tk8.7a5/generic/tkCanvLine.c

/*
 * tkCanvLine.c --
 *
 *	This file implements line items for canvas widgets.
 *
 * Copyright © 1991-1994 The Regents of the University of California.
 * Copyright © 1994-1997 Sun Microsystems, Inc.
 * Copyright © 1998-1999 Scriptics Corporation.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tkInt.h"
#include "tkCanvas.h"
#include "default.h"

/*
 * The structure below defines the record for each line item.
 */

typedef enum {
    ARROWS_NONE, ARROWS_FIRST, ARROWS_LAST, ARROWS_BOTH
} Arrows;

typedef struct LineItem {
    Tk_Item header;		/* Generic stuff that's the same for all
				 * types. MUST BE FIRST IN STRUCTURE. */
    Tk_Outline outline;		/* Outline structure */
    Tk_Canvas canvas;		/* Canvas containing item. Needed for parsing
				 * arrow shapes. */
    int numPoints;		/* Number of points in line (always >= 0). */
    double *coordPtr;		/* Pointer to malloc-ed array containing x-
				 * and y-coords of all points in line.
				 * X-coords are even-valued indices, y-coords
				 * are corresponding odd-valued indices. If
				 * the line has arrowheads then the first and
				 * last points have been adjusted to refer to
				 * the necks of the arrowheads rather than
				 * their tips. The actual endpoints are stored
				 * in the *firstArrowPtr and *lastArrowPtr, if
				 * they exist. */
    int capStyle;		/* Cap style for line. */
    int joinStyle;		/* Join style for line. */
    GC arrowGC;			/* Graphics context for drawing arrowheads. */
    Arrows arrow;		/* Indicates whether or not to draw arrowheads:
				 * "none", "first", "last", or "both". */
    float arrowShapeA;		/* Distance from tip of arrowhead to center. */
    float arrowShapeB;		/* Distance from tip of arrowhead to trailing
				 * point, measured along shaft. */
    float arrowShapeC;		/* Distance of trailing points from outside
				 * edge of shaft. */
    double *firstArrowPtr;	/* Points to array of PTS_IN_ARROW points
				 * describing polygon for arrowhead at first
				 * point in line. First point of arrowhead is
				 * tip. Malloc'ed. NULL means no arrowhead at
				 * first point. */
    double *lastArrowPtr;	/* Points to polygon for arrowhead at last
				 * point in line (PTS_IN_ARROW points, first
				 * of which is tip). Malloc'ed. NULL means no
				 * arrowhead at last point. */
    const Tk_SmoothMethod *smooth; /* Non-zero means draw line smoothed (i.e.
				 * with Bezier splines). */
    int splineSteps;		/* Number of steps in each spline segment. */
} LineItem;

/*
 * Number of points in an arrowHead:
 */

#define PTS_IN_ARROW 6

/*
 * Prototypes for functions defined in this file:
 */

static int		ArrowheadPostscript(Tcl_Interp *interp,
			    Tk_Canvas canvas, LineItem *linePtr,
			    double *arrowPtr, Tcl_Obj *psObj);
static void		ComputeLineBbox(Tk_Canvas canvas, LineItem *linePtr);
static int		ConfigureLine(Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr, int objc,
			    Tcl_Obj *const objv[], int flags);
static int		ConfigureArrows(Tk_Canvas canvas, LineItem *linePtr);
static int		CreateLine(Tcl_Interp *interp,
			    Tk_Canvas canvas, struct Tk_Item *itemPtr,
			    int objc, Tcl_Obj *const objv[]);
static void		DeleteLine(Tk_Canvas canvas,
			    Tk_Item *itemPtr, Display *display);
static void		DisplayLine(Tk_Canvas canvas,
			    Tk_Item *itemPtr, Display *display, Drawable dst,
			    int x, int y, int width, int height);
static int		GetLineIndex(Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr,
			    Tcl_Obj *obj, TkSizeT *indexPtr);
static int		LineCoords(Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr,
			    int objc, Tcl_Obj *const objv[]);
static void		LineDeleteCoords(Tk_Canvas canvas,
			    Tk_Item *itemPtr, TkSizeT first, TkSizeT last);
static void		LineInsert(Tk_Canvas canvas,
			    Tk_Item *itemPtr, TkSizeT beforeThis, Tcl_Obj *obj);
static int		LineToArea(Tk_Canvas canvas,
			    Tk_Item *itemPtr, double *rectPtr);
static double		LineToPoint(Tk_Canvas canvas,
			    Tk_Item *itemPtr, double *coordPtr);
static int		LineToPostscript(Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr, int prepass);
static int		ArrowParseProc(ClientData clientData,
			    Tcl_Interp *interp, Tk_Window tkwin,
			    const char *value, char *recordPtr, TkSizeT offset);
static const char * ArrowPrintProc(ClientData clientData,
			    Tk_Window tkwin, char *recordPtr, TkSizeT offset,
			    Tcl_FreeProc **freeProcPtr);
static int		ParseArrowShape(ClientData clientData,
			    Tcl_Interp *interp, Tk_Window tkwin,
			    const char *value, char *recordPtr, TkSizeT offset);
static const char * PrintArrowShape(ClientData clientData,
			    Tk_Window tkwin, char *recordPtr, TkSizeT offset,
			    Tcl_FreeProc **freeProcPtr);
static void		RotateLine(Tk_Canvas canvas, Tk_Item *itemPtr,
			    double originX, double originY, double angleRad);
static void		ScaleLine(Tk_Canvas canvas,
			    Tk_Item *itemPtr, double originX, double originY,
			    double scaleX, double scaleY);
static void		TranslateLine(Tk_Canvas canvas,
			    Tk_Item *itemPtr, double deltaX, double deltaY);

/*
 * Information used for parsing configuration specs. If you change any of the
 * default strings, be sure to change the corresponding default values in
 * CreateLine.
 */

static const Tk_CustomOption arrowShapeOption = {
    ParseArrowShape, PrintArrowShape, NULL
};
static const Tk_CustomOption arrowOption = {
    ArrowParseProc, ArrowPrintProc, NULL
};
static const Tk_CustomOption smoothOption = {
    TkSmoothParseProc, TkSmoothPrintProc, NULL
};
static const Tk_CustomOption stateOption = {
    TkStateParseProc, TkStatePrintProc, INT2PTR(2)
};
static const Tk_CustomOption tagsOption = {
    TkCanvasTagsParseProc, TkCanvasTagsPrintProc, NULL
};
static const Tk_CustomOption dashOption = {
    TkCanvasDashParseProc, TkCanvasDashPrintProc, NULL
};
static const Tk_CustomOption offsetOption = {
    TkOffsetParseProc, TkOffsetPrintProc,
    INT2PTR(TK_OFFSET_RELATIVE|TK_OFFSET_INDEX)
};
static const Tk_CustomOption pixelOption = {
    TkPixelParseProc, TkPixelPrintProc, NULL
};

static const Tk_ConfigSpec configSpecs[] = {
    {TK_CONFIG_CUSTOM, "-activedash", NULL, NULL,
	NULL, offsetof(LineItem, outline.activeDash),
	TK_CONFIG_NULL_OK, &dashOption},
    {TK_CONFIG_COLOR, "-activefill", NULL, NULL,
	NULL, offsetof(LineItem, outline.activeColor), TK_CONFIG_NULL_OK, NULL},
    {TK_CONFIG_BITMAP, "-activestipple", NULL, NULL,
	NULL, offsetof(LineItem, outline.activeStipple), TK_CONFIG_NULL_OK, NULL},
    {TK_CONFIG_CUSTOM, "-activewidth", NULL, NULL,
	"0.0", offsetof(LineItem, outline.activeWidth),
	TK_CONFIG_DONT_SET_DEFAULT, &pixelOption},
    {TK_CONFIG_CUSTOM, "-arrow", NULL, NULL,
	"none", offsetof(LineItem, arrow),
	TK_CONFIG_DONT_SET_DEFAULT, &arrowOption},
    {TK_CONFIG_CUSTOM, "-arrowshape", NULL, NULL,
	"8 10 3", offsetof(LineItem, arrowShapeA),
	TK_CONFIG_DONT_SET_DEFAULT, &arrowShapeOption},
    {TK_CONFIG_CAP_STYLE, "-capstyle", NULL, NULL,
	"butt", offsetof(LineItem, capStyle), TK_CONFIG_DONT_SET_DEFAULT, NULL},
    {TK_CONFIG_COLOR, "-fill", NULL, NULL,
	DEF_CANVITEM_OUTLINE, offsetof(LineItem, outline.color), TK_CONFIG_NULL_OK, NULL},
    {TK_CONFIG_CUSTOM, "-dash", NULL, NULL,
	NULL, offsetof(LineItem, outline.dash),
	TK_CONFIG_NULL_OK, &dashOption},
    {TK_CONFIG_PIXELS, "-dashoffset", NULL, NULL,
	"0", offsetof(LineItem, outline.offset), TK_CONFIG_DONT_SET_DEFAULT, NULL},
    {TK_CONFIG_CUSTOM, "-disableddash", NULL, NULL,
	NULL, offsetof(LineItem, outline.disabledDash),
	TK_CONFIG_NULL_OK, &dashOption},
    {TK_CONFIG_COLOR, "-disabledfill", NULL, NULL,
	NULL, offsetof(LineItem, outline.disabledColor), TK_CONFIG_NULL_OK, NULL},
    {TK_CONFIG_BITMAP, "-disabledstipple", NULL, NULL,
	NULL, offsetof(LineItem, outline.disabledStipple), TK_CONFIG_NULL_OK, NULL},
    {TK_CONFIG_CUSTOM, "-disabledwidth", NULL, NULL,
	"0.0", offsetof(LineItem, outline.disabledWidth),
	TK_CONFIG_DONT_SET_DEFAULT, &pixelOption},
    {TK_CONFIG_JOIN_STYLE, "-joinstyle", NULL, NULL,
	"round", offsetof(LineItem, joinStyle), TK_CONFIG_DONT_SET_DEFAULT, NULL},
    {TK_CONFIG_CUSTOM, "-offset", NULL, NULL,
	"0,0", offsetof(LineItem, outline.tsoffset),
	TK_CONFIG_DONT_SET_DEFAULT, &offsetOption},
    {TK_CONFIG_CUSTOM, "-smooth", NULL, NULL,
	"0", offsetof(LineItem, smooth),
	TK_CONFIG_DONT_SET_DEFAULT, &smoothOption},
    {TK_CONFIG_INT, "-splinesteps", NULL, NULL,
	"12", offsetof(LineItem, splineSteps), TK_CONFIG_DONT_SET_DEFAULT, NULL},
    {TK_CONFIG_CUSTOM, "-state", NULL, NULL,
	NULL, offsetof(Tk_Item, state), TK_CONFIG_NULL_OK, &stateOption},
    {TK_CONFIG_BITMAP, "-stipple", NULL, NULL,
	NULL, offsetof(LineItem, outline.stipple), TK_CONFIG_NULL_OK, NULL},
    {TK_CONFIG_CUSTOM, "-tags", NULL, NULL,
	NULL, 0, TK_CONFIG_NULL_OK, &tagsOption},
    {TK_CONFIG_CUSTOM, "-width", NULL, NULL,
	"1.0", offsetof(LineItem, outline.width),
	TK_CONFIG_DONT_SET_DEFAULT, &pixelOption},
    {TK_CONFIG_END, NULL, NULL, NULL, NULL, 0, 0, NULL}
};

