std::string result;

if(type == Type::ANGLE) {

result = SS.DegreeToString(valA) + "°";

} else if(type == Type::LENGTH_RATIO || type == Type::ARC_ARC_LEN_RATIO || type == Type::ARC_LINE_LEN_RATIO) {

result = ssprintf("%.3f:1", valA);

} else if(type == Type::COMMENT) {

result = comment;

} else if(type == Type::DIAMETER) {

if(!other) {

result = "⌀" + SS.MmToStringSI(valA);

} else {

result = "R" + SS.MmToStringSI(valA / 2);

}

} else {

// valA has units of distance

result = SS.MmToStringSI(fabs(valA));

}

if(reference) {

result += " REF";

}

return result;

const Camera &camera = canvas->GetCamera();

a = camera.AlignToPixelGrid(a);

b = camera.AlignToPixelGrid(b);

canvas->DrawLine(a, b, hcs);

Canvas::Stroke strokeStippled = *canvas->strokes.FindById(hcs);

strokeStippled.stipplePattern = StipplePattern::SHORT_DASH;

strokeStippled.stippleScale = 4.0;

Canvas::hStroke hcsStippled = canvas->GetStroke(strokeStippled);

DoLine(canvas, hcsStippled, a, b);

Vector ref, Vector *labelPos, Vector gr, Vector gu) {

const Camera &camera = canvas->GetCamera();

std::string s = Label();

double textHeight = Style::TextHeight(GetStyle()) / camera.scale;

double swidth = VectorFont::Builtin()->GetWidth(textHeight, s),

sheight = VectorFont::Builtin()->GetCapHeight(textHeight);

// By default, the reference is from the center; but the style could

// specify otherwise if one is present, and it could also specify a

// rotation.

if(type == Type::COMMENT && disp.style.v) {

Style *st = Style::Get(disp.style);

// rotation first

double rads = st->textAngle*PI/180;

double c = cos(rads), s = sin(rads);

Vector pr = gr, pu = gu;

gr = pr.ScaledBy( c).Plus(pu.ScaledBy(s));

gu = pr.ScaledBy(-s).Plus(pu.ScaledBy(c));

// then origin

uint32_t o = (uint32_t)st->textOrigin;

if(o & (uint32_t)Style::TextOrigin::LEFT) ref = ref.Plus(gr.WithMagnitude(swidth/2));

if(o & (uint32_t)Style::TextOrigin::RIGHT) ref = ref.Minus(gr.WithMagnitude(swidth/2));

if(o & (uint32_t)Style::TextOrigin::BOT) ref = ref.Plus(gu.WithMagnitude(sheight/2));

if(o & (uint32_t)Style::TextOrigin::TOP) ref = ref.Minus(gu.WithMagnitude(sheight/2));

}

Vector o = ref.Minus(gr.WithMagnitude(swidth/2)).Minus(

gu.WithMagnitude(sheight/2));

canvas->DrawVectorText(s, textHeight, o, gr.WithMagnitude(1), gu.WithMagnitude(1), hcs);

if(labelPos) *labelPos = o;

Vector *r, Vector n, Vector o) {

double d = r->DistanceToPlane(n, o);

Vector p = r->Minus(n.ScaledBy(d));

DoStippledLine(canvas, hcs, p, *r);

*r = p;

Vector p = r->ProjectInto(workplane);

DoStippledLine(canvas, hcs, p, *r);

*r = p;

Vector ref, Vector a, Vector b, bool extend) {

const Camera &camera = canvas->GetCamera();

double th = Style::TextHeight(GetStyle()) / camera.scale;

double pixels = 1.0 / camera.scale;

double swidth = VectorFont::Builtin()->GetWidth(th, Label()) + 8 * pixels,

sheight = VectorFont::Builtin()->GetCapHeight(th) + 8 * pixels;

Vector gu = camera.projUp.WithMagnitude(1),

gr = camera.projRight.WithMagnitude(1);

return DoLineTrimmedAgainstBox(canvas, hcs, ref, a, b, extend, gr, gu, swidth, sheight);

Vector ref, Vector a, Vector b, bool extend,

Vector gr, Vector gu, double swidth, double sheight) {

struct {

Vector n;

double d;

} planes[4];

// reference pos is the center of box occupied by text; build a rectangle

// around that, aligned to axes gr and gu, from four planes will all four

// normals pointing inward

planes[0].n = gu.ScaledBy(-1); planes[0].d = -(gu.Dot(ref) + sheight/2);

planes[1].n = gu; planes[1].d = gu.Dot(ref) - sheight/2;

planes[2].n = gr; planes[2].d = gr.Dot(ref) - swidth/2;

planes[3].n = gr.ScaledBy(-1); planes[3].d = -(gr.Dot(ref) + swidth/2);

double tmin = VERY_POSITIVE, tmax = VERY_NEGATIVE;

