */
	119	XColor selFgColorPtr; / Foreground color for selected text. */
	120	Tk_Item selItemPtr; / Pointer to selected item. NULL means
	121	* selection isn't in this canvas. */
	122	int selectFirst; /* Index of first selected character. */
	123	int selectLast; /* Index of last selected character. */
	124	Tk_Item anchorItemPtr; / Item corresponding to "selectAnchor":
	125	* not necessarily selItemPtr. */
	126	int selectAnchor; /* Fixed end of selection (i.e. "select to"
	127	* operation will use this as one end of the
	128	* selection). */
	129
	130	/*
	131	* Information for display insertion cursor in text:
	132	*/
	133
	134	Tk_3DBorder cursorBorder; /* Used to draw vertical bar for insertion
	135	* cursor. */
	136	int cursorWidth; /* Total width of insertion cursor. */
	137	int cursorBorderWidth; /* Width of 3-D border around insert cursor. */
	138	int cursorOnTime; /* Number of milliseconds cursor should spend
	139	* in "on" state for each blink. */
	140	int cursorOffTime; /* Number of milliseconds cursor should spend
	141	* in "off" state for each blink. */
	142	Tk_TimerToken cursorBlinkHandler;
	143	/* Timer handler used to blink cursor on and
	144	* off. */
	145	Tk_Item focusItemPtr; / Item that currently has the input focus,
	146	* or NULL if no such item. */
	147
	148	/*
	149	* Transformation applied to canvas as a whole: to compute screen
	150	* coordinates (X,Y) from canvas coordinates (x,y), do the following:
	151	*
	152	* X = x - xOrigin;
	153	* Y = y - yOrigin;
	154	*/
	155
	156	int xOrigin, yOrigin; /* Canvas coordinates corresponding to
	157	* upper-left corner of window, given in
	158	* canvas pixel units. */
	159	int drawableXOrigin, drawableYOrigin;
	160	/* During redisplay, these fields give the
	161	* canvas coordinates corresponding to
	162	* the upper-left corner of the drawable
	163	* where items are actually being drawn
	164	* (typically a pixmap smaller than the
	165	* whole window). */
	166
	167	/*
	168	* Information used for event bindings associated with items.
	169	*/
	170
	171	Tk_BindingTable bindingTable;
	172	/* Table of all bindings currently defined
	173	* for this canvas. NULL means that no
	174	* bindings exist, so the table hasn't been
	175	* created. Each "object" used for this
	176	* table is either a Tk_Uid for a tag or
	177	* the address of an item named by id. */
	178	Tk_Item currentItemPtr; / The item currently containing the mouse
	179	* pointer, or NULL if none. */
	180	double closeEnough; /* The mouse is assumed to be inside an
	181	* item if it is this close to it. */
	182	XEvent pickEvent; /* The event upon which the current choice
	183	* of currentItem is based. Must be saved
	184	* so that if the currentItem is deleted,
	185	* can pick another. */
	186
	187	/*
	188	* Information used for managing scrollbars:
	189	*/
	190
	191	char xScrollCmd; / Command prefix for communicating with
	192	* horizontal scrollbar. NULL means no
	193	* horizontal scrollbar. Malloc'ed*/
	194	char yScrollCmd; / Command prefix for communicating with
	195	* vertical scrollbar. NULL means no
	196	* vertical scrollbar. Malloc'ed*/
	197	int scrollX1, scrollY1, scrollX2, scrollY2;
	198	/* These four coordinates define the region
	199	* that is the 100% area for scrolling (i.e.
	200	* these numbers determine the size and
	201	* location of the sliders on scrollbars).
	202	* Units are pixels in canvas coords. */
	203	char regionString; / The option string from which scrollX1
	204	* etc. are derived. Malloc'ed. */
	205	int scrollIncrement; /* The number of canvas units that the
	206	* picture shifts when a scrollbar up or
	207	* down arrow is pressed. */
	208
	209	/*
	210	* Information used for scanning:
	211	*/
	212
	213	int scanX; /* X-position at which scan started (e.g.
	214	* button was pressed here). */
	215	int scanXOrigin; /* Value of xOrigin field when scan started. */
	216	int scanY; /* Y-position at which scan started (e.g.