/*
 * The structures below defines the line item type by means of functions that
 * can be invoked by generic item code.
 */

Tk_ItemType tkLineType = {
    "line",				/* name */
    sizeof(LineItem),			/* itemSize */
    CreateLine,				/* createProc */
    configSpecs,			/* configSpecs */
    ConfigureLine,			/* configureProc */
    LineCoords,				/* coordProc */
    DeleteLine,				/* deleteProc */
    DisplayLine,			/* displayProc */
    TK_CONFIG_OBJS | TK_MOVABLE_POINTS,	/* flags */
    LineToPoint,			/* pointProc */
    LineToArea,				/* areaProc */
    LineToPostscript,			/* postscriptProc */
    ScaleLine,				/* scaleProc */
    TranslateLine,			/* translateProc */
    GetLineIndex,			/* indexProc */
    NULL,				/* icursorProc */
    NULL,				/* selectionProc */
    LineInsert,				/* insertProc */
    LineDeleteCoords,			/* dTextProc */
    NULL,				/* nextPtr */
    RotateLine,				/* rotateProc */
    0, NULL, NULL
};

/*
 * The definition below determines how large are static arrays used to hold
 * spline points (splines larger than this have to have their arrays
 * malloc-ed).
 */

#define MAX_STATIC_POINTS 200

/*
 *--------------------------------------------------------------
 *
 * CreateLine --
 *
 *	This function is invoked to create a new line item in a canvas.
 *
 * Results:
 *	A standard Tcl return value. If an error occurred in creating the
 *	item, then an error message is left in the interp's result; in this
 *	case itemPtr is left uninitialized, so it can be safely freed by the
 *	caller.
 *
 * Side effects:
 *	A new line item is created.
 *
 *--------------------------------------------------------------
 */

static int
CreateLine(
    Tcl_Interp *interp,		/* Interpreter for error reporting. */
    Tk_Canvas canvas,		/* Canvas to hold new item. */
    Tk_Item *itemPtr,		/* Record to hold new item; header has been
				 * initialized by caller. */
    int objc,			/* Number of arguments in objv. */
    Tcl_Obj *const objv[])	/* Arguments describing line. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    int i;

    if (objc == 0) {
	Tcl_Panic("canvas did not pass any coords");
    }

    /*
     * Carry out initialization that is needed to set defaults and to allow
     * proper cleanup after errors during the the remainder of this function.
     */

    Tk_CreateOutline(&linePtr->outline);
    linePtr->canvas = canvas;
    linePtr->numPoints = 0;
    linePtr->coordPtr = NULL;
    linePtr->capStyle = CapButt;
    linePtr->joinStyle = JoinRound;
    linePtr->arrowGC = NULL;
    linePtr->arrow = ARROWS_NONE;
    linePtr->arrowShapeA = (float)8.0;
    linePtr->arrowShapeB = (float)10.0;
    linePtr->arrowShapeC = (float)3.0;
    linePtr->firstArrowPtr = NULL;
    linePtr->lastArrowPtr = NULL;
    linePtr->smooth = NULL;
    linePtr->splineSteps = 12;

    /*
     * Count the number of points and then parse them into a point array.
     * Leading arguments are assumed to be points if they start with a digit
     * or a minus sign followed by a digit.
     */

    for (i = 1; i < objc; i++) {
	const char *arg = Tcl_GetString(objv[i]);

	if ((arg[0] == '-') && (arg[1] >= 'a') && (arg[1] <= 'z')) {
	    break;
	}
    }
    if (LineCoords(interp, canvas, itemPtr, i, objv) != TCL_OK) {
	goto error;
    }
    if (ConfigureLine(interp, canvas, itemPtr, objc-i, objv+i, 0) == TCL_OK) {
	return TCL_OK;
    }

  error:
    DeleteLine(canvas, itemPtr, Tk_Display(Tk_CanvasTkwin(canvas)));
    return TCL_ERROR;
}

/*
 *--------------------------------------------------------------
 *
 * LineCoords --
 *
 *	This function is invoked to process the "coords" widget command on
 *	lines. See the user documentation for details on what it does.
 *
 * Results:
 *	Returns TCL_OK or TCL_ERROR, and sets the interp's result.
 *
 * Side effects:
 *	The coordinates for the given item may be changed.
 *
 *--------------------------------------------------------------
 */

static int
LineCoords(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item whose coordinates are to be read or
				 * modified. */
    int objc,			/* Number of coordinates supplied in objv. */
    Tcl_Obj *const objv[])	/* Array of coordinates: x1, y1, x2, y2, ... */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    int i, numPoints;
    double *coordPtr;

    if (objc == 0) {
	int numCoords;
	Tcl_Obj *subobj, *obj = Tcl_NewObj();

	numCoords = 2*linePtr->numPoints;
	if (linePtr->firstArrowPtr != NULL) {
	    coordPtr = linePtr->firstArrowPtr;
	} else {
	    coordPtr = linePtr->coordPtr;
	}
	for (i = 0; i < numCoords; i++, coordPtr++) {
	    if (i == 2) {
		coordPtr = linePtr->coordPtr+2;
	    }
	    if ((linePtr->lastArrowPtr != NULL) && (i == (numCoords-2))) {
		coordPtr = linePtr->lastArrowPtr;
	    }
	    subobj = Tcl_NewDoubleObj(*coordPtr);
	    Tcl_ListObjAppendElement(interp, obj, subobj);
	}
	Tcl_SetObjResult(interp, obj);
	return TCL_OK;
    }
    if (objc == 1) {
	if (Tcl_ListObjGetElements(interp, objv[0], &objc,
		(Tcl_Obj ***) &objv) != TCL_OK) {
	    return TCL_ERROR;
	}
    }
    if (objc & 1) {
	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
		"wrong # coordinates: expected an even number, got %d",
		objc));
	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "LINE", NULL);
	return TCL_ERROR;
    } else if (objc < 4) {
	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
		"wrong # coordinates: expected at least 4, got %d", objc));
	Tcl_SetErrorCode(interp, "TK", "CANVAS", "COORDS", "LINE", NULL);
	return TCL_ERROR;
    }

    numPoints = objc/2;
    if (linePtr->numPoints != numPoints) {
	coordPtr = (double *)ckalloc(sizeof(double) * objc);
	if (linePtr->coordPtr != NULL) {
	    ckfree(linePtr->coordPtr);
	}
	linePtr->coordPtr = coordPtr;
	linePtr->numPoints = numPoints;
    }
    coordPtr = linePtr->coordPtr;
    for (i = 0; i < objc ; i++) {
	if (Tk_CanvasGetCoordFromObj(interp, canvas, objv[i],
		coordPtr++) != TCL_OK) {
	    return TCL_ERROR;
	}
    }

    /*
     * Update arrowheads by throwing away any existing arrow-head information
     * and calling ConfigureArrows to recompute it.
     */

    if (linePtr->firstArrowPtr != NULL) {
	ckfree(linePtr->firstArrowPtr);
	linePtr->firstArrowPtr = NULL;
    }
    if (linePtr->lastArrowPtr != NULL) {
	ckfree(linePtr->lastArrowPtr);
	linePtr->lastArrowPtr = NULL;
    }
    if (linePtr->arrow != ARROWS_NONE) {
	ConfigureArrows(canvas, linePtr);
    }
    ComputeLineBbox(canvas, linePtr);
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * ConfigureLine --
 *
 *	This function is invoked to configure various aspects of a line item
 *	such as its background color.
 *
 * Results:
 *	A standard Tcl result code. If an error occurs, then an error message
 *	is left in the interp's result.
 *
 * Side effects:
 *	Configuration information, such as colors and stipple patterns, may be
 *	set for itemPtr.
 *
 *--------------------------------------------------------------
 */

static int
ConfigureLine(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tk_Canvas canvas,		/* Canvas containing itemPtr. */
    Tk_Item *itemPtr,		/* Line item to reconfigure. */
    int objc,			/* Number of elements in objv. */
    Tcl_Obj *const objv[],	/* Arguments describing things to configure. */
    int flags)			/* Flags to pass to Tk_ConfigureWidget. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    XGCValues gcValues;
    GC newGC, arrowGC;
    unsigned long mask;
    Tk_Window tkwin;
    Tk_State state;

    tkwin = Tk_CanvasTkwin(canvas);
    if (TCL_OK != Tk_ConfigureWidget(interp, tkwin, configSpecs, objc,
	    (const char **) objv, (char *) linePtr, flags|TK_CONFIG_OBJS)) {
	return TCL_ERROR;
    }

    /*
     * A few of the options require additional processing, such as graphics
     * contexts.
     */

    state = itemPtr->state;

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    if (linePtr->outline.activeWidth > linePtr->outline.width ||
	    linePtr->outline.activeDash.number != 0 ||
	    linePtr->outline.activeColor != NULL ||
	    linePtr->outline.activeStipple != None) {
	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
    } else {
	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
    }
    mask = Tk_ConfigOutlineGC(&gcValues, canvas, itemPtr, &linePtr->outline);
    if (mask) {
	if (linePtr->arrow == ARROWS_NONE) {
	    gcValues.cap_style = linePtr->capStyle;
	    mask |= GCCapStyle;
	}
	gcValues.join_style = linePtr->joinStyle;
	mask |= GCJoinStyle;
	newGC = Tk_GetGC(tkwin, mask, &gcValues);
#ifdef MAC_OSX_TK
	/*
	 * Mac OS X CG drawing needs access to linewidth even for arrow fills
	 * (as linewidth controls antialiasing).
	 */

	mask |= GCLineWidth;
#else
	gcValues.line_width = 0;
#endif
	arrowGC = Tk_GetGC(tkwin, mask, &gcValues);
    } else {
	newGC = arrowGC = NULL;
    }
    if (linePtr->outline.gc != NULL) {
	Tk_FreeGC(Tk_Display(tkwin), linePtr->outline.gc);
    }
    if (linePtr->arrowGC != NULL) {
	Tk_FreeGC(Tk_Display(tkwin), linePtr->arrowGC);
    }
    linePtr->outline.gc = newGC;
    linePtr->arrowGC = arrowGC;

