when dragging terminals of tristate buffers and analog switches (afte…

…r placing them), the middle terminal was sometimes impossible to connect (#92)

src/com/lushprojects/circuitjs1/client/AnalogSwitch2Elm.java

@@ -33,11 +33,12 @@ public AnalogSwitch2Elm(int xa, int ya, int xb, int yb, int f,
     void setPoints() {
 	super.setPoints();
 	calcLeads(32);
+	adjustLeadsToGrid();
 	swposts = newPointArray(2);
 	swpoles = newPointArray(2);
 	interpPoint2(lead1,  lead2,  swpoles[0], swpoles[1], 1, openhs);
 	interpPoint2(point1, point2, swposts[0], swposts[1], 1, openhs);
-	ctlPoint = interpPoint(point1, point2, .5, openhs);
+	ctlPoint = interpPoint(lead1, lead2, .5, openhs);
     }
     int getPostCount() { return 4; }
 

src/com/lushprojects/circuitjs1/client/AnalogSwitchElm.java

@@ -26,12 +26,14 @@ public AnalogSwitchElm(int xx, int yy) {
 	super(xx, yy);
 	r_on = 20;
 	r_off = 1e10;
+	noDiagonal = true;
     }
     public AnalogSwitchElm(int xa, int ya, int xb, int yb, int f,
 			   StringTokenizer st) {
 	super(xa, ya, xb, yb, f);
 	r_on = 20;
 	r_off = 1e10;
+	noDiagonal = true;
 	try {
 	    r_on = new Double(st.nextToken()).doubleValue();
 	    r_off = new Double(st.nextToken()).doubleValue();
@@ -49,10 +51,11 @@ String dump() {
     void setPoints() {
 	super.setPoints();
 	calcLeads(32);
+	adjustLeadsToGrid();
 	ps = new Point();
 	int openhs = 16;
-	point3 = interpPoint(point1, point2, .5, -openhs);
-	lead3  = interpPoint(point1, point2, .5, -openhs/2);
+	point3 = interpPoint(lead1, lead2, .5, -openhs);
+	lead3  = interpPoint(lead1, lead2, .5, -openhs/2);
     }
 
     void draw(Graphics g) {
@@ -91,20 +94,6 @@ void doStep() {
 	resistance = (open) ? r_off : r_on;
 	sim.stampResistor(nodes[0], nodes[1], resistance);
     }
-    void drag(int xx, int yy) {
-	xx = sim.snapGrid(xx);
-	yy = sim.snapGrid(yy);
-	if (abs(x-xx) < abs(y-yy))
-	    xx = x;
-	else
-	    yy = y;
-	int q1 = abs(x-xx)+abs(y-yy);
-	int q2 = (q1/2) % sim.gridSize;
-	if (q2 != 0)
-	    return;
-	x2 = xx; y2 = yy;
-	setPoints();
-    }
     int getPostCount() { return 3; }
     Point getPost(int n) {
 	return (n == 0) ? point1 : (n == 1) ? point2 : point3;

src/com/lushprojects/circuitjs1/client/CircuitElm.java

@@ -292,6 +292,16 @@ void calcLeads(int len) {
 	lead2 = interpPoint(point1, point2, (dn+len)/(2*dn));
     }
 
+    // adjust leads so that the point exactly between them is a grid point (so we can place a terminal there)
+    void adjustLeadsToGrid() {
+        int cx = (point1.x+point2.x)/2;
+        int cy = (point1.y+point2.y)/2;
+        int adjx = sim.snapGrid(cx)-cx;
+        int adjy = sim.snapGrid(cy)-cy;
+        lead1.move(adjx, adjy);
+        lead2.move(adjx, adjy);
+    }
+
     // calculate point fraction f between a and b, linearly interpolated
     Point interpPoint(Point a, Point b, double f) {
 	Point p = new Point();

src/com/lushprojects/circuitjs1/client/Point.java

@@ -57,4 +57,9 @@ public void setLocation(Point p) {
          @Override public int hashCode() {
              return (41 * (41 + x) + y);
          }
-}
+
+	public void move(int dx, int dy) {
+	     x += dx;
+	     y += dy;
+	}
+}

src/com/lushprojects/circuitjs1/client/TriStateElm.java

@@ -32,13 +32,15 @@ public TriStateElm(int xx, int yy) {
 	r_on = 0.1;
 	r_off = 1e10;
 	r_off_ground = 1e8;
+	noDiagonal = true;
     }
 
     public TriStateElm(int xa, int ya, int xb, int yb, int f, StringTokenizer st) {
 	super(xa, ya, xb, yb, f);
 	r_on = 0.1;
 	r_off = 1e10;
 	r_off_ground = 0;
+	noDiagonal = true;
 	try {
 	    r_on = new Double(st.nextToken()).doubleValue();
 	    r_off = new Double(st.nextToken()).doubleValue();
@@ -64,7 +66,10 @@ int getDumpType() {
 
     void setPoints() {
 	super.setPoints();
-	calcLeads(32);
+	int len = 32;
+	calcLeads(len);
+	adjustLeadsToGrid();
+
 	ps = new Point();
 	int hs = 16;
 
@@ -73,12 +78,12 @@ void setPoints() {
 	    ww = (int) (dn / 2);
 	Point triPoints[] = newPointArray(3);
 	interpPoint2(lead1, lead2, triPoints[0], triPoints[1], 0, hs + 2);
-	triPoints[2] = interpPoint(point1, point2, .5 + (ww - 2) / dn);
+	triPoints[2] = interpPoint(lead1, lead2, .5 + (ww - 2) / (double)len);
 	gatePoly = createPolygon(triPoints);
 
 	int sign = ((flags & FLAG_FLIP) == 0) ? -1 : 1;
-	point3 = interpPoint(point1, point2, .5, sign*hs);
-	lead3 = interpPoint(point1, point2, .5, sign*hs/2);
+	point3 = interpPoint(lead1, lead2, .5, sign*hs);
+	lead3 = interpPoint(lead1, lead2, .5, sign*hs/2);
     }
 
     void draw(Graphics g) {
@@ -155,14 +160,8 @@ void drag(int xx, int yy) {
 	    flip = !flip;
 	    yy = y;
 	}
-	int q1 = abs(x - xx) + abs(y - yy);
-	int q2 = (q1 / 2) % sim.gridSize;
-	if (q2 != 0)
-	    return;
-	x2 = xx;
-	y2 = yy;
 	flags = flip ? (flags | FLAG_FLIP) : (flags & ~FLAG_FLIP);
-	setPoints();
+	super.drag(xx, yy);
     }
 
     int getPostCount() {