tkcanvarc.c

linux系统下的音频通信

	    newDist = TkOvalToPoint(arcPtr->bbox, width, filled, pointPtr);
	    if (newDist < dist) {
		dist = newDist;
	    }
	}
    } else {
	if ((arcPtr->extent < -180.0) || (arcPtr->extent > 180.0)) {
	    if (filled && (polyDist < dist)) {
		dist = polyDist;
	    }
	}
    }
    return dist;
}

/*
 *--------------------------------------------------------------
 *
 * ArcToArea --
 *
 *	This procedure is called to determine whether an item
 *	lies entirely inside, entirely outside, or overlapping
 *	a given area.
 *
 * Results:
 *	-1 is returned if the item is entirely outside the area
 *	given by rectPtr, 0 if it overlaps, and 1 if it is entirely
 *	inside the given area.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

	/* ARGSUSED */
static int
ArcToArea(canvas, itemPtr, rectPtr)
    Tk_Canvas canvas;		/* Canvas containing item. */
    Tk_Item *itemPtr;		/* Item to check against arc. */
    double *rectPtr;		/* Pointer to array of four coordinates
				 * (x1, y1, x2, y2) describing rectangular
				 * area.  */
{
    ArcItem *arcPtr = (ArcItem *) itemPtr;
    double rx, ry;		/* Radii for transformed oval:  these define
				 * an oval centered at the origin. */
    double tRect[4];		/* Transformed version of x1, y1, x2, y2,
				 * for coord. system where arc is centered
				 * on the origin. */
    double center[2], width, angle, tmp;
    double points[20], *pointPtr;
    int numPoints, filled;
    int inside;			/* Non-zero means every test so far suggests
				 * that arc is inside rectangle.  0 means
				 * every test so far shows arc to be outside
				 * of rectangle. */
    int newInside;

    if ((arcPtr->fillGC != None) || (arcPtr->outlineGC == None)) {
	filled = 1;
    } else {
	filled = 0;
    }
    if (arcPtr->outlineGC == None) {
	width = 0.0;
    } else {
	width = arcPtr->width;
    }

    /*
     * Transform both the arc and the rectangle so that the arc's oval
     * is centered on the origin.
     */

    center[0] = (arcPtr->bbox[0] + arcPtr->bbox[2])/2.0;
    center[1] = (arcPtr->bbox[1] + arcPtr->bbox[3])/2.0;
    tRect[0] = rectPtr[0] - center[0];
    tRect[1] = rectPtr[1] - center[1];
    tRect[2] = rectPtr[2] - center[0];
    tRect[3] = rectPtr[3] - center[1];
    rx = arcPtr->bbox[2] - center[0] + width/2.0;
    ry = arcPtr->bbox[3] - center[1] + width/2.0;

    /*
     * Find the extreme points of the arc and see whether these are all
     * inside the rectangle (in which case we're done), partly in and
     * partly out (in which case we're done), or all outside (in which
     * case we have more work to do).  The extreme points include the
     * following, which are checked in order:
     *
     * 1. The outside points of the arc, corresponding to start and
     *	  extent.
     * 2. The center of the arc (but only in pie-slice mode).
     * 3. The 12, 3, 6, and 9-o'clock positions (but only if the arc
     *    includes those angles).
     */

    pointPtr = points;
    angle = -arcPtr->start*(PI/180.0);
    pointPtr[0] = rx*cos(angle);
    pointPtr[1] = ry*sin(angle);
    angle += -arcPtr->extent*(PI/180.0);
    pointPtr[2] = rx*cos(angle);
    pointPtr[3] = ry*sin(angle);
    numPoints = 2;
    pointPtr += 4;

    if ((arcPtr->style == pieSliceUid) && (arcPtr->extent < 180.0)) {
	pointPtr[0] = 0.0;
	pointPtr[1] = 0.0;
	numPoints++;
	pointPtr += 2;
    }

    tmp = -arcPtr->start;
    if (tmp < 0) {
	tmp += 360.0;
    }
    if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
	pointPtr[0] = rx;
	pointPtr[1] = 0.0;
	numPoints++;
	pointPtr += 2;
    }
    tmp = 90.0 - arcPtr->start;
    if (tmp < 0) {
	tmp += 360.0;
    }
    if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
	pointPtr[0] = 0.0;
	pointPtr[1] = -ry;
	numPoints++;
	pointPtr += 2;
    }
    tmp = 180.0 - arcPtr->start;
    if (tmp < 0) {
	tmp += 360.0;
    }
    if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
	pointPtr[0] = -rx;
	pointPtr[1] = 0.0;
	numPoints++;
	pointPtr += 2;
    }
    tmp = 270.0 - arcPtr->start;
    if (tmp < 0) {
	tmp += 360.0;
    }
    if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
	pointPtr[0] = 0.0;
	pointPtr[1] = ry;
	numPoints++;
    }

