qgraphicstransform.cpp

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39 -

40 /*! -

41 \class QGraphicsTransform -

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

43 advanced transformations on QGraphicsItems. -

44 \since 4.6 -

45 \ingroup graphicsview-api -

46 \inmodule QtWidgets -

47 -

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

49 create and control advanced transformations that can be configured -

50 independently using specialized properties. -

51 -

52 QGraphicsItem allows you to assign any number of QGraphicsTransform -

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

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

55 -

56 QGraphicsTransform is particularly useful for animations. Whereas -

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

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

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

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

61 QGraphicsTransform you can interpolate the property values of each -

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

63 single transform which is applied to QGraphicsItem. -

64 -

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

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

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

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

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

70 only occurring after the last QGraphicsTransform is applied. -

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

72 2D after each rotation to preserve the perspective effect around -

73 the X and Y axes. -

74 -

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

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

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

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

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

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

81 respectively. -

82 -

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

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

85 -

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

87 */ -

88 -

89 #include "qgraphicstransform.h" -

90 #include "qgraphicsitem_p.h" -

91 #include "qgraphicstransform_p.h" -

92 #include <QDebug> -

93 #include <QtCore/qmath.h> -

94 #include <QtCore/qnumeric.h> -

95 -

96 #ifndef QT_NO_GRAPHICSVIEW -

97 QT_BEGIN_NAMESPACE -

98 -

99 QGraphicsTransformPrivate::~QGraphicsTransformPrivate() -

100 { -

101 } -

102 -

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

104 { -

105

if (item == i)

item == i	Description
TRUE	never evaluated
FALSE	never evaluated

106

return;

never executed: return;

107 -

108

if (item) {

item	Description
TRUE	never evaluated
FALSE	never evaluated

109 Q_Q(QGraphicsTransform); -

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

111 -

112 item->prepareGeometryChange(); -

113 Q_ASSERT(d_ptr->transformData); -

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

115 d_ptr->dirtySceneTransform = 1; -

116 item = 0; -

117

}

never executed: end of block

118 -

119 item = i; -

120

}

never executed: end of block

121 -

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

123 { -

124 item->prepareGeometryChange(); -

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

126

}

never executed: end of block

127 -

128 /*! -

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

130 */ -

131 QGraphicsTransform::QGraphicsTransform(QObject *parent) -

132 : QObject(*new QGraphicsTransformPrivate, parent) -

133 { -

134

}

never executed: end of block

135 -

136 /*! -

137 Destroys the graphics transform. -

138 */ -

139 QGraphicsTransform::~QGraphicsTransform() -

140 { -

141 Q_D(QGraphicsTransform); -

142 d->setItem(0); -

143

}

never executed: end of block

144 -

145 /*! -

146 \internal -

147 */ -

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

149 : QObject(p, parent) -

150 { -

151

}

never executed: end of block

152 -

153 /*! -

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

155 -

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

157 -

158 It applies this transformation to \a matrix. -

159 -

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

161 */ -

162 -

163 /*! -

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

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

166 -

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

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

169 its transformation needs to be updated. -

170 -

171 \sa applyTo() -

172 */ -

173 void QGraphicsTransform::update() -

174 { -

175 Q_D(QGraphicsTransform); -

176

if (d->item)

d->item	Description
TRUE	never evaluated
FALSE	never evaluated

177

d->updateItem(d->item);

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

178

}

never executed: end of block

179 -

180 /*! -

181 \class QGraphicsScale -

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

183 \since 4.6 -

184 \inmodule QtWidgets -

185 -

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

187 should be applied. -

188 -

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

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

191 origin is QPointF(0, 0). -

192 -

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

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

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

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

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

198 item end for end. -

199 -

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

201 */ -

202 -

203 class QGraphicsScalePrivate : public QGraphicsTransformPrivate -

204 { -

205 public: -

206 QGraphicsScalePrivate() -

207

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

never executed: end of block

208 QVector3D origin; -

209 qreal xScale; -

210 qreal yScale; -

211 qreal zScale; -

212 }; -

213 -

214 /*! -

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

216 */ -

217 QGraphicsScale::QGraphicsScale(QObject *parent) -

218 : QGraphicsTransform(*new QGraphicsScalePrivate, parent) -

219 { -

220

}

never executed: end of block

221 -

222 /*! -

223 Destroys the graphics scale. -

224 */ -

225 QGraphicsScale::~QGraphicsScale() -

226 { -

227 } -

228 -

229 /*! -

230 \property QGraphicsScale::origin -

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

232 -

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

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

235 -

236 \sa xScale, yScale, zScale -

237 */ -

238 QVector3D QGraphicsScale::origin() const -

239 { -

240 Q_D(const QGraphicsScale); -

241

return d->origin;

never executed: return d->origin;

