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 "dimension.h"
26 Line::Line(Vector p1, Vector p2, Object * p/*= NULL*/): Object(p1, p), endpoint(p2),
27 draggingLine(false), draggingHandle1(false), draggingHandle2(false), //needUpdate(false),
28 length(Vector::Magnitude(p2, p1)), angle(Vector(endpoint - position).Unit()),
29 hitPoint1(false), hitPoint2(false), hitLine(false)
35 // Taking care of connections should be done by the Container, as we don't know
36 // anything about any other object connected to this one.
38 // If there are any attached Dimensions, we must set the attachment points
39 // to NULL since they will no longer be valid.
40 if (attachedDimension)
42 attachedDimension->SetPoint1(NULL);
43 attachedDimension->SetPoint2(NULL);
45 // IT WOULD BE NICE to have any object points attached to this line automagically
46 // connect to this dimension object at this point, instead of just becoming
51 /*virtual*/ void Line::Draw(Painter * painter)
53 painter->SetPen(QPen(Qt::red, 2.0, Qt::DotLine));
55 if ((state == OSSelected) || ((state == OSInactive) && hitPoint1))
56 painter->DrawHandle(position);
58 if ((state == OSSelected) || ((state == OSInactive) && hitPoint2))
59 painter->DrawHandle(endpoint);
61 if ((state == OSInactive) && !hitLine)
62 painter->SetPen(QPen(Qt::black, 1.0, Qt::SolidLine));
64 if (Object::fixedLength && (draggingHandle1 || draggingHandle2))
66 Vector point1 = (draggingHandle1 ? endpoint : position);
67 Vector point2 = (draggingHandle1 ? position : endpoint);
69 Vector current(point2 - point1);
70 Vector v = current.Unit() * length;
71 Vector v2 = point1 + v;
72 // painter->DrawLine((int)point1.x, (int)point1.y, (int)v2.x, (int)v2.y);
73 painter->DrawLine(point1, v2);
75 if (current.Magnitude() > length)
77 painter->SetPen(QPen(QColor(128, 0, 0), 1.0, Qt::DashLine));
78 // painter->DrawLine((int)v2.x, (int)v2.y, (int)point2.x, (int)point2.y);
79 painter->DrawLine(v2, point2);
82 // Problem: when drawing at large zoom levels, this throws away precision thus
83 // causing the line to rendered too short. !!! FIX !!! [DONE]
85 // painter->DrawLine((int)position.x, (int)position.y, (int)endpoint.x, (int)endpoint.y);
86 painter->DrawLine(position, endpoint);
89 /*virtual*/ Vector Line::Center(void)
91 // Technically, this is the midpoint but who are we to quibble? :-)
92 Vector v((position.x - endpoint.x) / 2.0, (position.y - endpoint.y) / 2.0);
96 /*virtual*/ bool Line::Collided(Vector point)
98 // We can assume this, since this is a mouse down event here.
99 objectWasDragged = false;
103 There's a small problem here with the implementation: You can have a dimension tied
104 to only one point while at the same time you can have a dimension sitting on this line.
105 Since there's only *one* dimPoint for each point, this can be problematic...
107 We solve this by allowing only *one* Dimension object to be attached to the Line,
108 Arc, etc. and by giving the Dimension object a pointer to our endpoints.
110 Problem still arises when we delete this object; The attached Dimension object will
111 then have bad pointers! What it *should* do is delete the object if and only if this
112 line is not attached to any other object. If it is, then one of those attachment
113 points should be sent to the dimension object (done for position & endpoint).
115 NOTE: The STL vector<T> *does not* take ownership of pointers, therefore is suitable
118 Also: It would be nice to have a preview of the dimension being drawn, with a modifier
119 key to make it draw/show on the other side...
121 TODO: Make Dimension preview with modifier keys for showing on other side
123 // Is the dimension tool active? Let's use it:
126 // User clicked on the line itself (endpoint checks should preceed this one):
127 // (Priorities are taken care of in HitTest()...)
