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"
24 #include "mathconstants.h"
28 Line::Line(Vector p1, Vector p2, Object * p/*= NULL*/): Object(p1, p),
29 /*type(OTLine),*/ endpoint(p2),
30 draggingLine(false), draggingHandle1(false), draggingHandle2(false), //needUpdate(false),
31 length(Vector::Magnitude(p2, p1)), angle(Vector(endpoint - position).Unit()),
32 hitPoint1(false), hitPoint2(false), hitLine(false)
40 // Taking care of connections should be done by the Container, as we don't know
41 // anything about any other object connected to this one.
43 // If there are any attached Dimensions, we must set the attachment points
44 // to NULL since they will no longer be valid.
45 if (attachedDimension)
47 attachedDimension->SetPoint1(NULL);
48 attachedDimension->SetPoint2(NULL);
50 // IT WOULD BE NICE to have any object points attached to this line automagically
51 // connect to this dimension object at this point, instead of just becoming
57 /*virtual*/ void Line::Draw(Painter * painter)
59 painter->SetPen(QPen(Qt::red, 2.0, Qt::DotLine));
61 if ((state == OSSelected) || ((state == OSInactive) && hitPoint1))
62 painter->DrawHandle(position);
64 if ((state == OSSelected) || ((state == OSInactive) && hitPoint2))
65 painter->DrawHandle(endpoint);
67 if ((state == OSInactive) && !hitLine)
68 painter->SetPen(QPen(Qt::black, 1.0, Qt::SolidLine));
70 if (Object::fixedLength && (draggingHandle1 || draggingHandle2))
72 Vector point1 = (draggingHandle1 ? endpoint : position);
73 Vector point2 = (draggingHandle1 ? position : endpoint);
75 Vector current(point2 - point1);
76 Vector v = current.Unit() * length;
77 Vector v2 = point1 + v;
78 painter->DrawLine(point1, v2);
80 if (current.Magnitude() > length)
82 painter->SetPen(QPen(QColor(128, 0, 0), 1.0, Qt::DashLine));
83 painter->DrawLine(v2, point2);
87 painter->DrawLine(position, endpoint);
89 // If we're dragging an endpoint, draw an information panel showing both
90 // the length and angle being set.
91 if (draggingHandle1 || draggingHandle2)
93 double absAngle = (Vector(endpoint - position).Angle()) * RADIANS_TO_DEGREES;
94 double absLength = Vector(position - endpoint).Magnitude();
98 text = QObject::tr("Length: %1 in.\n") + QChar(0x2221) + QObject::tr(": %2");
99 text = text.arg(absLength).arg(absAngle);
101 QPen pen = QPen(QColor(0x00, 0xFF, 0x00), 1.0, Qt::SolidLine);
102 painter->SetPen(pen);
103 painter->SetBrush(QBrush(QColor(0x40, 0xFF, 0x40, 0x9F)));
104 QRectF textRect(10.0, 10.0, 270.0, 70.0); // x, y, w, h (in Qt coords)
105 painter->DrawRoundedRect(textRect, 7.0, 7.0);
107 textRect.setLeft(textRect.left() + 14);
108 painter->SetFont(*Object::font);
109 pen = QPen(QColor(0x00, 0x5F, 0xDF));
110 painter->SetPen(pen);
111 painter->DrawText(textRect, Qt::AlignVCenter, text);
115 /*virtual*/ Vector Line::Center(void)
117 // Technically, this is the midpoint but who are we to quibble? :-)
118 Vector v((position.x - endpoint.x) / 2.0, (position.y - endpoint.y) / 2.0);
122 /*virtual*/ bool Line::Collided(Vector point)
124 // We can assume this, since this is a mouse down event here.
125 objectWasDragged = false;
128 // Now that we've done our hit testing on the non-snapped point, snap it if
131 point = SnapPointToGrid(point);
133 // this is shite. this should be checked for in the Container, not here!
134 #warning "!!! This should be checked for in Container, not here !!!"
