qgraphicstransform.cpp

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33 -

34 /*! -

35 \class QGraphicsTransform -

36 \brief The QGraphicsTransform class is an abstract base class for building -

37 advanced transformations on QGraphicsItems. -

38 \since 4.6 -

39 \ingroup graphicsview-api -

40 \inmodule QtWidgets -

41 -

42 As an alternative to QGraphicsItem::transform, QGraphicsTransform lets you -

43 create and control advanced transformations that can be configured -

44 independently using specialized properties. -

45 -

46 QGraphicsItem allows you to assign any number of QGraphicsTransform -

47 instances to one QGraphicsItem. Each QGraphicsTransform is applied in -

48 order, one at a time, to the QGraphicsItem it's assigned to. -

49 -

50 QGraphicsTransform is particularly useful for animations. Whereas -

51 QGraphicsItem::setTransform() lets you assign any transform directly to an -

52 item, there is no direct way to interpolate between two different -

53 transformations (e.g., when transitioning between two states, each for -

54 which the item has a different arbitrary transform assigned). Using -

55 QGraphicsTransform you can interpolate the property values of each -

56 independent transformation. The resulting operation is then combined into a -

57 single transform which is applied to QGraphicsItem. -

58 -

59 Transformations are computed in true 3D space using QMatrix4x4. -

60 When the transformation is applied to a QGraphicsItem, it will be -

61 projected back to a 2D QTransform. When multiple QGraphicsTransform -

62 objects are applied to a QGraphicsItem, all of the transformations -

63 are computed in true 3D space, with the projection back to 2D -

64 only occurring after the last QGraphicsTransform is applied. -

65 The exception to this is QGraphicsRotation, which projects back to -

66 2D after each rotation to preserve the perspective effect around -

67 the X and Y axes. -

68 -

69 If you want to create your own configurable transformation, you can create -

70 a subclass of QGraphicsTransform (or any or the existing subclasses), and -

71 reimplement the pure virtual applyTo() function, which takes a pointer to a -

72 QMatrix4x4. Each operation you would like to apply should be exposed as -

73 properties (e.g., customTransform->setVerticalShear(2.5)). Inside you -

74 reimplementation of applyTo(), you can modify the provided transform -

75 respectively. -

76 -

77 QGraphicsTransform can be used together with QGraphicsItem::setTransform(), -

78 QGraphicsItem::setRotation(), and QGraphicsItem::setScale(). -

79 -

80 \sa QGraphicsItem::transform(), QGraphicsScale, QGraphicsRotation -

81 */ -

82 -

83 #include "qgraphicstransform.h" -

84 #include "qgraphicsitem_p.h" -

85 #include "qgraphicstransform_p.h" -

86 #include <QDebug> -

87 #include <QtCore/qmath.h> -

88 #include <QtCore/qnumeric.h> -

89 -

90 #ifndef QT_NO_GRAPHICSVIEW -

91 QT_BEGIN_NAMESPACE -

92 -

93 QGraphicsTransformPrivate::~QGraphicsTransformPrivate() -

94 { -

95 } -

96 -

97 void QGraphicsTransformPrivate::setItem(QGraphicsItem *i) -

98 { -

if (item == i)

item == i	Description
TRUE	never evaluated
FALSE	never evaluated

100

return;

never executed: return;

