examples/painting/gradients/gradients.cpp

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  41
  42 #include "gradients.h"
  43 #include "hoverpoints.h"
  44
  45 ShadeWidget::ShadeWidget(ShadeType type, QWidget *parent)
  46     : QWidget(parent), m_shade_type(type), m_alpha_gradient(QLinearGradient(0, 0, 0, 0))
  47 {
  48
  49     // Checkers background
  50     if (m_shade_type == ARGBShade) {
  51         QPixmap pm(20, 20);
  52         QPainter pmp(&pm);
  53         pmp.fillRect(0, 0, 10, 10, Qt::lightGray);
  54         pmp.fillRect(10, 10, 10, 10, Qt::lightGray);
  55         pmp.fillRect(0, 10, 10, 10, Qt::darkGray);
  56         pmp.fillRect(10, 0, 10, 10, Qt::darkGray);
  57         pmp.end();
  58         QPalette pal = palette();
  59         pal.setBrush(backgroundRole(), QBrush(pm));
  60         setAutoFillBackground(true);
  61         setPalette(pal);
  62
  63     } else {
  64         setAttribute(Qt::WA_NoBackground);
  65
  66     }
  67
  68     QPolygonF points;
  69     points << QPointF(0, sizeHint().height())
  70            << QPointF(sizeHint().width(), 0);
  71
  72     m_hoverPoints = new HoverPoints(this, HoverPoints::CircleShape);
  73 //     m_hoverPoints->setConnectionType(HoverPoints::LineConnection);
  74     m_hoverPoints->setPoints(points);
  75     m_hoverPoints->setPointLock(0, HoverPoints::LockToLeft);
  76     m_hoverPoints->setPointLock(1, HoverPoints::LockToRight);
  77     m_hoverPoints->setSortType(HoverPoints::XSort);
  78
  79     setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
  80
  81     connect(m_hoverPoints, SIGNAL(pointsChanged(QPolygonF)), this, SIGNAL(colorsChanged()));
  82 }
  83
  84
  85 QPolygonF ShadeWidget::points() const
  86 {
  87     return m_hoverPoints->points();
  88 }
  89
  90
  91 uint ShadeWidget::colorAt(int x)
  92 {
  93     generateShade();
  94
  95     QPolygonF pts = m_hoverPoints->points();
  96     for (int i=1; i < pts.size(); ++i) {
  97         if (pts.at(i-1).x() <= x && pts.at(i).x() >= x) {
  98             QLineF l(pts.at(i-1), pts.at(i));
  99             l.setLength(l.length() * ((x - l.x1()) / l.dx()));
 100             return m_shade.pixel(qRound(qMin(l.x2(), (qreal(m_shade.width() - 1)))),
 101                                  qRound(qMin(l.y2(), qreal(m_shade.height() - 1))));
 102         }
 103     }
 104     return 0;
 105 }
 106
 107
 108 void ShadeWidget::setGradientStops(const QGradientStops &stops)
 109 {
 110     if (m_shade_type == ARGBShade) {
 111         m_alpha_gradient = QLinearGradient(0, 0, width(), 0);
 112
 113         for (int i=0; i<stops.size(); ++i) {
 114             QColor c = stops.at(i).second;
 115             m_alpha_gradient.setColorAt(stops.at(i).first, QColor(c.red(), c.green(), c.blue()));
 116         }
 117
 118         m_shade = QImage();
 119         generateShade();
 120         update();
 121     }
 122 }
 123
 124
 125 void ShadeWidget::paintEvent(QPaintEvent *)
 126 {
 127     generateShade();
 128
 129     QPainter p(this);
 130     p.drawImage(0, 0, m_shade);
 131
 132     p.setPen(QColor(146, 146, 146));
 133     p.drawRect(0, 0, width() - 1, height() - 1);
 134 }
 135
 136
 137 void ShadeWidget::generateShade()
 138 {
 139     if (m_shade.isNull() || m_shade.size() != size()) {
 140
 141         if (m_shade_type == ARGBShade) {
 142             m_shade = QImage(size(), QImage::Format_ARGB32_Premultiplied);
 143             m_shade.fill(0);
 144
 145             QPainter p(&m_shade);
 146             p.fillRect(rect(), m_alpha_gradient);
 147
 148             p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
 149             QLinearGradient fade(0, 0, 0, height());
 150             fade.setColorAt(0, QColor(0, 0, 0, 255));
 151             fade.setColorAt(1, QColor(0, 0, 0, 0));
