Add a diameter constraint, and add a `distance' entity that I can

remap when I copy circle entities, in order to make the radius
numerical somehow (analogy with the POINT_ and NORMAL_XFRMD) thing.

[git-p4: depot-paths = "//depot/solvespace/": change = 1710]

constraint.cpp

@@ -55,15 +55,22 @@ void Constraint::MenuConstrain(int id) {
                 Entity *e = SS.GetEntity(gs.entity[0]);
                 c.ptA = e->point[0];
                 c.ptB = e->point[1];
+            } else if(gs.circlesOrArcs == 1 && gs.n == 1) {
+                c.type = DIAMETER;
+                c.entityA = gs.entity[0];
             } else {
                 Error("Bad selection for distance / diameter constraint.");
                 return;
             }
+            if(c.type == PT_PT_DISTANCE) {
                 Vector n = SS.GW.projRight.Cross(SS.GW.projUp);
                 Vector a = SS.GetEntity(c.ptA)->PointGetNum();
                 Vector b = SS.GetEntity(c.ptB)->PointGetNum();
-
                 c.disp.offset = n.Cross(a.Minus(b)).WithMagnitude(50);
+            } else {
+                c.disp.offset = Vector::MakeFrom(0, 0, 0);
+            }
+
             c.exprA = Expr::FromString("0")->DeepCopyKeep();
             c.ModifyToSatisfy();
             AddConstraint(&c);
@@ -330,6 +337,13 @@ void Constraint::Generate(IdList<Equation,hEquation> *l) {
             break;
         }
 
+        case DIAMETER: {
+            Entity *circle = SS.GetEntity(entityA);
+            Expr *r = (SS.GetEntity(circle->distance))->DistanceGetExpr();
+            AddEq(l, (r->Times(Expr::FromConstant(2)))->Minus(exprA), 0);
+            break;
+        }
+
         case POINTS_COINCIDENT: {
             Entity *a = SS.GetEntity(ptA);
             Entity *b = SS.GetEntity(ptB);

drawconstraint.cpp

@@ -3,6 +3,7 @@
 bool Constraint::HasLabel(void) {
     switch(type) {
         case PT_PT_DISTANCE:
+        case DIAMETER:
             return true;
 
         default:
@@ -25,6 +26,35 @@ void Constraint::LineDrawOrGetDistance(Vector a, Vector b) {
     }
 }
 
+double Constraint::EllipticalInterpolation(double rx, double ry, double theta) {
+    double ex = rx*cos(theta);
+    double ey = ry*sin(theta);
+    double v = sqrt(ex*ex + ey*ey);
+
+    return v;
+}
+
+void Constraint::DoLabel(Vector ref, Vector *labelPos, Vector gr, Vector gu) {
+    char *s = exprA->Print();
+    if(labelPos) {
+        // labelPos is from the top left corner (for the text box used to
+        // edit things), but ref is from the center.
+        *labelPos = ref.Minus(gr.WithMagnitude(glxStrWidth(s)/2)).Minus(
+                             gu.WithMagnitude(glxStrHeight()/2));
+    }
+
+    if(dogd.drawing) {
+        glPushMatrix();
+            glxTranslatev(ref);
+            glxOntoWorkplane(gr, gu);
+            glxWriteTextRefCenter(s);
+        glPopMatrix();
+    } else {
+        Point2d o = SS.GW.ProjectPoint(ref);
+        dogd.dmin = min(dogd.dmin, o.DistanceTo(dogd.mp) - 10);
+    }
+}
+
 void Constraint::DrawOrGetDistance(Vector *labelPos) {
     if(!SS.GW.showConstraints) return;
     Group *g = SS.GetGroup(group);
@@ -47,7 +77,6 @@ void Constraint::DrawOrGetDistance(Vector *labelPos) {
             Vector bp = SS.GetEntity(ptB)->PointGetNum();
 
             Vector ref = ((ap.Plus(bp)).ScaledBy(0.5)).Plus(disp.offset);
-            if(labelPos) *labelPos = ref;
 
             Vector ab   = ap.Minus(bp);
             Vector ar   = ap.Minus(ref);
@@ -59,17 +88,26 @@ void Constraint::DrawOrGetDistance(Vector *labelPos) {
             LineDrawOrGetDistance(ap, ap.Plus(out));
             LineDrawOrGetDistance(bp, bp.Plus(out));
 