Vector dl = b.Minus(a);

for(int i = 0; i < 4; i++) {

bool parallel;

Vector p = Vector::AtIntersectionOfPlaneAndLine(

planes[i].n, planes[i].d,

a, b, &parallel);

if(parallel) continue;

int j;

for(j = 0; j < 4; j++) {

double d = (planes[j].n).Dot(p) - planes[j].d;

if(d < -LENGTH_EPS) break;

}

if(j < 4) continue;

double t = (p.Minus(a)).DivProjected(dl);

tmin = min(t, tmin);

tmax = max(t, tmax);

}

// Both in range; so there's pieces of the line on both sides of the label box.

if(tmin >= 0.0 && tmin <= 1.0 && tmax >= 0.0 && tmax <= 1.0) {

DoLine(canvas, hcs, a, a.Plus(dl.ScaledBy(tmin)));

DoLine(canvas, hcs, a.Plus(dl.ScaledBy(tmax)), b);

return 0;

}

// Only one intersection in range; so the box is right on top of the endpoint

if(tmin >= 0.0 && tmin <= 1.0) {

DoLine(canvas, hcs, a, a.Plus(dl.ScaledBy(tmin)));

return 0;

}

// Likewise.

if(tmax >= 0.0 && tmax <= 1.0) {

DoLine(canvas, hcs, a.Plus(dl.ScaledBy(tmax)), b);

return 0;

}

// The line does not intersect the label; so the line should get

// extended to just barely meet the label.

// 0 means the label lies within the line, negative means it's outside

// and closer to b, positive means outside and closer to a.

if(tmax < 0.0) {

if(extend) a = a.Plus(dl.ScaledBy(tmax));

DoLine(canvas, hcs, a, b);

return 1;

}

if(tmin > 1.0) {

if(extend) b = a.Plus(dl.ScaledBy(tmin));

DoLine(canvas, hcs, a, b);

return -1;

}

// This will happen if the entire line lies within the box.

return 0;

Vector p, Vector dir, Vector n, double width, double angle, double da) {

dir = dir.WithMagnitude(width / cos(angle));

dir = dir.RotatedAbout(n, da);

DoLine(canvas, hcs, p, p.Plus(dir.RotatedAbout(n, angle)));

DoLine(canvas, hcs, p, p.Plus(dir.RotatedAbout(n, -angle)));

Vector ref, Vector a, Vector b,

bool onlyOneExt)

{

const Camera &camera = canvas->GetCamera();

double pixels = 1.0 / camera.scale;

Vector ab = a.Minus(b);

Vector ar = a.Minus(ref);

// Normal to a plane containing the line and the label origin.

Vector n = ab.Cross(ar);

// Within that plane, and normal to the line AB; so that's our extension

// line.

Vector out = ab.Cross(n).WithMagnitude(1);

out = out.ScaledBy(-out.Dot(ar));

Vector ae = a.Plus(out), be = b.Plus(out);

// Extension lines extend 10 pixels beyond where the arrows get

// drawn (which is at the same offset perpendicular from AB as the

// label).

DoLine(canvas, hcs, a, ae.Plus(out.WithMagnitude(10*pixels)));

if(!onlyOneExt) {

DoLine(canvas, hcs, b, be.Plus(out.WithMagnitude(10*pixels)));

}

int within = DoLineTrimmedAgainstBox(canvas, hcs, ref, ae, be);

// Arrow heads are 13 pixels long, with an 18 degree half-angle.

double theta = 18*PI/180;

Vector arrow = (be.Minus(ae)).WithMagnitude(13*pixels);

if(within != 0) {

arrow = arrow.ScaledBy(-1);

Vector seg = (be.Minus(ae)).WithMagnitude(18*pixels);

if(within < 0) DoLine(canvas, hcs, ae, ae.Minus(seg));

if(within > 0) DoLine(canvas, hcs, be, be.Plus(seg));

}

DoArrow(canvas, hcs, ae, arrow, n, 13.0 * pixels, theta, 0.0);

DoArrow(canvas, hcs, be, arrow.Negated(), n, 13.0 * pixels, theta, 0.0);

Vector a, Vector b, Vector gn, Vector *refp) {

const Camera &camera = canvas->GetCamera();

Vector m = (a.ScaledBy(1.0/3)).Plus(b.ScaledBy(2.0/3));

if(refp) *refp = m;

Vector ab = a.Minus(b);

Vector n = (gn.Cross(ab)).WithMagnitude(10/camera.scale);

DoLine(canvas, hcs, m.Minus(n), m.Plus(n));

hEntity he, Vector *refp) {

const Camera &camera = canvas->GetCamera();

Entity *circ = SK.GetEntity(he);

Vector center = SK.GetEntity(circ->point[0])->PointGetDrawNum();

double r = circ->CircleGetRadiusNum();

