tkcanvline.c

MPICH是MPI的重要研究,提供了一系列的接口函数,为并行计算的实现提供了编程环境.

	linePtr->coordPtr[1] = linePtr->firstArrowPtr[1];
	ckfree((char *) linePtr->firstArrowPtr);
	linePtr->firstArrowPtr = NULL;
    }
    if ((linePtr->lastArrowPtr != NULL) && (linePtr->arrow != lastUid)
	    && (linePtr->arrow != bothUid)) {
	int index;

	index = 2*(linePtr->numPoints-1);
	linePtr->coordPtr[index] = linePtr->lastArrowPtr[0];
	linePtr->coordPtr[index+1] = linePtr->lastArrowPtr[1];
	ckfree((char *) linePtr->lastArrowPtr);
	linePtr->lastArrowPtr = NULL;
    }
    if (linePtr->arrow != noneUid) {
	if ((linePtr->arrow != firstUid) && (linePtr->arrow != lastUid)
		&& (linePtr->arrow != bothUid)) {
	    Tcl_AppendResult(canvasPtr->interp, "bad arrow spec \"",
		    linePtr->arrow, "\": must be none, first, last, or both",
		    (char *) NULL);
	    linePtr->arrow = noneUid;
	    return TCL_ERROR;
	}
	ConfigureArrows(canvasPtr, linePtr);
    }

    /*
     * Recompute bounding box for line.
     */

    ComputeLineBbox(canvasPtr, linePtr);

    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * DeleteLine --
 *
 *	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
DeleteLine(canvasPtr, itemPtr)
    Tk_Canvas *canvasPtr;		/* Info about overall canvas widget. */
    Tk_Item *itemPtr;			/* Item that is being deleted. */
{
    register LineItem *linePtr = (LineItem *) itemPtr;

    if (linePtr->coordPtr != NULL) {
	ckfree((char *) linePtr->coordPtr);
    }
    if (linePtr->fg != NULL) {
	Tk_FreeColor(linePtr->fg);
    }
    if (linePtr->fillStipple != None) {
	Tk_FreeBitmap(canvasPtr->display, linePtr->fillStipple);
    }
    if (linePtr->gc != None) {
	Tk_FreeGC(canvasPtr->display, linePtr->gc);
    }
    if (linePtr->firstArrowPtr != NULL) {
	ckfree((char *) linePtr->firstArrowPtr);
    }
    if (linePtr->lastArrowPtr != NULL) {
	ckfree((char *) linePtr->lastArrowPtr);
    }
}

/*
 *--------------------------------------------------------------
 *
 * ComputeLineBbox --
 *
 *	This procedure 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(canvasPtr, linePtr)
    register Tk_Canvas *canvasPtr;	/* Canvas that contains item. */
    LineItem *linePtr;			/* Item whose bbos is to be
					 * recomputed. */
{
    register double *coordPtr;
    int i;

    coordPtr = linePtr->coordPtr;
    linePtr->header.x1 = linePtr->header.x2 = *coordPtr;
    linePtr->header.y1 = linePtr->header.y2 = 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(canvasPtr, (Tk_Item *) linePtr, coordPtr);
    }
    linePtr->header.x1 -= linePtr->width;
    linePtr->header.x2 += linePtr->width;
    linePtr->header.y1 -= linePtr->width;
    linePtr->header.y2 += linePtr->width;

    /*
     * 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,
		    (double) linePtr->width, miter, miter+2)) {
		for (j = 0; j < 4; j += 2) {
		    TkIncludePoint(canvasPtr, (Tk_Item *) linePtr, miter+j);
		}
	    }
	}
    }

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

    if (linePtr->arrow != noneUid) {
	if (linePtr->arrow != lastUid) {
	    for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(canvasPtr, (Tk_Item *) linePtr, coordPtr);
	    }
	}
	if (linePtr->arrow != firstUid) {
	    for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		    i++, coordPtr += 2) {
		TkIncludePoint(canvasPtr, (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 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 canvasPtr.
 *
 *--------------------------------------------------------------
 */

static void
DisplayLine(canvasPtr, itemPtr, drawable)
    register Tk_Canvas *canvasPtr;	/* Canvas that contains item. */
    Tk_Item *itemPtr;			/* Item to be displayed. */
    Drawable drawable;			/* Pixmap or window in which to draw
					 * item. */
{
    register LineItem *linePtr = (LineItem *) itemPtr;
    XPoint staticPoints[MAX_STATIC_POINTS];
    XPoint *pointPtr;
    register XPoint *pPtr;
    register double *coordPtr;
    int i, numPoints;

    if (linePtr->gc == None) {
	return;
    }

    /*
     * 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 = 1 + linePtr->numPoints*linePtr->splineSteps;
    } else {
	numPoints = linePtr->numPoints;
    }