131 if (attachedDimension == NULL)
133 // How to get this object into the top level container???
135 The real question is do we care. I think so, because if this isn't in the top
136 level container, it won't get drawn...
137 But we can fix that by making this object call any attached object's (like
138 a dimension only) Draw() function... :-/
140 attachedDimension = new Dimension(&position, &endpoint, DTLinear, this);
143 parent->Add(attachedDimension);
147 // If there's one already there, tell it to flip sides...
148 attachedDimension->FlipSides();
151 // New approach here: We look for connected objects.
152 Object * attachedDimension = FindAttachedDimension();
154 if (attachedDimension)
156 // If there's an attached Dimension, tell it to switch sides...
157 ((Dimension *)attachedDimension)->FlipSides();
161 // Otherwise, we make a new one and attach it here.
162 attachedDimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
163 connected.push_back(Connection(attachedDimension, 0));
164 connected.push_back(Connection(attachedDimension, 1.0));
167 parent->Add(attachedDimension);
176 if (state == OSInactive)
178 //printf("Line: pp = %lf, length = %lf, distance = %lf\n", parameterizedPoint, lineSegment.Magnitude(), distance);
179 //printf(" v1.Magnitude = %lf, v2.Magnitude = %lf\n", v1.Magnitude(), v2.Magnitude());
180 //printf(" point = %lf,%lf,%lf; p1 = %lf,%lf,%lf; p2 = %lf,%lf,%lf\n", point.x, point.y, point.z, position.x, position.y, position.z, endpoint.x, endpoint.y, endpoint.z);
182 //How to translate this into pixels from Document space???
183 //Maybe we need to pass a scaling factor in here from the caller? That would make sense, as
184 //the caller knows about the zoom factor and all that good kinda crap
185 //I think what's needed is an Object class variable/method that can be changed by the TLC and
186 //called in derived classes to properly scale the location to the current zoom level. That *should* work.
188 // ALSO: Need to code a global (read: Object class) variable that tells use whether a modifier
189 // key was pressed in addition to the mouse click, so we can do stuff like, say, hold
190 // down CTRL and be able to do multiple selecting of objects (in that case, we would
191 // keep the Object state from changing).
196 oldPoint = position; //maybe "position"?
197 draggingHandle1 = true;
204 oldPoint = endpoint; //maybe "position"?
205 draggingHandle2 = true;
217 else if (state == OSSelected)
219 // Here we test for collision with handles as well! (SOON!) [I think it works...NOPE]
222 if (v1.Magnitude() < 2.0) // Handle #1
223 else if (v2.Magnitude() < 2.0) // Handle #2
228 // state = OSInactive;
235 // If we got here, we clicked on nothing, so set the object to inactive.
236 // (Once we can read key modifiers, we can override this to allow multiple selection.)
241 /*virtual*/ void Line::PointerMoved(Vector point)
243 // Hit test tells us what we hit (if anything) through boolean variables. It
244 // also tells us whether or not the state changed.
245 needUpdate = HitTest(point);
247 objectWasDragged = (draggingLine | draggingHandle1 | draggingHandle2);
249 if (objectWasDragged)
251 Vector delta = point - oldPoint;
253 if (draggingHandle1 || draggingLine)
256 if (draggingHandle2 || draggingLine)
264 We can't count on any coupling between the dimension object and us, so how do we do this???
265 Also, there may be more than one Dimension object connected to a single endpoint!
268 - Keep track of the state of the connected dimension
269 - Pass the Dimension the point that's being changed and the delta
272 - Pass the point in a notification function (how?)
273 - Pass the point as a reference to the class instance object (&endpoint). This way, the line
274 doesn't have to care about keeping track of Dimensions connected to it. But still have to
275 care about other connected entities (other Lines, Circles, Arcs, Splines, Texts, etc). I
276 think I'd be OK with this.