242 } -

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

244 { -

245 Q_D(QGraphicsScale); -

246

if (d->origin == point)

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

247

return;

never executed: return;

248 d->origin = point; -

249 update(); -

250 emit originChanged(); -

251

}

never executed: end of block

252 -

253 /*! -

254 \property QGraphicsScale::xScale -

255 \brief the horizontal scale factor. -

256 -

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

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

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

260 origin. -

261 -

262 \sa yScale, zScale, origin -

263 */ -

264 qreal QGraphicsScale::xScale() const -

265 { -

266 Q_D(const QGraphicsScale); -

267

return d->xScale;

never executed: return d->xScale;

268 } -

269 void QGraphicsScale::setXScale(qreal scale) -

270 { -

271 Q_D(QGraphicsScale); -

272

if (d->xScale == scale)

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

273

return;

never executed: return;

274 d->xScale = scale; -

275 update(); -

276 emit xScaleChanged(); -

277 emit scaleChanged(); -

278

}

never executed: end of block

279 -

280 /*! -

281 \property QGraphicsScale::yScale -

282 \brief the vertical scale factor. -

283 -

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

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

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

287 origin. -

288 -

289 \sa xScale, zScale, origin -

290 */ -

291 qreal QGraphicsScale::yScale() const -

292 { -

293 Q_D(const QGraphicsScale); -

294

return d->yScale;

never executed: return d->yScale;

295 } -

296 void QGraphicsScale::setYScale(qreal scale) -

297 { -

298 Q_D(QGraphicsScale); -

299

if (d->yScale == scale)

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

300

return;

never executed: return;

301 d->yScale = scale; -

302 update(); -

303 emit yScaleChanged(); -

304 emit scaleChanged(); -

305

}

never executed: end of block

306 -

307 /*! -

308 \property QGraphicsScale::zScale -

309 \brief the depth scale factor. -

310 -

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

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

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

314 origin. -

315 -

316 \sa xScale, yScale, origin -

317 */ -

318 qreal QGraphicsScale::zScale() const -

319 { -

320 Q_D(const QGraphicsScale); -

321

return d->zScale;

never executed: return d->zScale;

322 } -

323 void QGraphicsScale::setZScale(qreal scale) -

324 { -

325 Q_D(QGraphicsScale); -

326

if (d->zScale == scale)

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

327

return;

never executed: return;

