1 // line.cpp: Line object
3 // Part of the Architektonas Project
4 // (C) 2011 Underground Software
5 // See the README and GPLv3 files for licensing and warranty information
7 // JLH = James Hammons <jlhamm@acm.org>
10 // --- ---------- ------------------------------------------------------------
11 // JLH 03/22/2011 Created this file
12 // JLH 04/11/2011 Fixed attached dimensions to stay at correct length when
13 // "Fixed Length" button is down
14 // JLH 04/27/2011 Fixed attached dimension to stay a correct length when
15 // "Fixed Length" button is *not* down ;-)
16 // JLH 05/29/2011 Added (some) mouseover hints
22 #include "container.h"
23 #include "dimension.h"
25 #include "mathconstants.h"
29 Line::Line(Vector p1, Vector p2, Object * p/*= NULL*/): Object(p1, p),
30 /*type(OTLine),*/ endpoint(p2),
31 draggingLine(false), draggingHandle1(false), draggingHandle2(false), //needUpdate(false),
32 length(Vector::Magnitude(p2, p1)), angle(Vector(endpoint - position).Unit()),
33 hitPoint1(false), hitPoint2(false), hitLine(false)
41 // Taking care of connections should be done by the Container, as we don't know
42 // anything about any other object connected to this one.
44 // If there are any attached Dimensions, we must set the attachment points
45 // to NULL since they will no longer be valid.
46 if (attachedDimension)
48 attachedDimension->SetPoint1(NULL);
49 attachedDimension->SetPoint2(NULL);
51 // IT WOULD BE NICE to have any object points attached to this line automagically
52 // connect to this dimension object at this point, instead of just becoming
55 //actually not true, we know the object pointer and parameter!
56 //actuall, the Object base class does this for us...!
58 std::vector<Connection>::iterator i;
60 for(i=connected.begin(); i!=connected.end(); i++)
62 (*i).object->Disconnect(this, (*i).t);
68 /*virtual*/ void Line::Draw(Painter * painter)
70 painter->SetPen(QPen(Qt::red, 2.0, Qt::DotLine));
72 if ((state == OSSelected) || ((state == OSInactive) && hitPoint1))
73 painter->DrawHandle(position);
75 if ((state == OSSelected) || ((state == OSInactive) && hitPoint2))
76 painter->DrawHandle(endpoint);
78 if ((state == OSInactive) && !hitLine)
79 painter->SetPen(QPen(Qt::black, 1.0, Qt::SolidLine));
81 if (Object::fixedLength && (draggingHandle1 || draggingHandle2))
83 Vector point1 = (draggingHandle1 ? endpoint : position);
84 Vector point2 = (draggingHandle1 ? position : endpoint);
86 Vector current(point2 - point1);
87 Vector v = current.Unit() * length;
88 Vector v2 = point1 + v;
89 painter->DrawLine(point1, v2);
91 if (current.Magnitude() > length)
93 painter->SetPen(QPen(QColor(128, 0, 0), 1.0, Qt::DashLine));
94 painter->DrawLine(v2, point2);
98 painter->DrawLine(position, endpoint);
100 // If we're dragging an endpoint, draw an information panel showing both
101 // the length and angle being set.
102 if (draggingHandle1 || draggingHandle2)
104 double absAngle = (Vector(endpoint - position).Angle()) * RADIANS_TO_DEGREES;
105 double absLength = Vector(position - endpoint).Magnitude();
107 QString text = QObject::tr("Length: %1 in.\n") + QChar(0x2221) + QObject::tr(": %2");
108 text = text.arg(absLength).arg(absAngle);
109 painter->DrawInformativeText(text);
113 /*virtual*/ Vector Line::Center(void)
115 // Technically, this is the midpoint but who are we to quibble? :-)
116 Vector v((position.x - endpoint.x) / 2.0, (position.y - endpoint.y) / 2.0);
120 /*virtual*/ bool Line::Collided(Vector point)
123 what we can do here is set ignoreClicks to true to keep other objects that are
124 selected from deselecting themselves. Will that fuck up something else? Not sure
126 Actually, this is done here to keep tools from selecting stuff inadvertantly...
128 // We can assume this, since this is a mouse down event here.
129 objectWasDragged = false;
130 bool hit = HitTest(point);
132 // Someone told us to fuck off, so we'll fuck off. :-)
137 // Now that we've done our hit testing on the non-snapped point, snap it if
140 point = SnapPointToGrid(point);
142 // this is shite. this should be checked for in the Container, not here!
