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();
96 QString text = QObject::tr("Length: %1 in.\n") + QChar(0x2221) + QObject::tr(": %2");
97 text = text.arg(absLength).arg(absAngle);
99 QPen pen = QPen(QColor(0x00, 0xFF, 0x00), 1.0, Qt::SolidLine);
100 painter->SetPen(pen);
101 painter->SetBrush(QBrush(QColor(0x40, 0xFF, 0x40, 0x9F)));
102 QRectF textRect(10.0, 10.0, 270.0, 70.0); // x, y, w, h (in Qt coords)
103 painter->DrawRoundedRect(textRect, 7.0, 7.0);
105 textRect.setLeft(textRect.left() + 14);
106 painter->SetFont(*Object::font);
107 pen = QPen(QColor(0x00, 0x5F, 0xDF));
108 painter->SetPen(pen);
109 painter->DrawText(textRect, Qt::AlignVCenter, text);
111 painter->DrawInformativeText(text);
116 /*virtual*/ Vector Line::Center(void)
118 // Technically, this is the midpoint but who are we to quibble? :-)
119 Vector v((position.x - endpoint.x) / 2.0, (position.y - endpoint.y) / 2.0);
123 /*virtual*/ bool Line::Collided(Vector point)
125 // We can assume this, since this is a mouse down event here.
126 objectWasDragged = false;
129 // Now that we've done our hit testing on the non-snapped point, snap it if
132 point = SnapPointToGrid(point);
134 // this is shite. this should be checked for in the Container, not here!
135 #warning "!!! This should be checked for in Container, not here !!!"
136 // If we're part of a non-top-level container, send this signal to it
137 if (parent->type == OTContainer && !((Container *)parent)->isTopLevelContainer
138 && (hitLine || hitPoint1 || hitPoint2))
140 parent->state = OSSelected;
145 There's a small problem here with the implementation: You can have a dimension tied
146 to only one point while at the same time you can have a dimension sitting on this line.
147 Since there's only *one* dimPoint for each point, this can be problematic...
149 We solve this by allowing only *one* Dimension object to be attached to the Line,
150 Arc, etc. and by giving the Dimension object a pointer to our endpoints.
152 Problem still arises when we delete this object; The attached Dimension object will
153 then have bad pointers! What it *should* do is delete the object if and only if this
154 line is not attached to any other object. If it is, then one of those attachment
155 points should be sent to the dimension object (done for position & endpoint).
157 NOTE: The STL vector<T> *does not* take ownership of pointers, therefore is suitable
160 Also: It would be nice to have a preview of the dimension being drawn, with a modifier
161 key to make it draw/show on the other side...
163 TODO: Make Dimension preview with modifier keys for showing on other side
165 // Is the dimension tool active? Let's use it:
168 // User clicked on the line itself (endpoint checks should preceed this one):
169 // (Priorities are taken care of in HitTest()...)
173 if (attachedDimension == NULL)
175 // How to get this object into the top level container???
177 The real question is do we care. I think so, because if this isn't in the top
178 level container, it won't get drawn...
179 But we can fix that by making this object call any attached object's (like
180 a dimension only) Draw() function... :-/
182 attachedDimension = new Dimension(&position, &endpoint, DTLinear, this);
185 parent->Add(attachedDimension);
189 // If there's one already there, tell it to flip sides...
190 attachedDimension->FlipSides();
193 // New approach here: We look for connected objects.
194 Object * attachedDimension = FindAttachedDimension();
196 if (attachedDimension)
198 // If there's an attached Dimension, tell it to switch sides...
199 ((Dimension *)attachedDimension)->FlipSides();
203 // Otherwise, we make a new one and attach it here.
204 attachedDimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
205 connected.push_back(Connection(attachedDimension, 0));
206 connected.push_back(Connection(attachedDimension, 1.0));
209 parent->Add(attachedDimension);
217 if (state == OSInactive)
219 //How to translate this into pixels from Document space???
220 //Maybe we need to pass a scaling factor in here from the caller? That would
221 //make sense, as the caller knows about the zoom factor and all that good kinda
223 //I think what's needed is an Object class variable/method that can be changed
224 //by the TLC and called in derived classes to properly scale the location to
225 //the current zoom level. That *should* work.