    /*
     * Keep spline parameters within reasonable limits.
     */

    if (linePtr->splineSteps < 1) {
	linePtr->splineSteps = 1;
    } else if (linePtr->splineSteps > 100) {
	linePtr->splineSteps = 100;
    }

    if ((!linePtr->numPoints) || (state == TK_STATE_HIDDEN)) {
	ComputeLineBbox(canvas, linePtr);
	return TCL_OK;
    }

    /*
     * Setup arrowheads, if needed. If arrowheads are turned off, restore the
     * line's endpoints (they were shortened when the arrowheads were added).
     */

    if ((linePtr->firstArrowPtr != NULL) && (linePtr->arrow != ARROWS_FIRST)
	    && (linePtr->arrow != ARROWS_BOTH)) {
	linePtr->coordPtr[0] = linePtr->firstArrowPtr[0];
	linePtr->coordPtr[1] = linePtr->firstArrowPtr[1];
	ckfree(linePtr->firstArrowPtr);
	linePtr->firstArrowPtr = NULL;
    }
    if ((linePtr->lastArrowPtr != NULL) && (linePtr->arrow != ARROWS_LAST)
	    && (linePtr->arrow != ARROWS_BOTH)) {
	int i;

	i = 2*(linePtr->numPoints-1);
	linePtr->coordPtr[i] = linePtr->lastArrowPtr[0];
	linePtr->coordPtr[i+1] = linePtr->lastArrowPtr[1];
	ckfree(linePtr->lastArrowPtr);
	linePtr->lastArrowPtr = NULL;
    }
    if (linePtr->arrow != ARROWS_NONE) {
	ConfigureArrows(canvas, linePtr);
    }

    /*
     * Recompute bounding box for line.
     */

    ComputeLineBbox(canvas, linePtr);

    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * DeleteLine --
 *
 *	This function is called to clean up the data structure associated with
 *	a line item.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Resources associated with itemPtr are released.
 *
 *--------------------------------------------------------------
 */

static void
DeleteLine(
    TCL_UNUSED(Tk_Canvas),		/* Info about overall canvas widget. */
    Tk_Item *itemPtr,		/* Item that is being deleted. */
    Display *display)		/* Display containing window for canvas. */
{
    LineItem *linePtr = (LineItem *) itemPtr;

    Tk_DeleteOutline(display, &linePtr->outline);
    if (linePtr->coordPtr != NULL) {
	ckfree(linePtr->coordPtr);
    }
    if (linePtr->arrowGC != NULL) {
	Tk_FreeGC(display, linePtr->arrowGC);
    }
    if (linePtr->firstArrowPtr != NULL) {
	ckfree(linePtr->firstArrowPtr);
    }
    if (linePtr->lastArrowPtr != NULL) {
	ckfree(linePtr->lastArrowPtr);
    }
}

/*
 *--------------------------------------------------------------
 *
 * ComputeLineBbox --
 *
 *	This function is invoked to compute the bounding box of all the pixels
 *	that may be drawn as part of a line.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The fields x1, y1, x2, and y2 are updated in the header for itemPtr.
 *
 *--------------------------------------------------------------
 */

static void
ComputeLineBbox(
    Tk_Canvas canvas,		/* Canvas that contains item. */
    LineItem *linePtr)		/* Item whose bbos is to be recomputed. */
{
    double *coordPtr;
    int i, intWidth;
    double width;
    Tk_State state = linePtr->header.state;
    Tk_TSOffset *tsoffset;

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    if (!(linePtr->numPoints) || (state == TK_STATE_HIDDEN)) {
	linePtr->header.x1 = -1;
	linePtr->header.x2 = -1;
	linePtr->header.y1 = -1;
	linePtr->header.y2 = -1;
	return;
    }

    width = linePtr->outline.width;
    if (Canvas(canvas)->currentItemPtr == (Tk_Item *)linePtr) {
	if (linePtr->outline.activeWidth > width) {
	    width = linePtr->outline.activeWidth;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (linePtr->outline.disabledWidth > 0) {
	    width = linePtr->outline.disabledWidth;
	}
    }

    coordPtr = linePtr->coordPtr;
    linePtr->header.x1 = linePtr->header.x2 = (int) coordPtr[0];
    linePtr->header.y1 = linePtr->header.y2 = (int) coordPtr[1];

    /*
     * Compute the bounding box of all the points in the line, then expand in
     * all directions by the line's width to take care of butting or rounded
     * corners and projecting or rounded caps. This expansion is an
     * overestimate (worst-case is square root of two over two) but it's
     * simple. Don't do anything special for curves. This causes an additional
     * overestimate in the bounding box, but is faster.
     */

    for (i = 1, coordPtr = linePtr->coordPtr+2; i < linePtr->numPoints;
	    i++, coordPtr += 2) {
	TkIncludePoint((Tk_Item *) linePtr, coordPtr);
    }
    width = linePtr->outline.width;
    if (width < 1.0) {
	width = 1.0;
    }
    if (linePtr->arrow != ARROWS_NONE) {
	if (linePtr->arrow != ARROWS_LAST) {
	    TkIncludePoint((Tk_Item *) linePtr, linePtr->firstArrowPtr);
	}
	if (linePtr->arrow != ARROWS_FIRST) {
	    TkIncludePoint((Tk_Item *) linePtr, linePtr->lastArrowPtr);
	}
    }

    tsoffset = &linePtr->outline.tsoffset;
    if (tsoffset->flags & TK_OFFSET_INDEX) {
	coordPtr = linePtr->coordPtr
		+ (tsoffset->flags & ~TK_OFFSET_INDEX);

	if (tsoffset->flags <= 0) {
	    coordPtr = linePtr->coordPtr;
	    if ((linePtr->arrow == ARROWS_FIRST)
		    || (linePtr->arrow == ARROWS_BOTH)) {
		coordPtr = linePtr->firstArrowPtr;
	    }
	}
	if (tsoffset->flags > (linePtr->numPoints * 2)) {
	    coordPtr = linePtr->coordPtr + (linePtr->numPoints * 2);
	    if ((linePtr->arrow == ARROWS_LAST)
		    || (linePtr->arrow == ARROWS_BOTH)) {
		coordPtr = linePtr->lastArrowPtr;
	    }
	}
	tsoffset->xoffset = (int) (coordPtr[0] + 0.5);
	tsoffset->yoffset = (int) (coordPtr[1] + 0.5);
    } else {
	if (tsoffset->flags & TK_OFFSET_LEFT) {
	    tsoffset->xoffset = linePtr->header.x1;
	} else if (tsoffset->flags & TK_OFFSET_CENTER) {
	    tsoffset->xoffset = (linePtr->header.x1 + linePtr->header.x2)/2;
	} else if (tsoffset->flags & TK_OFFSET_RIGHT) {
	    tsoffset->xoffset = linePtr->header.x2;
	}
	if (tsoffset->flags & TK_OFFSET_TOP) {
	    tsoffset->yoffset = linePtr->header.y1;
	} else if (tsoffset->flags & TK_OFFSET_MIDDLE) {
	    tsoffset->yoffset = (linePtr->header.y1 + linePtr->header.y2)/2;
	} else if (tsoffset->flags & TK_OFFSET_BOTTOM) {
	    tsoffset->yoffset = linePtr->header.y2;
	}
    }

    intWidth = (int) (width + 0.5);
    linePtr->header.x1 -= intWidth;
    linePtr->header.x2 += intWidth;
    linePtr->header.y1 -= intWidth;
    linePtr->header.y2 += intWidth;

    if (linePtr->numPoints == 1) {
	linePtr->header.x1 -= 1;
	linePtr->header.x2 += 1;
	linePtr->header.y1 -= 1;
	linePtr->header.y2 += 1;
	return;
    }

    /*
     * For mitered lines, make a second pass through all the points. Compute
     * the locations of the two miter vertex points and add those into the
     * bounding box.
     */

    if (linePtr->joinStyle == JoinMiter) {
	for (i = linePtr->numPoints, coordPtr = linePtr->coordPtr; i >= 3;
		i--, coordPtr += 2) {
	    double miter[4];
	    int j;

	    if (TkGetMiterPoints(coordPtr, coordPtr+2, coordPtr+4,
		    width, miter, miter+2)) {
		for (j = 0; j < 4; j += 2) {
		    TkIncludePoint((Tk_Item *) linePtr, miter+j);
		}
	    }
	}
    }

    /*
     * Add in the sizes of arrowheads, if any.
     */

    if (linePtr->arrow != ARROWS_NONE) {
	if (linePtr->arrow != ARROWS_LAST) {
	    for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint((Tk_Item *) linePtr, coordPtr);
	    }
	}
	if (linePtr->arrow != ARROWS_FIRST) {
	    for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint((Tk_Item *) linePtr, coordPtr);
	    }
	}
    }

    /*
     * Add one more pixel of fudge factor just to be safe (e.g. X may round
     * differently than we do).
     */

    linePtr->header.x1 -= 1;
    linePtr->header.x2 += 1;
    linePtr->header.y1 -= 1;
    linePtr->header.y2 += 1;
}