	217	* button was pressed here). */
	218	int scanYOrigin; /* Value of yOrigin field when scan started. */
	219
	220	/*
	221	* Information used to speed up searches by remembering the last item
	222	* created or found with an item id search.
	223	*/
	224
	225	Tk_Item hotPtr; / Pointer to "hot" item (one that's been
	226	* recently used. NULL means there's no
	227	* hot item. */
	228	Tk_Item hotPrevPtr; / Pointer to predecessor to hotPtr (NULL
	229	* means item is first in list). This is
	230	* only a hint and may not really be hotPtr's
	231	* predecessor. */
	232
	233	/*
	234	* Miscellaneous information:
	235	*/
	236
	237	Cursor cursor; /* Current cursor for window, or None. */
	238	double pixelsPerMM; /* Scale factor between MM and pixels;
	239	* used when converting coordinates. */
	240	int flags; /* Various flags; see below for
	241	* definitions. */
	242	int nextId; /* Number to use as id for next item
	243	* created in widget. */
	244	Tk_TimerToken updateTimerToken; /* Added by Don to optimize rapid
	245	* updates. */
	246	} Tk_Canvas;
	247
	248	/*
	249	* Flag bits for canvases:
	250	*
	251	* REDRAW_PENDING - 1 means a DoWhenIdle handler has already
	252	* been created to redraw some or all of the
	253	* canvas.
	254	* REPICK_NEEDED - 1 means DisplayCanvas should pick a new
	255	* current item before redrawing the canvas.
	256	* GOT_FOCUS - 1 means the focus is currently in this
	257	* widget, so should draw the insertion cursor.
	258	* CURSOR_ON - 1 means the insertion cursor is in the "on"
	259	* phase of its blink cycle. 0 means either
	260	* we don't have the focus or the cursor is in
	261	* the "off" phase of its cycle.
	262	* BUTTON_DOWN - 1 means that a button is currently down;
	263	* this is used to implement grabs for the
	264	* duration of button presses.
	265	* UPDATE_SCROLLBARS - 1 means the scrollbars should get updated
	266	* as part of the next display operation.
	267	*/
	268
	269	#define REDRAW_PENDING 1
	270	#define REPICK_NEEDED 2
	271	#define GOT_FOCUS 4
	272	#define CURSOR_ON 8
	273	#define BUTTON_DOWN 0x10
	274	#define UPDATE_SCROLLBARS 0x20
	275
	276	/*
	277	* Records of the following type are used to describe a type of
	278	* item (e.g. lines, circles, etc.) that can form part of a
	279	* canvas widget.
	280	*/
	281
	282	typedef int Tk_ItemCreateProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	283	Tk_Item itemPtr, int argc, char *argv));
	284	typedef int Tk_ItemConfigureProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	285	Tk_Item itemPtr, int argc, char *argv, int flags));
	286	typedef int Tk_ItemCoordProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	287	Tk_Item itemPtr, int argc, char *argv));
	288	typedef void Tk_ItemDeleteProc _ANSI_ARGS_((Tk_Item *itemPtr));
	289	typedef void Tk_ItemDisplayProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	290	Tk_Item *itemPtr, Drawable dst));
	291	typedef double Tk_ItemPointProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	292	Tk_Item itemPtr, double pointPtr));
	293	typedef int Tk_ItemAreaProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	294	Tk_Item itemPtr, double rectPtr));
	295	typedef void Tk_ItemPostscriptProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	296	Tk_Item *itemPtr));
	297	typedef void Tk_ItemScaleProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	298	Tk_Item *itemPtr, double originX, double originY,
	299	double scaleX, double scaleY));
	300	typedef void Tk_ItemTranslateProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	301	Tk_Item *itemPtr, double deltaX, double deltaY));
	302	typedef int Tk_ItemIndexProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	303	Tk_Item itemPtr, char indexString,
	304	int *indexPtr));
	305	typedef void Tk_ItemCursorProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	306	Tk_Item *itemPtr, int index));
	307	typedef int Tk_ItemSelectionProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	308	Tk_Item itemPtr, int offset, char buffer,