 152             p.fillRect(rect(), fade);
 153
 154         } else {
 155             m_shade = QImage(size(), QImage::Format_RGB32);
 156             QLinearGradient shade(0, 0, 0, height());
 157             shade.setColorAt(1, Qt::black);
 158
 159             if (m_shade_type == RedShade)
 160                 shade.setColorAt(0, Qt::red);
 161             else if (m_shade_type == GreenShade)
 162                 shade.setColorAt(0, Qt::green);
 163             else
 164                 shade.setColorAt(0, Qt::blue);
 165
 166             QPainter p(&m_shade);
 167             p.fillRect(rect(), shade);
 168         }
 169     }
 170
 171
 172 }
 173
 174
 175 GradientEditor::GradientEditor(QWidget *parent)
 176     : QWidget(parent)
 177 {
 178     QVBoxLayout *vbox = new QVBoxLayout(this);
 179     vbox->setSpacing(1);
 180     vbox->setMargin(1);
 181
 182     m_red_shade = new ShadeWidget(ShadeWidget::RedShade, this);
 183     m_green_shade = new ShadeWidget(ShadeWidget::GreenShade, this);
 184     m_blue_shade = new ShadeWidget(ShadeWidget::BlueShade, this);
 185     m_alpha_shade = new ShadeWidget(ShadeWidget::ARGBShade, this);
 186
 187     vbox->addWidget(m_red_shade);
 188     vbox->addWidget(m_green_shade);
 189     vbox->addWidget(m_blue_shade);
 190     vbox->addWidget(m_alpha_shade);
 191
 192     connect(m_red_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
 193     connect(m_green_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
 194     connect(m_blue_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
 195     connect(m_alpha_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
 196 }
 197
 198
 199 inline static bool x_less_than(const QPointF &p1, const QPointF &p2)
 200 {
 201     return p1.x() < p2.x();
 202 }
 203
 204
 205 void GradientEditor::pointsUpdated()
 206 {
 207     qreal w = m_alpha_shade->width();
 208
 209     QGradientStops stops;
 210
 211     QPolygonF points;
 212
 213     points += m_red_shade->points();
 214     points += m_green_shade->points();
 215     points += m_blue_shade->points();
 216     points += m_alpha_shade->points();
 217
 218     qSort(points.begin(), points.end(), x_less_than);
 219
 220     for (int i=0; i<points.size(); ++i) {
 221         qreal x = int(points.at(i).x());
 222         if (i+1 < points.size() && x == points.at(i+1).x())
 223             continue;
 224         QColor color((0x00ff0000 & m_red_shade->colorAt(int(x))) >> 16,
 225                      (0x0000ff00 & m_green_shade->colorAt(int(x))) >> 8,
 226                      (0x000000ff & m_blue_shade->colorAt(int(x))),
 227                      (0xff000000 & m_alpha_shade->colorAt(int(x))) >> 24);
 228
 229         if (x / w > 1)
 230             return;
 231
 232         stops << QGradientStop(x / w, color);
 233     }
 234
 235     m_alpha_shade->setGradientStops(stops);
 236
 237     emit gradientStopsChanged(stops);
 238 }
 239
 240
 241 static void set_shade_points(const QPolygonF &points, ShadeWidget *shade)
 242 {
 243     shade->hoverPoints()->setPoints(points);
 244     shade->hoverPoints()->setPointLock(0, HoverPoints::LockToLeft);
 245     shade->hoverPoints()->setPointLock(points.size() - 1, HoverPoints::LockToRight);
 246     shade->update();
 247 }
 248
 249 void GradientEditor::setGradientStops(const QGradientStops &stops)
 250 {
 251     QPolygonF pts_red, pts_green, pts_blue, pts_alpha;
 252
 253     qreal h_red = m_red_shade->height();
 254     qreal h_green = m_green_shade->height();
 255     qreal h_blue = m_blue_shade->height();
 256     qreal h_alpha = m_alpha_shade->height();
 257
 258     for (int i=0; i<stops.size(); ++i) {
 259         qreal pos = stops.at(i).first;
 260         QRgb color = stops.at(i).second.rgba();