    /*
     * Now that we've located the extreme points, loop through them all
     * to see which are inside the rectangle.
     */

    inside = (points[0] > tRect[0]) && (points[0] < tRect[2])
	    && (points[1] > tRect[1]) && (points[1] < tRect[3]);
    for (pointPtr = points+2; numPoints > 1; pointPtr += 2, numPoints--) {
	newInside = (pointPtr[0] > tRect[0]) && (pointPtr[0] < tRect[2])
		&& (pointPtr[1] > tRect[1]) && (pointPtr[1] < tRect[3]);
	if (newInside != inside) {
	    return 0;
	}
    }

    if (inside) {
	return 1;
    }

    /*
     * So far, oval appears to be outside rectangle, but can't yet tell
     * for sure.  Next, test each of the four sides of the rectangle
     * against the bounding region for the arc.  If any intersections
     * are found, then return "overlapping".  First, test against the
     * polygon(s) forming the sides of a chord or pie-slice.
     */

    if (arcPtr->style == pieSliceUid) {
	if (width >= 1.0) {
	    if (TkPolygonToArea(arcPtr->outlinePtr, PIE_OUTLINE1_PTS,
		    rectPtr) != -1)  {
		return 0;
	    }
	    if (TkPolygonToArea(arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS,
		    PIE_OUTLINE2_PTS, rectPtr) != -1) {
		return 0;
	    }
	} else {
	    if ((TkLineToArea(center, arcPtr->center1, rectPtr) != -1) ||
		    (TkLineToArea(center, arcPtr->center2, rectPtr) != -1)) {
		return 0;
	    }
	}
    } else if (arcPtr->style == chordUid) {
	if (width >= 1.0) {
	    if (TkPolygonToArea(arcPtr->outlinePtr, CHORD_OUTLINE_PTS,
		    rectPtr) != -1) {
		return 0;
	    }
	} else {
	    if (TkLineToArea(arcPtr->center1, arcPtr->center2,
		    rectPtr) != -1) {
		return 0;
	    }
	}
    }

    /*
     * Next check for overlap between each of the four sides and the
     * outer perimiter of the arc.  If the arc isn't filled, then also
     * check the inner perimeter of the arc.
     */

    if (HorizLineToArc(tRect[0], tRect[2], tRect[1], rx, ry, arcPtr->start,
		arcPtr->extent)
	    || HorizLineToArc(tRect[0], tRect[2], tRect[3], rx, ry,
		arcPtr->start, arcPtr->extent)
	    || VertLineToArc(tRect[0], tRect[1], tRect[3], rx, ry,
		arcPtr->start, arcPtr->extent)
	    || VertLineToArc(tRect[2], tRect[1], tRect[3], rx, ry,
		arcPtr->start, arcPtr->extent)) {
	return 0;
    }
    if ((width > 1.0) && !filled) {
	rx -= width;
	ry -= width;
	if (HorizLineToArc(tRect[0], tRect[2], tRect[1], rx, ry, arcPtr->start,
		    arcPtr->extent)
		|| HorizLineToArc(tRect[0], tRect[2], tRect[3], rx, ry,
		    arcPtr->start, arcPtr->extent)
		|| VertLineToArc(tRect[0], tRect[1], tRect[3], rx, ry,
		    arcPtr->start, arcPtr->extent)
		|| VertLineToArc(tRect[2], tRect[1], tRect[3], rx, ry,
		    arcPtr->start, arcPtr->extent)) {
	    return 0;
	}
    }

    /*
     * The arc still appears to be totally disjoint from the rectangle,
     * but it's also possible that the rectangle is totally inside the arc.
     * Do one last check, which is to check one point of the rectangle
     * to see if it's inside the arc.  If it is, we've got overlap.  If
     * it isn't, the arc's really outside the rectangle.
     */

    if (ArcToPoint(canvas, itemPtr, rectPtr) == 0.0) {
	return 0;
    }
    return -1;
}

/*
 *--------------------------------------------------------------
 *
 * ScaleArc --
 *
 *	This procedure is invoked to rescale an arc item.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The arc 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
ScaleArc(canvas, itemPtr, originX, originY, scaleX, scaleY)
    Tk_Canvas canvas;			/* Canvas containing arc. */
    Tk_Item *itemPtr;			/* Arc to be scaled. */
    double originX, originY;		/* Origin about which to scale rect. */
    double scaleX;			/* Amount to scale in X direction. */
    double scaleY;			/* Amount to scale in Y direction. */
{
    ArcItem *arcPtr = (ArcItem *) itemPtr;

    arcPtr->bbox[0] = originX + scaleX*(arcPtr->bbox[0] - originX);
    arcPtr->bbox[1] = originY + scaleY*(arcPtr->bbox[1] - originY);
    arcPtr->bbox[2] = originX + scaleX*(arcPtr->bbox[2] - originX);
    arcPtr->bbox[3] = originY + scaleY*(arcPtr->bbox[3] - originY);
    ComputeArcBbox(canvas, arcPtr);
}