Quaternion q = circ->Normal()->NormalGetNum();

Vector u = q.RotationU(), v = q.RotationV();

double theta;

if(circ->type == Entity::Type::CIRCLE) {

theta = PI/2;

} else if(circ->type == Entity::Type::ARC_OF_CIRCLE) {

double thetaa, thetab, dtheta;

circ->ArcGetAngles(&thetaa, &thetab, &dtheta);

theta = thetaa + dtheta/2;

} else ssassert(false, "Unexpected entity type");

Vector d = u.ScaledBy(cos(theta)).Plus(v.ScaledBy(sin(theta)));

d = d.ScaledBy(r);

Vector p = center.Plus(d);

if(refp) *refp = p;

Vector tick = d.WithMagnitude(10/camera.scale);

DoLine(canvas, hcs, p.Plus(tick), p.Minus(tick));

Vector a0, Vector da, Vector b0, Vector db,

Vector offset, Vector *ref, bool trim,

Vector explodeOffset)

{

const Camera &camera = canvas->GetCamera();

double pixels = 1.0 / camera.scale;

Vector gr = camera.projRight.ScaledBy(1.0);

Vector gu = camera.projUp.ScaledBy(1.0);

if(workplane != Entity::FREE_IN_3D) {

a0 = a0.ProjectInto(workplane);

b0 = b0.ProjectInto(workplane);

da = da.ProjectVectorInto(workplane);

db = db.ProjectVectorInto(workplane);

}

a0 = a0.Plus(explodeOffset);

b0 = b0.Plus(explodeOffset);

Vector a1 = a0.Plus(da);

Vector b1 = b0.Plus(db);

bool skew;

Vector pi = Vector::AtIntersectionOfLines(a0, a0.Plus(da),

b0, b0.Plus(db), &skew);

if(!skew) {

*ref = pi.Plus(offset);

// We draw in a coordinate system centered at the intersection point.

// One basis vector is da, and the other is normal to da and in

// the plane that contains our lines (so normal to its normal).

da = da.WithMagnitude(1);

db = db.WithMagnitude(1);

Vector norm = da.Cross(db);

Vector dna = norm.Cross(da).WithMagnitude(1.0);

Vector dnb = norm.Cross(db).WithMagnitude(1.0);

// da and db magnitudes are 1.0

double thetaf = acos(da.Dot(db));

// Calculate median

Vector m = da.ScaledBy(cos(thetaf/2)).Plus(

dna.ScaledBy(sin(thetaf/2)));

Vector rm = (*ref).Minus(pi);

// Test which side we have to place an arc

if(m.Dot(rm) < 0) {

da = da.ScaledBy(-1); dna = dna.ScaledBy(-1);

db = db.ScaledBy(-1); dnb = dnb.ScaledBy(-1);

}

double rda = rm.Dot(da), rdna = rm.Dot(dna);

// Introduce minimal arc radius in pixels

double r = max(sqrt(rda*rda + rdna*rdna), 15.0 * pixels);

double th = Style::TextHeight(GetStyle()) / camera.scale;

double swidth = VectorFont::Builtin()->GetWidth(th, Label()) + 8*pixels,

sheight = VectorFont::Builtin()->GetCapHeight(th) + 6*pixels;

double textR = sqrt(swidth * swidth + sheight * sheight) / 2.0;

*ref = pi.Plus(rm.WithMagnitude(std::max(rm.Magnitude(), 15 * pixels + textR)));

// Arrow points

Vector apa = da. ScaledBy(r).Plus(pi);

Vector apb = da. ScaledBy(r*cos(thetaf)).Plus(

dna.ScaledBy(r*sin(thetaf))).Plus(pi);

double arrowW = 13 * pixels;

double arrowA = 18.0 * PI / 180.0;

bool arrowVisible = apb.Minus(apa).Magnitude() > 2.5 * arrowW;

// Arrow reversing indicator

bool arrowRev = false;

// The minimal extension length in angular representation

double extAngle = 18 * pixels / r;

// Arc additional angle

double addAngle = 0.0;

// Arc start angle

double startAngle = 0.0;

// Arc extension to db.

// We have just enlarge angle value.

if(HasLabel() && rm.Dot(dnb) > 0.0) {

// rm direction projected to plane with u = da, v = dna

Vector rmp = da.ScaledBy(rda).Plus(dna.ScaledBy(rdna)).WithMagnitude(1.0);

// rmp and db magnitudes are 1.0

addAngle = std::max(acos(rmp.Dot(db)), extAngle);

if(arrowVisible) {

startAngle = -extAngle;

addAngle += extAngle;

arrowRev = true;

}

}

// Arc extension to da.

