/*
 * tkoPathCanvPath.c --
 *
 *  This file implements a path canvas item modelled after its
 *  SVG counterpart. See http://www.w3.org/TR/SVG11/.
 *
 * Copyright (c) 2005-2008  Mats Bengtsson
 *
 */

#include "tkoPath.h"

/* Values for the PathItem's flag. */

enum {
    kPathItemNeedNewNormalizedPath = (1L << 0)
};

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

typedef struct PathItem {
    Tk_PathItemEx headerEx;    /* Generic stuff that's the same for all
                                * path types.  MUST BE FIRST IN STRUCTURE. */
    Tcl_Obj *pathObjPtr;       /* The object containing the path definition. */
    int pathLen;
    Tcl_Obj *normPathObjPtr;   /* The object containing the normalized path. */
    TkPathAtom *atomPtr;
    int maxNumSegments;        /* Max number of straight segments (for subpath)
                                * needed for Area and Point functions. */
    TkPathArrowDescr startarrow;
    TkPathArrowDescr endarrow;
    long flags;                /* Various flags, see enum. */
} PathItem;

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

static void ComputePathBbox(
    Tk_PathCanvas canvas,
    PathItem * pathPtr);
static int ConfigurePath(
    Tcl_Interp * interp,
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    Tcl_Size objc,
    Tcl_Obj * const objv[],
    int flags);
static int CreatePath(
    Tcl_Interp * interp,
    Tk_PathCanvas canvas,
    struct Tk_PathItem *itemPtr,
    Tcl_Size objc,
    Tcl_Obj * const objv[]);
static int ProcessPath(
    Tcl_Interp * interp,
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    Tcl_Size objc,
    Tcl_Obj * const objv[]);
static int PathCoords(
    Tcl_Interp * interp,
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    Tcl_Size objc,
    Tcl_Obj * const objv[]);
static void DeletePath(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    Display * display);
static void DisplayPath(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    Display * display,
    Drawable dst,
    int x,
    int y,
    int width,
    int height);
static void PathBbox(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    int mask);
static int PathToArea(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    double *areaPtr);
static int PathToPdf(
    Tcl_Interp * interp,
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    Tcl_Size objc,
    Tcl_Obj * const objv[],
    int prepass);
static double PathToPoint(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    double *coordPtr);
static void ScalePath(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    int compensate,
    double originX,
    double originY,
    double scaleX,
    double scaleY);
static void TranslatePath(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    int compensate,
    double deltaX,
    double deltaY);
static int ConfigureArrows(
    Tk_PathCanvas canvas,
    PathItem * pathPtr);

/* Support functions. */

static int GetSubpathMaxNumSegments(
    TkPathAtom * atomPtr);

TK_PATH_STYLE_CUSTOM_OPTION_RECORDS
    TK_PATH_CUSTOM_OPTION_TAGS
    TK_PATH_OPTION_STRING_TABLES_FILL
    TK_PATH_OPTION_STRING_TABLES_STROKE
    TK_PATH_OPTION_STRING_TABLES_STATE static Tk_OptionSpec optionSpecs[] = {
    TK_PATH_OPTION_SPEC_CORE(Tk_PathItemEx),
    TK_PATH_OPTION_SPEC_PARENT,
    TK_PATH_OPTION_SPEC_STYLE_FILL(Tk_PathItemEx, ""),
    TK_PATH_OPTION_SPEC_STYLE_MATRIX(Tk_PathItemEx),
    TK_PATH_OPTION_SPEC_STYLE_STROKE(Tk_PathItemEx, "black"),
    TK_PATH_OPTION_SPEC_STARTARROW_GRP(PathItem),
    TK_PATH_OPTION_SPEC_ENDARROW_GRP(PathItem),
    TK_PATH_OPTION_SPEC_END
};

/*
 * The structures below defines the 'path' item type by means
 * of procedures that can be invoked by generic item code.
 */