143 #warning "!!! This should be checked for in Container, not here !!!"
144 // If we're part of a non-top-level container, send this signal to it
145 if (parent->type == OTContainer && !((Container *)parent)->isTopLevelContainer
146 && (hitLine || hitPoint1 || hitPoint2))
148 parent->state = OSSelected;
153 There's a small problem here with the implementation: You can have a dimension tied
154 to only one point while at the same time you can have a dimension sitting on this line.
155 Since there's only *one* dimPoint for each point, this can be problematic...
157 We solve this by allowing only *one* Dimension object to be attached to the Line,
158 Arc, etc. and by giving the Dimension object a pointer to our endpoints.
160 Problem still arises when we delete this object; The attached Dimension object will
161 then have bad pointers! What it *should* do is delete the object if and only if this
162 line is not attached to any other object. If it is, then one of those attachment
163 points should be sent to the dimension object (done for position & endpoint).
165 NOTE: The STL vector<T> *does not* take ownership of pointers, therefore is suitable
168 Also: It would be nice to have a preview of the dimension being drawn, with a modifier
169 key to make it draw/show on the other side...
171 TODO: Make Dimension preview with modifier keys for showing on other side
175 N.B.: This no longer works, as the DrawDimension object takes precedence over this code.
176 THIS DOES NOTHING ANYMORE!!!
180 // Is the dimension tool active? Let's use it:
183 // User clicked on the line itself (endpoint checks should preceed this one):
184 // (Priorities are taken care of in HitTest()...)
188 if (attachedDimension == NULL)
190 // How to get this object into the top level container???
192 The real question is do we care. I think so, because if this isn't in the top
193 level container, it won't get drawn...
194 But we can fix that by making this object call any attached object's (like
195 a dimension only) Draw() function... :-/
197 attachedDimension = new Dimension(&position, &endpoint, DTLinear, this);
200 parent->Add(attachedDimension);
204 // If there's one already there, tell it to flip sides...
205 attachedDimension->FlipSides();
208 // New approach here: We look for connected objects.
209 Object * attachedDimension = FindAttachedDimension();
211 if (attachedDimension)
213 // If there's an attached Dimension, tell it to switch sides...
214 ((Dimension *)attachedDimension)->FlipSides();
218 // Otherwise, we make a new one and attach it here.
219 attachedDimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
220 connected.push_back(Connection(attachedDimension, 0));
221 connected.push_back(Connection(attachedDimension, 1.0));
224 parent->Add(attachedDimension);
233 if (state == OSInactive)
235 //How to translate this into pixels from Document space???
236 //Maybe we need to pass a scaling factor in here from the caller? That would
237 //make sense, as the caller knows about the zoom factor and all that good kinda
239 //I think what's needed is an Object class variable/method that can be changed
240 //by the TLC and called in derived classes to properly scale the location to
241 //the current zoom level. That *should* work.
243 // ALSO: Need to code a global (read: Object class) variable that tells use
244 // whether a modifier key was pressed in addition to the mouse click, so
245 // we can do stuff like, say, hold down CTRL and be able to do multiple
246 // selecting of objects (in that case, we would keep the Object state
253 draggingHandle1 = true;
261 draggingHandle2 = true;
273 else if (state == OSSelected)
278 // state = OSInactive;
282 // Toggle selected state if CTRL held
283 if (qApp->keyboardModifiers() == Qt::ControlModifier)
290 // If CTRL is held, then we bypass the "turn off" code. Still didn't hit
291 // *this* object though. :-)
292 if (qApp->keyboardModifiers() == Qt::ControlModifier)
295 // If we got here, we clicked on nothing, so set the object to inactive.
296 // (Once we can read key modifiers, we can override this to allow multiple selection.)
302 /*virtual*/ bool Line::PointerMoved(Vector point)
304 if (selectionInProgress)
306 // Check for whether or not the rect contains this line
307 if (selection.contains(position.x, position.y)
308 && selection.contains(endpoint.x, endpoint.y))
316 // Hit test tells us what we hit (if anything) through boolean variables. (It
317 // also tells us whether or not the state changed. --not any more)
319 bool hovered = HitTest(point);
320 needUpdate = HitStateChanged();
322 objectWasDragged = (draggingLine | draggingHandle1 | draggingHandle2);
324 if (objectWasDragged)
326 Vector delta = point - oldPoint;
328 if (draggingHandle1 || draggingLine)
331 if (draggingHandle2 || draggingLine)
337 //doesn't work QMainWindow::statusBar()->setText("You are manipulating a line");
339 // Tell connected objects to move themselves...