// We are enlarge angle value and rewrite basis to align along rm projection.

if(HasLabel() && rm.Dot(dna) < 0.0) {

// rm direction projected to plane with u = da, v = dna

Vector rmp = da.ScaledBy(rda).Plus(dna.ScaledBy(rdna)).WithMagnitude(1.0);

// rmp and da magnitudes are 1.0

startAngle = -std::max(acos(rmp.Dot(da)), extAngle);

addAngle = -startAngle;

if(arrowVisible) {

addAngle += extAngle;

arrowRev = true;

}

}

Vector prev;

int n = 30;

for(int i = 0; i <= n; i++) {

double theta = startAngle + (i*(thetaf + addAngle))/n;

Vector p = da.ScaledBy(r*cos(theta)).Plus(

dna.ScaledBy(r*sin(theta))).Plus(pi);

if(i > 0) {

if(trim) {

DoLineTrimmedAgainstBox(canvas, hcs, *ref, prev, p,

/*extend=*/false, gr, gu, swidth, sheight + 2*pixels);

} else {

DoLine(canvas, hcs, prev, p);

}

}

prev = p;

}

DoLineExtend(canvas, hcs, a0, a1, apa, 5.0 * pixels);

DoLineExtend(canvas, hcs, b0, b1, apb, 5.0 * pixels);

// Draw arrows only when we have enough space.

if(arrowVisible) {

double angleCorr = arrowW / (2.0 * r);

if(arrowRev) {

dna = dna.ScaledBy(-1.0);

angleCorr = -angleCorr;

}

DoArrow(canvas, hcs, apa, dna, norm, arrowW, arrowA, angleCorr);

DoArrow(canvas, hcs, apb, dna, norm, arrowW, arrowA, thetaf + PI - angleCorr);

}

} else {

// The lines are skew; no wonderful way to illustrate that.

*ref = a0.Plus(b0);

*ref = (*ref).ScaledBy(0.5).Plus(disp.offset);

gu = gu.WithMagnitude(1);

double textHeight = Style::TextHeight(GetStyle()) / camera.scale;

Vector trans =

(*ref).Plus(gu.ScaledBy(-1.5*VectorFont::Builtin()->GetCapHeight(textHeight)));

canvas->DrawVectorText("angle between skew lines", textHeight,

trans, gr.WithMagnitude(1), gu.WithMagnitude(1),

hcs);

}

if(SS.GW.showConstraints == GraphicsWindow::ShowConstraintMode::SCM_NOSHOW)

return false;

bool isDim = false;

if(SS.GW.showConstraints == GraphicsWindow::ShowConstraintMode::SCM_SHOW_DIM)

switch(type) {

case ConstraintBase::Type::ANGLE:

case ConstraintBase::Type::DIAMETER:

case ConstraintBase::Type::PT_PT_DISTANCE:

case ConstraintBase::Type::PT_FACE_DISTANCE:

case ConstraintBase::Type::PT_LINE_DISTANCE:

case ConstraintBase::Type::PT_PLANE_DISTANCE: isDim = true; break;

default:;

}

if(SS.GW.showConstraints == GraphicsWindow::ShowConstraintMode::SCM_SHOW_ALL || isDim ) {

Group *g = SK.GetGroup(group);

// If the group is hidden, then the constraints are hidden and not

// able to be selected.

if(!(g->visible)) return false;

// And likewise if the group is not the active group; except for comments

// with an assigned style.

if(g->h != SS.GW.activeGroup && !(type == Type::COMMENT && disp.style.v)) {

return false;

}

if(disp.style.v) {

Style *s = Style::Get(disp.style);

if(!s->visible) return false;

}

return true;

}

return false;

Vector p0, Vector p1, Vector pt, double salient) {

Vector dir = p1.Minus(p0);

double k = dir.Dot(pt.Minus(p0)) / dir.Dot(dir);

Vector ptOnLine = p0.Plus(dir.ScaledBy(k));

// Draw projection line.

DoLine(canvas, hcs, pt, ptOnLine);

// Calculate salient direction.

Vector sd = dir.WithMagnitude(1.0).ScaledBy(salient);

Vector from;

Vector to;

if(k < 0.0) {

from = p0;

to = ptOnLine.Minus(sd);

} else if(k > 1.0) {

from = p1;

to = ptOnLine.Plus(sd);

} else {

return false;

}

// Draw extension line.