Tk_PathItemType tkPathTypePath = {
    "path",    /* name */
    sizeof(PathItem),   /* itemSize */
    CreatePath, /* createProc */
    optionSpecs,        /* optionSpecs */
    ConfigurePath,      /* configureProc */
    PathCoords, /* coordProc */
    DeletePath, /* deleteProc */
    DisplayPath,        /* displayProc */
    0,         /* flags */
    PathBbox,  /* bboxProc */
    PathToPoint,        /* pointProc */
    PathToArea, /* areaProc */
    PathToPdf, /* pdfProc */
    ScalePath, /* scaleProc */
    TranslatePath,      /* translateProc */
    (Tk_PathItemIndexProc *) NULL,      /* indexProc */
    (Tk_PathItemCursorProc *) NULL,     /* icursorProc */
    (Tk_PathItemSelectionProc *) NULL,  /* selectionProc */
    (Tk_PathItemInsertProc *) NULL,     /* insertProc */
    (Tk_PathItemDCharsProc *) NULL,     /* dTextProc */
    (Tk_PathItemType *) NULL,   /* nextPtr */
    1,         /* isPathType */
};

/* Be sure rect is not empty (see above) before doing this. */
static void
NormalizePathRect(
    TkPathRect * r)
{
double min, max;

    min = MIN(r->x1, r->x2);
    max = MAX(r->x1, r->x2);
    r->x1 = min;
    r->x2 = max;
    min = MIN(r->y1, r->y2);
    max = MAX(r->y1, r->y2);
    r->y1 = min;
    r->y2 = max;
}

/*
 +++ This starts the canvas item part +++
 */

/*
 *--------------------------------------------------------------
 *
 * CreatePath --
 *
 *    This procedure 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
CreatePath(
    Tcl_Interp * interp,       /* Used for error reporting. */
    Tk_PathCanvas canvas,      /* Canvas containing item. */
    Tk_PathItem * itemPtr,     /* Item to create. */
    Tcl_Size objc,                  /* Number of elements in objv.  */
    Tcl_Obj * const objv[])
{              /* Arguments describing the item. */
    PathItem *pathPtr = (PathItem *) itemPtr;
    Tk_PathItemEx *itemExPtr = &pathPtr->headerEx;
    Tk_OptionTable optionTable;

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

    /*
     * Carry out initialization that is needed to set defaults and to
     * allow proper cleanup after errors during the the remainder of
     * this procedure.
     */
    TkPathInitStyle(&itemExPtr->style);
    itemExPtr->canvas = canvas;
    itemExPtr->styleObj = NULL;
    itemExPtr->styleInst = NULL;
    pathPtr->pathObjPtr = NULL;
    pathPtr->pathLen = 0;
    pathPtr->normPathObjPtr = NULL;
    pathPtr->atomPtr = NULL;
    itemPtr->bbox = TkPathNewEmptyPathRect();
    itemPtr->totalBbox = TkPathNewEmptyPathRect();
    pathPtr->maxNumSegments = 0;
    TkPathArrowDescrInit(&pathPtr->startarrow);
    TkPathArrowDescrInit(&pathPtr->endarrow);
    pathPtr->flags = 0L;

    /* Forces a computation of the normalized path in PathCoords. */
    pathPtr->flags |= kPathItemNeedNewNormalizedPath;

    optionTable = Tk_CreateOptionTable(interp, optionSpecs);
    itemPtr->optionTable = optionTable;
    if(Tk_InitOptions(interp, (char *)pathPtr, optionTable,
            Tk_PathCanvasTkwin(canvas)) != TCL_OK) {
        goto error;
    }

    /*
     * The first argument must be the path definition list.
     */

    if(ProcessPath(interp, canvas, itemPtr, 1, objv) != TCL_OK) {
        goto error;
    }
    if(ConfigurePath(interp, canvas, itemPtr, objc - 1, objv + 1, 0) == TCL_OK) {
        return TCL_OK;
    }

  error:
    /*
     * NB: We must unlink the item here since the TkPathCanvasItemExConfigure()
     *     link it to the root by default.
     */
    TkPathCanvasItemDetach(itemPtr);
    DeletePath(canvas, itemPtr, Tk_Display(Tk_PathCanvasTkwin(canvas)));
    return TCL_ERROR;
}

/*
 *--------------------------------------------------------------
 *
 * ProcessPath --
 *
 *    Does the main job of processing the drawing path in 'PathCoords'
 *      but doesn't do the bbox calculation since this cannot be done
 *      before we have callaed 'ConfigurePath' because we need
 *      the inherited style.
 *
 * 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
ProcessPath(
    Tcl_Interp * interp,       /* Used for error reporting. */
    Tk_PathCanvas canvas,      /* Canvas containing item. */
    Tk_PathItem * itemPtr,     /* Item whose coordinates are to be
                                * read or modified. */
    Tcl_Size objc,                  /*  */
    Tcl_Obj * const objv[])
{              /*  */
    PathItem *pathPtr = (PathItem *) itemPtr;
    TkPathAtom *atomPtr = NULL;
    int result;
    Tcl_Size len;

    if(objc == 0) {
        /* @@@ We have an option here if to return the normalized or original path. */
#if 0
        Tcl_SetObjResult(interp, pathPtr->pathObjPtr);
#endif