/*
 *--------------------------------------------------------------
 *
 * DisplayLine --
 *
 *	This function is invoked to draw a line item in a given drawable.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	ItemPtr is drawn in drawable using the transformation information in
 *	canvas.
 *
 *--------------------------------------------------------------
 */

static void
DisplayLine(
    Tk_Canvas canvas,		/* Canvas that contains item. */
    Tk_Item *itemPtr,		/* Item to be displayed. */
    Display *display,		/* Display on which to draw item. */
    Drawable drawable,		/* Pixmap or window in which to draw item. */
    TCL_UNUSED(int),		/* Describes region of canvas that must be */
    TCL_UNUSED(int),		/* redisplayed (not used). */
    TCL_UNUSED(int),
    TCL_UNUSED(int))
{
    LineItem *linePtr = (LineItem *)itemPtr;
    XPoint staticPoints[MAX_STATIC_POINTS*3];
    XPoint *pointPtr;
    double linewidth;
    int numPoints;
    Tk_State state = itemPtr->state;

    if (!linePtr->numPoints || (linePtr->outline.gc == NULL)) {
	return;
    }

    if (state == TK_STATE_NULL) {
	    state = Canvas(canvas)->canvas_state;
    }
    linewidth = linePtr->outline.width;
    if (Canvas(canvas)->currentItemPtr == itemPtr) {
	if (linePtr->outline.activeWidth != linewidth) {
	    linewidth = linePtr->outline.activeWidth;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (linePtr->outline.disabledWidth != linewidth) {
	    linewidth = linePtr->outline.disabledWidth;
	}
    }
    /*
     * Build up an array of points in screen coordinates. Use a static array
     * unless the line has an enormous number of points; in this case,
     * dynamically allocate an array. For smoothed lines, generate the curve
     * points on each redisplay.
     */

    if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
	numPoints = linePtr->smooth->coordProc(canvas, NULL,
		linePtr->numPoints, linePtr->splineSteps, NULL, NULL);
    } else {
	numPoints = linePtr->numPoints;
    }

    if (numPoints <= MAX_STATIC_POINTS) {
	pointPtr = staticPoints;
    } else {
	pointPtr = (XPoint *)ckalloc(numPoints * 3 * sizeof(XPoint));
    }

    if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
	numPoints = linePtr->smooth->coordProc(canvas, linePtr->coordPtr,
		linePtr->numPoints, linePtr->splineSteps, pointPtr, NULL);
    } else {
	numPoints = TkCanvTranslatePath((TkCanvas *) canvas, numPoints,
		linePtr->coordPtr, 0, pointPtr);
    }

    /*
     * Display line, the free up line storage if it was dynamically allocated.
     * If we're stippling, then modify the stipple offset in the GC. Be sure
     * to reset the offset when done, since the GC is supposed to be
     * read-only.
     */

    if (Tk_ChangeOutlineGC(canvas, itemPtr, &linePtr->outline)) {
	Tk_CanvasSetOffset(canvas, linePtr->arrowGC,
		&linePtr->outline.tsoffset);
    }
    if (numPoints > 1) {
	XDrawLines(display, drawable, linePtr->outline.gc, pointPtr, numPoints,
		CoordModeOrigin);
    } else {
	int intwidth = (int) (linewidth + 0.5);

	if (intwidth < 1) {
	    intwidth = 1;
	}
	XFillArc(display, drawable, linePtr->outline.gc,
		pointPtr->x - intwidth/2, pointPtr->y - intwidth/2,
		(unsigned) intwidth+1, (unsigned) intwidth+1, 0, 64*360);
    }
    if (pointPtr != staticPoints) {
	ckfree(pointPtr);
    }

    /*
     * Display arrowheads, if they are wanted.
     */

    if (linePtr->firstArrowPtr != NULL) {
	TkFillPolygon(canvas, linePtr->firstArrowPtr, PTS_IN_ARROW,
		display, drawable, linePtr->arrowGC, NULL);
    }
    if (linePtr->lastArrowPtr != NULL) {
	TkFillPolygon(canvas, linePtr->lastArrowPtr, PTS_IN_ARROW,
		display, drawable, linePtr->arrowGC, NULL);
    }
    if (Tk_ResetOutlineGC(canvas, itemPtr, &linePtr->outline)) {
	XSetTSOrigin(display, linePtr->arrowGC, 0, 0);
    }
}

/*
 *--------------------------------------------------------------
 *
 * LineInsert --
 *
 *	Insert coords into a line item at a given index.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The coords in the given item is modified.
 *
 *--------------------------------------------------------------
 */

static void
LineInsert(
    Tk_Canvas canvas,		/* Canvas containing text item. */
    Tk_Item *itemPtr,		/* Line item to be modified. */
    TkSizeT beforeThis,		/* Index before which new coordinates are to
				 * be inserted. */
    Tcl_Obj *obj)		/* New coordinates to be inserted. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    int length, objc, i;
    double *newCoordPtr, *coordPtr;
    Tk_State state = itemPtr->state;
    Tcl_Obj **objv;

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    if (!obj || (Tcl_ListObjGetElements(NULL, obj, &objc, &objv) != TCL_OK)
	    || !objc || objc&1) {
	return;
    }
    length = 2*linePtr->numPoints;
    if (beforeThis == TCL_INDEX_NONE) {
	beforeThis = 0;
    }
    if (beforeThis + 1 > (TkSizeT)length + 1) {
	beforeThis = length;
    }
    if (linePtr->firstArrowPtr != NULL) {
	linePtr->coordPtr[0] = linePtr->firstArrowPtr[0];
	linePtr->coordPtr[1] = linePtr->firstArrowPtr[1];
    }
    if (linePtr->lastArrowPtr != NULL) {
	linePtr->coordPtr[length-2] = linePtr->lastArrowPtr[0];
	linePtr->coordPtr[length-1] = linePtr->lastArrowPtr[1];
    }
    newCoordPtr = (double *)ckalloc(sizeof(double) * (length + objc));
    for (i=0; i<(int)beforeThis; i++) {
	newCoordPtr[i] = linePtr->coordPtr[i];
    }
    for (i=0; i<objc; i++) {
	if (Tcl_GetDoubleFromObj(NULL, objv[i],
		&newCoordPtr[i + beforeThis]) != TCL_OK) {
	    Tcl_ResetResult(Canvas(canvas)->interp);
	    ckfree(newCoordPtr);
	    return;
	}
    }

    for (i=beforeThis; i<length; i++) {
	newCoordPtr[i+objc] = linePtr->coordPtr[i];
    }
    if (linePtr->coordPtr) {
        ckfree(linePtr->coordPtr);
    }
    linePtr->coordPtr = newCoordPtr;
    length += objc ;
    linePtr->numPoints = length / 2;

    if ((length > 3) && (state != TK_STATE_HIDDEN)) {
	/*
	 * This is some optimizing code that will result that only the part of
	 * the polygon that changed (and the objects that are overlapping with
	 * that part) need to be redrawn. A special flag is set that instructs
	 * the general canvas code not to redraw the whole object. If this
	 * flag is not set, the canvas will do the redrawing, otherwise I have
	 * to do it here.
	 */

	itemPtr->redraw_flags |= TK_ITEM_DONT_REDRAW;

	if ((int)beforeThis > 0) {
	    beforeThis -= 2;
	    objc += 2;
	}
	if ((int)beforeThis+objc < length) {
	    objc += 2;
	}
	if (linePtr->smooth) {
	    if ((int)beforeThis > 0) {
		beforeThis -= 2;
		objc += 2;
	    }
	    if ((int)beforeThis+objc+2 < length) {
		objc += 2;
	    }
	}
	itemPtr->x1 = itemPtr->x2 = (int) linePtr->coordPtr[beforeThis];
	itemPtr->y1 = itemPtr->y2 = (int) linePtr->coordPtr[beforeThis+1];
	if ((linePtr->firstArrowPtr != NULL) && ((int)beforeThis < 1)) {
	    /*
	     * Include old first arrow.
	     */

	    for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	if ((linePtr->lastArrowPtr != NULL) && ((int)beforeThis+objc >= length)) {
	    /*
	     * Include old last arrow.
	     */

	    for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	coordPtr = linePtr->coordPtr + beforeThis + 2;
	for (i=2; i<objc; i+=2) {
	    TkIncludePoint(itemPtr, coordPtr);
	    coordPtr += 2;
	}
    }
    if (linePtr->firstArrowPtr != NULL) {
	ckfree(linePtr->firstArrowPtr);
	linePtr->firstArrowPtr = NULL;
    }
    if (linePtr->lastArrowPtr != NULL) {
	ckfree(linePtr->lastArrowPtr);
	linePtr->lastArrowPtr = NULL;
    }
    if (linePtr->arrow != ARROWS_NONE) {
	ConfigureArrows(canvas, linePtr);
    }

    if (itemPtr->redraw_flags & TK_ITEM_DONT_REDRAW) {
	double width;
	int intWidth;

	if ((linePtr->firstArrowPtr != NULL) && ((int)beforeThis > 2)) {
	    /*
	     * Include new first arrow.
	     */

	    for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	if ((linePtr->lastArrowPtr != NULL) && ((int)beforeThis+objc < length-2)) {
	    /*
	     * Include new right arrow.
	     */

	    for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	width = linePtr->outline.width;
	if (Canvas(canvas)->currentItemPtr == itemPtr) {
	    if (linePtr->outline.activeWidth > width) {
		width = linePtr->outline.activeWidth;
	    }
	} else if (state == TK_STATE_DISABLED) {
	    if (linePtr->outline.disabledWidth > 0) {
		width = linePtr->outline.disabledWidth;
	    }
	}
	intWidth = (int) (width + 0.5);
	if (intWidth < 1) {
	    intWidth = 1;
	}
	itemPtr->x1 -= intWidth;
	itemPtr->y1 -= intWidth;
	itemPtr->x2 += intWidth;
	itemPtr->y2 += intWidth;
	Tk_CanvasEventuallyRedraw(canvas, itemPtr->x1, itemPtr->y1,
		itemPtr->x2, itemPtr->y2);
    }

    ComputeLineBbox(canvas, linePtr);
}

/*
 *--------------------------------------------------------------
 *
 * LineDeleteCoords --
 *
 *	Delete one or more coordinates from a line item.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Characters between "first" and "last", inclusive, get deleted from
 *	itemPtr.
 *
 *--------------------------------------------------------------
 */

static void
LineDeleteCoords(
    Tk_Canvas canvas,		/* Canvas containing itemPtr. */
    Tk_Item *itemPtr,		/* Item in which to delete characters. */
    TkSizeT first,			/* Index of first character to delete. */
    TkSizeT last)			/* Index of last character to delete. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    int count, i, first1, last1;
    int length = 2*linePtr->numPoints;
    double *coordPtr;
    Tk_State state = itemPtr->state;