DoLine(canvas, hcs, from, to);

return true;

Vector *labelPos, std::vector<Vector> *refs) {

if(!(how == DrawAs::HOVERED || how == DrawAs::SELECTED) &&

!IsVisible()) return;

// Unit vectors that describe our current view of the scene. One pixel

// long, not one actual unit.

const Camera &camera = canvas->GetCamera();

Vector gr = camera.projRight.ScaledBy(1/camera.scale);

Vector gu = camera.projUp.ScaledBy(1/camera.scale);

Vector gn = (gr.Cross(gu)).WithMagnitude(1/camera.scale);

double textHeight = Style::TextHeight(GetStyle()) / camera.scale;

RgbaColor color = {};

switch(how) {

case DrawAs::DEFAULT: color = Style::Color(GetStyle()); break;

case DrawAs::HOVERED: color = Style::Color(Style::HOVERED); break;

case DrawAs::SELECTED: color = Style::Color(Style::SELECTED); break;

}

Canvas::Stroke stroke = Style::Stroke(GetStyle());

stroke.layer = Canvas::Layer::FRONT;

stroke.color = color;

stroke.zIndex = 4;

Canvas::hStroke hcs = canvas->GetStroke(stroke);

Canvas::Fill fill = {};

fill.layer = Canvas::Layer::FRONT;

fill.color = color;

fill.zIndex = stroke.zIndex;

Canvas::hFill hcf = canvas->GetFill(fill);

switch(type) {

case Type::PT_PT_DISTANCE: {

Vector ap = SK.GetEntity(ptA)->PointGetNum();

Vector bp = SK.GetEntity(ptB)->PointGetNum();

if(workplane != Entity::FREE_IN_3D) {

DoProjectedPoint(canvas, hcs, &ap);

DoProjectedPoint(canvas, hcs, &bp);

}

if(ShouldDrawExploded()) {

// Offset A and B by the same offset so the constraint is drawn

// in the plane of one of the exploded points (rather than at an

// angle)

Vector offset = SK.GetEntity(ptA)->ExplodeOffset();

ap = ap.Plus(offset);

bp = bp.Plus(offset);

}

Vector ref = ((ap.Plus(bp)).ScaledBy(0.5)).Plus(disp.offset);

if(refs) refs->push_back(ref);

DoLineWithArrows(canvas, hcs, ref, ap, bp, /*onlyOneExt=*/false);

DoLabel(canvas, hcs, ref, labelPos, gr, gu);

return;

}

case Type::PROJ_PT_DISTANCE: {

Vector ap = SK.GetEntity(ptA)->PointGetNum(),

bp = SK.GetEntity(ptB)->PointGetNum(),

dp = (bp.Minus(ap)),

pp = SK.GetEntity(entityA)->VectorGetNum();

if(ShouldDrawExploded()) {

// explode for whichever point is in the workplane (or the first if both are)

Entity *pt = SK.GetEntity(ptA);

if(pt->group != group) {

pt = SK.GetEntity(ptB);

}

if(pt->group == group) {

Vector offset = pt->ExplodeOffset();

ap = ap.Plus(offset);

bp = bp.Plus(offset);

}

}

Vector ref = ((ap.Plus(bp)).ScaledBy(0.5)).Plus(disp.offset);

if(refs) refs->push_back(ref);

pp = pp.WithMagnitude(1);

double d = dp.Dot(pp);

Vector bpp = ap.Plus(pp.ScaledBy(d));

DoStippledLine(canvas, hcs, ap, bpp);

DoStippledLine(canvas, hcs, bp, bpp);

DoLineWithArrows(canvas, hcs, ref, ap, bpp, /*onlyOneExt=*/false);

DoLabel(canvas, hcs, ref, labelPos, gr, gu);

return;

}

case Type::PT_FACE_DISTANCE:

case Type::PT_PLANE_DISTANCE: {

Vector pt = SK.GetEntity(ptA)->PointGetDrawNum();

Entity *enta = SK.GetEntity(entityA);

Vector n, p;

if(type == Type::PT_PLANE_DISTANCE) {

n = enta->Normal()->NormalN();

p = enta->WorkplaneGetOffset();

} else {

n = enta->FaceGetNormalNum();

p = enta->FaceGetPointNum();

}

double d = (p.Minus(pt)).Dot(n);

Vector closest = pt.Plus(n.WithMagnitude(d));

Vector ref = ((closest.Plus(pt)).ScaledBy(0.5)).Plus(disp.offset);

if(refs) refs->push_back(ref);

if(!pt.Equals(closest)) {

DoLineWithArrows(canvas, hcs, ref, pt, closest, /*onlyOneExt=*/true);

}

DoLabel(canvas, hcs, ref, labelPos, gr, gu);

return;

}

case Type::PT_LINE_DISTANCE: {

Entity *ptEntity = SK.GetEntity(ptA);

Vector pt = ptEntity->PointGetNum();

Entity *line = SK.GetEntity(entityA);

Vector lA = SK.GetEntity(line->point[0])->PointGetNum();

Vector lB = SK.GetEntity(line->point[1])->PointGetNum();

Vector dl = lB.Minus(lA);

if(workplane != Entity::FREE_IN_3D) {

lA = lA.ProjectInto(workplane);

lB = lB.ProjectInto(workplane);

DoProjectedPoint(canvas, hcs, &pt);