 261         pts_red << QPointF(pos * m_red_shade->width(), h_red - qRed(color) * h_red / 255);
 262         pts_green << QPointF(pos * m_green_shade->width(), h_green - qGreen(color) * h_green / 255);
 263         pts_blue << QPointF(pos * m_blue_shade->width(), h_blue - qBlue(color) * h_blue / 255);
 264         pts_alpha << QPointF(pos * m_alpha_shade->width(), h_alpha - qAlpha(color) * h_alpha / 255);
 265     }
 266
 267     set_shade_points(pts_red, m_red_shade);
 268     set_shade_points(pts_green, m_green_shade);
 269     set_shade_points(pts_blue, m_blue_shade);
 270     set_shade_points(pts_alpha, m_alpha_shade);
 271
 272 }
 273
 274 GradientWidget::GradientWidget(QWidget *parent)
 275     : QWidget(parent)
 276 {
 277     setWindowTitle(tr("Gradients"));
 278
 279     m_renderer = new GradientRenderer(this);
 280
 281     QGroupBox *mainGroup = new QGroupBox(this);
 282     mainGroup->setTitle(tr("Gradients"));
 283
 284     QGroupBox *editorGroup = new QGroupBox(mainGroup);
 285     editorGroup->setTitle(tr("Color Editor"));
 286     m_editor = new GradientEditor(editorGroup);
 287
 288     QGroupBox *typeGroup = new QGroupBox(mainGroup);
 289     typeGroup->setTitle(tr("Gradient Type"));
 290     m_linearButton = new QRadioButton(tr("Linear Gradient"), typeGroup);
 291     m_radialButton = new QRadioButton(tr("Radial Gradient"), typeGroup);
 292     m_conicalButton = new QRadioButton(tr("Conical Gradient"), typeGroup);
 293
 294     QGroupBox *spreadGroup = new QGroupBox(mainGroup);
 295     spreadGroup->setTitle(tr("Spread Method"));
 296     m_padSpreadButton = new QRadioButton(tr("Pad Spread"), spreadGroup);
 297     m_reflectSpreadButton = new QRadioButton(tr("Reflect Spread"), spreadGroup);
 298     m_repeatSpreadButton = new QRadioButton(tr("Repeat Spread"), spreadGroup);
 299
 300     QGroupBox *defaultsGroup = new QGroupBox(mainGroup);
 301     defaultsGroup->setTitle(tr("Defaults"));
 302     QPushButton *default1Button = new QPushButton(tr("1"), defaultsGroup);
 303     QPushButton *default2Button = new QPushButton(tr("2"), defaultsGroup);
 304     QPushButton *default3Button = new QPushButton(tr("3"), defaultsGroup);
 305     QPushButton *default4Button = new QPushButton(tr("Reset"), editorGroup);
 306
 307     QPushButton *showSourceButton = new QPushButton(mainGroup);
 308     showSourceButton->setText(tr("Show Source"));
 309 #ifdef QT_OPENGL_SUPPORT
 310     QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
 311     enableOpenGLButton->setText(tr("Use OpenGL"));
 312     enableOpenGLButton->setCheckable(true);
 313     enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
 314     if (!QGLFormat::hasOpenGL())
 315         enableOpenGLButton->hide();
 316 #endif
 317     QPushButton *whatsThisButton = new QPushButton(mainGroup);
 318     whatsThisButton->setText(tr("What's This?"));
 319     whatsThisButton->setCheckable(true);
 320
 321     // Layouts
 322     QHBoxLayout *mainLayout = new QHBoxLayout(this);
 323     mainLayout->addWidget(m_renderer);
 324     mainLayout->addWidget(mainGroup);
 325
 326     mainGroup->setFixedWidth(180);
 327     QVBoxLayout *mainGroupLayout = new QVBoxLayout(mainGroup);
 328     mainGroupLayout->addWidget(editorGroup);
 329     mainGroupLayout->addWidget(typeGroup);
 330     mainGroupLayout->addWidget(spreadGroup);
 331     mainGroupLayout->addWidget(defaultsGroup);
 332     mainGroupLayout->addStretch(1);
 333     mainGroupLayout->addWidget(showSourceButton);
 334 #ifdef QT_OPENGL_SUPPORT
 335     mainGroupLayout->addWidget(enableOpenGLButton);
 336 #endif
 337     mainGroupLayout->addWidget(whatsThisButton);
 338
 339     QVBoxLayout *editorGroupLayout = new QVBoxLayout(editorGroup);
 340     editorGroupLayout->addWidget(m_editor);
 341
