grid.c

spice中支持多层次元件模型仿真的可单独运行的插件源码

        } else if (i > 2) {
            j = 5;
            break;
        }
    }
    k = 1;

    /* SetLinestyle(1); takes too long */
    /* Problems with Suns on very large radii && linestyle */
    SetLinestyle(0);

    /* Now plot all the arc sets.  Go as high as 5 times the radius that
     * will fit on the screen.  The base magnitude is one more than 
     * the least magnitude that will fit...
     */
    if (i > 20)
        basemag = mag;
    else
        basemag = mag + 1;
    /* Go back one order of magnitude and have a closer look */
    mag -= 2;
    j *= 10;
    while (mag < 20) {
        i = j * pow(10.0, (double) mag) * pixperunit / 2;
        if (i / 5 > gr_radius + ((xoff > 0) ? xoff : - xoff))
            break;
	rnorm[k] = j * pow(10.0, (double) (mag - basemag));
	dphi[k] = 2.0 * atan(rnorm[k]);
	ir[k] = pixperunit * (1 + cos(dphi[k])) / sin(dphi[k]);
	rr[k] = pixperunit * 0.5 * (((1 - rnorm[k]) / (1 + rnorm[k])) + 1);
        (void) sprintf(plab, "%lg", rnorm[k]);
	plen = strlen(plab);

	/* See if the label will fit on the upper xaxis */
	/* wait for some k, so we don't get fooled */
	if (k > 6) {
	if ((int) (gr_radius - xoff - pixperunit + 2 * rr[k]) <
	     plen * gi_fntwidth + 2)
	    break;
	}
	/* See if the label will fit on the lower xaxis */
	/* First look at the leftmost circle possible*/
	if ((int) (pixperunit - 2 * rr[k] + gr_radius + xoff +
	    fabs((double) yoff)) < plen * gi_fntwidth + 4) { 
	    if (j == 95) {
		j = 10;
		mag++;
	    } else {
		if (j < 20)
		  j += 1;
		else 
		  j += 5;
	    }
	    continue;
	}
	/* Then look at the circles following in the viewport */
	if (k>1 && (int) 2 * (rr[k-1] - rr[k]) < plen * gi_fntwidth + 4) {
        if (j == 95) {
            j = 10;
            mag++;
        } else {
	    if (j < 20)
	      j += 1;
	    else 
	      j += 5;
	}
	continue;
	}
        if (j == 95) {
            j = 10;
            mag++;
        } else {
	    if (j < 20)
	      j += 1;
	    else 
	      j += 5;
	}
	ki[k-1] = ir[k];
        kr[k-1] = rr[k];
	k++;
	if (k == CMAX) {
	    printf("drawsmithgrid: grid too complex\n");
	    break;
	}
    }
    k--;

    /* Now adjust the clipping radii */
    for (i = 0; i < k; i++)
	ks[i] = ki[i];
    for (i = k-1, j = k-1; i >= 0; i -= 2, j--) {
	ki[i] = ks[j];
	if (i > 0)
	    ki[i-1] = ks[j];
    }
    for (i = 0; i < k; i++)
	ks[i] = kr[i];
    for (i = k-1, j = k-1; (i >= 0) && (dphi[i] > M_PI / 2); i -= 2, j--) {
	kr[i] = ks[j];
	if (i > 0)
	    kr[i-1] = ks[j];
    }
    for ( ; i >= 0; i--, j--)
	kr[i] = ks[j];

    if ((yoff > - gr_radius) && (yoff < gr_radius)) {
        zheight = gr_radius * cos(asin((double) yoff / gr_radius));
	zheight = (zheight > 0) ? zheight : - zheight;
    } else {
	zheight = gr_radius;
    }
    for (ki[k] = kr[k] = (double) 0; k > 0; k--) {
        (void) sprintf(plab, "%lg", rnorm[k]);
        (void) sprintf(nlab, "-%lg", rnorm[k]);
        arcset(graph, rr[k], kr[k], ir[k], ki[k], pixperunit,
		gr_radius, gr_xcenter, gr_ycenter,
                xoff, yoff, plab, nlab,
		(int) (0.5 + RAD_TO_DEG * (M_PI - dphi[k])),
		(int) (0.5 + RAD_TO_DEG * (M_PI + dphi[k])),
		gr_xcenter - zheight,
		gr_xcenter + zheight);
    }
    if (mag == 20) {
        fprintf(cp_err, "smithgrid: Internal Error: screwed up\n");
        return;
    }

    SetLinestyle(0);