}

// Only explode if the point and line are in the same group (and that group is a sketch

// with explode enabled) otherwise it's too visually confusing to figure out what the

// correct projections should be.

bool shouldExplode = ShouldDrawExploded()

&& ptEntity->group == group

&& line->group == group;

if(shouldExplode) {

Vector explodeOffset = ptEntity->ExplodeOffset();

pt = pt.Plus(explodeOffset);

lA = lA.Plus(explodeOffset);

lB = lB.Plus(explodeOffset);

}

// Find the closest point on the line

Vector closest = pt.ClosestPointOnLine(lA, dl);

Vector ref = ((closest.Plus(pt)).ScaledBy(0.5)).Plus(disp.offset);

if(refs) refs->push_back(ref);

DoLabel(canvas, hcs, ref, labelPos, gr, gu);

if(!pt.Equals(closest)) {

DoLineWithArrows(canvas, hcs, ref, pt, closest, /*onlyOneExt=*/true);

// Draw projected point

Vector a = pt;

Vector b = closest;

Vector ab = a.Minus(b);

Vector ar = a.Minus(ref);

Vector n = ab.Cross(ar);

Vector out = ab.Cross(n).WithMagnitude(1);

out = out.ScaledBy(-out.Dot(ar));

Vector be = b.Plus(out);

Vector np = lA.Minus(pt).Cross(lB.Minus(pt)).WithMagnitude(1.0);

DoProjectedPoint(canvas, hcs, &be, np, pt);

// Extensions to line

double pixels = 1.0 / camera.scale;

Vector refClosest = ref.ClosestPointOnLine(lA, dl);

double ddl = dl.Dot(dl);

if(fabs(ddl) > LENGTH_EPS * LENGTH_EPS) {

double t = refClosest.Minus(lA).Dot(dl) / ddl;

if(t < 0.0) {

DoLine(canvas, hcs, refClosest.Minus(dl.WithMagnitude(10.0 * pixels)), lA);

} else if(t > 1.0) {

DoLine(canvas, hcs, refClosest.Plus(dl.WithMagnitude(10.0 * pixels)), lB);

}

}

}

if(workplane != Entity::FREE_IN_3D) {

// Draw the projection marker from the closest point on the

// projected line to the projected point on the real line.

Vector lAB = (lA.Minus(lB));

double t = (lA.Minus(closest)).DivProjected(lAB);

Vector lA = SK.GetEntity(line->point[0])->PointGetNum();

Vector lB = SK.GetEntity(line->point[1])->PointGetNum();

Vector c2 = (lA.ScaledBy(1-t)).Plus(lB.ScaledBy(t));

DoProjectedPoint(canvas, hcs, &c2);

}

return;

}

case Type::DIAMETER: {

Entity *circle = SK.GetEntity(entityA);

Vector center = SK.GetEntity(circle->point[0])->PointGetDrawNum();

Quaternion q = SK.GetEntity(circle->normal)->NormalGetNum();

Vector n = q.RotationN().WithMagnitude(1);

double r = circle->CircleGetRadiusNum();

Vector ref = center.Plus(disp.offset);

// Force the label into the same plane as the circle.

ref = ref.Minus(n.ScaledBy(n.Dot(ref) - n.Dot(center)));

if(refs) refs->push_back(ref);

Vector mark = ref.Minus(center);

mark = mark.WithMagnitude(mark.Magnitude()-r);

DoLineTrimmedAgainstBox(canvas, hcs, ref, ref, ref.Minus(mark));

Vector topLeft;

DoLabel(canvas, hcs, ref, &topLeft, gr, gu);

if(labelPos) *labelPos = topLeft;

return;

}

case Type::POINTS_COINCIDENT: {

if(how == DrawAs::DEFAULT) {

// Let's adjust the color of this constraint to have the same

// rough luma as the point color, so that the constraint does not

// stand out in an ugly way.

RgbaColor cd = Style::Color(Style::DATUM),

cc = Style::Color(Style::CONSTRAINT);

// convert from 8-bit color to a vector

Vector vd = Vector::From(cd.redF(), cd.greenF(), cd.blueF()),

vc = Vector::From(cc.redF(), cc.greenF(), cc.blueF());

// and scale the constraint color to have the same magnitude as

// the datum color, maybe a bit dimmer

vc = vc.WithMagnitude(vd.Magnitude()*0.9);

// and set the color to that.

fill.color = RGBf(vc.x, vc.y, vc.z);

hcf = canvas->GetFill(fill);

}

for(int a = 0; a < 2; a++) {

Vector r = camera.projRight.ScaledBy((a+1)/camera.scale);

