tkcanvline.c

linux系统下的音频通信

    char *value;		/* Textual specification of arrow shape. */
    char *recordPtr;		/* Pointer to item record in which to
				 * store arrow information. */
    int offset;			/* Offset of shape information in widget
				 * record. */
{
    LineItem *linePtr = (LineItem *) recordPtr;
    double a, b, c;
    int argc;
    char **argv = NULL;

    if (offset != Tk_Offset(LineItem, arrowShapeA)) {
	panic("ParseArrowShape received bogus offset");
    }

    if (Tcl_SplitList(interp, value, &argc, &argv) != TCL_OK) {
	syntaxError:
	Tcl_ResetResult(interp);
	Tcl_AppendResult(interp, "bad arrow shape \"", value,
		"\": must be list with three numbers", (char *) NULL);
	if (argv != NULL) {
	    ckfree((char *) argv);
	}
	return TCL_ERROR;
    }
    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((char *) argv);
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * PrintArrowShape --
 *
 *	This procedure is a callback invoked by the configuration
 *	code to return a printable value describing an arrow shape.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

    /* ARGSUSED */
static char *
PrintArrowShape(clientData, tkwin, recordPtr, offset, freeProcPtr)
    ClientData clientData;	/* Not used. */
    Tk_Window tkwin;		/* Window associated with linePtr's widget. */
    char *recordPtr;		/* Pointer to item record containing current
				 * shape information. */
    int offset;			/* Offset of arrow information in record. */
    Tcl_FreeProc **freeProcPtr;	/* Store address of procedure to call to
				 * free string here. */
{
    LineItem *linePtr = (LineItem *) recordPtr;
    char *buffer;

    buffer = (char *) ckalloc(120);
    sprintf(buffer, "%.5g %.5g %.5g", linePtr->arrowShapeA,
	    linePtr->arrowShapeB, linePtr->arrowShapeC);
    *freeProcPtr = TCL_DYNAMIC;
    return buffer;
}

/*
 *--------------------------------------------------------------
 *
 * ConfigureArrows --
 *
 *	If arrowheads have been requested for a line, this
 *	procedure 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.
 *
 *--------------------------------------------------------------
 */

	/* ARGSUSED */
static int
ConfigureArrows(canvas, linePtr)
    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). */

    /*
     * 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 + linePtr->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 = (linePtr->width/2.0)/shapeC;
    backup = fracHeight*shapeB + shapeA*(1.0 - fracHeight)/2.0;
    if (linePtr->arrow != lastUid) {
	poly = linePtr->firstArrowPtr;
	if (poly == NULL) {
	    poly = (double *) ckalloc((unsigned)
		    (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 != firstUid) {
	coordPtr = linePtr->coordPtr + 2*(linePtr->numPoints-2);
	poly = linePtr->lastArrowPtr;
	if (poly == NULL) {
	    poly = (double *) ckalloc((unsigned)
		    (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 procedure 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 interp->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(interp, canvas, itemPtr, prepass)
    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. */
    int prepass;			/* 1 means this is a prepass to
					 * collect font information;  0 means
					 * final Postscript is being created. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    char buffer[200];
    char *style;

    if (linePtr->fg == NULL) {
	return TCL_OK;
    }

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

    if ((!linePtr->smooth) || (linePtr->numPoints <= 2)) {
	Tk_CanvasPsPath(interp, canvas, linePtr->coordPtr, linePtr->numPoints);
    } else {
	if (linePtr->fillStipple == None) {
	    TkMakeBezierPostscript(interp, canvas, linePtr->coordPtr,
		    linePtr->numPoints);
	} 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 = 1 + linePtr->numPoints*linePtr->splineSteps;
	    pointPtr = staticPoints;
	    if (numPoints > MAX_STATIC_POINTS) {
		pointPtr = (double *) ckalloc((unsigned)
			(numPoints * 2 * sizeof(double)));
	    }
	    numPoints = TkMakeBezierCurve(canvas, linePtr->coordPtr,
		    linePtr->numPoints, linePtr->splineSteps, (XPoint *) NULL,
		    pointPtr);
	    Tk_CanvasPsPath(interp, canvas, pointPtr, numPoints);
	    if (pointPtr != staticPoints) {
		ckfree((char *) pointPtr);
	    }
	}
    }

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

    sprintf(buffer, "%d setlinewidth\n", linePtr->width);
    Tcl_AppendResult(interp, buffer, (char *) NULL);
    style = "0 setlinecap\n";
    if (linePtr->capStyle == CapRound) {
	style = "1 setlinecap\n";
    } else if (linePtr->capStyle == CapProjecting) {
	style = "2 setlinecap\n";
    }
    Tcl_AppendResult(interp, style, (char *) NULL);
    style = "0 setlinejoin\n";
    if (linePtr->joinStyle == JoinRound) {
	style = "1 setlinejoin\n";
    } else if (linePtr->joinStyle == JoinBevel) {
	style = "2 setlinejoin\n";
    }
    Tcl_AppendResult(interp, style, (char *) NULL);
    if (Tk_CanvasPsColor(interp, canvas, linePtr->fg) != TCL_OK) {
	return TCL_ERROR;
    };
    if (linePtr->fillStipple != None) {
	Tcl_AppendResult(interp, "StrokeClip ", (char *) NULL);
	if (Tk_CanvasPsStipple(interp, canvas, linePtr->fillStipple)
		!= TCL_OK) {
	    return TCL_ERROR;
	}
    } else {
	Tcl_AppendResult(interp, "stroke\n", (char *) NULL);
    }

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

    if (linePtr->firstArrowPtr != NULL) {
	if (linePtr->fillStipple != None) {
	    Tcl_AppendResult(interp, "grestore gsave\n",
		    (char *) NULL);
	}
	if (ArrowheadPostscript(interp, canvas, linePtr,
		linePtr->firstArrowPtr) != TCL_OK) {
	    return TCL_ERROR;
	}
    }
    if (linePtr->lastArrowPtr != NULL) {
	if (linePtr->fillStipple != None) {
	    Tcl_AppendResult(interp, "grestore gsave\n", (char *) NULL);
	}
	if (ArrowheadPostscript(interp, canvas, linePtr,
		linePtr->lastArrowPtr) != TCL_OK) {
	    return TCL_ERROR;
	}
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * ArrowheadPostscript --
 *
 *	This procedure 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 interp->result, replacing whatever used
 *	to be there.  If no error occurs, then Postscript for the
 *	arrowhead is appended to the result.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
ArrowheadPostscript(interp, canvas, linePtr, arrowPtr)
    Tcl_Interp *interp;			/* Leave Postscript or error message
					 * here. */
    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. */
{
    Tk_CanvasPsPath(interp, canvas, arrowPtr, PTS_IN_ARROW);
    if (linePtr->fillStipple != None) {
	Tcl_AppendResult(interp, "clip ", (char *) NULL);
	if (Tk_CanvasPsStipple(interp, canvas, linePtr->fillStipple)
		!= TCL_OK) {
	    return TCL_ERROR;
	}
    } else {
	Tcl_AppendResult(interp, "fill\n", (char *) NULL);
    }
    return TCL_OK;
}