-            if(dogd.drawing) {
+            DoLabel(ref, labelPos, gr, gu);
-                glPushMatrix();
+            break;
-                    glxTranslatev(ref);
-                    glxOntoWorkplane(gr, gu);
-                    glxWriteText(exprA->Print());
-                glPopMatrix();
-            } else {
-                Point2d o = SS.GW.ProjectPoint(ref);
-                dogd.dmin = min(dogd.dmin, o.DistanceTo(dogd.mp) - 10);
         }
 
+        case DIAMETER: {
+            Entity *circle = SS.GetEntity(entityA);
+            Vector center = SS.GetEntity(circle->point[0])->PointGetNum();
+            double r = SS.GetEntity(circle->distance)->DistanceGetNum();
+            Vector ref = center.Plus(disp.offset);
+
+            double theta = atan2(disp.offset.Dot(gu), disp.offset.Dot(gr));
+            double adj = EllipticalInterpolation(
+                glxStrWidth(exprA->Print())/2, glxStrHeight()/2, theta);
+
+            Vector mark = ref.Minus(center);
+            mark = mark.WithMagnitude(mark.Magnitude()-r);
+            LineDrawOrGetDistance(ref.Minus(mark.WithMagnitude(adj)),
+                                  ref.Minus(mark));
+
+            DoLabel(ref, labelPos, gr, gu);
             break;
         }
 
@@ -106,7 +144,7 @@ void Constraint::DrawOrGetDistance(Vector *labelPos) {
 
         case PT_ON_LINE:
         case PT_IN_PLANE: {
-            double s = 7;
+            double s = 7/SS.GW.scale;
             Vector p = SS.GetEntity(ptA)->PointGetNum();
             Vector r = gr.WithMagnitude(s);
             Vector d = gu.WithMagnitude(s);

entity.cpp

@@ -31,6 +31,28 @@ void Entity::WorkplaneGetPlaneExprs(ExprVector *n, Expr **dn) {
     }
 }
 
+double Entity::DistanceGetNum(void) {
+    if(type == DISTANCE) {
+        return SS.GetParam(param[0])->val;
+    } else if(type == DISTANCE_XFRMD) {
+        return numDistance;
+    } else oops();
+}
+Expr *Entity::DistanceGetExpr(void) {
+    if(type == DISTANCE) {
+        return Expr::FromParam(param[0]);
+    } else if(type == DISTANCE_XFRMD) {
+        return Expr::FromConstant(numDistance);
+    } else oops();
+}
+void Entity::DistanceForceTo(double v) {
+    if(type == DISTANCE) {
+        (SS.GetParam(param[0]))->val = v;
+    } else if(type == DISTANCE_XFRMD) {
+        // do nothing, it's locked
+    } else oops();
+}
+
 Entity *Entity::Normal(void) {
     return SS.GetEntity(normal);
 }
@@ -404,6 +426,11 @@ void Entity::DrawOrGetDistance(int order) {
             break;
         }
 
+        case DISTANCE:
+        case DISTANCE_XFRMD:
+            // These are used only as data structures, nothing to display.
+            break;
+
         case WORKPLANE: {
             if(order >= 0 && order != 0) break;
             if(!SS.GW.showWorkplanes) break;
@@ -477,7 +504,7 @@ void Entity::DrawOrGetDistance(int order) {
             if(order >= 0 && order != 1) break;
 
             Quaternion q = SS.GetEntity(normal)->NormalGetNum();
-            double r = SS.GetParam(param[0])->val;
+            double r = SS.GetEntity(distance)->DistanceGetNum();
             Vector center = SS.GetEntity(point[0])->PointGetNum();
             Vector u = q.RotationU(), v = q.RotationV();
 

file.cpp

@@ -77,6 +77,7 @@ const SolveSpace::SaveTable SolveSpace::SAVED[] = {
     { 'e',  "Entity.point[2].v",        'x',        &(SS.sv.e.point[2].v)   },
     { 'e',  "Entity.point[3].v",        'x',        &(SS.sv.e.point[3].v)   },
     { 'e',  "Entity.normal.v",          'x',        &(SS.sv.e.normal.v)     },
+    { 'e',  "Entity.distance.v",        'x',        &(SS.sv.e.distance.v)   },
     { 'e',  "Entity.workplane.v",       'x',        &(SS.sv.e.workplane.v)  },
     { 'e',  "Entity.numPoint.x",        'f',        &(SS.sv.e.numPoint.x)   },
     { 'e',  "Entity.numPoint.y",        'f',        &(SS.sv.e.numPoint.y)   },

glhelper.cpp

@@ -6,7 +6,7 @@
 static bool ColorLocked;
 