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    first &= -2;
    last &= -2;

    if ((int)first < 0) {
	first = 0;
    }
    if ((int)last >= length) {
	last = length-2;
    }
    if ((int)first > (int)last) {
	return;
    }
    if (linePtr->firstArrowPtr != NULL) {
	linePtr->coordPtr[0] = linePtr->firstArrowPtr[0];
	linePtr->coordPtr[1] = linePtr->firstArrowPtr[1];
    }
    if (linePtr->lastArrowPtr != NULL) {
	linePtr->coordPtr[length-2] = linePtr->lastArrowPtr[0];
	linePtr->coordPtr[length-1] = linePtr->lastArrowPtr[1];
    }
    first1 = first;
    last1 = last;
    if (first1 > 0) {
	first1 -= 2;
    }
    if (last1 < length-2) {
	last1 += 2;
    }
    if (linePtr->smooth) {
	if (first1 > 0) {
	    first1 -= 2;
	}
	if (last1 < length-2) {
	    last1 += 2;
	}
    }

    if ((first1 >= 2) || (last1 < length-2)) {
	/*
	 * This is some optimizing code that will result that only the part of
	 * the line that changed (and the objects that are overlapping with
	 * that part) need to be redrawn. A special flag is set that instructs
	 * the general canvas code not to redraw the whole object. If this
	 * flag is set, the redrawing has to be done here, otherwise the
	 * general Canvas code will take care of it.
	 */

	itemPtr->redraw_flags |= TK_ITEM_DONT_REDRAW;
	itemPtr->x1 = itemPtr->x2 = (int) linePtr->coordPtr[first1];
	itemPtr->y1 = itemPtr->y2 = (int) linePtr->coordPtr[first1+1];
	if ((linePtr->firstArrowPtr != NULL) && (first1 < 2)) {
	    /*
	     * Include old first arrow.
	     */

	    for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	if ((linePtr->lastArrowPtr != NULL) && (last1 >= length-2)) {
	    /*
	     * Include old last arrow.
	     */

	    for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	coordPtr = linePtr->coordPtr+first1+2;
	for (i=first1+2; i<=last1; i+=2) {
	    TkIncludePoint(itemPtr, coordPtr);
	    coordPtr += 2;
	}
    }

    count = last + 2 - first;
    for (i=last+2; i<length; i++) {
	linePtr->coordPtr[i-count] = linePtr->coordPtr[i];
    }
    linePtr->numPoints -= count/2;
    if (linePtr->firstArrowPtr != NULL) {
	ckfree(linePtr->firstArrowPtr);
	linePtr->firstArrowPtr = NULL;
    }
    if (linePtr->lastArrowPtr != NULL) {
	ckfree(linePtr->lastArrowPtr);
	linePtr->lastArrowPtr = NULL;
    }
    if (linePtr->arrow != ARROWS_NONE) {
	ConfigureArrows(canvas, linePtr);
    }
    if (itemPtr->redraw_flags & TK_ITEM_DONT_REDRAW) {
	double width;
	int intWidth;

	if ((linePtr->firstArrowPtr != NULL) && (first1 < 4)) {
	    /*
	     * Include new first arrow.
	     */

	    for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	if ((linePtr->lastArrowPtr != NULL) && (last1 > length-4)) {
	    /*
	     * Include new right arrow.
	     */

	    for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(itemPtr, coordPtr);
	    }
	}
	width = linePtr->outline.width;
	if (Canvas(canvas)->currentItemPtr == itemPtr) {
	    if (linePtr->outline.activeWidth > width) {
		width = linePtr->outline.activeWidth;
	    }
	} else if (state == TK_STATE_DISABLED) {
	    if (linePtr->outline.disabledWidth > 0) {
		width = linePtr->outline.disabledWidth;
	    }
	}
	intWidth = (int) (width + 0.5);
	if (intWidth < 1) {
	    intWidth = 1;
	}
	itemPtr->x1 -= intWidth;
	itemPtr->y1 -= intWidth;
	itemPtr->x2 += intWidth;
	itemPtr->y2 += intWidth;
	Tk_CanvasEventuallyRedraw(canvas, itemPtr->x1, itemPtr->y1,
		itemPtr->x2, itemPtr->y2);
    }
    ComputeLineBbox(canvas, linePtr);
}

/*
 *--------------------------------------------------------------
 *
 * LineToPoint --
 *
 *	Computes the distance from a given point to a given line, in canvas
 *	units.
 *
 * Results:
 *	The return value is 0 if the point whose x and y coordinates are
 *	pointPtr[0] and pointPtr[1] is inside the line. If the point isn't
 *	inside the line then the return value is the distance from the point
 *	to the line.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static double
LineToPoint(
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item to check against point. */
    double *pointPtr)		/* Pointer to x and y coordinates. */
{
    Tk_State state = itemPtr->state;
    LineItem *linePtr = (LineItem *) itemPtr;
    double *coordPtr, *linePoints;
    double staticSpace[2*MAX_STATIC_POINTS];
    double poly[10];
    double bestDist, dist, width;
    int numPoints, count;
    int changedMiterToBevel;	/* Non-zero means that a mitered corner had to
				 * be treated as beveled after all because the
				 * angle was < 11 degrees. */

    bestDist = 1.0e36;

    /*
     * Handle smoothed lines by generating an expanded set of points against
     * which to do the check.
     */

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    width = linePtr->outline.width;
    if (Canvas(canvas)->currentItemPtr == itemPtr) {
	if (linePtr->outline.activeWidth > width) {
	    width = linePtr->outline.activeWidth;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (linePtr->outline.disabledWidth > 0) {
	    width = linePtr->outline.disabledWidth;
	}
    }

    if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
	numPoints = linePtr->smooth->coordProc(canvas, NULL,
		linePtr->numPoints, linePtr->splineSteps, NULL, NULL);
	if (numPoints <= MAX_STATIC_POINTS) {
	    linePoints = staticSpace;
	} else {
	    linePoints = (double *)ckalloc(2 * numPoints * sizeof(double));
	}
	numPoints = linePtr->smooth->coordProc(canvas, linePtr->coordPtr,
		linePtr->numPoints, linePtr->splineSteps, NULL, linePoints);
    } else {
	numPoints = linePtr->numPoints;
	linePoints = linePtr->coordPtr;
    }

    if (width < 1.0) {
	width = 1.0;
    }

    if (!numPoints || itemPtr->state == TK_STATE_HIDDEN) {
	return bestDist;
    } else if (numPoints == 1) {
	bestDist = hypot(linePoints[0]-pointPtr[0], linePoints[1]-pointPtr[1])
		- width/2.0;
	if (bestDist < 0) {
	    bestDist = 0;
	}
	return bestDist;
    }

    /*
     * The overall idea is to iterate through all of the edges of the line,
     * computing a polygon for each edge and testing the point against that
     * polygon. In addition, there are additional tests to deal with rounded
     * joints and caps.
     */

    changedMiterToBevel = 0;
    for (count = numPoints, coordPtr = linePoints; count >= 2;
	    count--, coordPtr += 2) {
	/*
	 * If rounding is done around the first point then compute the
	 * distance between the point and the point.
	 */

	if (((linePtr->capStyle == CapRound) && (count == numPoints))
		|| ((linePtr->joinStyle == JoinRound)
			&& (count != numPoints))) {
	    dist = hypot(coordPtr[0] - pointPtr[0], coordPtr[1] - pointPtr[1])
		    - width/2.0;
	    if (dist <= 0.0) {
		bestDist = 0.0;
		goto done;
	    } else if (dist < bestDist) {
		bestDist = dist;
	    }
	}

	/*
	 * Compute the polygonal shape corresponding to this edge, consisting
	 * of two points for the first point of the edge and two points for
	 * the last point of the edge.
	 */

	if (count == numPoints) {
	    TkGetButtPoints(coordPtr+2, coordPtr, width,
		    linePtr->capStyle == CapProjecting, poly, poly+2);
	} else if ((linePtr->joinStyle == JoinMiter) && !changedMiterToBevel) {
	    poly[0] = poly[6];
	    poly[1] = poly[7];
	    poly[2] = poly[4];
	    poly[3] = poly[5];
	} else {
	    TkGetButtPoints(coordPtr+2, coordPtr, width, 0, poly, poly+2);

	    /*
	     * If this line uses beveled joints, then check the distance to a
	     * polygon comprising the last two points of the previous polygon
	     * and the first two from this polygon; this checks the wedges
	     * that fill the mitered joint.
	     */

	    if ((linePtr->joinStyle == JoinBevel) || changedMiterToBevel) {
		poly[8] = poly[0];
		poly[9] = poly[1];
		dist = TkPolygonToPoint(poly, 5, pointPtr);
		if (dist <= 0.0) {
		    bestDist = 0.0;
		    goto done;
		} else if (dist < bestDist) {
		    bestDist = dist;
		}
		changedMiterToBevel = 0;
	    }
	}
	if (count == 2) {
	    TkGetButtPoints(coordPtr, coordPtr+2, width,
		    linePtr->capStyle == CapProjecting, poly+4, poly+6);
	} else if (linePtr->joinStyle == JoinMiter) {
	    if (TkGetMiterPoints(coordPtr, coordPtr+2, coordPtr+4,
		    width, poly+4, poly+6) == 0) {
		changedMiterToBevel = 1;
		TkGetButtPoints(coordPtr, coordPtr+2, width, 0,
			poly+4, poly+6);
	    }
	} else {
	    TkGetButtPoints(coordPtr, coordPtr+2, width, 0,
		    poly+4, poly+6);
	}
	poly[8] = poly[0];
	poly[9] = poly[1];
	dist = TkPolygonToPoint(poly, 5, pointPtr);
	if (dist <= 0.0) {
	    bestDist = 0.0;
	    goto done;
	} else if (dist < bestDist) {
	    bestDist = dist;
	}
    }

    /*
     * If caps are rounded, check the distance to the cap around the final end
     * point of the line.
     */

    if (linePtr->capStyle == CapRound) {
	dist = hypot(coordPtr[0] - pointPtr[0], coordPtr[1] - pointPtr[1])
		- width/2.0;
	if (dist <= 0.0) {
	    bestDist = 0.0;
	    goto done;
	} else if (dist < bestDist) {
	    bestDist = dist;
	}
    }