101 -

102

if (item) {

item	Description
TRUE	never evaluated
FALSE	never evaluated

103 Q_Q(QGraphicsTransform); -

104 QGraphicsItemPrivate *d_ptr = item->d_ptr.data(); -

105 -

106 item->prepareGeometryChange(); -

107 Q_ASSERT(d_ptr->transformData); -

108 d_ptr->transformData->graphicsTransforms.removeAll(q); -

109 d_ptr->dirtySceneTransform = 1; -

110 item = 0; -

111

}

never executed: end of block

112 -

113 item = i; -

114

}

never executed: end of block

115 -

116 void QGraphicsTransformPrivate::updateItem(QGraphicsItem *item) -

117 { -

118 item->prepareGeometryChange(); -

119 item->d_ptr->dirtySceneTransform = 1; -

120

}

never executed: end of block

121 -

122 /*! -

123 Constructs a new QGraphicsTransform with the given \a parent. -

124 */ -

125 QGraphicsTransform::QGraphicsTransform(QObject *parent) -

126 : QObject(*new QGraphicsTransformPrivate, parent) -

127 { -

128

}

never executed: end of block

129 -

130 /*! -

131 Destroys the graphics transform. -

132 */ -

133 QGraphicsTransform::~QGraphicsTransform() -

134 { -

135 Q_D(QGraphicsTransform); -

136 d->setItem(0); -

137

}

never executed: end of block

138 -

139 /*! -

140 \internal -

141 */ -

142 QGraphicsTransform::QGraphicsTransform(QGraphicsTransformPrivate &p, QObject *parent) -

143 : QObject(p, parent) -

144 { -

145

}

never executed: end of block

146 -

147 /*! -

148 \fn void QGraphicsTransform::applyTo(QMatrix4x4 *matrix) const -

149 -

150 This pure virtual method has to be reimplemented in derived classes. -

151 -

152 It applies this transformation to \a matrix. -

153 -

154 \sa QGraphicsItem::transform(), QMatrix4x4::toTransform() -

155 */ -

156 -

157 /*! -

158 Notifies that this transform operation has changed its parameters in such a -

159 way that applyTo() will return a different result than before. -

160 -

161 When implementing you own custom graphics transform, you must call this -

162 function every time you change a parameter, to let QGraphicsItem know that -

163 its transformation needs to be updated. -

164 -

165 \sa applyTo() -

166 */ -

167 void QGraphicsTransform::update() -

168 { -

169 Q_D(QGraphicsTransform); -

170

if (d->item)

d->item	Description
TRUE	never evaluated
FALSE	never evaluated

171

d->updateItem(d->item);

never executed: d->updateItem(d->item);

172

}

never executed: end of block

173 -

174 /*! -

175 \class QGraphicsScale -

176 \brief The QGraphicsScale class provides a scale transformation. -

177 \since 4.6 -

178 \inmodule QtWidgets -

179 -

180 QGraphicsScene provides certain parameters to help control how the scale -

181 should be applied. -

182 -

183 The origin is the point that the item is scaled from (i.e., it stays fixed -

184 relative to the parent as the rest of the item grows). By default the -

185 origin is QPointF(0, 0). -

186 -

187 The parameters xScale, yScale, and zScale describe the scale factors to -

188 apply in horizontal, vertical, and depth directions. They can take on any -

189 value, including 0 (to collapse the item to a point) or negative value. -

190 A negative xScale value will mirror the item horizontally. A negative yScale -

191 value will flip the item vertically. A negative zScale will flip the -

192 item end for end. -

193 -

194 \sa QGraphicsTransform, QGraphicsItem::setScale(), QTransform::scale() -

195 */ -

196 -

197 class QGraphicsScalePrivate : public QGraphicsTransformPrivate -

198 { -

199 public: -

200 QGraphicsScalePrivate() -

201

: xScale(1), yScale(1), zScale(1) {}

never executed: end of block

202 QVector3D origin; -

203 qreal xScale; -

204 qreal yScale; -

205 qreal zScale; -

206 }; -

207 -

208 /*! -

209 Constructs an empty QGraphicsScale object with the given \a parent. -

210 */ -

211 QGraphicsScale::QGraphicsScale(QObject *parent) -

212 : QGraphicsTransform(*new QGraphicsScalePrivate, parent) -

213 { -

214

}

never executed: end of block

215 -

216 /*! -

217 Destroys the graphics scale. -

218 */ -

219 QGraphicsScale::~QGraphicsScale() -

220 { -

221 } -

222 -

223 /*! -

224 \property QGraphicsScale::origin -

225 \brief the origin of the scale in 3D space. -

226 -

227 All scaling will be done relative to this point (i.e., this point -

228 will stay fixed, relative to the parent, when the item is scaled). -

229 -

230 \sa xScale, yScale, zScale -

231 */ -

232 QVector3D QGraphicsScale::origin() const -

233 { -

234 Q_D(const QGraphicsScale); -

235

return d->origin;

never executed: return d->origin;

236 } -

237 void QGraphicsScale::setOrigin(const QVector3D &point) -

238 { -

239 Q_D(QGraphicsScale); -

240

if (d->origin == point)

d->origin == point	Description
TRUE	never evaluated
FALSE	never evaluated

241

return;

never executed: return;

242 d->origin = point; -

243 update(); -

244 emit originChanged(); -

245

}

never executed: end of block

246 -

247 /*! -

248 \property QGraphicsScale::xScale -

249 \brief the horizontal scale factor. -

250 -

251 The scale factor can be any real number; the default value is 1.0. If you -

252 set the factor to 0.0, the item will be collapsed to a single point. If you -