 #define FONT_SCALE (0.5)
-static int StrWidth(char *str) {
+double glxStrWidth(char *str) {
     int w = 0;
     for(; *str; str++) {
         int c = *str;
@@ -15,14 +15,17 @@ static int StrWidth(char *str) {
 
         w += Font[c].width;
     }
-    return w;
+    return w*FONT_SCALE/SS.GW.scale;
+}
+double glxStrHeight(void) {
+    // The characters have height ~21, as they appear in the table.
+    return 21.0*FONT_SCALE/SS.GW.scale;
 }
 void glxWriteTextRefCenter(char *str)
 {
     double scale = FONT_SCALE/SS.GW.scale;
-    // The characters have height ~21, as they appear in the table.
+    double fh = glxStrHeight();
-    double fh = (21.0)*scale;
+    double fw = glxStrWidth(str);
-    double fw = StrWidth(str)*scale;
     glPushMatrix();
         glTranslated(-fw/2, -fh/2, 0);
         // Undo the (+5, +5) offset that glxWriteText applies.

graphicswin.cpp

@@ -513,7 +513,8 @@ void GraphicsWindow::MouseMoved(double x, double y, bool leftDown,
             Entity *circle = SS.GetEntity(pending.circle);
             Vector center = SS.GetEntity(circle->point[0])->PointGetNum();
             Point2d c2 = ProjectPoint(center);
-            SS.GetParam(circle->param[0])->val = c2.DistanceTo(mp)*scale;
+            double r = c2.DistanceTo(mp)*scale;
+            SS.GetEntity(circle->distance)->DistanceForceTo(r);
             break;
         }
 
@@ -634,6 +635,7 @@ void GraphicsWindow::GroupSelection(void) {
             switch(e->type) {
                 case Entity::WORKPLANE:     (gs.workplanes)++; break;
                 case Entity::LINE_SEGMENT:  (gs.lineSegments)++; break;
+                case Entity::CIRCLE:        (gs.circlesOrArcs)++; break;
             }
         }
     }
@@ -726,7 +728,7 @@ void GraphicsWindow::MouseLeftDown(double mx, double my) {
         case MNU_CIRCLE:
             hr = AddRequest(Request::CIRCLE);
             SS.GetEntity(hr.entity(1))->PointForceTo(v);
-            SS.GetEntity(hr.entity(16))->NormalForceTo(
+            SS.GetEntity(hr.entity(32))->NormalForceTo(
                 Quaternion::MakeFrom(SS.GW.projRight, SS.GW.projUp));
             MAYBE_PLACE(hr.entity(1));
 
@@ -757,7 +759,7 @@ void GraphicsWindow::MouseLeftDown(double mx, double my) {
         case MNU_WORKPLANE:
             hr = AddRequest(Request::WORKPLANE);
             SS.GetEntity(hr.entity(1))->PointForceTo(v);
-            SS.GetEntity(hr.entity(16))->NormalForceTo( 
+            SS.GetEntity(hr.entity(32))->NormalForceTo( 
                 Quaternion::MakeFrom(SS.GW.projRight, SS.GW.projUp));
             MAYBE_PLACE(hr.entity(1));
 

sketch.cpp

@@ -126,7 +126,7 @@ void Group::CopyEntity(hEntity in, int a, hParam dx, hParam dy, hParam dz,
         case Entity::CIRCLE:
             en.point[0] = Remap(ep->point[0], a);
             en.normal   = Remap(ep->normal, a);
-            en.param[0] = ep->param[0]; // XXX make numerical somehow later
+            en.distance = Remap(ep->distance, a);
             break;
 
         case Entity::POINT_IN_3D:
@@ -159,6 +159,11 @@ void Group::CopyEntity(hEntity in, int a, hParam dx, hParam dy, hParam dz,
             en.point[0] = Remap(ep->point[0], a);
             break;
 
+        case Entity::DISTANCE:
+            en.type = Entity::DISTANCE_XFRMD;
+            en.numDistance = ep->DistanceGetNum();
+            break;
+
         default:
             oops();
     }
@@ -302,6 +307,7 @@ void Request::Generate(IdList<Entity,hEntity> *entity,
     int params = 0;
     int et = 0;
     bool hasNormal = false;
+    bool hasDistance = false;
     int i;
 