        /* We may need to recompute the normalized path from the atoms. */
        if(pathPtr->flags & kPathItemNeedNewNormalizedPath) {
            if(pathPtr->normPathObjPtr != NULL) {
                Tcl_DecrRefCount(pathPtr->normPathObjPtr);
            }
            TkPathNormalize(interp, pathPtr->atomPtr,
                &(pathPtr->normPathObjPtr));
            Tcl_IncrRefCount(pathPtr->normPathObjPtr);
            pathPtr->flags &= ~kPathItemNeedNewNormalizedPath;
        }
        Tcl_SetObjResult(interp, pathPtr->normPathObjPtr);
        return TCL_OK;
    } else if(objc == 1) {
        result = TkPathParseToAtoms(interp, objv[0], &atomPtr, &len);
        if(result == TCL_OK) {

            /* Free any old atoms. */
            if(pathPtr->atomPtr != NULL) {
                TkPathFreeAtoms(pathPtr->atomPtr);
            }
            pathPtr->atomPtr = atomPtr;
            pathPtr->pathLen = len;
            if(pathPtr->pathObjPtr != NULL) {
                Tcl_DecrRefCount(pathPtr->pathObjPtr);
            }
            pathPtr->pathObjPtr = objv[0];
            pathPtr->maxNumSegments = GetSubpathMaxNumSegments(atomPtr);
            Tcl_IncrRefCount(pathPtr->pathObjPtr);
            pathPtr->flags |= kPathItemNeedNewNormalizedPath;
        }
        return result;
    } else {
        Tcl_WrongNumArgs(interp, 0, objv, "pathName coords id ?pathSpec?");
        return TCL_ERROR;
    }
}

/*
 *--------------------------------------------------------------
 *
 * PathCoords --
 *
 *    This procedure 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
PathCoords(
    Tcl_Interp * interp,       /* Used for error reporting. */
    Tk_PathCanvas canvas,      /* Canvas containing item. */
    Tk_PathItem * itemPtr,     /* Item whose coordinates are to be
                                * read or modified. */
    Tcl_Size objc,                  /*  */
    Tcl_Obj * const objv[])
{              /*  */
    PathItem *pathPtr = (PathItem *) itemPtr;
    int result;

    result = ProcessPath(interp, canvas, itemPtr, objc, objv);
    if((result == TCL_OK) && (objc == 1)) {
        ConfigureArrows(canvas, pathPtr);
        ComputePathBbox(canvas, pathPtr);
    }
    return result;
}

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

static void
ComputePathBbox(
    Tk_PathCanvas canvas,      /* Canvas that contains item. */
    PathItem * pathPtr)
{              /* Item whose bbox is to be
                * recomputed. */
Tk_PathItemEx *itemExPtr = &pathPtr->headerEx;
Tk_PathItem *itemPtr = &itemExPtr->header;
Tk_PathStyle style;
Tk_PathState state = itemExPtr->header.state;

    if(state == TK_PATHSTATE_NULL) {
        state = TkPathCanvasState(canvas);
    }
    if(pathPtr->pathObjPtr == NULL || (pathPtr->pathLen < 4)
        || (state == TK_PATHSTATE_HIDDEN)) {
        itemExPtr->header.x1 = itemExPtr->header.x2 = itemExPtr->header.y1 =
            itemExPtr->header.y2 = -1;
        return;
    }
    style = TkPathCanvasInheritStyle(itemPtr, TK_PATH_MERGESTYLE_NOTFILL);