277 Since the Dimension has a pointer to our object, all we have to do is update our coordinates
278 and the Dimension object will adjust itself on the next repaint. Problem solved, and we don't
279 have to know anything about how many Dimensions are connected to us, or where! \o/
280 The question then becomes, how do we do this kind of coupling???
282 We need to know about connected entities so that we can have them either move in expected ways
283 or constrain the movement of this Line object. This is how we will be a cut above all other CAD
284 software currently out there: the GUI will try to do the right thing, most of the time. :-)
288 // should only do this if "Fixed Length" is set... !!! FIX !!! [DONE]
289 Vector point1 = (draggingHandle1 ? endpoint : position);
290 Vector point2 = (draggingHandle1 ? position : endpoint);
293 Vector current(point2, point1);
294 Vector v = current.Unit() * length;
295 Vector v2 = point1 + v;
298 if (!Object::fixedLength)
302 if (Object::fixedAngle)
304 // Here we calculate the component of the current vector along the fixed angle.
305 // A_compB = (A . Bu) * Bu
306 double magnitudeAlongB = Vector::Dot(Vector(point2 - point1), angle);
308 Actually, this isn't quite right. What we want to do is look for the intersection along either
309 the horizontal line or vertical line that intersects from the current mouse position.
313 position = endpoint + (angle * magnitudeAlongB);
316 endpoint = position + (angle * magnitudeAlongB);
321 //If we tell the dimension to flip sides, this is no longer a valid
322 //assumption. !!! FIX !!!
323 //Ideally, we should just send the point that's changing to the Dimension object
324 //and have it figure out which point needs to move... Or is it???
325 // Ideally, we shouldn't have to fuck around with this shit. We need to fix the rendering code
326 // so that we don't have to wait until the dragging is done to correct the position of the
327 // point in question, but we'd need another variable tho.
330 dimPoint1->SetPoint1(draggingHandle1 ? v2 : position);
333 dimPoint2->SetPoint2(draggingHandle2 ? v2 : endpoint);
338 /*virtual*/ void Line::PointerReleased(void)
340 if (draggingHandle1 || draggingHandle2)
342 // Set the length (in case the global state was set to fixed (or not))
343 if (Object::fixedLength)
345 if (draggingHandle1) // startpoint
347 Vector v = Vector(position - endpoint).Unit() * length;
348 position = endpoint + v;
352 // Vector v1 = endpoint - position;
353 Vector v = Vector(endpoint - position).Unit() * length;
354 endpoint = position + v;
359 // Otherwise, we calculate the new length, just in case on the next move
360 // it turns out to have a fixed length. :-)
361 length = Vector(endpoint - position).Magnitude();
364 if (!Object::fixedAngle)
366 // Calculate the new angle, just in case on the next move it turns out to
368 angle = Vector(endpoint - position).Unit();
372 draggingLine = false;
373 draggingHandle1 = false;
374 draggingHandle2 = false;
376 // hitPoint1 = hitPoint2 = hitLine = false;
378 // Here we check for just a click: If object was clicked and dragged, then
379 // revert to the old state (OSInactive). Otherwise, keep the new state that
381 /*Maybe it would be better to just check for "object was dragged" state and not have to worry
382 about keeping track of old states...
384 if (objectWasDragged)
388 // Check to see if the point passed in coincides with any we have. If so, return a
389 // pointer to it; otherwise, return NULL.
390 /*virtual*/ Vector * Line::GetPointAt(Vector v)
394 else if (v == endpoint)
402 void Line::SetDimensionOnPoint1(Dimension * dimension)
404 dimPoint1 = dimension;
407 dimension->SetPoint1(position);
410 void Line::SetDimensionOnPoint2(Dimension * dimension)
412 dimPoint2 = dimension;
415 dimension->SetPoint2(endpoint);
418 void Line::SetDimensionOnLine(Dimension * dimension/*=NULL*/)
420 // If they don't pass one in, create it for the caller.