227 // ALSO: Need to code a global (read: Object class) variable that tells use
228 // whether a modifier key was pressed in addition to the mouse click, so
229 // we can do stuff like, say, hold down CTRL and be able to do multiple
230 // selecting of objects (in that case, we would keep the Object state
237 draggingHandle1 = true;
245 draggingHandle2 = true;
257 else if (state == OSSelected)
262 // state = OSInactive;
266 // Toggle selected state if CTRL held
267 if (qApp->keyboardModifiers() == Qt::ControlModifier)
274 // If CTRL is held, then we bypass the "turn off" code. Still didn't hit
275 // *this* object though. :-)
276 if (qApp->keyboardModifiers() == Qt::ControlModifier)
279 // If we got here, we clicked on nothing, so set the object to inactive.
280 // (Once we can read key modifiers, we can override this to allow multiple selection.)
286 /*virtual*/ void Line::PointerMoved(Vector point)
288 if (selectionInProgress)
290 // Check for whether or not the rect contains this line
292 if (selection.normalized().contains(Extents()))
294 // if (selection.normalized().contains(position.x, position.y)
295 // && selection.normalized().contains(endpoint.x, endpoint.y))
296 if (selection.contains(position.x, position.y)
297 && selection.contains(endpoint.x, endpoint.y))
306 // Hit test tells us what we hit (if anything) through boolean variables. (It
307 // also tells us whether or not the state changed. --not any more)
310 needUpdate = HitStateChanged();
312 objectWasDragged = (draggingLine | draggingHandle1 | draggingHandle2);
314 if (objectWasDragged)
316 Vector delta = point - oldPoint;
318 if (draggingHandle1 || draggingLine)
321 if (draggingHandle2 || draggingLine)
327 //doesn't work QMainWindow::statusBar()->setText("You are manipulating a line");
331 We can't count on any coupling between the dimension object and us, so how do we do this???
332 Also, there may be more than one Dimension object connected to a single endpoint!
335 - Keep track of the state of the connected dimension
336 - Pass the Dimension the point that's being changed and the delta
339 - Pass the point in a notification function (how?)
340 - Pass the point as a reference to the class instance object (&endpoint). This
341 way, the line doesn't have to care about keeping track of Dimensions
342 connected to it. But still have to care about other connected entities
343 (other Lines, Circles, Arcs, Splines, Texts, etc). I think I'd be OK with
344 this. Since the Dimension has a pointer to our object, all we have to do is
345 update our coordinates and the Dimension object will adjust itself on the
346 next repaint. Problem solved, and we don't have to know anything about how
347 many Dimensions are connected to us, or where! \o/
348 The question then becomes, how do we do this kind of coupling???
350 We need to know about connected entities so that we can have them either move
351 in expected ways or constrain the movement of this Line object. This is how we
352 will be a cut above all other CAD software currently out there: the GUI will
353 try to do the right thing, most of the time. :-)
357 // should only do this if "Fixed Length" is set... !!! FIX !!! [DONE]
358 Vector point1 = (draggingHandle1 ? endpoint : position);
359 Vector point2 = (draggingHandle1 ? position : endpoint);
361 if (Object::fixedAngle)
363 // Here we calculate the component of the current vector along the fixed angle.
364 // A_compB = (A . Bu) * Bu
365 double magnitudeAlongB = Vector::Dot(Vector(point2 - point1), angle);
367 Actually, this isn't quite right. What we want to do is look for the intersection along either
368 the horizontal line or vertical line that intersects from the current mouse position.
372 position = endpoint + (angle * magnitudeAlongB);
375 endpoint = position + (angle * magnitudeAlongB);
380 //If we tell the dimension to flip sides, this is no longer a valid
381 //assumption. !!! FIX !!!
382 //Ideally, we should just send the point that's changing to the Dimension object
383 //and have it figure out which point needs to move... Or is it???
384 // Ideally, we shouldn't have to fuck around with this shit. We need to fix the rendering code
385 // so that we don't have to wait until the dragging is done to correct the position of the
386 // point in question, but we'd need another variable tho.