328 d->zScale = scale; -

329 update(); -

330 emit zScaleChanged(); -

331 emit scaleChanged(); -

332

}

never executed: end of block

333 -

334 /*! -

335 \reimp -

336 */ -

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

338 { -

339 Q_D(const QGraphicsScale); -

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

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

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

343

}

never executed: end of block

344 -

345 /*! -

346 \fn QGraphicsScale::originChanged() -

347 -

348 QGraphicsScale emits this signal when its origin changes. -

349 -

350 \sa QGraphicsScale::origin -

351 */ -

352 -

353 /*! -

354 \fn QGraphicsScale::xScaleChanged() -

355 \since 4.7 -

356 -

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

358 */ -

359 -

360 /*! -

361 \fn QGraphicsScale::yScaleChanged() -

362 \since 4.7 -

363 -

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

365 */ -

366 -

367 /*! -

368 \fn QGraphicsScale::zScaleChanged() -

369 \since 4.7 -

370 -

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

372 */ -

373 -

374 /*! -

375 \fn QGraphicsScale::scaleChanged() -

376 -

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

378 of the object changes. -

379 -

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

381 \sa QGraphicsScale::zScale -

382 */ -

383 -

384 /*! -

385 \class QGraphicsRotation -

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

387 a given axis. -

388 \since 4.6 -

389 \inmodule QtWidgets -

390 -

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

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

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

394 -

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

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

397 -

398 QGraphicsRotation provides certain parameters to help control how the -

399 rotation should be applied. -

400 -

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

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

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

404 -

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

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

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

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

409 animate how an item rotates several times. -

410 -

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

412 3D space followed by a projection back to 2D. If several rotations -

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

414 they were all around the Z axis. -

415 -

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

417 */ -

418 -

419 class QGraphicsRotationPrivate : public QGraphicsTransformPrivate -

420 { -

421 public: -

422 QGraphicsRotationPrivate() -

423

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

never executed: end of block

424 QVector3D origin; -

425 qreal angle; -

426 QVector3D axis; -

427 }; -

428 -

429 /*! -

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

431 */ -

432 QGraphicsRotation::QGraphicsRotation(QObject *parent) -

433 : QGraphicsTransform(*new QGraphicsRotationPrivate, parent) -

434 { -

435

}

never executed: end of block

436 -

437 /*! -

438 Destroys the graphics rotation. -

439 */ -

440 QGraphicsRotation::~QGraphicsRotation() -

441 { -

442 } -

443 -

444 /*! -

445 \property QGraphicsRotation::origin -

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

447 -

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

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

450 -

451 \sa angle -

452 */ -

453 QVector3D QGraphicsRotation::origin() const -

454 { -

455 Q_D(const QGraphicsRotation); -

456

return d->origin;

never executed: return d->origin;

457 } -

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

459 { -

460 Q_D(QGraphicsRotation); -

461

if (d->origin == point)

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

462

return;

never executed: return;

463 d->origin = point; -

464 update(); -

465 emit originChanged(); -

466

}

never executed: end of block

467 -

468 /*! -

469 \property QGraphicsRotation::angle -

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

471 -

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

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

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

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

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

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

478 -

479 \sa origin -

480 */ -

481 qreal QGraphicsRotation::angle() const -

482 { -

483 Q_D(const QGraphicsRotation); -

484

return d->angle;

never executed: return d->angle;

485 } -

486 void QGraphicsRotation::setAngle(qreal angle) -

487 { -

488 Q_D(QGraphicsRotation); -

489

if (d->angle == angle)

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

490

return;

never executed: return;

491 d->angle = angle; -

492 update(); -

493 emit angleChanged(); -

494

}

never executed: end of block

495 -

496 /*! -

497 \fn QGraphicsRotation::originChanged() -

498 -

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

500 -

501 \sa QGraphicsRotation::origin -

502 */ -

503 -

504 /*! -

505 \fn void QGraphicsRotation::angleChanged() -

506 -

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

508 -

509 \sa QGraphicsRotation::angle -

510 */ -

511 -

512 /*! -

513 \property QGraphicsRotation::axis -

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

515 -

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

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

518 QGraphicsRotation will provide a transformation that rotates -

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

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

521 -

522 \sa QTransform, QGraphicsRotation::angle -

523 */ -

524 QVector3D QGraphicsRotation::axis() const -

525 { -

526 Q_D(const QGraphicsRotation); -

527

return d->axis;

never executed: return d->axis;

528 } -

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

530 { -

531 Q_D(QGraphicsRotation); -

532

if (d->axis == axis)

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

533

return;

never executed: return;

534 d->axis = axis; -

535 update(); -

536 emit axisChanged(); -

537

}

never executed: end of block

538 -

539 /*! -

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

541 -

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

543 -

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

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

546 class implements a correct mathematical rotation. The following -

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

548 -

549 \code -

550 QTransform t; -

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

552 -

553 QGraphicsRotation r; -

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

555 r.setAngle(-45); -

556 \endcode -

557 */ -

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

559 { -

560 switch (axis) -

561 { -

562

case Qt::XAxis:

never executed: case Qt::XAxis:

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

564

break;

never executed: break;

565

case Qt::YAxis:

never executed: case Qt::YAxis:

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

567

break;

never executed: break;

568

case Qt::ZAxis:

never executed: case Qt::ZAxis:

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

570

break;

never executed: break;

571 } -

572

}

never executed: end of block

573 -

574 /*! -

575 \reimp -

576 */ -

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

578 { -

579 Q_D(const QGraphicsRotation); -

580 -

581

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

582

return;

never executed: return;

583 -

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

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

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

587

}

never executed: end of block

588 -

589 /*! -

590 \fn void QGraphicsRotation::axisChanged() -

591 -

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

593 -

594 \sa QGraphicsRotation::axis -

595 */ -

596 -

597 #include "moc_qgraphicstransform.cpp" -

598 -

599 QT_END_NAMESPACE -

600 #endif //QT_NO_GRAPHICSVIEW -

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