135 // If we're part of a non-top-level container, send this signal to it
136 if (parent->type == OTContainer && !((Container *)parent)->isTopLevelContainer
137 && (hitLine || hitPoint1 || hitPoint2))
139 parent->state = OSSelected;
144 There's a small problem here with the implementation: You can have a dimension tied
145 to only one point while at the same time you can have a dimension sitting on this line.
146 Since there's only *one* dimPoint for each point, this can be problematic...
148 We solve this by allowing only *one* Dimension object to be attached to the Line,
149 Arc, etc. and by giving the Dimension object a pointer to our endpoints.
151 Problem still arises when we delete this object; The attached Dimension object will
152 then have bad pointers! What it *should* do is delete the object if and only if this
153 line is not attached to any other object. If it is, then one of those attachment
154 points should be sent to the dimension object (done for position & endpoint).
156 NOTE: The STL vector<T> *does not* take ownership of pointers, therefore is suitable
159 Also: It would be nice to have a preview of the dimension being drawn, with a modifier
160 key to make it draw/show on the other side...
162 TODO: Make Dimension preview with modifier keys for showing on other side
164 // Is the dimension tool active? Let's use it:
167 // User clicked on the line itself (endpoint checks should preceed this one):
168 // (Priorities are taken care of in HitTest()...)
172 if (attachedDimension == NULL)
174 // How to get this object into the top level container???
176 The real question is do we care. I think so, because if this isn't in the top
177 level container, it won't get drawn...
178 But we can fix that by making this object call any attached object's (like
179 a dimension only) Draw() function... :-/
181 attachedDimension = new Dimension(&position, &endpoint, DTLinear, this);
184 parent->Add(attachedDimension);
188 // If there's one already there, tell it to flip sides...
189 attachedDimension->FlipSides();
192 // New approach here: We look for connected objects.
193 Object * attachedDimension = FindAttachedDimension();
195 if (attachedDimension)
197 // If there's an attached Dimension, tell it to switch sides...
198 ((Dimension *)attachedDimension)->FlipSides();
202 // Otherwise, we make a new one and attach it here.
203 attachedDimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
204 connected.push_back(Connection(attachedDimension, 0));
205 connected.push_back(Connection(attachedDimension, 1.0));
208 parent->Add(attachedDimension);
216 if (state == OSInactive)
218 //How to translate this into pixels from Document space???
219 //Maybe we need to pass a scaling factor in here from the caller? That would
220 //make sense, as the caller knows about the zoom factor and all that good kinda
222 //I think what's needed is an Object class variable/method that can be changed
223 //by the TLC and called in derived classes to properly scale the location to
224 //the current zoom level. That *should* work.
226 // ALSO: Need to code a global (read: Object class) variable that tells use
227 // whether a modifier key was pressed in addition to the mouse click, so
228 // we can do stuff like, say, hold down CTRL and be able to do multiple
229 // selecting of objects (in that case, we would keep the Object state
236 draggingHandle1 = true;
244 draggingHandle2 = true;
256 else if (state == OSSelected)
261 // state = OSInactive;
265 // Toggle selected state if CTRL held
266 if (qApp->keyboardModifiers() == Qt::ControlModifier)
273 // If CTRL is held, then we bypass the "turn off" code. Still didn't hit
274 // *this* object though. :-)
275 if (qApp->keyboardModifiers() == Qt::ControlModifier)
278 // If we got here, we clicked on nothing, so set the object to inactive.
279 // (Once we can read key modifiers, we can override this to allow multiple selection.)
285 /*virtual*/ void Line::PointerMoved(Vector point)
287 if (selectionInProgress)
289 // Check for whether or not the rect contains this line
291 if (selection.normalized().contains(Extents()))
293 // if (selection.normalized().contains(position.x, position.y)
294 // && selection.normalized().contains(endpoint.x, endpoint.y))
295 if (selection.contains(position.x, position.y)
296 && selection.contains(endpoint.x, endpoint.y))
305 // Hit test tells us what we hit (if anything) through boolean variables. (It
306 // also tells us whether or not the state changed. --not any more)
309 needUpdate = HitStateChanged();
311 objectWasDragged = (draggingLine | draggingHandle1 | draggingHandle2);
313 if (objectWasDragged)
315 Vector delta = point - oldPoint;
317 if (draggingHandle1 || draggingLine)
320 if (draggingHandle2 || draggingLine)
326 //doesn't work QMainWindow::statusBar()->setText("You are manipulating a line");