389 dimPoint1->SetPoint1(draggingHandle1 ? v2 : position);
392 dimPoint2->SetPoint2(draggingHandle2 ? v2 : endpoint);
398 /*virtual*/ void Line::PointerReleased(void)
400 if (draggingHandle1 || draggingHandle2)
402 // Set the length (in case the global state was set to fixed (or not))
403 if (Object::fixedLength)
405 if (draggingHandle1) // startpoint
407 Vector v = Vector(position - endpoint).Unit() * length;
408 position = endpoint + v;
412 Vector v = Vector(endpoint - position).Unit() * length;
413 endpoint = position + v;
418 // Otherwise, we calculate the new length, just in case on the next
419 // move it turns out to have a fixed length. :-)
420 length = Vector(endpoint - position).Magnitude();
423 if (!Object::fixedAngle)
425 // Calculate the new angle, just in case on the next move it turns
426 // out to be fixed. :-)
427 angle = Vector(endpoint - position).Unit();
431 draggingLine = false;
432 draggingHandle1 = false;
433 draggingHandle2 = false;
435 if (objectWasDragged)
440 /*virtual*/ bool Line::HitTest(Point point)
444 hitPoint1 = hitPoint2 = hitLine = false;
445 Vector lineSegment = endpoint - position;
446 Vector v1 = point - position;
447 Vector v2 = point - endpoint;
448 double t = Vector::Parameter(position, endpoint, point);
451 // Geometric interpretation:
452 // The parameter "t" on the vector lineSegment is where the normal of
453 // lineSegment coincides with point. If t < 0, the normal lies beyond the
454 // 1st endpoint. If t > 1, then the normal lies beyond the 2nd endpoint. We
455 // only calculate the length of the normal between the point and the
456 // lineSegment when the parameter is between 0 and 1.
458 // Geometric interpretation of "distance = ?Det?(ls, v1) / |ls|":
459 // If the segment endpoints are s and e, and the point is p, then the test
460 // for the perpendicular intercepting the segment is equivalent to insisting
461 // that the two dot products {s-e}.{s-p} and {e-s}.{e-p} are both non-negative.
462 // Perpendicular distance from the point to the segment is computed by first
463 // computing the area of the triangle the three points form, then dividing by
464 // the length of the segment. Distances are done just by the Pythagorean
465 // theorem. Twice the area of the triangle formed by three points is the
466 // determinant of the following matrix:
468 // sx sy 1 0 0 1 0 0 0
469 // ex ey 1 ==> ex ey 1 ==> ex ey 0
470 // px py 1 px py 1 px py 0
472 // By translating the start point to the origin, and subtracting row 1 from
473 // all other rows, we end up with the matrix on the right which greatly
474 // simplifies the calculation of the determinant.
477 distance = v1.Magnitude();
479 distance = v2.Magnitude();
481 // distance = ?Det?(ls, v1) / |ls|
482 distance = fabs((lineSegment.x * v1.y - v1.x * lineSegment.y)
483 / lineSegment.Magnitude());
485 if ((v1.Magnitude() * Painter::zoom) < 8.0)
487 else if ((v2.Magnitude() * Painter::zoom) < 8.0)
489 else if ((distance * Painter::zoom) < 5.0)
492 return (hitPoint1 || hitPoint2 || hitLine ? true : false);
493 // return HitStateChanged();
497 // Check to see if the point passed in coincides with any we have. If so, return a
498 // pointer to it; otherwise, return NULL.
499 /*virtual*/ Vector * Line::GetPointAt(Vector v)
503 else if (v == endpoint)
510 /*virtual*/ void Line::Enumerate(FILE * file)
512 fprintf(file, "LINE %i (%lf,%lf) (%lf,%lf)\n", layer, position.x, position.y, endpoint.x, endpoint.y);
516 /*virtual*/ Object * Line::Copy(void)
518 #warning "!!! This doesn't take care of attached Dimensions !!!"
520 This is a real problem. While having a pointer in the Dimension to this line's points
521 is fast & easy, it creates a huge problem when trying to replicate an object like this.
523 Maybe a way to fix that then, is to have reference numbers instead of pointers. That
524 way, if you copy them, ... you might still have problems. Because you can't be sure if
525 a copy will be persistant or not, you then *definitely* do not want them to have the
526 same reference number.
528 return new Line(position, endpoint, parent);
532 /*virtual*/ Vector Line::GetPointAtParameter(double parameter)
536 else if (parameter >= 1.0)
539 // Our parameter lies between zero and one, so calculate it!
540 Vector v(endpoint, position);
541 double length = v.Magnitude();
542 // We scale the magnitude of v so that it lies between 0 and 1...
543 // By multiplying the parameter by the magnitude, we obtain the point we
544 // want. No scaling necessary as it's inherent in the approach!
545 double spotOnLength = length * parameter;
547 // To get our point, we use the initial point of the line and add in our
549 Vector result = position + (v * spotOnLength);
554 /*virtual*/ QRectF Line::Extents(void)
556 QRectF rect(QPointF(position.x, position.y), QPointF(endpoint.x, endpoint.y));
557 return rect.normalized();
561 /*virtual*/ void Line::Translate(Vector amount)
568 /*virtual*/ void Line::Rotate(Vector point, double angle)
573 /*virtual*/ void Line::Scale(Vector point, double amount)
578 void Line::SetDimensionOnLine(Dimension * dimension/*=NULL*/)
580 // If they don't pass one in, create it for the caller.