    /*
     * Get an approximation of the path's bounding box
     * assuming zero stroke width.
     */
    itemPtr->bbox = TkPathGetGenericBarePathBbox(pathPtr->atomPtr);
    TkPathIncludeArrowPointsInRect(&itemPtr->bbox, &pathPtr->startarrow);
    TkPathIncludeArrowPointsInRect(&itemPtr->bbox, &pathPtr->endarrow);
    itemPtr->totalBbox = TkPathGetGenericPathTotalBboxFromBare(pathPtr->atomPtr,
        &style, &itemPtr->bbox);
    TkPathSetGenericPathHeaderBbox(&itemExPtr->header, style.matrixPtr,
        &itemPtr->totalBbox);
    TkPathCanvasFreeInheritedStyle(&style);
}

static int
ConfigureArrows(
    Tk_PathCanvas canvas,
    PathItem * pathPtr)
{
TkPathPoint *pfirstp;
TkPathPoint psecond;
TkPathPoint ppenult;
TkPathPoint *plastp;

int error = TkPathGetSegmentsFromPathAtomList(pathPtr->atomPtr, &pfirstp,
        &psecond, &ppenult, &plastp);

    if(error == TCL_OK) {
TkPathPoint pfirst = *pfirstp;
TkPathPoint plast = *plastp;
Tk_PathStyle *lineStyle = &pathPtr->headerEx.style;
int isOpen = lineStyle->fill == NULL &&
    ((pfirst.x != plast.x) || (pfirst.y != plast.y));

        TkPathPreconfigureArrow(&pfirst, &pathPtr->startarrow);
        TkPathPreconfigureArrow(&plast, &pathPtr->endarrow);

        *pfirstp = TkPathConfigureArrow(pfirst, psecond,
            &pathPtr->startarrow, lineStyle, isOpen);
        *plastp = TkPathConfigureArrow(plast, ppenult, &pathPtr->endarrow,
            lineStyle, isOpen);
    } else {
        TkPathFreeArrow(&pathPtr->startarrow);
        TkPathFreeArrow(&pathPtr->endarrow);
    }

    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * ConfigurePath --
 *
 *    This procedure 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
ConfigurePath(
    Tcl_Interp * interp,       /* Used for error reporting. */
    Tk_PathCanvas canvas,      /* Canvas containing itemPtr. */
    Tk_PathItem * itemPtr,     /* Line item to reconfigure. */
    Tcl_Size objc,                  /* Number of elements in objv.  */
    Tcl_Obj * const objv[],    /* Arguments describing things to configure. */
    int flags)
{              /* Flags to pass to Tk_ConfigureWidget. */
    PathItem *pathPtr = (PathItem *) itemPtr;
    Tk_PathItemEx *itemExPtr = &pathPtr->headerEx;
    Tk_PathStyle *stylePtr = &itemExPtr->style;
    Tk_Window tkwin;
    Tk_SavedOptions savedOptions;
    Tcl_Obj *errorResult = NULL;
    int mask, error;

    tkwin = Tk_PathCanvasTkwin(canvas);
    for(error = 0; error <= 1; error++) {
        if(!error) {
            if(Tk_SetOptions(interp, (char *)pathPtr, itemPtr->optionTable,
                    objc, objv, tkwin, &savedOptions, &mask) != TCL_OK) {
                continue;
            }
        } else {
            errorResult = Tcl_GetObjResult(interp);
            Tcl_IncrRefCount(errorResult);
            Tk_RestoreSavedOptions(&savedOptions);
        }
        if(TkPathCanvasItemExConfigure(interp, canvas, itemExPtr,
                mask) != TCL_OK) {
            continue;
        }

        /*
         * If we reach this on the first pass we are OK and continue below.
         */
        break;
    }
    if(!error) {
        Tk_FreeSavedOptions(&savedOptions);
        stylePtr->mask |= mask;
    }

    stylePtr->strokeOpacity = MAX(0.0, MIN(1.0, stylePtr->strokeOpacity));
    stylePtr->fillOpacity = MAX(0.0, MIN(1.0, stylePtr->fillOpacity));

    ConfigureArrows(canvas, pathPtr);

    /*
     * Recompute bounding box for path.
     */
    if(error) {
        Tcl_SetObjResult(interp, errorResult);
        Tcl_DecrRefCount(errorResult);
        return TCL_ERROR;
    } else {
        ComputePathBbox(canvas, pathPtr);
        return TCL_OK;
    }
}