330 We can't count on any coupling between the dimension object and us, so how do we do this???
331 Also, there may be more than one Dimension object connected to a single endpoint!
334 - Keep track of the state of the connected dimension
335 - Pass the Dimension the point that's being changed and the delta
338 - Pass the point in a notification function (how?)
339 - Pass the point as a reference to the class instance object (&endpoint). This
340 way, the line doesn't have to care about keeping track of Dimensions
341 connected to it. But still have to care about other connected entities
342 (other Lines, Circles, Arcs, Splines, Texts, etc). I think I'd be OK with
343 this. Since the Dimension has a pointer to our object, all we have to do is
344 update our coordinates and the Dimension object will adjust itself on the
345 next repaint. Problem solved, and we don't have to know anything about how
346 many Dimensions are connected to us, or where! \o/
347 The question then becomes, how do we do this kind of coupling???
349 We need to know about connected entities so that we can have them either move
350 in expected ways or constrain the movement of this Line object. This is how we
351 will be a cut above all other CAD software currently out there: the GUI will
352 try to do the right thing, most of the time. :-)
356 // should only do this if "Fixed Length" is set... !!! FIX !!! [DONE]
357 Vector point1 = (draggingHandle1 ? endpoint : position);
358 Vector point2 = (draggingHandle1 ? position : endpoint);
360 if (Object::fixedAngle)
362 // Here we calculate the component of the current vector along the fixed angle.
363 // A_compB = (A . Bu) * Bu
364 double magnitudeAlongB = Vector::Dot(Vector(point2 - point1), angle);
366 Actually, this isn't quite right. What we want to do is look for the intersection along either
367 the horizontal line or vertical line that intersects from the current mouse position.
371 position = endpoint + (angle * magnitudeAlongB);
374 endpoint = position + (angle * magnitudeAlongB);
379 //If we tell the dimension to flip sides, this is no longer a valid
380 //assumption. !!! FIX !!!
381 //Ideally, we should just send the point that's changing to the Dimension object
382 //and have it figure out which point needs to move... Or is it???
383 // Ideally, we shouldn't have to fuck around with this shit. We need to fix the rendering code
384 // so that we don't have to wait until the dragging is done to correct the position of the
385 // point in question, but we'd need another variable tho.
388 dimPoint1->SetPoint1(draggingHandle1 ? v2 : position);
391 dimPoint2->SetPoint2(draggingHandle2 ? v2 : endpoint);
397 /*virtual*/ void Line::PointerReleased(void)
399 if (draggingHandle1 || draggingHandle2)
401 // Set the length (in case the global state was set to fixed (or not))
402 if (Object::fixedLength)
404 if (draggingHandle1) // startpoint
406 Vector v = Vector(position - endpoint).Unit() * length;
407 position = endpoint + v;
411 Vector v = Vector(endpoint - position).Unit() * length;
412 endpoint = position + v;
417 // Otherwise, we calculate the new length, just in case on the next
418 // move it turns out to have a fixed length. :-)
419 length = Vector(endpoint - position).Magnitude();
422 if (!Object::fixedAngle)
424 // Calculate the new angle, just in case on the next move it turns
425 // out to be fixed. :-)
426 angle = Vector(endpoint - position).Unit();
430 draggingLine = false;
431 draggingHandle1 = false;
432 draggingHandle2 = false;
434 if (objectWasDragged)
439 /*virtual*/ bool Line::HitTest(Point point)
443 hitPoint1 = hitPoint2 = hitLine = false;
444 Vector lineSegment = endpoint - position;
445 Vector v1 = point - position;
446 Vector v2 = point - endpoint;
447 double t = Vector::Parameter(position, endpoint, point);
450 // Geometric interpretation:
451 // The parameter "t" on the vector lineSegment is where the normal of
452 // lineSegment coincides with point. If t < 0, the normal lies beyond the
453 // 1st endpoint. If t > 1, then the normal lies beyond the 2nd endpoint. We
454 // only calculate the length of the normal between the point and the
455 // lineSegment when the parameter is between 0 and 1.