    Arc(gr_xcenter, gr_ycenter, gr_radius, 0.0, 0.0);
/*
    if ((xoff > - gr_radius) && (xoff < gr_radius)) {
        zheight = gr_radius * sin(acos((double) xoff / gr_radius));
        if (zheight < 0)
            zheight = - zheight;
        DrawLine(gr_xcenter + xoff, gr_ycenter - zheight,
                gr_xcenter + xoff, gr_ycenter + zheight);
    }
 */
    if ((yoff > - gr_radius) && (yoff < gr_radius)) {
        zheight = gr_radius * cos(asin((double) yoff / gr_radius));
        if (zheight < 0)
            zheight = - zheight;
        DrawLine(gr_xcenter - zheight, gr_ycenter + yoff,
                gr_xcenter + zheight, gr_ycenter + yoff);
	Text("0", gr_xcenter + zheight + gi_fntwidth, gr_ycenter + yoff - 
            gi_fntheight / 2);
	Text("o", gr_xcenter + zheight + gi_fntwidth * 2, gr_ycenter + yoff);
	Text("180", gr_xcenter - zheight - gi_fntwidth * 5, gr_ycenter 
            + yoff - gi_fntheight / 2);
	Text("o", gr_xcenter - zheight - gi_fntwidth * 2, gr_ycenter + yoff);
    }

/*    (void) sprintf(buf, "e%d", basemag); */
    (void) sprintf(buf, "e%d", 0);
    Text(buf, gr_xcenter + gr_radius, gr_ycenter - gr_radius);

    Update();
    return;
}

/* Draw one arc set.  The arcs should have radius rad. The outermost circle is
 * described by (centx, centy) and maxrad, and the distance from the right side
 * of the bounding circle to the logical center of the other circles in pixels
 * is xoffset (positive brings the negative plane into the picture).
 * plab and nlab are the labels to put on the positive and negative X-arcs,
 * respectively...  If the X-axis isn't on the screen, then we have to be
 * clever...
 */

static void
arcset(graph, rad, prevrad, irad, iprevrad, radoff, maxrad, centx, centy,
       xoffset, yoffset, plab, nlab, pdeg, ndeg, pxmin, pxmax)
    GRAPH *graph;
    int ndeg, pdeg, pxmin, pxmax ;
    double rad, prevrad, irad, iprevrad, radoff;
    int maxrad, centx, centy, xoffset, yoffset;
    char *plab, *nlab;
{
    char buf[64];
    double aclip;
    double angle = atan2((double) iprevrad, (double) rad);
    double iangle = atan2((double) prevrad, (double) irad);
    int x, xlab, ylab;

    /* Let's be lazy and just draw everything -- we won't get called too
     * much and the circles get clipped anyway...
     */
    SetColor(18);

    cliparc((double) (centx + xoffset + radoff - rad),
	    (double) (centy + yoffset), rad, 2*angle,
            2 * M_PI - 2 * angle, centx, centy, maxrad, 0);


    /* These circles are not part of the smith chart
     * Let's draw them anyway
     */
    cliparc((double) (centx + xoffset + radoff + rad),
	    (double) (centy + yoffset), rad, M_PI + 2 * angle,
            M_PI - 2 * angle, centx, centy, maxrad, 0);

    /* Draw the upper and lower circles.  */
    SetColor(19);
    aclip = cliparc((double) (centx + xoffset + radoff),
	    (double) (centy + yoffset + irad), irad,
	    (double) (M_PI * 1.5 + 2 * iangle),
            (double) (M_PI * 1.5 - 2 * iangle), centx, centy, maxrad, 1);
    if ((aclip > M_PI / 180) && (pdeg > 1)) {
	xlab = centx + xoffset + radoff + irad * cos(aclip);
	ylab = centy + yoffset + irad * (1 + sin(aclip));
	if ((ylab - gr_ycenter) > graph->fontheight) {
	SetColor(1);
	adddeglabel(graph, pdeg, xlab, ylab,
	    gr_xcenter, gr_ycenter, gr_xcenter, gr_ycenter);
/*
	ylab = centy + yoffset - irad * (1 + sin(aclip));
	adddeglabel(graph, ndeg, xlab, ylab,
	    gr_xcenter, gr_ycenter, gr_xcenter, gr_ycenter);
 */
	SetColor(19);
	}
    }
    aclip = cliparc((double) (centx + xoffset + radoff),
	    (double) (centy + yoffset - irad), irad,
	    (double) (M_PI / 2 + 2 * iangle),
            (double) (M_PI / 2 - 2 * iangle), centx, centy, maxrad,
	    (iangle == 0)?2:0);
    if ((aclip >= 0 && aclip < 2*M_PI - M_PI/180) && (pdeg < 359)) {
	xlab = centx + xoffset + radoff + irad * cos(aclip);
	ylab = centy + yoffset + irad * (sin(aclip) - 1);
	SetColor(1);
	adddeglabel(graph, ndeg, xlab, ylab,
	    gr_xcenter, gr_ycenter, gr_xcenter, gr_ycenter);
	SetColor(19);
    }
    