421 if (dimension == NULL)
423 printf("Line::SetDimensionOnLine(): Creating new dimension...\n");
424 // dimension = new Dimension(position, endpoint, DTLinear, this);
425 dimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
429 printf("Line::SetDimensionOnLine(): Adding to parent...\n");
430 parent->Add(dimension);
435 dimension->Connect(this, 0);
436 dimension->Connect(this, 1.0);
439 // Make sure the Dimension is connected to us...
441 connected.push_back(Connection(dimension, 0));
442 connected.push_back(Connection(dimension, 1.0));
444 Connect(dimension, 0);
445 Connect(dimension, 1.0);
448 // attachedDimension = dimension;
451 // After we set the points here, we don't have to care about them anymore.
454 dimension->SetPoint1(&position);
455 dimension->SetPoint2(&endpoint);
462 Object * Line::FindAttachedDimension(void)
464 // Is there anything connected to this line? If not, return NULL
465 if (connected.size() < 2)
468 // Otherwise, we have to search our objects to see if there's a likely
469 // candidate. In this case, we're looking for a pointer to the same object
470 // with a parameter of 0 and 1 respectively. This is O((n^2)/2).
471 for(uint i=0; i<connected.size(); i++)
473 for(uint j=i+1; j<connected.size(); j++)
475 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);
476 if ((connected[i].object == connected[j].object)
477 && ((connected[i].t == 0 && connected[j].t == 1.0)
478 || (connected[i].t == 1.0 && connected[j].t == 0)))
479 return connected[i].object;
483 // Didn't find anything, so return NULL
488 bool Line::HitTest(Point point)
492 hitPoint1 = hitPoint2 = hitLine = false;
493 Vector lineSegment = endpoint - position;
494 Vector v1 = point - position;
495 Vector v2 = point - endpoint;
496 double parameterizedPoint = lineSegment.Dot(v1) / lineSegment.Magnitude(), distance;
498 // Geometric interpretation:
499 // The parameterized point on the vector lineSegment is where the perpendicular
500 // intersects lineSegment. If pp < 0, then the perpendicular lies beyond the 1st
501 // endpoint. If pp > length of ls, then the perpendicular lies beyond the 2nd endpoint.
503 if (parameterizedPoint < 0.0)
504 distance = v1.Magnitude();
505 else if (parameterizedPoint > lineSegment.Magnitude())
506 distance = v2.Magnitude();
508 // distance = ?Det?(ls, v1) / |ls|
509 distance = fabs((lineSegment.x * v1.y - v1.x * lineSegment.y) / lineSegment.Magnitude());
511 // Geometric interpretation of the above:
512 // If the segment endpoints are s and e, and the point is p, then the test
513 // for the perpendicular intercepting the segment is equivalent to insisting
514 // that the two dot products {s-e}.{s-p} and {e-s}.{e-p} are both non-negative.
515 // Perpendicular distance from the point to the segment is computed by first
516 // computing the area of the triangle the three points form, then dividing by
517 // the length of the segment. Distances are done just by the Pythagorean
518 // theorem. Twice the area of the triangle formed by three points is the
519 // determinant of the following matrix:
521 // sx sy 1 0 0 1 0 0 0
522 // ex ey 1 ==> ex ey 1 ==> ex ey 0
523 // px py 1 px py 1 px py 0
525 // By translating the start point to the origin, and subtracting row 1 from
526 // all other rows, we end up with the matrix on the right which greatly
527 // simplifies the calculation of the determinant.
529 //How do we determine distance here? Especially if zoomed in or out???
530 //#warning "!!! Distances tested for may not be valid if zoomed in or out !!!"