/*
 *--------------------------------------------------------------
 *
 * DeletePath --
 *
 *    This procedure 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
DeletePath(
    Tk_PathCanvas canvas,      /* Info about overall canvas widget. */
    Tk_PathItem * itemPtr,     /* Item that is being deleted. */
    Display * display)
{              /* Display containing window for
                * canvas. */
PathItem *pathPtr = (PathItem *) itemPtr;
Tk_PathItemEx *itemExPtr = &pathPtr->headerEx;
Tk_PathStyle *stylePtr = &itemExPtr->style;

    if(stylePtr->fill != NULL) {
        TkPathFreePathColor(stylePtr->fill);
    }
    if(itemExPtr->styleInst != NULL) {
        TkPathFreeStyle(itemExPtr->styleInst);
    }
    if(pathPtr->pathObjPtr != NULL) {
        Tcl_DecrRefCount(pathPtr->pathObjPtr);
    }
    if(pathPtr->normPathObjPtr != NULL) {
        Tcl_DecrRefCount(pathPtr->normPathObjPtr);
    }
    if(pathPtr->atomPtr != NULL) {
        TkPathFreeAtoms(pathPtr->atomPtr);
        pathPtr->atomPtr = NULL;
    }
    TkPathFreeArrow(&pathPtr->startarrow);
    TkPathFreeArrow(&pathPtr->endarrow);
    Tk_FreeConfigOptions((char *)pathPtr, itemPtr->optionTable,
        Tk_PathCanvasTkwin(canvas));
}

/*
 *--------------------------------------------------------------
 *
 * DisplayPath --
 *
 *    This procedure 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
DisplayPath(
    Tk_PathCanvas canvas,      /* Canvas that contains item. */
    Tk_PathItem * itemPtr,     /* Item to be displayed. */
    Display * display,         /* Display on which to draw item. */
    Drawable drawable,         /* Pixmap or window in which to draw
                                * item. */
    int x,
    int y,                     /* Describes region of canvas that */
    int width,
    int height)
{              /* must be redisplayed (not used). */
    PathItem *pathPtr = (PathItem *) itemPtr;
    TkPathMatrix m = TkPathGetCanvasTMatrix(canvas);
    Tk_PathStyle style;

    if(pathPtr->pathLen > 2) {
        style = TkPathCanvasInheritStyle(itemPtr, 0);
        TkPathDrawPath(ContextOfCanvas(canvas), pathPtr->atomPtr, &style,
            &m, &itemPtr->bbox);
        /*
         * Display arrowheads, if they are wanted.
         */
        TkPathDisplayArrow(canvas, &pathPtr->startarrow, &style, &m,
            &itemPtr->bbox);
        TkPathDisplayArrow(canvas, &pathPtr->endarrow, &style, &m,
            &itemPtr->bbox);

        TkPathCanvasFreeInheritedStyle(&style);
    }
}

static void
PathBbox(
    Tk_PathCanvas canvas,
    Tk_PathItem * itemPtr,
    int mask)
{
    PathItem *pathPtr = (PathItem *) itemPtr;
    /*
     * Try to be economical here.
     */
    if((mask & TK_PATH_STYLE_OPTION_MATRIX) ||
        (mask & TK_PATH_STYLE_OPTION_STROKE) ||
        (mask & TK_PATH_STYLE_OPTION_STROKE_WIDTH) ||
        (mask & TK_PATH_CORE_OPTION_PARENT) ||
        (mask & TK_PATH_CORE_OPTION_STYLENAME)) {
        ComputePathBbox(canvas, pathPtr);
    }
}

/*
 *--------------------------------------------------------------
 *
 * PathToPoint --
 *
 *    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
PathToPoint(
    Tk_PathCanvas canvas,      /* Canvas containing item. */
    Tk_PathItem * itemPtr,     /* Item to check against point. */
    double *pointPtr)
{              /* Pointer to x and y coordinates. */
    PathItem *pathPtr = (PathItem *) itemPtr;
    TkPathAtom *atomPtr = pathPtr->atomPtr;
    Tk_PathStyle style;
    double dist;

    style = TkPathCanvasInheritStyle(itemPtr, 0);
    dist = TkPathGenericPathToPoint(canvas, itemPtr, &style, atomPtr,
        pathPtr->maxNumSegments, pointPtr);
    TkPathCanvasFreeInheritedStyle(&style);
    return dist;
}