253 provide a negative value, the item will be mirrored horizontally around its -

254 origin. -

255 -

256 \sa yScale, zScale, origin -

257 */ -

258 qreal QGraphicsScale::xScale() const -

259 { -

260 Q_D(const QGraphicsScale); -

261

return d->xScale;

never executed: return d->xScale;

262 } -

263 void QGraphicsScale::setXScale(qreal scale) -

264 { -

265 Q_D(QGraphicsScale); -

266

if (d->xScale == scale)

d->xScale == scale	Description
TRUE	never evaluated
FALSE	never evaluated

267

return;

never executed: return;

268 d->xScale = scale; -

269 update(); -

270 emit xScaleChanged(); -

271 emit scaleChanged(); -

272

}

never executed: end of block

273 -

274 /*! -

275 \property QGraphicsScale::yScale -

276 \brief the vertical scale factor. -

277 -

278 The scale factor can be any real number; the default value is 1.0. If you -

279 set the factor to 0.0, the item will be collapsed to a single point. If you -

280 provide a negative value, the item will be flipped vertically around its -

281 origin. -

282 -

283 \sa xScale, zScale, origin -

284 */ -

285 qreal QGraphicsScale::yScale() const -

286 { -

287 Q_D(const QGraphicsScale); -

288

return d->yScale;

never executed: return d->yScale;

289 } -

290 void QGraphicsScale::setYScale(qreal scale) -

291 { -

292 Q_D(QGraphicsScale); -

293

if (d->yScale == scale)

d->yScale == scale	Description
TRUE	never evaluated
FALSE	never evaluated

294

return;

never executed: return;

295 d->yScale = scale; -

296 update(); -

297 emit yScaleChanged(); -

298 emit scaleChanged(); -

299

}

never executed: end of block

300 -

301 /*! -

302 \property QGraphicsScale::zScale -

303 \brief the depth scale factor. -

304 -

305 The scale factor can be any real number; the default value is 1.0. If you -

306 set the factor to 0.0, the item will be collapsed to a single point. If you -

307 provide a negative value, the item will be flipped end for end around its -

308 origin. -

309 -

310 \sa xScale, yScale, origin -

311 */ -

312 qreal QGraphicsScale::zScale() const -

313 { -

314 Q_D(const QGraphicsScale); -

315

return d->zScale;

never executed: return d->zScale;

316 } -

317 void QGraphicsScale::setZScale(qreal scale) -

318 { -

319 Q_D(QGraphicsScale); -

320

if (d->zScale == scale)

d->zScale == scale	Description
TRUE	never evaluated
FALSE	never evaluated

321

return;

never executed: return;

322 d->zScale = scale; -

323 update(); -

324 emit zScaleChanged(); -

325 emit scaleChanged(); -

326

}

never executed: end of block

327 -

328 /*! -

329 \reimp -

330 */ -

331 void QGraphicsScale::applyTo(QMatrix4x4 *matrix) const -

332 { -

333 Q_D(const QGraphicsScale); -

334 matrix->translate(d->origin); -

335 matrix->scale(d->xScale, d->yScale, d->zScale); -

336 matrix->translate(-d->origin); -

337

}

never executed: end of block

338 -

339 /*! -

340 \fn QGraphicsScale::originChanged() -

341 -

342 QGraphicsScale emits this signal when its origin changes. -

343 -

344 \sa QGraphicsScale::origin -

345 */ -

346 -

347 /*! -

348 \fn QGraphicsScale::xScaleChanged() -

349 \since 4.7 -

350 -

351 This signal is emitted whenever the \l xScale property changes. -

352 */ -

353 -

354 /*! -

355 \fn QGraphicsScale::yScaleChanged() -

356 \since 4.7 -

357 -

358 This signal is emitted whenever the \l yScale property changes. -

359 */ -

360 -

361 /*! -

362 \fn QGraphicsScale::zScaleChanged() -

363 \since 4.7 -

364 -

365 This signal is emitted whenever the \l zScale property changes. -

366 */ -

367 -

368 /*! -

369 \fn QGraphicsScale::scaleChanged() -

370 -

371 This signal is emitted whenever the xScale, yScale, or zScale -

372 of the object changes. -

373 -

374 \sa QGraphicsScale::xScale, QGraphicsScale::yScale -

375 \sa QGraphicsScale::zScale -

376 */ -

377 -

378 /*! -

379 \class QGraphicsRotation -

380 \brief The QGraphicsRotation class provides a rotation transformation around -