 342     QVBoxLayout *typeGroupLayout = new QVBoxLayout(typeGroup);
 343     typeGroupLayout->addWidget(m_linearButton);
 344     typeGroupLayout->addWidget(m_radialButton);
 345     typeGroupLayout->addWidget(m_conicalButton);
 346
 347     QVBoxLayout *spreadGroupLayout = new QVBoxLayout(spreadGroup);
 348     spreadGroupLayout->addWidget(m_padSpreadButton);
 349     spreadGroupLayout->addWidget(m_repeatSpreadButton);
 350     spreadGroupLayout->addWidget(m_reflectSpreadButton);
 351
 352     QHBoxLayout *defaultsGroupLayout = new QHBoxLayout(defaultsGroup);
 353     defaultsGroupLayout->addWidget(default1Button);
 354     defaultsGroupLayout->addWidget(default2Button);
 355     defaultsGroupLayout->addWidget(default3Button);
 356     editorGroupLayout->addWidget(default4Button);
 357
 358     connect(m_editor, SIGNAL(gradientStopsChanged(QGradientStops)),
 359             m_renderer, SLOT(setGradientStops(QGradientStops)));
 360
 361     connect(m_linearButton, SIGNAL(clicked()), m_renderer, SLOT(setLinearGradient()));
 362     connect(m_radialButton, SIGNAL(clicked()), m_renderer, SLOT(setRadialGradient()));
 363     connect(m_conicalButton, SIGNAL(clicked()), m_renderer, SLOT(setConicalGradient()));
 364
 365     connect(m_padSpreadButton, SIGNAL(clicked()), m_renderer, SLOT(setPadSpread()));
 366     connect(m_reflectSpreadButton, SIGNAL(clicked()), m_renderer, SLOT(setReflectSpread()));
 367     connect(m_repeatSpreadButton, SIGNAL(clicked()), m_renderer, SLOT(setRepeatSpread()));
 368
 369     connect(default1Button, SIGNAL(clicked()), this, SLOT(setDefault1()));
 370     connect(default2Button, SIGNAL(clicked()), this, SLOT(setDefault2()));
 371     connect(default3Button, SIGNAL(clicked()), this, SLOT(setDefault3()));
 372     connect(default4Button, SIGNAL(clicked()), this, SLOT(setDefault4()));
 373
 374     connect(showSourceButton, SIGNAL(clicked()), m_renderer, SLOT(showSource()));
 375 #ifdef QT_OPENGL_SUPPORT
 376     connect(enableOpenGLButton, SIGNAL(clicked(bool)), m_renderer, SLOT(enableOpenGL(bool)));
 377 #endif
 378     connect(whatsThisButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setDescriptionEnabled(bool)));
 379     connect(whatsThisButton, SIGNAL(clicked(bool)),
 380             m_renderer->hoverPoints(), SLOT(setDisabled(bool)));
 381     connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
 382             whatsThisButton, SLOT(setChecked(bool)));
 383     connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
 384             m_renderer->hoverPoints(), SLOT(setDisabled(bool)));
 385
 386     m_renderer->loadSourceFile(":res/gradients/gradients.cpp");
 387     m_renderer->loadDescription(":res/gradients/gradients.html");
 388
 389     QTimer::singleShot(50, this, SLOT(setDefault1()));
 390 }
 391
 392 void GradientWidget::setDefault(int config)
 393 {
 394     QGradientStops stops;
 395     QPolygonF points;
 396     switch (config) {
 397     case 1:
 398         stops << QGradientStop(0.00, QColor::fromRgba(0));
 399         stops << QGradientStop(0.04, QColor::fromRgba(0xff131360));
 400         stops << QGradientStop(0.08, QColor::fromRgba(0xff202ccc));
 401         stops << QGradientStop(0.42, QColor::fromRgba(0xff93d3f9));
 402         stops << QGradientStop(0.51, QColor::fromRgba(0xffb3e6ff));
 403         stops << QGradientStop(0.73, QColor::fromRgba(0xffffffec));
 404         stops << QGradientStop(0.92, QColor::fromRgba(0xff5353d9));
 405         stops << QGradientStop(0.96, QColor::fromRgba(0xff262666));
 406         stops << QGradientStop(1.00, QColor::fromRgba(0));
 407         m_linearButton->animateClick();
 408         m_repeatSpreadButton->animateClick();
 409         break;
 410
 411     case 2:
 412         stops << QGradientStop(0.00, QColor::fromRgba(0xffffffff));