	309	int maxBytes));
	310	typedef int Tk_ItemInsertProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	311	Tk_Item itemPtr, int beforeThis, char string));
	312	typedef int Tk_ItemDCharsProc _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	313	Tk_Item *itemPtr, int first, int last));
	314
	315	typedef struct Tk_ItemType {
	316	char name; / The name of this type of item, such
	317	* as "line". */
	318	int itemSize; /* Total amount of space needed for
	319	* item's record. */
	320	Tk_ItemCreateProc createProc; / Procedure to create a new item of
	321	* this type. */
	322	Tk_ConfigSpec configSpecs; / Pointer to array of configuration
	323	* specs for this type. Used for
	324	* returning configuration info. */
	325	Tk_ItemConfigureProc configProc; / Procedure to call to change
	326	* configuration options. */
	327	Tk_ItemCoordProc coordProc; / Procedure to call to get and set
	328	* the item's coordinates. */
	329	Tk_ItemDeleteProc deleteProc; / Procedure to delete existing item of
	330	* this type. */
	331	Tk_ItemDisplayProc displayProc; / Procedure to display items of
	332	* this type. */
	333	int alwaysRedraw; /* Non-zero means displayProc should
	334	* be called even when the item has
	335	* been moved off-screen. */
	336	Tk_ItemPointProc pointProc; / Computes distance from item to
	337	* a given point. */
	338	Tk_ItemAreaProc areaProc; / Computes whether item is inside,
	339	* outside, or overlapping an area. */
	340	Tk_ItemPostscriptProc *postscriptProc;
	341	/* Procedure to write a Postscript
	342	* description for items of this
	343	* type. */
	344	Tk_ItemScaleProc scaleProc; / Procedure to rescale items of
	345	* this type. */
	346	Tk_ItemTranslateProc translateProc;/ Procedure to translate items of
	347	* this type. */
	348	Tk_ItemIndexProc indexProc; / Procedure to determine index of
	349	* indicated character. NULL if
	350	* item doesn't support indexing. */
	351	Tk_ItemCursorProc cursorProc; / Procedure to set cursor position
	352	* to just before a given position. */
	353	Tk_ItemSelectionProc selectionProc;/ Procedure to return selection (in
	354	* STRING format) when it is in this
	355	* item. */
	356	Tk_ItemInsertProc insertProc; / Procedure to insert something into
	357	* an item. */
	358	Tk_ItemDCharsProc dCharsProc; / Procedure to delete characters
	359	* from an item. */
	360	struct Tk_ItemType nextPtr; / Used to link types together into
	361	* a list. */
	362	} Tk_ItemType;
	363
	364	/*
	365	* Macros to transform a point from double-precision canvas coordinates
	366	* to integer pixel coordinates in the pixmap where redisplay is being
	367	* done.
	368	*/
	369
	370	#define SCREEN_X(canvasPtr, x) \
	371	(((int) ((x) + 0.5)) - (canvasPtr)->drawableXOrigin)
	372	#define SCREEN_Y(canvasPtr, y) \
	373	(((int) ((y) + 0.5)) - (canvasPtr)->drawableYOrigin)
	374
	375	/*
	376	* Canvas-related variables that are shared among Tk modules but not
	377	* exported to the outside world:
	378	*/
	379
	380	extern Tk_CustomOption tkCanvasTagsOption;
	381
	382	/*
	383	* Canvas-related procedures that are shared among Tk modules but not
	384	* exported to the outside world:
	385	*/
	386
	387	extern void TkBezierScreenPoints _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	388	double control[], int numSteps,
	389	XPoint *xPointPtr));
	390	extern void TkFillPolygon _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	391	double *coordPtr, int numPoints, Drawable drawable,
	392	GC gc));
	393	extern int TkGetCanvasCoord _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	394	char string, double doublePtr));
	395	extern void TkIncludePoint _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	396	Tk_Item itemPtr, double pointPtr));
	397	extern int TkMakeBezierCurve _ANSI_ARGS_((Tk_Canvas *canvasPtr,
	398	double *pointPtr, int numPoints, int numSteps,
	399	XPoint xPoints[], double dblPoints[]));
	400
	401	#endif /* _TKCANVAS */