457 // Geometric interpretation of "distance = ?Det?(ls, v1) / |ls|":
458 // If the segment endpoints are s and e, and the point is p, then the test
459 // for the perpendicular intercepting the segment is equivalent to insisting
460 // that the two dot products {s-e}.{s-p} and {e-s}.{e-p} are both non-negative.
461 // Perpendicular distance from the point to the segment is computed by first
462 // computing the area of the triangle the three points form, then dividing by
463 // the length of the segment. Distances are done just by the Pythagorean
464 // theorem. Twice the area of the triangle formed by three points is the
465 // determinant of the following matrix:
467 // sx sy 1 0 0 1 0 0 0
468 // ex ey 1 ==> ex ey 1 ==> ex ey 0
469 // px py 1 px py 1 px py 0
471 // By translating the start point to the origin, and subtracting row 1 from
472 // all other rows, we end up with the matrix on the right which greatly
473 // simplifies the calculation of the determinant.
476 distance = v1.Magnitude();
478 distance = v2.Magnitude();
480 // distance = ?Det?(ls, v1) / |ls|
481 distance = fabs((lineSegment.x * v1.y - v1.x * lineSegment.y)
482 / lineSegment.Magnitude());
484 if ((v1.Magnitude() * Painter::zoom) < 8.0)
486 else if ((v2.Magnitude() * Painter::zoom) < 8.0)
488 else if ((distance * Painter::zoom) < 5.0)
491 return (hitPoint1 || hitPoint2 || hitLine ? true : false);
492 // return HitStateChanged();
496 // Check to see if the point passed in coincides with any we have. If so, return a
497 // pointer to it; otherwise, return NULL.
498 /*virtual*/ Vector * Line::GetPointAt(Vector v)
502 else if (v == endpoint)
509 /*virtual*/ void Line::Enumerate(FILE * file)
511 fprintf(file, "LINE (%lf,%lf) (%lf,%lf)\n", position.x, position.y, endpoint.x, endpoint.y);
515 /*virtual*/ Object * Line::Copy(void)
517 #warning "!!! This doesn't take care of attached Dimensions !!!"
519 This is a real problem. While having a pointer in the Dimension to this line's points
520 is fast & easy, it creates a huge problem when trying to replicate an object like this.
522 Maybe a way to fix that then, is to have reference numbers instead of pointers. That
523 way, if you copy them, ... you might still have problems. Because you can't be sure if
524 a copy will be persistant or not, you then *definitely* do not want them to have the
525 same reference number.
527 return new Line(position, endpoint, parent);
531 /*virtual*/ Vector Line::GetPointAtParameter(double parameter)
535 else if (parameter >= 1.0)
538 // Our parameter lies between zero and one, so calculate it!
539 Vector v(endpoint, position);
540 double length = v.Magnitude();
541 // We scale the magnitude of v so that it lies between 0 and 1...
542 // By multiplying the parameter by the magnitude, we obtain the point we
543 // want. No scaling necessary as it's inherent in the approach!
544 double spotOnLength = length * parameter;
546 // To get our point, we use the initial point of the line and add in our
548 Vector result = position + (v * spotOnLength);
553 /*virtual*/ QRectF Line::Extents(void)
555 QRectF rect(QPointF(position.x, position.y), QPointF(endpoint.x, endpoint.y));
556 return rect.normalized();
560 /*virtual*/ void Line::Translate(Vector amount)
567 /*virtual*/ void Line::Rotate(Vector point, double angle)
572 /*virtual*/ void Line::Scale(Vector point, double amount)
577 void Line::SetDimensionOnLine(Dimension * dimension/*=NULL*/)
579 // If they don't pass one in, create it for the caller.