    /*
     * If there are arrowheads, check the distance to the arrowheads.
     */

    if (linePtr->arrow != ARROWS_NONE) {
	if (linePtr->arrow != ARROWS_LAST) {
	    dist = TkPolygonToPoint(linePtr->firstArrowPtr, PTS_IN_ARROW,
		    pointPtr);
	    if (dist <= 0.0) {
		bestDist = 0.0;
		goto done;
	    } else if (dist < bestDist) {
		bestDist = dist;
	    }
	}
	if (linePtr->arrow != ARROWS_FIRST) {
	    dist = TkPolygonToPoint(linePtr->lastArrowPtr, PTS_IN_ARROW,
		    pointPtr);
	    if (dist <= 0.0) {
		bestDist = 0.0;
		goto done;
	    } else if (dist < bestDist) {
		bestDist = dist;
	    }
	}
    }

  done:
    if ((linePoints != staticSpace) && (linePoints != linePtr->coordPtr)) {
	ckfree(linePoints);
    }
    return bestDist;
}

/*
 *--------------------------------------------------------------
 *
 * LineToArea --
 *
 *	This function is called to determine whether an item lies entirely
 *	inside, entirely outside, or overlapping a given rectangular area.
 *
 * Results:
 *	-1 is returned if the item is entirely outside the area, 0 if it
 *	overlaps, and 1 if it is entirely inside the given area.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
LineToArea(
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item to check against line. */
    double *rectPtr)
{
    LineItem *linePtr = (LineItem *) itemPtr;
    double staticSpace[2*MAX_STATIC_POINTS];
    double *linePoints;
    int numPoints, result;
    double radius, width;
    Tk_State state = itemPtr->state;

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }
    width = linePtr->outline.width;
    if (Canvas(canvas)->currentItemPtr == itemPtr) {
	if (linePtr->outline.activeWidth > width) {
	    width = linePtr->outline.activeWidth;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (linePtr->outline.disabledWidth > 0) {
	    width = linePtr->outline.disabledWidth;
	}
    }

    radius = (width+1.0)/2.0;

    if ((state == TK_STATE_HIDDEN) || !linePtr->numPoints) {
	return -1;
    } else if (linePtr->numPoints == 1) {
	double oval[4];

	oval[0] = linePtr->coordPtr[0]-radius;
	oval[1] = linePtr->coordPtr[1]-radius;
	oval[2] = linePtr->coordPtr[0]+radius;
	oval[3] = linePtr->coordPtr[1]+radius;
	return TkOvalToArea(oval, rectPtr);
    }

    /*
     * Handle smoothed lines by generating an expanded set of points against
     * which to do the check.
     */

    if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
	numPoints = linePtr->smooth->coordProc(canvas, NULL,
		linePtr->numPoints, linePtr->splineSteps, NULL, NULL);
	if (numPoints <= MAX_STATIC_POINTS) {
	    linePoints = staticSpace;
	} else {
	    linePoints = (double *)ckalloc(2 * numPoints * sizeof(double));
	}
	numPoints = linePtr->smooth->coordProc(canvas, linePtr->coordPtr,
		linePtr->numPoints, linePtr->splineSteps, NULL, linePoints);
    } else {
	numPoints = linePtr->numPoints;
	linePoints = linePtr->coordPtr;
    }

    /*
     * Check the segments of the line.
     */

    if (width < 1.0) {
	width = 1.0;
    }

    result = TkThickPolyLineToArea(linePoints, numPoints, width,
	    linePtr->capStyle, linePtr->joinStyle, rectPtr);
    if (result == 0) {
	goto done;
    }

    /*
     * Check arrowheads, if any.
     */

    if (linePtr->arrow != ARROWS_NONE) {
	if (linePtr->arrow != ARROWS_LAST) {
	    if (TkPolygonToArea(linePtr->firstArrowPtr, PTS_IN_ARROW,
		    rectPtr) != result) {
		result = 0;
		goto done;
	    }
	}
	if (linePtr->arrow != ARROWS_FIRST) {
	    if (TkPolygonToArea(linePtr->lastArrowPtr, PTS_IN_ARROW,
		    rectPtr) != result) {
		result = 0;
		goto done;
	    }
	}
    }

  done:
    if ((linePoints != staticSpace) && (linePoints != linePtr->coordPtr)) {
	ckfree(linePoints);
    }
    return result;
}

/*
 *--------------------------------------------------------------
 *
 * ScaleLine --
 *
 *	This function is invoked to rescale a line item.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The line referred to by itemPtr is rescaled so that the following
 *	transformation is applied to all point coordinates:
 *		x' = originX + scaleX*(x-originX)
 *		y' = originY + scaleY*(y-originY)
 *
 *--------------------------------------------------------------
 */

static void
ScaleLine(
    Tk_Canvas canvas,		/* Canvas containing line. */
    Tk_Item *itemPtr,		/* Line to be scaled. */
    double originX, double originY,
				/* Origin about which to scale rect. */
    double scaleX,		/* Amount to scale in X direction. */
    double scaleY)		/* Amount to scale in Y direction. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    double *coordPtr;
    int i;

    /*
     * Delete any arrowheads before scaling all the points (so that the
     * end-points of the line get restored).
     */

    if (linePtr->firstArrowPtr != NULL) {
	linePtr->coordPtr[0] = linePtr->firstArrowPtr[0];
	linePtr->coordPtr[1] = linePtr->firstArrowPtr[1];
	ckfree(linePtr->firstArrowPtr);
	linePtr->firstArrowPtr = NULL;
    }
    if (linePtr->lastArrowPtr != NULL) {
	i = 2*(linePtr->numPoints-1);
	linePtr->coordPtr[i] = linePtr->lastArrowPtr[0];
	linePtr->coordPtr[i+1] = linePtr->lastArrowPtr[1];
	ckfree(linePtr->lastArrowPtr);
	linePtr->lastArrowPtr = NULL;
    }
    for (i = 0, coordPtr = linePtr->coordPtr; i < linePtr->numPoints;
	    i++, coordPtr += 2) {
	coordPtr[0] = originX + scaleX*(*coordPtr - originX);
	coordPtr[1] = originY + scaleY*(coordPtr[1] - originY);
    }
    if (linePtr->arrow != ARROWS_NONE) {
	ConfigureArrows(canvas, linePtr);
    }
    ComputeLineBbox(canvas, linePtr);
}

/*
 *--------------------------------------------------------------
 *
 * GetLineIndex --
 *
 *	Parse an index into a line item and return either its value or an
 *	error.
 *
 * Results:
 *	A standard Tcl result. If all went well, then *indexPtr is filled in
 *	with the index (into itemPtr) corresponding to string. Otherwise an
 *	error message is left in interp->result.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
GetLineIndex(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item for which the index is being
				 * specified. */
    Tcl_Obj *obj,		/* Specification of a particular coord in
				 * itemPtr's line. */
    TkSizeT *indexPtr)		/* Where to store converted index. */
{
    TkSizeT idx, length;
    LineItem *linePtr = (LineItem *) itemPtr;
    const char *string;
    (void)canvas;

    if (TCL_OK == TkGetIntForIndex(obj, 2*linePtr->numPoints - 1, 1, &idx)) {
	if (idx == TCL_INDEX_NONE) {
	    idx = 0;
	} else if (idx > (2*(TkSizeT)linePtr->numPoints)) {
	    idx = 2*linePtr->numPoints;
	} else {
	    idx &= (TkSizeT)-2;	/* If index is odd, make it even. */
	}
	*indexPtr = idx;
	return TCL_OK;
    }

    string = Tcl_GetStringFromObj(obj, &length);

    if (string[0] == '@') {
	int i;
	double x, y, bestDist, dist, *coordPtr;
	char *end;
	const char *p;

	p = string+1;
	x = strtod(p, &end);
	if ((end == p) || (*end != ',')) {
	    goto badIndex;
	}
	p = end+1;
	y = strtod(p, &end);
	if ((end == p) || (*end != 0)) {
	    goto badIndex;
	}
	bestDist = 1.0e36;
	coordPtr = linePtr->coordPtr;
	*indexPtr = 0;
	for (i=0; i<linePtr->numPoints; i++) {
	    dist = hypot(coordPtr[0] - x, coordPtr[1] - y);
	    if (dist < bestDist) {
		bestDist = dist;
		*indexPtr = 2*i;
	    }
	    coordPtr += 2;
	}
    } else {

	/*
	 * Some of the paths here leave messages in interp->result, so we have to
	 * clear it out before storing our own message.
	 */

    badIndex:
	Tcl_SetObjResult(interp, Tcl_ObjPrintf("bad index \"%s\"", string));
	Tcl_SetErrorCode(interp, "TK", "CANVAS", "ITEM_INDEX", "LINE", NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * TranslateLine --
 *
 *	This function is called to move a line by a given amount.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The position of the line is offset by (xDelta, yDelta), and the
 *	bounding box is updated in the generic part of the item structure.
 *
 *--------------------------------------------------------------
 */

static void
TranslateLine(
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item that is being moved. */
    double deltaX, double deltaY)
				/* Amount by which item is to be moved. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    double *coordPtr;
    int i;

    for (i = 0, coordPtr = linePtr->coordPtr; i < linePtr->numPoints;
	    i++, coordPtr += 2) {
	coordPtr[0] += deltaX;
	coordPtr[1] += deltaY;
    }
    if (linePtr->firstArrowPtr != NULL) {
	for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		i++, coordPtr += 2) {
	    coordPtr[0] += deltaX;
	    coordPtr[1] += deltaY;
	}
    }
    if (linePtr->lastArrowPtr != NULL) {
	for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		i++, coordPtr += 2) {
	    coordPtr[0] += deltaX;
	    coordPtr[1] += deltaY;
	}
    }
    ComputeLineBbox(canvas, linePtr);
}

/*
 *--------------------------------------------------------------
 *
 * RotateLine --
 *
 *	This function is called to rotate a line by a given amount about a
 *	point.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The position of the line is rotated by angleRad about (originX,
 *	originY), and the bounding box is updated in the generic part of the
 *	item structure.
 *
 *--------------------------------------------------------------
 */

static void
RotateLine(
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item that is being moved. */
    double originX, double originY,
    double angleRad)		/* Amount by which item is to be rotated. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    double *coordPtr;
    int i;
    double s = sin(angleRad), c = cos(angleRad);

    for (i = 0, coordPtr = linePtr->coordPtr; i < linePtr->numPoints;
	    i++, coordPtr += 2) {
	TkRotatePoint(originX, originY, s, c, &coordPtr[0], &coordPtr[1]);
    }
    if (linePtr->firstArrowPtr != NULL) {
	for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		i++, coordPtr += 2) {
	    TkRotatePoint(originX, originY, s, c, &coordPtr[0], &coordPtr[1]);
	}
    }
    if (linePtr->lastArrowPtr != NULL) {
	for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		i++, coordPtr += 2) {
	    TkRotatePoint(originX, originY, s, c, &coordPtr[0], &coordPtr[1]);
	}
    }
    ComputeLineBbox(canvas, linePtr);
}