342 std::vector<Connection>::iterator i;
344 for(i=connected.begin(); i!=connected.end(); i++)
346 if ((*i).object->type == OTLine)
347 ((Line *)((*i).object))->MovePointAtParameter((*i).t, delta);
348 else if ((*i).object->type == OTDimension)
349 ((Dimension *)((*i).object))->MovePointAtParameter((*i).t, delta);
355 We can't count on any coupling between the dimension object and us, so how do we do this???
356 Also, there may be more than one Dimension object connected to a single endpoint!
359 - Keep track of the state of the connected dimension
360 - Pass the Dimension the point that's being changed and the delta
363 - Pass the point in a notification function (how?)
364 - Pass the point as a reference to the class instance object (&endpoint). This
365 way, the line doesn't have to care about keeping track of Dimensions
366 connected to it. But still have to care about other connected entities
367 (other Lines, Circles, Arcs, Splines, Texts, etc). I think I'd be OK with
368 this. Since the Dimension has a pointer to our object, all we have to do is
369 update our coordinates and the Dimension object will adjust itself on the
370 next repaint. Problem solved, and we don't have to know anything about how
371 many Dimensions are connected to us, or where! \o/
372 The question then becomes, how do we do this kind of coupling???
374 We need to know about connected entities so that we can have them either move
375 in expected ways or constrain the movement of this Line object. This is how we
376 will be a cut above all other CAD software currently out there: the GUI will
377 try to do the right thing, most of the time. :-)
381 // should only do this if "Fixed Length" is set... !!! FIX !!! [DONE]
382 Vector point1 = (draggingHandle1 ? endpoint : position);
383 Vector point2 = (draggingHandle1 ? position : endpoint);
385 if (Object::fixedAngle)
387 // Here we calculate the component of the current vector along the fixed angle.
388 // A_compB = (A . Bu) * Bu
389 double magnitudeAlongB = Vector::Dot(Vector(point2 - point1), angle);
391 Actually, this isn't quite right. What we want to do is look for the intersection along either
392 the horizontal line or vertical line that intersects from the current mouse position.
396 position = endpoint + (angle * magnitudeAlongB);
399 endpoint = position + (angle * magnitudeAlongB);
404 //If we tell the dimension to flip sides, this is no longer a valid
405 //assumption. !!! FIX !!!
406 //Ideally, we should just send the point that's changing to the Dimension object
407 //and have it figure out which point needs to move... Or is it???
408 // Ideally, we shouldn't have to fuck around with this shit. We need to fix the rendering code
409 // so that we don't have to wait until the dragging is done to correct the position of the
410 // point in question, but we'd need another variable tho.
413 dimPoint1->SetPoint1(draggingHandle1 ? v2 : position);
416 dimPoint2->SetPoint2(draggingHandle2 ? v2 : endpoint);
424 /*virtual*/ void Line::PointerReleased(void)
426 if (draggingHandle1 || draggingHandle2)
428 // Set the length (in case the global state was set to fixed (or not))
429 if (Object::fixedLength)
431 if (draggingHandle1) // startpoint
433 Vector v = Vector(position - endpoint).Unit() * length;
434 position = endpoint + v;
438 Vector v = Vector(endpoint - position).Unit() * length;
439 endpoint = position + v;
444 // Otherwise, we calculate the new length, just in case on the next
445 // move it turns out to have a fixed length. :-)
446 length = Vector(endpoint - position).Magnitude();
449 if (!Object::fixedAngle)
451 // Calculate the new angle, just in case on the next move it turns
452 // out to be fixed. :-)
453 angle = Vector(endpoint - position).Unit();
457 draggingLine = false;
458 draggingHandle1 = false;
459 draggingHandle2 = false;
461 if (objectWasDragged)
466 /*virtual*/ bool Line::HitTest(Point point)
468 hitPoint1 = hitPoint2 = hitLine = false;
469 Vector lineSegment = endpoint - position;
470 Vector v1 = point - position;
471 Vector v2 = point - endpoint;
472 double t = Geometry::ParameterOfLineAndPoint(position, endpoint, point);
475 // Geometric interpretation of "distance = ?Det?(ls, v1) / |ls|":
476 // If the segment endpoints are s and e, and the point is p, then the test
477 // for the perpendicular intercepting the segment is equivalent to insisting
478 // that the two dot products {s-e}.{s-p} and {e-s}.{e-p} are both non-negative.