580 if (dimension == NULL)
582 //printf("Line::SetDimensionOnLine(): Creating new dimension...\n");
583 // dimension = new Dimension(position, endpoint, DTLinear, this);
584 dimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
588 //printf("Line::SetDimensionOnLine(): Adding to parent...\n");
589 parent->Add(dimension);
594 dimension->Connect(this, 0);
595 dimension->Connect(this, 1.0);
598 // Make sure the Dimension is connected to us...
599 Connect(dimension, 0);
600 Connect(dimension, 1.0);
604 Object * Line::FindAttachedDimension(void)
606 // Is there anything connected to this line? If not, return NULL
607 if (connected.size() < 2)
610 // Otherwise, we have to search our objects to see if there's a likely
611 // candidate. In this case, we're looking for a pointer to the same object
612 // with a parameter of 0 and 1 respectively. This is O((n^2)/2).
613 for(uint i=0; i<connected.size(); i++)
615 for(uint j=i+1; j<connected.size(); j++)
617 //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);
618 if ((connected[i].object == connected[j].object)
619 && ((connected[i].t == 0 && connected[j].t == 1.0)
620 || (connected[i].t == 1.0 && connected[j].t == 0)))
621 return connected[i].object;
625 // Didn't find anything, so return NULL
630 void Line::SaveHitState(void)
632 oldHitPoint1 = hitPoint1;
633 oldHitPoint2 = hitPoint2;
634 oldHitLine = hitLine;
638 bool Line::HitStateChanged(void)
640 if ((hitPoint1 != oldHitPoint1) || (hitPoint2 != oldHitPoint2) || (hitLine != oldHitLine))
648 Intersection of two lines:
650 Find where the lines with equations r = i + j + t (3i - j) and r = -i + s (j) intersect.
652 When they intersect, we can set the equations equal to one another:
654 i + j + t (3i - j) = -i + s (j)
656 Equating coefficients:
657 1 + 3t = -1 and 1 - t = s
658 So t = -2/3 and s = 5/3
660 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 .
663 so, let's say we have two lines, l1 and l2. Points are v0(p0x, p0y), v1(p1x, p1y) for l1
664 and v2(p2x, p2y), v3(p3x, p3y) for l2.
666 d1 = v1 - v0, d2 = v3 - v2
668 Our parametric equations for the line then are:
673 Set r1 = r2, thus we have:
675 v0 + t(d1) = v2 + s(d2)
677 Taking coefficients, we have:
679 p0x + t(d1x) = p2x + s(d2x)
680 p0y + t(d1y) = p2y + s(d2y)
684 t(d1x) - s(d2x) = p2x - p0x
685 t(d1y) - s(d2y) = p2y - p0y
687 Determinant D is ad - bc where the matrix looks like:
692 so D = (d1x)(d2y) - (d2x)(d1y)
693 if D = 0, the lines are parallel.
694 Dx = (p2x - p0x)(d2y) - (d2x)(p2y - p0y)
695 Dy = (d1x)(p2y - p0y) - (p2x - p0x)(d1y)
698 We only need to calculate t, as we can then multiply it by d1 to get the intersection point.
700 ---------------------------------------------------------------------------------------------------
702 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:
708 Perp product is equal with dot product of normal of first vector and the second vector, so we need normals:
715 dp1 = n3 . v2 = -by3 * bx2 + bx3 * by2;
716 dp2 = n1 . v2 = -by1 * bx2 + bx1 * by2;
719 crossing vector = v1 * ratio;
723 -----------------------------------
725 So... to code this, let's say we have two Lines: l1 & l2.
727 Vector v1 = l1.endpoint - l1.position;
728 Vector v2 = l2.endpoint - l2.position;
731 Vector normal1(-v1.y, v1.x);
732 Vector normal3(-v3.y, v3.x);
734 double dotProduct1 = v2.Dot(normal1);
735 double dotProduct2 = v2.Dot(normal3);
737 if (dotProduct2 == 0)
738 return ParallelLines;
741 // I think we'd still have to add the intersection to the position point to get the intersection...
742 Point intersection = v1 * (dotProduct1 / dotProduct2);