    /* Now toss the labels on... */
    SetColor(1);

    x = centx + xoffset + (int)radoff - 2 * (int)rad -
	gi_fntwidth * strlen(plab) - 2;
    if ((x > pxmin) && (x < pxmax)) {
	if ((yoffset > - gr_radius) && (yoffset < gr_radius))
	    Text(plab, x, centy + yoffset - gi_fntheight - 1);
	else
	    Text(plab, x, gr_ymargin - 3 * gi_fntheight - 2);
    }
/*
    x = centx + xoffset + (int) radoff + 2 * (int)rad -
	gi_fntwidth * strlen(nlab) - 2;
    if ((x > gr_xmargin) && (x < gi_maxx))
        Text(nlab, x, centy + yoffset - gi_fntheight - 1);
 */

    return;
}

/* This routine draws an arc and clips it to a circle.  It's hard to figure
 * out how it works without looking at the piece of scratch paaper I have
 * in front of me, so let's hope it doesn't break...
 * Converted to all doubles for CRAYs 
 */

static double
cliparc(cx, cy, rad, start, end, iclipx, iclipy, icliprad, flag)
    double cx, cy, rad;
    int iclipx, iclipy, icliprad, flag;
    double start, end;
{
    double clipx, clipy, cliprad;
    double x, y, tx, ty, dist;
    double alpha, theta, phi, a1, a2, d, l;
    double sclip, eclip;
    bool in;

    clipx = (double) iclipx;
    clipy = (double) iclipy;
    cliprad = (double) icliprad;
    x = cx - clipx;
    y = cy - clipy;
    dist = sqrt((double) (x * x + y * y));

    if (!rad || !cliprad)
        return(-1);
    if (dist + rad < cliprad) {
        /* The arc is entirely in the boundary. */
        Arc((int)cx, (int)cy, (int)rad, start, end);
        return(flag?start:end);
    } else if ((dist - rad >= cliprad) || (rad - dist >= cliprad)) {
        /* The arc is outside of the boundary. */
        return(-1);
    }
    /* Now let's figure out the angles at which the arc crosses the
     * circle. We know dist != 0.
     */
    if (x)
        phi = atan2((double) y, (double) x);
    else if (y > 0)
        phi = M_PI * 1.5;
    else
        phi = M_PI / 2;
    if (cx > clipx)
        theta = M_PI + phi;
    else
        theta = phi;

    alpha = (double) (dist * dist + rad * rad - cliprad * cliprad) /
            (2 * dist * rad);

    /* Sanity check */
    if (alpha > 1.0)
	alpha = 0.0;
    else if (alpha < -1.0)
	alpha = M_PI;
    else
        alpha = acos(alpha);

    a1 = theta + alpha;
    a2 = theta - alpha;
    while (a1 < 0)
        a1 += M_PI * 2;
    while (a2 < 0)
        a2 += M_PI * 2;
    while (a1 >= M_PI * 2)
        a1 -= M_PI * 2;
    while (a2 >= M_PI * 2)
        a2 -= M_PI * 2;

    tx = cos(start) * rad + x;
    ty = sin(start) * rad + y;
    d = sqrt((double) tx * tx + ty * ty);
    in = (d > cliprad) ? false : true;

    /* Now begin with start.  If the point is in, draw to either end, a1,
     * or a2, whichever comes first.
     */
    d = M_PI * 3;
    if ((end < d) && (end > start))
        d = end;
    if ((a1 < d) && (a1 > start))
        d = a1;
    if ((a2 < d) && (a2 > start))
        d = a2;
    if (d == M_PI * 3) {
        d = end;
        if (a1 < d)
            d = a1;
        if (a2 < d)
            d = a2;
    }

    if (in) {
	if (start > d) {
	    double tmp;
	    tmp = start;
	    start = d;
	    d = tmp;
	}
        Arc((int)cx, (int)cy, (int)rad, start, d);
	sclip = start;
	eclip = d;
    }
    if (d == end)
        return(flag?sclip:eclip);
    if (a1 != a2)
        in = in ? false : true;

    /* Now go from here to the next point. */
    l = d;
    d = M_PI * 3;
    if ((end < d) && (end > l))
        d = end;
    if ((a1 < d) && (a1 > l))
        d = a1;
    if ((a2 < d) && (a2 > l))
        d = a2;
    if (d == M_PI * 3) {
        d = end;
        if (a1 < d)
            d = a1;
        if (a2 < d)
            d = a2;
    }

    if (in) {
        Arc((int)cx, (int)cy, (int)rad, l, d);
	sclip = l;
	eclip = d;
    }
    if (d == end)
        return(flag?sclip:eclip);
    in = in ? false : true;
    
    /* And from here to the end. */
    if (in) {
        Arc((int)cx, (int)cy, (int)rad, d, end);
	/* special case */
	if (flag != 2) {
	  sclip = d;
	  eclip = end;
	}
    }
    return(flag%2?sclip:eclip);
}