381 a given axis. -

382 \since 4.6 -

383 \inmodule QtWidgets -

384 -

385 You can provide the desired axis by assigning a QVector3D to the axis property -

386 or by passing a member if Qt::Axis to the setAxis convenience function. -

387 By default the axis is (0, 0, 1) i.e., rotation around the Z axis. -

388 -

389 The angle property, which is provided by QGraphicsRotation, now -

390 describes the number of degrees to rotate around this axis. -

391 -

392 QGraphicsRotation provides certain parameters to help control how the -

393 rotation should be applied. -

394 -

395 The origin is the point that the item is rotated around (i.e., it stays -

396 fixed relative to the parent as the rest of the item is rotated). By -

397 default the origin is QPointF(0, 0). -

398 -

399 The angle property provides the number of degrees to rotate the item -

400 clockwise around the origin. This value also be negative, indicating a -

401 counter-clockwise rotation. For animation purposes it may also be useful to -

402 provide rotation angles exceeding (-360, 360) degrees, for instance to -

403 animate how an item rotates several times. -

404 -

405 Note: the final rotation is the combined effect of a rotation in -

406 3D space followed by a projection back to 2D. If several rotations -

407 are performed in succession, they will not behave as expected unless -

408 they were all around the Z axis. -

409 -

410 \sa QGraphicsTransform, QGraphicsItem::setRotation(), QTransform::rotate() -

411 */ -

412 -

413 class QGraphicsRotationPrivate : public QGraphicsTransformPrivate -

414 { -

415 public: -

416 QGraphicsRotationPrivate() -

417

: angle(0), axis(0, 0, 1) {}

never executed: end of block

418 QVector3D origin; -

419 qreal angle; -

420 QVector3D axis; -

421 }; -

422 -

423 /*! -

424 Constructs a new QGraphicsRotation with the given \a parent. -

425 */ -

426 QGraphicsRotation::QGraphicsRotation(QObject *parent) -

427 : QGraphicsTransform(*new QGraphicsRotationPrivate, parent) -

428 { -

429

}

never executed: end of block

430 -

431 /*! -

432 Destroys the graphics rotation. -

433 */ -

434 QGraphicsRotation::~QGraphicsRotation() -

435 { -

436 } -

437 -

438 /*! -

439 \property QGraphicsRotation::origin -

440 \brief the origin of the rotation in 3D space. -

441 -

442 All rotations will be done relative to this point (i.e., this point -

443 will stay fixed, relative to the parent, when the item is rotated). -

444 -

445 \sa angle -

446 */ -

447 QVector3D QGraphicsRotation::origin() const -

448 { -

449 Q_D(const QGraphicsRotation); -

450

return d->origin;

never executed: return d->origin;

451 } -

452 void QGraphicsRotation::setOrigin(const QVector3D &point) -

453 { -

454 Q_D(QGraphicsRotation); -

455

if (d->origin == point)

d->origin == point	Description
TRUE	never evaluated
FALSE	never evaluated

456

return;

never executed: return;

457 d->origin = point; -

458 update(); -

459 emit originChanged(); -

460

}

never executed: end of block

461 -

462 /*! -

463 \property QGraphicsRotation::angle -

464 \brief the angle for clockwise rotation, in degrees. -

465 -

466 The angle can be any real number; the default value is 0.0. A value of 180 -

467 will rotate 180 degrees, clockwise. If you provide a negative number, the -

468 item will be rotated counter-clockwise. Normally the rotation angle will be -

469 in the range (-360, 360), but you can also provide numbers outside of this -

470 range (e.g., a angle of 370 degrees gives the same result as 10 degrees). -

471 Setting the angle to NaN results in no rotation. -

472 -

473 \sa origin -

474 */ -

475 qreal QGraphicsRotation::angle() const -

476 { -

477 Q_D(const QGraphicsRotation); -

478

return d->angle;

never executed: return d->angle;

479 } -

480 void QGraphicsRotation::setAngle(qreal angle) -

481 { -

482 Q_D(QGraphicsRotation); -

483

if (d->angle == angle)

d->angle == angle	Description
TRUE	never evaluated
FALSE	never evaluated

484

return;

never executed: return;