Vector d = camera.projUp.ScaledBy((2-a)/camera.scale);

for(int i = 0; i < 2; i++) {

Vector p = SK.GetEntity(i == 0 ? ptA : ptB)->PointGetDrawNum();

if(refs) refs->push_back(p);

canvas->DrawQuad(p.Plus (r).Plus (d),

p.Plus (r).Minus(d),

p.Minus(r).Minus(d),

p.Minus(r).Plus (d),

hcf);

}

}

return;

}

case Type::PT_ON_CIRCLE:

case Type::PT_ON_LINE:

case Type::PT_ON_FACE:

case Type::PT_IN_PLANE: {

double s = 8/camera.scale;

Vector p = SK.GetEntity(ptA)->PointGetDrawNum();

if(refs) refs->push_back(p);

Vector r, d;

if(type == Type::PT_ON_FACE) {

Vector n = SK.GetEntity(entityA)->FaceGetNormalNum();

r = n.Normal(0);

d = n.Normal(1);

} else if(type == Type::PT_IN_PLANE) {

EntityBase *n = SK.GetEntity(entityA)->Normal();

r = n->NormalU();

d = n->NormalV();

} else {

r = gr;

d = gu;

s *= (6.0/8); // draw these a little smaller

}

r = r.WithMagnitude(s); d = d.WithMagnitude(s);

DoLine(canvas, hcs, p.Plus (r).Plus (d), p.Plus (r).Minus(d));

DoLine(canvas, hcs, p.Plus (r).Minus(d), p.Minus(r).Minus(d));

DoLine(canvas, hcs, p.Minus(r).Minus(d), p.Minus(r).Plus (d));

DoLine(canvas, hcs, p.Minus(r).Plus (d), p.Plus (r).Plus (d));

return;

}

case Type::WHERE_DRAGGED: {

Vector p = SK.GetEntity(ptA)->PointGetDrawNum();

if(refs) refs->push_back(p);

Vector u = p.Plus(gu.WithMagnitude(8/camera.scale)).Plus(

gr.WithMagnitude(8/camera.scale)),

uu = u.Minus(gu.WithMagnitude(5/camera.scale)),

ur = u.Minus(gr.WithMagnitude(5/camera.scale));

// Draw four little crop marks, uniformly spaced (by ninety

// degree rotations) around the point.

int i;

for(i = 0; i < 4; i++) {

DoLine(canvas, hcs, u, uu);

DoLine(canvas, hcs, u, ur);

u = u.RotatedAbout(p, gn, PI/2);

ur = ur.RotatedAbout(p, gn, PI/2);

uu = uu.RotatedAbout(p, gn, PI/2);

}

return;

}

case Type::SAME_ORIENTATION: {

for(int i = 0; i < 2; i++) {

Entity *e = SK.GetEntity(i == 0 ? entityA : entityB);

Quaternion q = e->NormalGetNum();

Vector n = q.RotationN().WithMagnitude(25/camera.scale);

Vector u = q.RotationU().WithMagnitude(6/camera.scale);

Vector p = SK.GetEntity(e->point[0])->PointGetNum();

p = p.Plus(n.WithMagnitude(10/camera.scale));

if(refs) refs->push_back(p);

DoLine(canvas, hcs, p.Plus(u), p.Minus(u).Plus(n));

DoLine(canvas, hcs, p.Minus(u), p.Plus(u).Plus(n));

}

return;

}

case Type::EQUAL_ANGLE: {

Vector ref;

Entity *a = SK.GetEntity(entityA);

Entity *b = SK.GetEntity(entityB);

Entity *c = SK.GetEntity(entityC);

Entity *d = SK.GetEntity(entityD);

Vector a0 = a->VectorGetStartPoint();

Vector b0 = b->VectorGetStartPoint();

Vector c0 = c->VectorGetStartPoint();

Vector d0 = d->VectorGetStartPoint();

Vector da = a->VectorGetNum();

Vector db = b->VectorGetNum();

Vector dc = c->VectorGetNum();

Vector dd = d->VectorGetNum();

if(other) {

a0 = a0.Plus(da);

da = da.ScaledBy(-1);

}

DoArcForAngle(canvas, hcs, a0, da, b0, db,

da.WithMagnitude(40/camera.scale), &ref, /*trim=*/false, a->ExplodeOffset());

if(refs) refs->push_back(ref);

DoArcForAngle(canvas, hcs, c0, dc, d0, dd,

dc.WithMagnitude(40/camera.scale), &ref, /*trim=*/false, c->ExplodeOffset());

if(refs) refs->push_back(ref);

return;

}

case Type::ANGLE: {

Entity *a = SK.GetEntity(entityA);

Entity *b = SK.GetEntity(entityB);

Vector a0 = a->VectorGetStartPoint();

Vector b0 = b->VectorGetStartPoint();

Vector da = a->VectorGetNum();

Vector db = b->VectorGetNum();

if(other) {

a0 = a0.Plus(da);

da = da.ScaledBy(-1);