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

    if (linePtr->smooth) {
	numPoints = TkMakeBezierCurve(canvasPtr, linePtr->coordPtr,
		linePtr->numPoints, linePtr->splineSteps, pointPtr,
		(double *) NULL);
    } else {
	for (i = 0, coordPtr = linePtr->coordPtr, pPtr = pointPtr;
		i < linePtr->numPoints;  i += 1, coordPtr += 2, pPtr++) {
	    pPtr->x = SCREEN_X(canvasPtr, *coordPtr);
	    pPtr->y = SCREEN_Y(canvasPtr, coordPtr[1]);
	}
    }

    /*
     * 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 (linePtr->fillStipple != None) {
	XSetTSOrigin(Tk_Display(canvasPtr->tkwin), linePtr->gc,
		-canvasPtr->drawableXOrigin, -canvasPtr->drawableYOrigin);
    }
    XDrawLines(Tk_Display(canvasPtr->tkwin), drawable, linePtr->gc,
	    pointPtr, numPoints, CoordModeOrigin);
    if (pointPtr != staticPoints) {
	ckfree((char *) pointPtr);
    }

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

    if (linePtr->arrow != noneUid) {
	if (linePtr->arrow != lastUid) {
	    TkFillPolygon(canvasPtr, linePtr->firstArrowPtr, PTS_IN_ARROW,
		    drawable, linePtr->gc);
	}
	if (linePtr->arrow != firstUid) {
	    TkFillPolygon(canvasPtr, linePtr->lastArrowPtr, PTS_IN_ARROW,
		    drawable, linePtr->gc);
	}
    }
    if (linePtr->fillStipple != None) {
	XSetTSOrigin(Tk_Display(canvasPtr->tkwin), linePtr->gc, 0, 0);
    }
}

/*
 *--------------------------------------------------------------
 *
 * 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.
 *
 *--------------------------------------------------------------
 */

	/* ARGSUSED */
static double
LineToPoint(canvasPtr, itemPtr, pointPtr)
    Tk_Canvas *canvasPtr;	/* Canvas containing item. */
    Tk_Item *itemPtr;		/* Item to check against point. */
    double *pointPtr;		/* Pointer to x and y coordinates. */
{
    register LineItem *linePtr = (LineItem *) itemPtr;
    register double *coordPtr, *linePoints;
    double staticSpace[2*MAX_STATIC_POINTS];
    double poly[10];
    double bestDist, dist;
    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 = 1.0e40;

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

    if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
	numPoints = 1 + linePtr->numPoints*linePtr->splineSteps;
	if (numPoints <= MAX_STATIC_POINTS) {
	    linePoints = staticSpace;
	} else {
	    linePoints = (double *) ckalloc((unsigned)
		    (2*numPoints*sizeof(double)));
	}
	numPoints = TkMakeBezierCurve(canvasPtr, linePtr->coordPtr,
		linePtr->numPoints, linePtr->splineSteps, (XPoint *) NULL,
		linePoints);
    } else {
	numPoints = linePtr->numPoints;
	linePoints = linePtr->coordPtr;
    }

    /*
     * 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])
		    - linePtr->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, (double) linePtr->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, (double) linePtr->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, (double) linePtr->width,
		    linePtr->capStyle == CapProjecting, poly+4, poly+6);
	} else if (linePtr->joinStyle == JoinMiter) {
	    if (TkGetMiterPoints(coordPtr, coordPtr+2, coordPtr+4,
		    (double) linePtr->width, poly+4, poly+6) == 0) {
		changedMiterToBevel = 1;
		TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->width,
			0, poly+4, poly+6);
	    }
	} else {
	    TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->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])
		- linePtr->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 != noneUid) {
	if (linePtr->arrow != lastUid) {
	    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 != firstUid) {
	    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((char *) linePoints);
    }
    return bestDist;
}

/*