/*
 * Get maximum number of segments needed to describe path.
 * Needed to see if we can use static space or need to allocate more.
 */

static int
GetArcNumSegments(
    double currentX,
    double currentY,
    TkArcAtom * arc)
{
    int result;
    int ntheta, nlength;
    int numSteps;              /* Number of curve points to
                                * generate.  */
    double cx, cy, rx, ry;
    double theta1, dtheta;

    result = TkPathEndpointToCentralArcParameters(currentX, currentY,
        arc->x, arc->y, arc->radX, arc->radY,
        DEGREES_TO_RADIANS * arc->angle,
        arc->largeArcFlag, arc->sweepFlag,
        &cx, &cy, &rx, &ry, &theta1, &dtheta);
    if(result == TK_PATH_ARC_Line) {
        return 2;
    } else if(result == TK_PATH_ARC_Skip) {
        return 0;
    }

    /* Estimate the number of steps needed.
     * Max 10 degrees or length 50.
     */
    ntheta = (int)(dtheta / 5.0 + 0.5);
    nlength = (int)(0.5 * (rx + ry) * dtheta / 50 + 0.5);
    numSteps = MAX(4, MAX(ntheta, nlength));;
    return numSteps;
}

static int
GetSubpathMaxNumSegments(
    TkPathAtom * atomPtr)
{
int num;
int maxNumSegments;
double currentX = 0.0, currentY = 0.0;
double startX = 0.0, startY = 0.0;
TkMoveToAtom *move;
TkLineToAtom *line;
TkArcAtom *arc;
TkQuadBezierAtom *quad;
TkCurveToAtom *curve;

    num = 0;
    maxNumSegments = 0;

    while(atomPtr != NULL) {

        switch (atomPtr->type) {
        case TK_PATH_ATOM_M:{
            move = (TkMoveToAtom *) atomPtr;
            num = 1;
            currentX = move->x;
            currentY = move->y;
            startX = currentX;
            startY = currentY;
            break;
        }
        case TK_PATH_ATOM_L:{
            line = (TkLineToAtom *) atomPtr;
            num++;
            currentX = line->x;
            currentY = line->y;
            break;
        }
        case TK_PATH_ATOM_A:{
            arc = (TkArcAtom *) atomPtr;
            num += GetArcNumSegments(currentX, currentY, arc);
            currentX = arc->x;
            currentY = arc->y;
            break;
        }
        case TK_PATH_ATOM_Q:{
            quad = (TkQuadBezierAtom *) atomPtr;
            num += TK_PATH_NUMSEGEMENTS_QuadBezier;
            currentX = quad->anchorX;
            currentY = quad->anchorY;
            break;
        }
        case TK_PATH_ATOM_C:{
            curve = (TkCurveToAtom *) atomPtr;
            num += TK_PATH_NUMSEGEMENTS_CurveTo;
            currentX = curve->anchorX;
            currentY = curve->anchorY;
            break;
        }
        case TK_PATH_ATOM_Z:{
            num++;
            currentX = startX;
            currentY = startY;
            break;
        }
        case TK_PATH_ATOM_ELLIPSE:
        case TK_PATH_ATOM_RECT:{
            /* Empty. */
            break;
        }
        }
        if(num > maxNumSegments) {
            maxNumSegments = num;
        }
        atomPtr = atomPtr->nextPtr;
    }
    return maxNumSegments;
}

/*
 *--------------------------------------------------------------
 *
 * PathToArea --
 *
 *    This procedure is called to determine whether an item
 *    lies entirely inside, entirely outside, or overlapping
 *    a given rectangular area.
 *
 *    Each subpath is treated in turn. Generate straight line
 *    segments for each subpath and treat it as a polygon.
 *
 * 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
PathToArea(
    Tk_PathCanvas canvas,      /* Canvas containing item. */
    Tk_PathItem * itemPtr,     /* Item to check against line. */
    double *areaPtr)
{              /* Pointer to array of four coordinates
                * (x1, y1, x2, y2) describing rectangular
                * area.  */
    PathItem *pathPtr = (PathItem *) itemPtr;
    Tk_PathStyle style;
    int area;

    style = TkPathCanvasInheritStyle(itemPtr, 0);
    area = TkPathGenericPathToArea(canvas, itemPtr, &style,
        pathPtr->atomPtr, pathPtr->maxNumSegments, areaPtr);
    TkPathCanvasFreeInheritedStyle(&style);
    return area;
}