532 if ((v1.Magnitude() * Painter::zoom) < 8.0)
534 else if ((v2.Magnitude() * Painter::zoom) < 8.0)
536 else if ((distance * Painter::zoom) < 5.0)
539 return StateChanged();
542 void Line::SaveState(void)
544 oldHitPoint1 = hitPoint1;
545 oldHitPoint2 = hitPoint2;
546 oldHitLine = hitLine;
549 bool Line::StateChanged(void)
551 if ((hitPoint1 != oldHitPoint1) || (hitPoint2 != oldHitPoint2) || (hitLine != oldHitLine))
558 Intersection of two lines:
560 Find where the lines with equations r = i + j + t (3i - j) and r = -i + s (j) intersect.
562 When they intersect, we can set the equations equal to one another:
564 i + j + t (3i - j) = -i + s (j)
566 Equating coefficients:
567 1 + 3t = -1 and 1 - t = s
568 So t = -2/3 and s = 5/3
570 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 .
573 so, let's say we have two lines, l1 and l2. Points are v0(p0x, p0y), v1(p1x, p1y) for l1
574 and v2(p2x, p2y), v3(p3x, p3y) for l2.
576 d1 = v1 - v0, d2 = v3 - v2
578 Our parametric equations for the line then are:
583 Set r1 = r2, thus we have:
585 v0 + t(d1) = v2 + s(d2)
587 Taking coefficients, we have:
589 p0x + t(d1x) = p2x + s(d2x)
590 p0y + t(d1y) = p2y + s(d2y)
594 t(d1x) - s(d2x) = p2x - p0x
595 t(d1y) - s(d2y) = p2y - p0y
597 Determinant D is ad - bc where the matrix looks like:
602 so D = (d1x)(d2y) - (d2x)(d1y)
603 if D = 0, the lines are parallel.
604 Dx = (p2x - p0x)(d2y) - (d2x)(p2y - p0y)
605 Dy = (d1x)(p2y - p0y) - (p2x - p0x)(d1y)
608 We only need to calculate t, as we can then multiply it by d1 to get the intersection point.
610 ---------------------------------------------------------------------------------------------------
612 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:
618 Perp product is equal with dot product of normal of first vector and the second vector, so we need normals:
625 dp1 = n3 . v2 = -by3 * bx2 + bx3 * by2;
626 dp2 = n1 . v2 = -by1 * bx2 + bx1 * by2;
629 crossing vector = v1 * ratio;
633 -----------------------------------
635 So... to code this, let's say we have two Lines: l1 & l2.
637 Vector v1 = l1.endpoint - l1.position;
638 Vector v2 = l2.endpoint - l2.position;
641 Vector normal1(-v1.y, v1.x);
642 Vector normal3(-v3.y, v3.x);
644 double dotProduct1 = v2.Dot(normal1);
645 double dotProduct2 = v2.Dot(normal3);
647 if (dotProduct2 == 0)
648 return ParallelLines;
651 // I think we'd still have to add the intersection to the position point to get the intersection...
652 Point intersection = v1 * (dotProduct1 / dotProduct2);
657 /*virtual*/ void Line::Enumerate(FILE * file)
659 fprintf(file, "LINE (%lf,%lf) (%lf,%lf)\n", position.x, position.y, endpoint.x, endpoint.y);
663 /*virtual*/ Object * Line::Copy(void)
665 #warning "!!! This doesn't take care of attached Dimensions !!!"
667 This is a real problem. While having a pointer in the Dimension to this line's points is fast & easy,
668 it creates a huge problem when trying to replicate an object like this.
670 Maybe a way to fix that then, is to have reference numbers instead of pointers. That way, if you copy
671 them, ... you might still have problems. Because you can't be sure if a copy will be persistant or not,
672 you then *definitely* do not want them to have the same reference number.
674 return new Line(position, endpoint, parent);
678 /*virtual*/ Vector Line::GetPointAtParameter(double parameter)
682 else if (parameter >= 1.0)
685 // Our parameter lies between zero and one, so calculate it!
686 Vector v(endpoint, position);
687 double length = v.Magnitude();
688 // We scale the magnitude of v so that it lies between 0 and 1...
689 // By multiplying the parameter by the magnitude, we obtain the point we
690 // want. No scaling necessary as it's inherent in the approach!
691 double spotOnLength = length * parameter;
693 // To get our point, we use the initial point of the line and add in our
695 Vector result = position + (v * spotOnLength);