     Entity e;
@@ -328,6 +334,7 @@ void Request::Generate(IdList<Entity,hEntity> *entity,
             points = 1;
             params = 1;
             hasNormal = true;
+            hasDistance = true;
             break;
 
         case Request::CUBIC:
@@ -373,7 +380,7 @@ void Request::Generate(IdList<Entity,hEntity> *entity,
         Entity n;
         memset(&n, 0, sizeof(n));
         n.workplane = workplane;
-        n.h = h.entity(16);
+        n.h = h.entity(32);
         n.group = group;
         if(workplane.v == Entity::FREE_IN_3D.v) {
             n.type = Entity::NORMAL_IN_3D;
@@ -393,6 +400,17 @@ void Request::Generate(IdList<Entity,hEntity> *entity,
         entity->Add(&n);
         e.normal = n.h;
     }
+    if(hasDistance) {
+        Entity d;
+        memset(&d, 0, sizeof(d));
+        d.workplane = workplane;
+        d.h = h.entity(64);
+        d.group = group;
+        d.type = Entity::DISTANCE;
+        d.param[0] = AddParam(param, h.param(64));
+        entity->Add(&d);
+        e.distance = d.h;
+    }
     // And generate any params not associated with the point that
     // we happen to need.
     for(i = 0; i < params; i++) {

sketch.h

@@ -168,6 +168,9 @@ public:
     static const int NORMAL_IN_PLANE        =  3002;
     static const int NORMAL_XFRMD           =  3010;
 
+    static const int DISTANCE               =  4000;
+    static const int DISTANCE_XFRMD         =  4001;
+
     static const int WORKPLANE              = 10000;
     static const int LINE_SEGMENT           = 11000;
     static const int CUBIC                  = 12000;
@@ -177,13 +180,17 @@ public:
 
     // When it comes time to draw an entity, we look here to get the
     // defining variables.
-    hParam      param[4];
     hEntity     point[4];
     hEntity     normal;
+    hEntity     distance;
+    // The only types that have their own params are points, normals,
+    // and directions.
+    hParam      param[4];
 
-    // Derived points are a symbolic offset from a constant base.
+    // Transformed points/normals/distances have their numerical value.
     Vector      numPoint;
     Quaternion  numNormal;
+    double      numDistance;
 
     hGroup      group;
     hEntity     workplane;   // or Entity::FREE_IN_3D
@@ -197,6 +204,11 @@ public:
     bool HasDirection(void);
     ExprVector GetDirection(void);
 
+    // For distances
+    double DistanceGetNum(void);
+    Expr *DistanceGetExpr(void);
+    void DistanceForceTo(double v);
+
     bool IsWorkplane(void);
     // The plane is points P such that P dot (xn, yn, zn) - d = 0
     void WorkplaneGetPlaneExprs(ExprVector *n, Expr **d);
@@ -301,9 +313,9 @@ public:
     static const int EQUAL_LENGTH_LINES = 50;
     static const int SYMMETRIC          = 60;
     static const int AT_MIDPOINT        = 70;
-
     static const int HORIZONTAL         = 80;
     static const int VERTICAL           = 81;
+    static const int DIAMETER           = 90;
 
     int         tag;
     hConstraint h;
@@ -339,6 +351,8 @@ public:
     } dogd; // state for drawing or getting distance (for hit testing)
     void LineDrawOrGetDistance(Vector a, Vector b);
     void DrawOrGetDistance(Vector *labelPos);
+    double EllipticalInterpolation(double rx, double ry, double theta);
+    void DoLabel(Vector ref, Vector *labelPos, Vector gr, Vector gu);
 
     double GetDistance(Point2d mp);
     Vector GetLabelPos(void);

solvespace.h

@@ -71,6 +71,8 @@ void glxFillPolygon(SPolygon *p);
 void glxMarkPolygonNormal(SPolygon *p);
 void glxWriteText(char *str);
 void glxWriteTextRefCenter(char *str);
+double glxStrWidth(char *str);
+double glxStrHeight(void);
 void glxTranslatev(Vector u);
 void glxOntoWorkplane(Vector u, Vector v);
 void glxLockColorTo(double r, double g, double b);

ui.h

@@ -222,6 +222,7 @@ public:
         int         entities;
         int         workplanes;
         int         lineSegments;
+        int         circlesOrArcs;
         int         n;
     } gs;
     void GroupSelection(void);