}

Vector ref;

DoArcForAngle(canvas, hcs, a0, da, b0, db, disp.offset, &ref, /*trim=*/true, a->ExplodeOffset());

DoLabel(canvas, hcs, ref, labelPos, gr, gu);

if(refs) refs->push_back(ref);

return;

}

case Type::PERPENDICULAR: {

Vector u = Vector::From(0, 0, 0), v = Vector::From(0, 0, 0);

Vector rn, ru;

if(workplane == Entity::FREE_IN_3D) {

rn = gn;

ru = gu;

} else {

EntityBase *normal = SK.GetEntity(workplane)->Normal();

rn = normal->NormalN();

ru = normal->NormalV(); // ru meaning r_up, not u/v

}

for(int i = 0; i < 2; i++) {

Entity *e = SK.GetEntity(i == 0 ? entityA : entityB);

if(i == 0) {

// Calculate orientation of perpendicular sign only

// once, so that it's the same both times it's drawn

u = e->VectorGetNum();

u = u.WithMagnitude(16/camera.scale);

v = (rn.Cross(u)).WithMagnitude(16/camera.scale);

// a bit of bias to stop it from flickering between the

// two possibilities

if(fabs(u.Dot(ru)) < fabs(v.Dot(ru)) + LENGTH_EPS) {

swap(u, v);

}

if(u.Dot(ru) < 0) u = u.ScaledBy(-1);

}

Vector p = e->VectorGetRefPoint().Plus(e->ExplodeOffset());

Vector s = p.Plus(u).Plus(v);

DoLine(canvas, hcs, s, s.Plus(v));

Vector m = s.Plus(v.ScaledBy(0.5));

DoLine(canvas, hcs, m, m.Plus(u));

if(refs) refs->push_back(m);

}

return;

}

case Type::CURVE_CURVE_TANGENT:

case Type::CUBIC_LINE_TANGENT:

case Type::ARC_LINE_TANGENT: {

Vector textAt, u, v;

if(type == Type::ARC_LINE_TANGENT) {

Entity *arc = SK.GetEntity(entityA);

Entity *norm = SK.GetEntity(arc->normal);

Vector c = SK.GetEntity(arc->point[0])->PointGetDrawNum();

Vector p =

SK.GetEntity(arc->point[other ? 2 : 1])->PointGetDrawNum();

Vector r = p.Minus(c);

textAt = p.Plus(r.WithMagnitude(14/camera.scale));

u = norm->NormalU();

v = norm->NormalV();

} else if(type == Type::CUBIC_LINE_TANGENT) {

Vector n;

if(workplane == Entity::FREE_IN_3D) {

u = gr;

v = gu;

n = gn;

} else {

EntityBase *wn = SK.GetEntity(workplane)->Normal();

u = wn->NormalU();

v = wn->NormalV();

n = wn->NormalN();

}

Entity *cubic = SK.GetEntity(entityA);

Vector p = other ? cubic->CubicGetFinishNum() :

cubic->CubicGetStartNum();

p = p.Plus(cubic->ExplodeOffset());

Vector dir = SK.GetEntity(entityB)->VectorGetNum();

Vector out = n.Cross(dir);

textAt = p.Plus(out.WithMagnitude(14/camera.scale));

} else {

Vector n, dir;

EntityBase *wn = SK.GetEntity(workplane)->Normal();

u = wn->NormalU();

v = wn->NormalV();

n = wn->NormalN();

Entity *eA = SK.GetEntity(entityA);

// Big pain; we have to get a vector tangent to the curve

// at the shared point, which could be from either a cubic

// or an arc.

if(other) {

textAt = eA->EndpointFinish().Plus(eA->ExplodeOffset());

if(eA->type == Entity::Type::CUBIC) {

dir = eA->CubicGetFinishTangentNum();

} else {

dir = SK.GetEntity(eA->point[0])->PointGetNum().Minus(

SK.GetEntity(eA->point[2])->PointGetNum());

dir = n.Cross(dir);

}

} else {

textAt = eA->EndpointStart().Plus(eA->ExplodeOffset());

if(eA->type == Entity::Type::CUBIC) {

dir = eA->CubicGetStartTangentNum();

} else {

dir = SK.GetEntity(eA->point[0])->PointGetNum().Minus(

SK.GetEntity(eA->point[1])->PointGetNum());

dir = n.Cross(dir);

}

}

dir = n.Cross(dir);

textAt = textAt.Plus(dir.WithMagnitude(14/camera.scale));

}

Vector ex = VectorFont::Builtin()->GetExtents(textHeight, "T");

canvas->DrawVectorText("T", textHeight, textAt.Minus(ex.ScaledBy(0.5)),

u.WithMagnitude(1), v.WithMagnitude(1), hcs);

if(refs) refs->push_back(textAt);

return;

}