479 // Perpendicular distance from the point to the segment is computed by first
480 // computing the area of the triangle the three points form, then dividing by
481 // the length of the segment. Distances are done just by the Pythagorean
482 // theorem. Twice the area of the triangle formed by three points is the
483 // determinant of the following matrix:
485 // sx sy 1 0 0 1 0 0 0
486 // ex ey 1 ==> ex ey 1 ==> ex ey 0
487 // px py 1 px py 1 px py 0
489 // By translating the start point to the origin, and subtracting row 1 from
490 // all other rows, we end up with the matrix on the right which greatly
491 // simplifies the calculation of the determinant.
494 distance = v1.Magnitude();
496 distance = v2.Magnitude();
498 // distance = ?Det?(ls, v1) / |ls|
499 distance = fabs((lineSegment.x * v1.y - v1.x * lineSegment.y)
500 / lineSegment.Magnitude());
502 if ((v1.Magnitude() * Painter::zoom) < 8.0)
504 else if ((v2.Magnitude() * Painter::zoom) < 8.0)
506 else if ((distance * Painter::zoom) < 5.0)
509 return (hitPoint1 || hitPoint2 || hitLine ? true : false);
513 // Check to see if the point passed in coincides with any we have. If so, return a
514 // pointer to it; otherwise, return NULL.
515 /*virtual*/ Vector * Line::GetPointAt(Vector v)
519 else if (v == endpoint)
526 /*virtual*/ void Line::Enumerate(FILE * file)
528 fprintf(file, "LINE %i (%lf,%lf) (%lf,%lf)\n", layer, position.x, position.y, endpoint.x, endpoint.y);
532 /*virtual*/ Object * Line::Copy(void)
534 #warning "!!! This doesn't take care of attached Dimensions !!!"
536 This is a real problem. While having a pointer in the Dimension to this line's points
537 is fast & easy, it creates a huge problem when trying to replicate an object like this.
539 Maybe a way to fix that then, is to have reference numbers instead of pointers. That
540 way, if you copy them, ... you might still have problems. Because you can't be sure if
541 a copy will be persistant or not, you then *definitely* do not want them to have the
542 same reference number.
544 return new Line(position, endpoint, parent);
548 /*virtual*/ Vector Line::GetPointAtParameter(double parameter)
550 // Is there any real reason to clamp this to the endpoints?
551 // (hey, whaddya know? this was masking a bug!)
555 else if (parameter >= 1.0)
559 // The parameter is a percentage of the length of the vector, so all we
560 // have to do is scale the vector by it to find the point.
561 return position + (Vector(position, endpoint) * parameter);
565 /*virtual*/ void Line::MovePointAtParameter(double parameter, Vector v)
569 else if (parameter == 1.0)
572 {} // Not sure how to handle this case :-P
576 /*virtual*/ QRectF Line::Extents(void)
578 QRectF rect(QPointF(position.x, position.y), QPointF(endpoint.x, endpoint.y));
579 return rect.normalized();
583 /*virtual*/ void Line::Translate(Vector amount)
590 /*virtual*/ void Line::Rotate(Point point, double angle)
592 Point l1 = Geometry::RotatePointAroundPoint(position, point, angle);
593 Point l2 = Geometry::RotatePointAroundPoint(endpoint, point, angle);
599 /*virtual*/ void Line::Scale(Point point, double amount)
604 /*virtual*/ void Line::Mirror(Point p1, Point p2)
606 Point l1 = Geometry::MirrorPointAroundLine(position, p1, p2);
607 Point l2 = Geometry::MirrorPointAroundLine(endpoint, p1, p2);
613 /*virtual*/ void Line::Save(void)
616 oldEndpoint = endpoint;
620 /*virtual*/ void Line::Restore(void)
623 endpoint = oldEndpoint;
627 void Line::SetDimensionOnLine(Dimension * dimension/*= NULL*/)
629 // If they don't pass one in, create it for the caller.
630 // But ONLY if this line has a parent container!
631 // This is really bad to do here, it should be done in the parent container, always!
632 #warning "!!! Parent container should be creating Dimension object !!!"
633 if ((dimension == NULL) && (parent != NULL))
635 //printf("Line::SetDimensionOnLine(): Creating new dimension...\n");
636 dimension = new Dimension(position, endpoint, DTLinear, parent);
637 // dimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
639 // THIS IS SERIOUS!!! WITHOUT A PARENT, THIS OBJECT IS IN LIMBO!!!