581 if (dimension == NULL)
583 //printf("Line::SetDimensionOnLine(): Creating new dimension...\n");
584 // dimension = new Dimension(position, endpoint, DTLinear, this);
585 dimension = new Dimension(Connection(this, 0), Connection(this, 1.0), DTLinear, this);
589 //printf("Line::SetDimensionOnLine(): Adding to parent...\n");
590 parent->Add(dimension);
595 dimension->Connect(this, 0);
596 dimension->Connect(this, 1.0);
599 // Make sure the Dimension is connected to us...
600 Connect(dimension, 0);
601 Connect(dimension, 1.0);
605 Object * Line::FindAttachedDimension(void)
607 // Is there anything connected to this line? If not, return NULL
608 if (connected.size() < 2)
611 // Otherwise, we have to search our objects to see if there's a likely
612 // candidate. In this case, we're looking for a pointer to the same object
613 // with a parameter of 0 and 1 respectively. This is O((n^2)/2).
614 for(uint i=0; i<connected.size(); i++)
616 for(uint j=i+1; j<connected.size(); j++)
618 //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);
619 if ((connected[i].object == connected[j].object)
620 && ((connected[i].t == 0 && connected[j].t == 1.0)
621 || (connected[i].t == 1.0 && connected[j].t == 0)))
622 return connected[i].object;
626 // Didn't find anything, so return NULL
631 void Line::SaveHitState(void)
633 oldHitPoint1 = hitPoint1;
634 oldHitPoint2 = hitPoint2;
635 oldHitLine = hitLine;
639 bool Line::HitStateChanged(void)
641 if ((hitPoint1 != oldHitPoint1) || (hitPoint2 != oldHitPoint2) || (hitLine != oldHitLine))
649 Intersection of two lines:
651 Find where the lines with equations r = i + j + t (3i - j) and r = -i + s (j) intersect.
653 When they intersect, we can set the equations equal to one another:
655 i + j + t (3i - j) = -i + s (j)
657 Equating coefficients:
658 1 + 3t = -1 and 1 - t = s
659 So t = -2/3 and s = 5/3
661 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 .
664 so, let's say we have two lines, l1 and l2. Points are v0(p0x, p0y), v1(p1x, p1y) for l1
665 and v2(p2x, p2y), v3(p3x, p3y) for l2.
667 d1 = v1 - v0, d2 = v3 - v2
669 Our parametric equations for the line then are:
674 Set r1 = r2, thus we have:
676 v0 + t(d1) = v2 + s(d2)
678 Taking coefficients, we have:
680 p0x + t(d1x) = p2x + s(d2x)
681 p0y + t(d1y) = p2y + s(d2y)
685 t(d1x) - s(d2x) = p2x - p0x
686 t(d1y) - s(d2y) = p2y - p0y
688 Determinant D is ad - bc where the matrix looks like:
693 so D = (d1x)(d2y) - (d2x)(d1y)
694 if D = 0, the lines are parallel.
695 Dx = (p2x - p0x)(d2y) - (d2x)(p2y - p0y)
696 Dy = (d1x)(p2y - p0y) - (p2x - p0x)(d1y)
699 We only need to calculate t, as we can then multiply it by d1 to get the intersection point.
701 ---------------------------------------------------------------------------------------------------
703 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:
709 Perp product is equal with dot product of normal of first vector and the second vector, so we need normals:
716 dp1 = n3 . v2 = -by3 * bx2 + bx3 * by2;
717 dp2 = n1 . v2 = -by1 * bx2 + bx1 * by2;
720 crossing vector = v1 * ratio;
724 -----------------------------------
726 So... to code this, let's say we have two Lines: l1 & l2.
728 Vector v1 = l1.endpoint - l1.position;
729 Vector v2 = l2.endpoint - l2.position;
732 Vector normal1(-v1.y, v1.x);
733 Vector normal3(-v3.y, v3.x);
735 double dotProduct1 = v2.Dot(normal1);
736 double dotProduct2 = v2.Dot(normal3);
738 if (dotProduct2 == 0)
739 return ParallelLines;
742 // I think we'd still have to add the intersection to the position point to get the intersection...
743 Point intersection = v1 * (dotProduct1 / dotProduct2);