/*
 *--------------------------------------------------------------
 *
 * TranslateArc --
 *
 *	This procedure is called to move an arc by a given amount.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The position of the arc is offset by (xDelta, yDelta), and
 *	the bounding box is updated in the generic part of the item
 *	structure.
 *
 *--------------------------------------------------------------
 */

static void
TranslateArc(canvas, itemPtr, deltaX, deltaY)
    Tk_Canvas canvas;			/* Canvas containing item. */
    Tk_Item *itemPtr;			/* Item that is being moved. */
    double deltaX, deltaY;		/* Amount by which item is to be
					 * moved. */
{
    ArcItem *arcPtr = (ArcItem *) itemPtr;

    arcPtr->bbox[0] += deltaX;
    arcPtr->bbox[1] += deltaY;
    arcPtr->bbox[2] += deltaX;
    arcPtr->bbox[3] += deltaY;
    ComputeArcBbox(canvas, arcPtr);
}

/*
 *--------------------------------------------------------------
 *
 * ComputeArcOutline --
 *
 *	This procedure creates a polygon describing everything in
 *	the outline for an arc except what's in the curved part.
 *	For a "pie slice" arc this is a V-shaped chunk, and for
 *	a "chord" arc this is a linear chunk (with cutaway corners).
 *	For "arc" arcs, this stuff isn't relevant.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The information at arcPtr->outlinePtr gets modified, and
 *	storage for arcPtr->outlinePtr may be allocated or freed.
 *
 *--------------------------------------------------------------
 */

static void
ComputeArcOutline(arcPtr)
    ArcItem *arcPtr;			/* Information about arc. */
{
    double sin1, cos1, sin2, cos2, angle, halfWidth;
    double boxWidth, boxHeight;
    double vertex[2], corner1[2], corner2[2];
    double *outlinePtr;

    /*
     * Make sure that the outlinePtr array is large enough to hold
     * either a chord or pie-slice outline.
     */

    if (arcPtr->numOutlinePoints == 0) {
	arcPtr->outlinePtr = (double *) ckalloc((unsigned)
		(26 * sizeof(double)));
	arcPtr->numOutlinePoints = 22;
    }
    outlinePtr = arcPtr->outlinePtr;

    /*
     * First compute the two points that lie at the centers of
     * the ends of the curved arc segment, which are marked with
     * X's in the figure below:
     *
     *
     *				  * * *
     *			      *          *
     *			   *      * *      *
     *			 *    *         *    *
     *			*   *             *   *
     *			 X *               * X
     *
     * The code is tricky because the arc can be ovular in shape.
     * It computes the position for a unit circle, and then
     * scales to fit the shape of the arc's bounding box.
     *
     * Also, watch out because angles go counter-clockwise like you
     * might expect, but the y-coordinate system is inverted.  To
     * handle this, just negate the angles in all the computations.
     */

    boxWidth = arcPtr->bbox[2] - arcPtr->bbox[0];
    boxHeight = arcPtr->bbox[3] - arcPtr->bbox[1];
    angle = -arcPtr->start*PI/180.0;
    sin1 = sin(angle);
    cos1 = cos(angle);
    angle -= arcPtr->extent*PI/180.0;
    sin2 = sin(angle);
    cos2 = cos(angle);
    vertex[0] = (arcPtr->bbox[0] + arcPtr->bbox[2])/2.0;
    vertex[1] = (arcPtr->bbox[1] + arcPtr->bbox[3])/2.0;
    arcPtr->center1[0] = vertex[0] + cos1*boxWidth/2.0;
    arcPtr->center1[1] = vertex[1] + sin1*boxHeight/2.0;
    arcPtr->center2[0] = vertex[0] + cos2*boxWidth/2.0;
    arcPtr->center2[1] = vertex[1] + sin2*boxHeight/2.0;

    /*
     * Next compute the "outermost corners" of the arc, which are
     * marked with X's in the figure below:
     *
     *				  * * *
     *			      *          *
     *			   *      * *      *
     *			 *    *         *    *
     *			X   *             *   X
     *			   *               *
     *
     * The code below is tricky because it has to handle eccentricity
     * in the shape of the oval.  The key in the code below is to
     * realize that the slope of the line from arcPtr->center1 to corner1
     * is (boxWidth*sin1)/(boxHeight*cos1), and similarly for arcPtr->center2
     * and corner2.  These formulas can be computed from the formula for
     * the oval.
     */

    halfWidth = arcPtr->width/2.0;
    if (((boxWidth*sin1) == 0.0) && ((boxHeight*cos1) == 0.0)) {
	angle = 0.0;
    } else {