642 //printf("Line::SetDimensionOnLine(): Adding to parent...\n");
643 parent->Add(dimension);
647 dimension->Connect(this, 0);
648 dimension->Connect(this, 1.0);
650 // Make sure the Dimension is connected to us...
651 Connect(dimension, 0);
652 Connect(dimension, 1.0);
654 dimension->position = position;
655 dimension->endpoint = endpoint;
659 Object * Line::FindAttachedDimension(void)
661 // Is there anything connected to this line? If not, return NULL
662 if (connected.size() < 2)
665 // Otherwise, we have to search our objects to see if there's a likely
666 // candidate. In this case, we're looking for a pointer to the same object
667 // with a parameter of 0 and 1 respectively. This is O((n^2)/2).
668 for(uint i=0; i<connected.size(); i++)
670 for(uint j=i+1; j<connected.size(); j++)
672 //printf("Line: connected[i]=%X, connected[j]=%X, connected[i].t=%lf, connected[j].t=%lf\n", connected[i].object, connected[j].object, connected[i].t, connected[j].t);
673 if ((connected[i].object == connected[j].object)
674 && ((connected[i].t == 0 && connected[j].t == 1.0)
675 || (connected[i].t == 1.0 && connected[j].t == 0)))
676 return connected[i].object;
680 // Didn't find anything, so return NULL
685 void Line::SaveHitState(void)
687 oldHitPoint1 = hitPoint1;
688 oldHitPoint2 = hitPoint2;
689 oldHitLine = hitLine;
693 bool Line::HitStateChanged(void)
695 if ((hitPoint1 != oldHitPoint1) || (hitPoint2 != oldHitPoint2) || (hitLine != oldHitLine))
703 Intersection of two lines:
705 Find where the lines with equations r = i + j + t (3i - j) and r = -i + s (j) intersect.
707 When they intersect, we can set the equations equal to one another:
709 i + j + t (3i - j) = -i + s (j)
711 Equating coefficients:
712 1 + 3t = -1 and 1 - t = s
713 So t = -2/3 and s = 5/3
715 The position vector of the intersection point is therefore given by putting t = -2/3 or s = 5/3 into one of the above equations. This gives -i +5j/3 .
718 so, let's say we have two lines, l1 and l2. Points are v0(p0x, p0y), v1(p1x, p1y) for l1
719 and v2(p2x, p2y), v3(p3x, p3y) for l2.
721 d1 = v1 - v0, d2 = v3 - v2
723 Our parametric equations for the line then are:
728 Set r1 = r2, thus we have:
730 v0 + t(d1) = v2 + s(d2)
732 Taking coefficients, we have:
734 p0x + t(d1x) = p2x + s(d2x)
735 p0y + t(d1y) = p2y + s(d2y)
739 t(d1x) - s(d2x) = p2x - p0x
740 t(d1y) - s(d2y) = p2y - p0y
742 Determinant D is ad - bc where the matrix looks like:
747 so D = (d1x)(d2y) - (d2x)(d1y)
748 if D = 0, the lines are parallel.
749 Dx = (p2x - p0x)(d2y) - (d2x)(p2y - p0y)
750 Dy = (d1x)(p2y - p0y) - (p2x - p0x)(d1y)
753 We only need to calculate t, as we can then multiply it by d1 to get the intersection point.
755 ---------------------------------------------------------------------------------------------------
757 The first and most preferred method for intersection calculation is the perp-product calculation. There are two vectors, v1 and v2. Create a third vector vector between the starting points of these vectors, and calculate the perp product of v2 and the two other vectors. These two scalars have to be divided to get the mulitplication ratio of v1 to reach intersection point. So:
763 Perp product is equal with dot product of normal of first vector and the second vector, so we need normals:
770 dp1 = n3 . v2 = -by3 * bx2 + bx3 * by2;
771 dp2 = n1 . v2 = -by1 * bx2 + bx1 * by2;
774 crossing vector = v1 * ratio;
778 -----------------------------------
780 So... to code this, let's say we have two Lines: l1 & l2.
782 Vector v1 = l1.endpoint - l1.position;
783 Vector v2 = l2.endpoint - l2.position;
786 Vector normal1(-v1.y, v1.x);
787 Vector normal3(-v3.y, v3.x);
789 double dotProduct1 = v2.Dot(normal1);
790 double dotProduct2 = v2.Dot(normal3);
792 if (dotProduct2 == 0)
793 return ParallelLines;
796 // I think we'd still have to add the intersection to the position point to get the intersection...
797 Point intersection = v1 * (dotProduct1 / dotProduct2);