 413         stops << QGradientStop(0.11, QColor::fromRgba(0xfff9ffa0));
 414         stops << QGradientStop(0.13, QColor::fromRgba(0xfff9ff99));
 415         stops << QGradientStop(0.14, QColor::fromRgba(0xfff3ff86));
 416         stops << QGradientStop(0.49, QColor::fromRgba(0xff93b353));
 417         stops << QGradientStop(0.87, QColor::fromRgba(0xff264619));
 418         stops << QGradientStop(0.96, QColor::fromRgba(0xff0c1306));
 419         stops << QGradientStop(1.00, QColor::fromRgba(0));
 420         m_radialButton->animateClick();
 421         m_padSpreadButton->animateClick();
 422         break;
 423
 424     case 3:
 425         stops << QGradientStop(0.00, QColor::fromRgba(0));
 426         stops << QGradientStop(0.10, QColor::fromRgba(0xffe0cc73));
 427         stops << QGradientStop(0.17, QColor::fromRgba(0xffc6a006));
 428         stops << QGradientStop(0.46, QColor::fromRgba(0xff600659));
 429         stops << QGradientStop(0.72, QColor::fromRgba(0xff0680ac));
 430         stops << QGradientStop(0.92, QColor::fromRgba(0xffb9d9e6));
 431         stops << QGradientStop(1.00, QColor::fromRgba(0));
 432         m_conicalButton->animateClick();
 433         m_padSpreadButton->animateClick();
 434         break;
 435
 436     case 4:
 437         stops << QGradientStop(0.00, QColor::fromRgba(0xff000000));
 438         stops << QGradientStop(1.00, QColor::fromRgba(0xffffffff));
 439         break;
 440
 441     default:
 442         qWarning("bad default: %d\n", config);
 443         break;
 444     }
 445
 446     QPolygonF pts;
 447     int h_off = m_renderer->width() / 10;
 448     int v_off = m_renderer->height() / 8;
 449     pts << QPointF(m_renderer->width() / 2, m_renderer->height() / 2)
 450         << QPointF(m_renderer->width() / 2 - h_off, m_renderer->height() / 2 - v_off);
 451
 452     m_editor->setGradientStops(stops);
 453     m_renderer->hoverPoints()->setPoints(pts);
 454     m_renderer->setGradientStops(stops);
 455 }
 456
 457
 458 GradientRenderer::GradientRenderer(QWidget *parent)
 459     : ArthurFrame(parent)
 460 {
 461     m_hoverPoints = new HoverPoints(this, HoverPoints::CircleShape);
 462     m_hoverPoints->setPointSize(QSize(20, 20));
 463     m_hoverPoints->setConnectionType(HoverPoints::NoConnection);
 464     m_hoverPoints->setEditable(false);
 465
 466     QVector<QPointF> points;
 467     points << QPointF(100, 100) << QPointF(200, 200);
 468     m_hoverPoints->setPoints(points);
 469
 470     m_spread = QGradient::PadSpread;
 471     m_gradientType = Qt::LinearGradientPattern;
 472 }
 473
 474 void GradientRenderer::setGradientStops(const QGradientStops &stops)
 475 {
 476     m_stops = stops;
 477     update();
 478 }
 479
 480
 481 void GradientRenderer::mousePressEvent(QMouseEvent *)
 482 {
 483     setDescriptionEnabled(false);
 484 }
 485
 486 void GradientRenderer::paint(QPainter *p)
 487 {
 488     QPolygonF pts = m_hoverPoints->points();
 489
 490     QGradient g;
 491
 492     if (m_gradientType == Qt::LinearGradientPattern) {
 493         g = QLinearGradient(pts.at(0), pts.at(1));
 494
 495     } else if (m_gradientType == Qt::RadialGradientPattern) {
 496         g = QRadialGradient(pts.at(0), qMin(width(), height()) / 3.0, pts.at(1));
 497
 498     } else {
 499         QLineF l(pts.at(0), pts.at(1));
 500         qreal angle = l.angle(QLineF(0, 0, 1, 0));
 501         if (l.dy() > 0)
 502             angle = 360 - angle;
 503         g = QConicalGradient(pts.at(0), angle);
 504     }
 505
 506     for (int i=0; i<m_stops.size(); ++i)
 507         g.setColorAt(m_stops.at(i).first, m_stops.at(i).second);
 508
 509     g.setSpread(m_spread);
 510
 511     p->setBrush(g);
 512     p->setPen(Qt::NoPen);
 513
 514     p->drawRect(rect());
 515
 516 }