/*
 *--------------------------------------------------------------
 *
 * ParseArrowShape --
 *
 *	This function is called back during option parsing to parse arrow
 *	shape information.
 *
 * Results:
 *	The return value is a standard Tcl result: TCL_OK means that the arrow
 *	shape information was parsed ok, and TCL_ERROR means it couldn't be
 *	parsed.
 *
 * Side effects:
 *	Arrow information in recordPtr is updated.
 *
 *--------------------------------------------------------------
 */

static int
ParseArrowShape(
    TCL_UNUSED(void *),	/* Not used. */
    Tcl_Interp *interp,		/* Used for error reporting. */
    TCL_UNUSED(Tk_Window),		/* Not used. */
    const char *value,		/* Textual specification of arrow shape. */
    char *recordPtr,		/* Pointer to item record in which to store
				 * arrow information. */
    TkSizeT offset)			/* Offset of shape information in widget
				 * record. */
{
    LineItem *linePtr = (LineItem *) recordPtr;
    double a, b, c;
    int argc;
    const char **argv = NULL;

    if ((size_t)offset != offsetof(LineItem, arrowShapeA)) {
	Tcl_Panic("ParseArrowShape received bogus offset");
    }

    if (Tcl_SplitList(interp, (char *) value, &argc, &argv) != TCL_OK) {
	goto syntaxError;
    } else if (argc != 3) {
	goto syntaxError;
    }
    if ((Tk_CanvasGetCoord(interp, linePtr->canvas, argv[0], &a) != TCL_OK)
	    || (Tk_CanvasGetCoord(interp, linePtr->canvas, argv[1], &b)
		!= TCL_OK)
	    || (Tk_CanvasGetCoord(interp, linePtr->canvas, argv[2], &c)
		!= TCL_OK)) {
	goto syntaxError;
    }

    linePtr->arrowShapeA = (float) a;
    linePtr->arrowShapeB = (float) b;
    linePtr->arrowShapeC = (float) c;
    ckfree(argv);
    return TCL_OK;

  syntaxError:
    Tcl_ResetResult(interp);
    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
	    "bad arrow shape \"%s\": must be list with three numbers",
	    value));
    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ARROW_SHAPE", NULL);
    if (argv != NULL) {
	ckfree(argv);
    }
    return TCL_ERROR;
}

/*
 *--------------------------------------------------------------
 *
 * PrintArrowShape --
 *
 *	This function is a callback invoked by the configuration code to
 *	return a printable value describing an arrow shape.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static const char *
PrintArrowShape(
    TCL_UNUSED(void *),	/* Not used. */
    TCL_UNUSED(Tk_Window),		/* Window associated with linePtr's widget. */
    char *recordPtr,		/* Pointer to item record containing current
				 * shape information. */
    TCL_UNUSED(TkSizeT),			/* Offset of arrow information in record. */
    Tcl_FreeProc **freeProcPtr)	/* Store address of function to call to free
				 * string here. */
{
    LineItem *linePtr = (LineItem *) recordPtr;
    char *buffer = (char *)ckalloc(120);

    sprintf(buffer, "%.5g %.5g %.5g", linePtr->arrowShapeA,
	    linePtr->arrowShapeB, linePtr->arrowShapeC);
    *freeProcPtr = TCL_DYNAMIC;
    return buffer;
}

/*
 *--------------------------------------------------------------
 *
 * ArrowParseProc --
 *
 *	This function is invoked during option processing to handle the
 *	"-arrow" option.
 *
 * Results:
 *	A standard Tcl return value.
 *
 * Side effects:
 *	The arrow for a given item gets replaced by the arrow indicated in the
 *	value argument.
 *
 *--------------------------------------------------------------
 */

static int
ArrowParseProc(
    TCL_UNUSED(void *),
    Tcl_Interp *interp,		/* Used for reporting errors. */
    TCL_UNUSED(Tk_Window),		/* Window containing canvas widget. */
    const char *value,		/* Value of option. */
    char *widgRec,		/* Pointer to record for item. */
    TkSizeT offset)			/* Offset into item. */
{
    int c;
    size_t length;
    Arrows *arrowPtr = (Arrows *) (widgRec + offset);

    if (value == NULL || *value == 0) {
	*arrowPtr = ARROWS_NONE;
	return TCL_OK;
    }

    c = value[0];
    length = strlen(value);

    if ((c == 'n') && (strncmp(value, "none", length) == 0)) {
	*arrowPtr = ARROWS_NONE;
	return TCL_OK;
    }
    if ((c == 'f') && (strncmp(value, "first", length) == 0)) {
	*arrowPtr = ARROWS_FIRST;
	return TCL_OK;
    }
    if ((c == 'l') && (strncmp(value, "last", length) == 0)) {
	*arrowPtr = ARROWS_LAST;
	return TCL_OK;
    }
    if ((c == 'b') && (strncmp(value, "both", length) == 0)) {
	*arrowPtr = ARROWS_BOTH;
	return TCL_OK;
    }

    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
	    "bad arrow spec \"%s\": must be none, first, last, or both",
	    value));
    Tcl_SetErrorCode(interp, "TK", "CANVAS", "ARROW", NULL);
    *arrowPtr = ARROWS_NONE;
    return TCL_ERROR;
}

/*
 *--------------------------------------------------------------
 *
 * ArrowPrintProc --
 *
 *	This function is invoked by the Tk configuration code to produce a
 *	printable string for the "-arrow" configuration option.
 *
 * Results:
 *	The return value is a string describing the arrows for the item
 *	referred to by "widgRec". In addition, *freeProcPtr is filled in with
 *	the address of a function to call to free the result string when it's
 *	no longer needed (or NULL to indicate that the string doesn't need to
 *	be freed).
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static const char *
ArrowPrintProc(
    TCL_UNUSED(void *),	/* Ignored. */
    TCL_UNUSED(Tk_Window),		/* Window containing canvas widget. */
    char *widgRec,		/* Pointer to record for item. */
    TkSizeT offset,			/* Offset into item. */
    TCL_UNUSED(Tcl_FreeProc **))	/* Pointer to variable to fill in with
				 * information about how to reclaim storage
				 * for return string. */
{
    Arrows *arrowPtr = (Arrows *) (widgRec + offset);

    switch (*arrowPtr) {
    case ARROWS_FIRST:
	return "first";
    case ARROWS_LAST:
	return "last";
    case ARROWS_BOTH:
	return "both";
    default:
	return "none";
    }
}

/*
 *--------------------------------------------------------------
 *
 * ConfigureArrows --
 *
 *	If arrowheads have been requested for a line, this function makes
 *	arrangements for the arrowheads.
 *
 * Results:
 *	Always returns TCL_OK.
 *
 * Side effects:
 *	Information in linePtr is set up for one or two arrowheads. The
 *	firstArrowPtr and lastArrowPtr polygons are allocated and initialized,
 *	if need be, and the end points of the line are adjusted so that a
 *	thick line doesn't stick out past the arrowheads.
 *
 *--------------------------------------------------------------
 */

static int
ConfigureArrows(
    Tk_Canvas canvas,		/* Canvas in which arrows will be displayed
				 * (interp and tkwin fields are needed). */
    LineItem *linePtr)		/* Item to configure for arrows. */
{
    double *poly, *coordPtr;
    double dx, dy, length, sinTheta, cosTheta, temp;
    double fracHeight;		/* Line width as fraction of arrowhead
				 * width. */
    double backup;		/* Distance to backup end points so the line
				 * ends in the middle of the arrowhead. */
    double vertX, vertY;	/* Position of arrowhead vertex. */
    double shapeA, shapeB, shapeC;
				/* Adjusted coordinates (see explanation
				 * below). */
    double width;
    Tk_State state = linePtr->header.state;

    if (linePtr->numPoints < 2) {
	return TCL_OK;
    }

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    width = linePtr->outline.width;
    if (Canvas(canvas)->currentItemPtr == (Tk_Item *)linePtr) {
	if (linePtr->outline.activeWidth > width) {
	    width = linePtr->outline.activeWidth;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (linePtr->outline.disabledWidth > 0) {
	    width = linePtr->outline.disabledWidth;
	}
    }

    /*
     * The code below makes a tiny increase in the shape parameters for the
     * line. This is a bit of a hack, but it seems to result in displays that
     * more closely approximate the specified parameters. Without the
     * adjustment, the arrows come out smaller than expected.
     */

    shapeA = linePtr->arrowShapeA + 0.001;
    shapeB = linePtr->arrowShapeB + 0.001;
    shapeC = linePtr->arrowShapeC + width/2.0 + 0.001;

    /*
     * If there's an arrowhead on the first point of the line, compute its
     * polygon and adjust the first point of the line so that the line doesn't
     * stick out past the leading edge of the arrowhead.
     */

    fracHeight = (width/2.0)/shapeC;
    backup = fracHeight*shapeB + shapeA*(1.0 - fracHeight)/2.0;
    if (linePtr->arrow != ARROWS_LAST) {
	poly = linePtr->firstArrowPtr;
	if (poly == NULL) {
	    poly = (double *)ckalloc(2 * PTS_IN_ARROW * sizeof(double));
	    poly[0] = poly[10] = linePtr->coordPtr[0];
	    poly[1] = poly[11] = linePtr->coordPtr[1];
	    linePtr->firstArrowPtr = poly;
	}
	dx = poly[0] - linePtr->coordPtr[2];
	dy = poly[1] - linePtr->coordPtr[3];
	length = hypot(dx, dy);
	if (length == 0) {
	    sinTheta = cosTheta = 0.0;
	} else {
	    sinTheta = dy/length;
	    cosTheta = dx/length;
	}
	vertX = poly[0] - shapeA*cosTheta;
	vertY = poly[1] - shapeA*sinTheta;
	temp = shapeC*sinTheta;
	poly[2] = poly[0] - shapeB*cosTheta + temp;
	poly[8] = poly[2] - 2*temp;
	temp = shapeC*cosTheta;
	poly[3] = poly[1] - shapeB*sinTheta - temp;
	poly[9] = poly[3] + 2*temp;
	poly[4] = poly[2]*fracHeight + vertX*(1.0-fracHeight);
	poly[5] = poly[3]*fracHeight + vertY*(1.0-fracHeight);
	poly[6] = poly[8]*fracHeight + vertX*(1.0-fracHeight);
	poly[7] = poly[9]*fracHeight + vertY*(1.0-fracHeight);