/*
 *--------------------------------------------------------------
 *
 * ScalePath --
 *
 *    This procedure is invoked to rescale a path 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
ScalePath(
    Tk_PathCanvas canvas,      /* Canvas containing line. */
    Tk_PathItem * itemPtr,     /* Path to be scaled. */
    int compensate,            /* Compensate matrix. */
    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. */
    PathItem *pathPtr = (PathItem *) itemPtr;
    TkPathAtom *atomPtr = pathPtr->atomPtr;

    TkPathCompensateScale(itemPtr, compensate, &originX, &originY, &scaleX,
        &scaleY);

    /* @@@ TODO: Arc atoms with nonzero rotation angle is WRONG! */

    TkPathScalePathAtoms(atomPtr, originX, originY, scaleX, scaleY);

    /*
     * Set flags bit so we know that PathCoords need to update the
     * normalized path before being used.
     */
    pathPtr->flags |= kPathItemNeedNewNormalizedPath;

    /* Just scale the bbox'es as well. */
    TkPathScalePathRect(&itemPtr->bbox, originX, originY, scaleX, scaleY);
    NormalizePathRect(&itemPtr->bbox);

    TkPathScaleArrow(&pathPtr->startarrow, originX, originY, scaleX, scaleY);
    TkPathScaleArrow(&pathPtr->endarrow, originX, originY, scaleX, scaleY);
    ConfigureArrows(canvas, pathPtr);
    TkPathScaleItemHeader(itemPtr, originX, originY, scaleX, scaleY);
}

/*
 *--------------------------------------------------------------
 *
 * TranslatePath --
 *
 *    This procedure is called to move a path 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
TranslatePath(
    Tk_PathCanvas canvas,      /* Canvas containing item. */
    Tk_PathItem * itemPtr,     /* Item that is being moved. */
    int compensate,            /* Compensate matrix. */
    double deltaX,             /* Amount by which item is to be */
    double deltaY)
{              /* moved. */
    PathItem *pathPtr = (PathItem *) itemPtr;
    TkPathAtom *atomPtr = pathPtr->atomPtr;

    TkPathCompensateTranslate(itemPtr, compensate, &deltaX, &deltaY);

    TkPathTranslatePathAtoms(atomPtr, deltaX, deltaY);

    /*
     * Set flags bit so we know that PathCoords need to update the
     * normalized path before being used.
     */
    pathPtr->flags |= kPathItemNeedNewNormalizedPath;

    /* Just translate the bbox'es as well. */
    TkPathTranslatePathRect(&itemPtr->bbox, deltaX, deltaY);
    TkPathTranslateArrow(&pathPtr->startarrow, deltaX, deltaY);
    TkPathTranslateArrow(&pathPtr->endarrow, deltaX, deltaY);
    TkPathTranslateItemHeader(itemPtr, deltaX, deltaY);
}

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

static int
PathToPdf(
    Tcl_Interp * interp,       /* Leave Pdf or error message
                                * here. */
    Tk_PathCanvas canvas,      /* Information about overall canvas. */
    Tk_PathItem * itemPtr,     /* Item for which Pdf is
                                * wanted. */
    Tcl_Size objc,                  /* Number of arguments. */
    Tcl_Obj * const objv[],    /* Argument list. */
    int prepass)
{              /* 1 means this is a prepass to
                * collect font information;  0 means
                * final Pdf is being created. */
    Tk_PathStyle style;
    PathItem *pathPtr = (PathItem *) itemPtr;
    Tk_PathState state = itemPtr->state;
    int result = TCL_OK;

    if(state == TK_PATHSTATE_NULL) {
        state = TkPathCanvasState(canvas);
    }
    if((pathPtr->pathObjPtr == NULL) || (state == TK_PATHSTATE_HIDDEN)) {
        return result;
    }
    if(pathPtr->pathLen > 2) {
        style = TkPathCanvasInheritStyle(itemPtr, 0);
        result = TkPathPdf(interp, pathPtr->atomPtr, &style, &itemPtr->bbox,
            objc, objv);
        if(result == TCL_OK) {
            result = TkPathPdfArrow(interp, &pathPtr->startarrow, &style);
            if(result == TCL_OK) {
                result = TkPathPdfArrow(interp, &pathPtr->endarrow, &style);
            }
        }
        TkPathCanvasFreeInheritedStyle(&style);
    }
    return result;
}

/* vim: set ts=4 sw=4 sts=4 ff=unix et : */