485 d->angle = angle; -

486 update(); -

487 emit angleChanged(); -

488

}

never executed: end of block

489 -

490 /*! -

491 \fn QGraphicsRotation::originChanged() -

492 -

493 This signal is emitted whenever the origin has changed. -

494 -

495 \sa QGraphicsRotation::origin -

496 */ -

497 -

498 /*! -

499 \fn void QGraphicsRotation::angleChanged() -

500 -

501 This signal is emitted whenever the angle has changed. -

502 -

503 \sa QGraphicsRotation::angle -

504 */ -

505 -

506 /*! -

507 \property QGraphicsRotation::axis -

508 \brief a rotation axis, specified by a vector in 3D space. -

509 -

510 This can be any axis in 3D space. By default the axis is (0, 0, 1), -

511 which is aligned with the Z axis. If you provide another axis, -

512 QGraphicsRotation will provide a transformation that rotates -

513 around this axis. For example, if you would like to rotate an item -

514 around its X axis, you could pass (1, 0, 0) as the axis. -

515 -

516 \sa QTransform, QGraphicsRotation::angle -

517 */ -

518 QVector3D QGraphicsRotation::axis() const -

519 { -

520 Q_D(const QGraphicsRotation); -

521

return d->axis;

never executed: return d->axis;

522 } -

523 void QGraphicsRotation::setAxis(const QVector3D &axis) -

524 { -

525 Q_D(QGraphicsRotation); -

526

if (d->axis == axis)

d->axis == axis	Description
TRUE	never evaluated
FALSE	never evaluated

527

return;

never executed: return;

528 d->axis = axis; -

529 update(); -

530 emit axisChanged(); -

531

}

never executed: end of block

532 -

533 /*! -

534 \fn void QGraphicsRotation::setAxis(Qt::Axis axis) -

535 -

536 Convenience function to set the axis to \a axis. -

537 -

538 Note: the Qt::YAxis rotation for QTransform is inverted from the -

539 correct mathematical rotation in 3D space. The QGraphicsRotation -

540 class implements a correct mathematical rotation. The following -

541 two sequences of code will perform the same transformation: -

542 -

543 \code -

544 QTransform t; -

545 t.rotate(45, Qt::YAxis); -

546 -

547 QGraphicsRotation r; -

548 r.setAxis(Qt::YAxis); -

549 r.setAngle(-45); -

550 \endcode -

551 */ -

552 void QGraphicsRotation::setAxis(Qt::Axis axis) -

553 { -

554 switch (axis) -

555 { -

556

case Qt::XAxis:

never executed: case Qt::XAxis:

557 setAxis(QVector3D(1, 0, 0)); -

558

break;

never executed: break;

559

case Qt::YAxis:

never executed: case Qt::YAxis:

560 setAxis(QVector3D(0, 1, 0)); -

561

break;

never executed: break;

562

case Qt::ZAxis:

never executed: case Qt::ZAxis:

563 setAxis(QVector3D(0, 0, 1)); -

564

break;

never executed: break;

565 } -

566

}

never executed: end of block

567 -

568 /*! -

569 \reimp -

570 */ -

571 void QGraphicsRotation::applyTo(QMatrix4x4 *matrix) const -

572 { -

573 Q_D(const QGraphicsRotation); -

574 -

575

if (d->angle == 0. || d->axis.isNull() || qIsNaN(d->angle))

d->angle == 0.	Description
TRUE	never evaluated
FALSE	never evaluated

d->axis.isNull()	Description
TRUE	never evaluated
FALSE	never evaluated

qIsNaN(d->angle)	Description
TRUE	never evaluated
FALSE	never evaluated

576

return;

never executed: return;

577 -

578 matrix->translate(d->origin); -

579 matrix->projectedRotate(d->angle, d->axis.x(), d->axis.y(), d->axis.z()); -

580 matrix->translate(-d->origin); -

581

}

never executed: end of block

582 -

583 /*! -

584 \fn void QGraphicsRotation::axisChanged() -

585 -

586 This signal is emitted whenever the axis of the object changes. -

587 -

588 \sa QGraphicsRotation::axis -

589 */ -

590 -

591 #include "moc_qgraphicstransform.cpp" -

592 -

593 QT_END_NAMESPACE -

594 #endif //QT_NO_GRAPHICSVIEW -

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