	/*
	 * Polygon done. Now move the first point towards the second so that
	 * the corners at the end of the line are inside the arrowhead.
	 */

	linePtr->coordPtr[0] = poly[0] - backup*cosTheta;
	linePtr->coordPtr[1] = poly[1] - backup*sinTheta;
    }

    /*
     * Similar arrowhead calculation for the last point of the line.
     */

    if (linePtr->arrow != ARROWS_FIRST) {
	coordPtr = linePtr->coordPtr + 2*(linePtr->numPoints-2);
	poly = linePtr->lastArrowPtr;
	if (poly == NULL) {
	    poly = (double *)ckalloc(2 * PTS_IN_ARROW * sizeof(double));
	    poly[0] = poly[10] = coordPtr[2];
	    poly[1] = poly[11] = coordPtr[3];
	    linePtr->lastArrowPtr = poly;
	}
	dx = poly[0] - coordPtr[0];
	dy = poly[1] - coordPtr[1];
	length = hypot(dx, dy);
	if (length == 0) {
	    sinTheta = cosTheta = 0.0;
	} else {
	    sinTheta = dy/length;
	    cosTheta = dx/length;
	}
	vertX = poly[0] - shapeA*cosTheta;
	vertY = poly[1] - shapeA*sinTheta;
	temp = shapeC * sinTheta;
	poly[2] = poly[0] - shapeB*cosTheta + temp;
	poly[8] = poly[2] - 2*temp;
	temp = shapeC * cosTheta;
	poly[3] = poly[1] - shapeB*sinTheta - temp;
	poly[9] = poly[3] + 2*temp;
	poly[4] = poly[2]*fracHeight + vertX*(1.0-fracHeight);
	poly[5] = poly[3]*fracHeight + vertY*(1.0-fracHeight);
	poly[6] = poly[8]*fracHeight + vertX*(1.0-fracHeight);
	poly[7] = poly[9]*fracHeight + vertY*(1.0-fracHeight);
	coordPtr[2] = poly[0] - backup*cosTheta;
	coordPtr[3] = poly[1] - backup*sinTheta;
    }

    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * LineToPostscript --
 *
 *	This function is called to generate Postscript for line items.
 *
 * Results:
 *	The return value is a standard Tcl result. If an error occurs in
 *	generating Postscript then an error message is left in the interp's
 *	result, replacing whatever used to be there. If no error occurs, then
 *	Postscript for the item is appended to the result.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
LineToPostscript(
    Tcl_Interp *interp,		/* Leave Postscript or error message here. */
    Tk_Canvas canvas,		/* Information about overall canvas. */
    Tk_Item *itemPtr,		/* Item for which Postscript is wanted. */
    TCL_UNUSED(int))		/* 1 means this is a prepass to collect font
				 * information; 0 means final Postscript is
				 * being created. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    int style;
    double width;
    XColor *color;
    Pixmap stipple;
    Tk_State state = itemPtr->state;
    Tcl_Obj *psObj;
    Tcl_InterpState interpState;

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    width = linePtr->outline.width;
    color = linePtr->outline.color;
    stipple = linePtr->outline.stipple;
    if (Canvas(canvas)->currentItemPtr == itemPtr) {
	if (linePtr->outline.activeWidth > width) {
	    width = linePtr->outline.activeWidth;
	}
	if (linePtr->outline.activeColor != NULL) {
	    color = linePtr->outline.activeColor;
	}
	if (linePtr->outline.activeStipple != None) {
	    stipple = linePtr->outline.activeStipple;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (linePtr->outline.disabledWidth > 0) {
	    width = linePtr->outline.disabledWidth;
	}
	if (linePtr->outline.disabledColor != NULL) {
	    color = linePtr->outline.disabledColor;
	}
	if (linePtr->outline.disabledStipple != None) {
	    stipple = linePtr->outline.disabledStipple;
	}
    }

    if (color == NULL || linePtr->numPoints < 1 || linePtr->coordPtr == NULL){
	return TCL_OK;
    }

    /*
     * Make our working space.
     */

    psObj = Tcl_NewObj();
    interpState = Tcl_SaveInterpState(interp, TCL_OK);

    /*
     * Check if we're just doing a "pixel".
     */

    if (linePtr->numPoints == 1) {
	Tcl_AppendToObj(psObj, "matrix currentmatrix\n", -1);
	Tcl_AppendPrintfToObj(psObj, "%.15g %.15g translate %.15g %.15g",
		linePtr->coordPtr[0], Tk_CanvasPsY(canvas, linePtr->coordPtr[1]),
		width/2.0, width/2.0);
	Tcl_AppendToObj(psObj,
		" scale 1 0 moveto 0 0 1 0 360 arc\nsetmatrix\n", -1);

	Tcl_ResetResult(interp);
	Tk_CanvasPsColor(interp, canvas, color);
	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));

	if (stipple != None) {
	    Tcl_AppendToObj(psObj, "clip ", -1);
	    Tcl_ResetResult(interp);
	    Tk_CanvasPsStipple(interp, canvas, stipple);
	    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
	} else {
	    Tcl_AppendToObj(psObj, "fill\n", -1);
	}
	goto done;
    }

    /*
     * Generate a path for the line's center-line (do this differently for
     * straight lines and smoothed lines).
     */

    Tcl_ResetResult(interp);
    if ((!linePtr->smooth) || (linePtr->numPoints < 3)) {
	Tk_CanvasPsPath(interp, canvas, linePtr->coordPtr, linePtr->numPoints);
    } else if ((stipple == None) && linePtr->smooth->postscriptProc) {
	linePtr->smooth->postscriptProc(interp, canvas, linePtr->coordPtr,
		linePtr->numPoints, linePtr->splineSteps);
    } else {
	/*
	 * Special hack: Postscript printers don't appear to be able to turn a
	 * path drawn with "curveto"s into a clipping path without exceeding
	 * resource limits, so TkMakeBezierPostscript won't work for stippled
	 * curves. Instead, generate all of the intermediate points here and
	 * output them into the Postscript file with "lineto"s instead.
	 */

	double staticPoints[2*MAX_STATIC_POINTS];
	double *pointPtr;
	int numPoints;

	numPoints = linePtr->smooth->coordProc(canvas, NULL,
		linePtr->numPoints, linePtr->splineSteps, NULL, NULL);
	pointPtr = staticPoints;
	if (numPoints > MAX_STATIC_POINTS) {
	    pointPtr = (double *)ckalloc(numPoints * 2 * sizeof(double));
	}
	numPoints = linePtr->smooth->coordProc(canvas, linePtr->coordPtr,
		linePtr->numPoints, linePtr->splineSteps, NULL, pointPtr);
	Tk_CanvasPsPath(interp, canvas, pointPtr, numPoints);
	if (pointPtr != staticPoints) {
	    ckfree(pointPtr);
	}
    }
    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));

    /*
     * Set other line-drawing parameters and stroke out the line.
     */

    if (linePtr->capStyle == CapRound) {
	style = 1;
    } else if (linePtr->capStyle == CapProjecting) {
	style = 2;
    } else {
	style = 0;
    }
    Tcl_AppendPrintfToObj(psObj, "%d setlinecap\n", style);
    if (linePtr->joinStyle == JoinRound) {
	style = 1;
    } else if (linePtr->joinStyle == JoinBevel) {
	style = 2;
    } else {
	style = 0;
    }
    Tcl_AppendPrintfToObj(psObj, "%d setlinejoin\n", style);

    Tcl_ResetResult(interp);
    Tk_CanvasPsOutline(canvas, itemPtr, &linePtr->outline);
    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));

    /*
     * Output polygons for the arrowheads, if there are any.
     */

    if (linePtr->firstArrowPtr != NULL) {
	if (stipple != None) {
	    Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
	}
	ArrowheadPostscript(interp, canvas, linePtr,
		linePtr->firstArrowPtr, psObj);
    }
    if (linePtr->lastArrowPtr != NULL) {
	if (stipple != None) {
	    Tcl_AppendToObj(psObj, "grestore gsave\n", -1);
	}
	ArrowheadPostscript(interp, canvas, linePtr,
		linePtr->lastArrowPtr, psObj);
    }

    /*
     * Plug the accumulated postscript back into the result.
     */

  done:
    (void) Tcl_RestoreInterpState(interp, interpState);
    Tcl_AppendObjToObj(Tcl_GetObjResult(interp), psObj);
    Tcl_DecrRefCount(psObj);
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * ArrowheadPostscript --
 *
 *	This function is called to generate Postscript for an arrowhead for a
 *	line item.
 *
 * Results:
 *	The return value is a standard Tcl result. If an error occurs in
 *	generating Postscript then an error message is left in the interp's
 *	result, replacing whatever used to be there. If no error occurs, then
 *	Postscript for the arrowhead is appended to the given object.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
ArrowheadPostscript(
    Tcl_Interp *interp,		/* Leave error message here; non-error results
				 * will be discarded by caller. */
    Tk_Canvas canvas,		/* Information about overall canvas. */
    LineItem *linePtr,		/* Line item for which Postscript is being
				 * generated. */
    double *arrowPtr,		/* Pointer to first of five points describing
				 * arrowhead polygon. */
    Tcl_Obj *psObj)		/* Append postscript to this object. */
{
    Pixmap stipple;
    Tk_State state = linePtr->header.state;

    if (state == TK_STATE_NULL) {
	state = Canvas(canvas)->canvas_state;
    }

    stipple = linePtr->outline.stipple;
    if (Canvas(canvas)->currentItemPtr == (Tk_Item *) linePtr) {
	if (linePtr->outline.activeStipple!=None) {
	    stipple = linePtr->outline.activeStipple;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (linePtr->outline.activeStipple!=None) {
	    stipple = linePtr->outline.disabledStipple;
	}
    }

    Tcl_ResetResult(interp);
    Tk_CanvasPsPath(interp, canvas, arrowPtr, PTS_IN_ARROW);
    Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));

    if (stipple != None) {
	Tcl_AppendToObj(psObj, "clip ", -1);

	Tcl_ResetResult(interp);
	Tk_CanvasPsStipple(interp, canvas, stipple);
	Tcl_AppendObjToObj(psObj, Tcl_GetObjResult(interp));
    } else {
	Tcl_AppendToObj(psObj, "fill\n", -1);
    }
    return TCL_OK;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */