gradients.cpp Example File
demos/gradients/gradients.cpp
/****************************************************************************
**
** Copyright (C) 2005-2005 Trolltech AS. All rights reserved.
**
** This file is part of the documentation of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file. Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/
#include "gradients.h"
#include "hoverpoints.h"
ShadeWidget::ShadeWidget(ShadeType type, QWidget *parent)
: QWidget(parent), m_shade_type(type), m_alpha_gradient(QLinearGradient(0, 0, 0, 0))
{
// Checkers background
if (m_shade_type == ARGBShade) {
QPixmap pm(20, 20);
QPainter pmp(&pm);
pmp.fillRect(0, 0, 10, 10, Qt::lightGray);
pmp.fillRect(10, 10, 10, 10, Qt::lightGray);
pmp.fillRect(0, 10, 10, 10, Qt::darkGray);
pmp.fillRect(10, 0, 10, 10, Qt::darkGray);
pmp.end();
QPalette pal = palette();
pal.setBrush(backgroundRole(), QBrush(pm));
setPalette(pal);
} else {
setAttribute(Qt::WA_NoBackground);
}
QPolygonF points;
points << QPointF(0, sizeHint().height())
<< QPointF(sizeHint().width(), 0);
m_hoverPoints = new HoverPoints(this, HoverPoints::CircleShape);
// m_hoverPoints->setConnectionType(HoverPoints::LineConnection);
m_hoverPoints->setPoints(points);
m_hoverPoints->setPointLock(0, HoverPoints::LockToLeft);
m_hoverPoints->setPointLock(1, HoverPoints::LockToRight);
m_hoverPoints->setSortType(HoverPoints::XSort);
setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
connect(m_hoverPoints, SIGNAL(pointsChanged(const QPolygonF &)), this, SIGNAL(colorsChanged()));
}
QPolygonF ShadeWidget::points() const
{
return m_hoverPoints->points();
}
uint ShadeWidget::colorAt(int x)
{
generateShade();
QPolygonF pts = m_hoverPoints->points();
for (int i=1; i < pts.size(); ++i) {
if (pts.at(i-1).x() <= x && pts.at(i).x() >= x) {
QLineF l(pts.at(i-1), pts.at(i));
l.setLength(l.length() * ((x - l.x1()) / l.dx()));
return m_shade.pixel(qRound(qMin(l.x2(), (qreal(m_shade.width() - 1)))),
qRound(qMin(l.y2(), qreal(m_shade.height() - 1))));
}
}
return 0;
}
void ShadeWidget::setGradientStops(const QGradientStops &stops)
{
if (m_shade_type == ARGBShade) {
m_alpha_gradient = QLinearGradient(0, 0, width(), 0);
for (int i=0; i<stops.size(); ++i) {
QColor c = stops.at(i).second;
m_alpha_gradient.setColorAt(stops.at(i).first, QColor(c.red(), c.green(), c.blue()));
}
m_shade = QImage();
generateShade();
update();
}
}
void ShadeWidget::paintEvent(QPaintEvent *)
{
generateShade();
QPainter p(this);
p.drawImage(0, 0, m_shade);
p.setPen(QColor(146, 146, 146));
p.drawRect(0, 0, width() - 1, height() - 1);
}
void ShadeWidget::generateShade()
{
if (m_shade.isNull() || m_shade.size() != size()) {
if (m_shade_type == ARGBShade) {
m_shade = QImage(size(), QImage::Format_ARGB32_Premultiplied);
m_shade.fill(0);
QPainter p(&m_shade);
p.fillRect(rect(), m_alpha_gradient);
p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
QLinearGradient fade(0, 0, 0, height());
fade.setColorAt(0, QColor(0, 0, 0, 255));
fade.setColorAt(1, QColor(0, 0, 0, 0));
p.fillRect(rect(), fade);
} else {
m_shade = QImage(size(), QImage::Format_RGB32);
QLinearGradient shade(0, 0, 0, height());
shade.setColorAt(1, Qt::black);
if (m_shade_type == RedShade)
shade.setColorAt(0, Qt::red);
else if (m_shade_type == GreenShade)
shade.setColorAt(0, Qt::green);
else
shade.setColorAt(0, Qt::blue);
QPainter p(&m_shade);
p.fillRect(rect(), shade);
}
}
}
GradientEditor::GradientEditor(QWidget *parent)
: QWidget(parent)
{
QVBoxLayout *vbox = new QVBoxLayout(this);
vbox->setSpacing(1);
vbox->setMargin(1);
m_red_shade = new ShadeWidget(ShadeWidget::RedShade, this);
m_green_shade = new ShadeWidget(ShadeWidget::GreenShade, this);
m_blue_shade = new ShadeWidget(ShadeWidget::BlueShade, this);
m_alpha_shade = new ShadeWidget(ShadeWidget::ARGBShade, this);
vbox->addWidget(m_red_shade);
vbox->addWidget(m_green_shade);
vbox->addWidget(m_blue_shade);
vbox->addWidget(m_alpha_shade);
connect(m_red_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
connect(m_green_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
connect(m_blue_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
connect(m_alpha_shade, SIGNAL(colorsChanged()), this, SLOT(pointsUpdated()));
}
inline static bool x_less_than(const QPointF &p1, const QPointF &p2)
{
return p1.x() < p2.x();
}
void GradientEditor::pointsUpdated()
{
double w = m_alpha_shade->width();
QGradientStops stops;
QPolygonF points;
points += m_red_shade->points();
points += m_green_shade->points();
points += m_blue_shade->points();
points += m_alpha_shade->points();
qSort(points.begin(), points.end(), x_less_than);
for (int i=0; i<points.size(); ++i) {
double x = int(points.at(i).x());
if (i < points.size() - 1 && x == points.at(i+1).x())
continue;
QColor color((0x00ff0000 & m_red_shade->colorAt(int(x))) >> 16,
(0x0000ff00 & m_green_shade->colorAt(int(x))) >> 8,
(0x000000ff & m_blue_shade->colorAt(int(x))),
(0xff000000 & m_alpha_shade->colorAt(int(x))) >> 24);
if (x / w > 1)
return;
stops << QGradientStop(x / w, color);
}
m_alpha_shade->setGradientStops(stops);
emit gradientStopsChanged(stops);
}
static void set_shade_points(const QPolygonF &points, ShadeWidget *shade)
{
shade->hoverPoints()->setPoints(points);
shade->hoverPoints()->setPointLock(0, HoverPoints::LockToLeft);
shade->hoverPoints()->setPointLock(points.size() - 1, HoverPoints::LockToRight);
shade->update();
}
void GradientEditor::setGradientStops(const QGradientStops &stops)
{
QPolygonF pts_red, pts_green, pts_blue, pts_alpha;
double h_red = m_red_shade->height();
double h_green = m_green_shade->height();
double h_blue = m_blue_shade->height();
double h_alpha = m_alpha_shade->height();
for (int i=0; i<stops.size(); ++i) {
double pos = stops.at(i).first;
QRgb color = stops.at(i).second.rgba();
pts_red << QPointF(pos * m_red_shade->width(), h_red - qRed(color) * h_red / 255);
pts_green << QPointF(pos * m_green_shade->width(), h_green - qGreen(color) * h_green / 255);
pts_blue << QPointF(pos * m_blue_shade->width(), h_blue - qBlue(color) * h_blue / 255);
pts_alpha << QPointF(pos * m_alpha_shade->width(), h_alpha - qAlpha(color) * h_alpha / 255);
}
set_shade_points(pts_red, m_red_shade);
set_shade_points(pts_green, m_green_shade);
set_shade_points(pts_blue, m_blue_shade);
set_shade_points(pts_alpha, m_alpha_shade);
}
GradientWidget::GradientWidget(QWidget *parent)
: QWidget(parent)
{
setWindowTitle("Gradients");
m_renderer = new GradientRenderer(this);
QGroupBox *mainGroup = new QGroupBox(this);
mainGroup->setTitle("Gradients");
QGroupBox *editorGroup = new QGroupBox(mainGroup);
editorGroup->setAttribute(Qt::WA_ContentsPropagated);
editorGroup->setTitle("Color Editor");
m_editor = new GradientEditor(editorGroup);
QGroupBox *typeGroup = new QGroupBox(mainGroup);
typeGroup->setAttribute(Qt::WA_ContentsPropagated);
typeGroup->setTitle("Gradient Type");
m_linearButton = new QRadioButton("Linear Gradient", typeGroup);
m_radialButton = new QRadioButton("Radial Gradient", typeGroup);
m_conicalButton = new QRadioButton("Conical Gradient", typeGroup);
QGroupBox *spreadGroup = new QGroupBox(mainGroup);
spreadGroup->setAttribute(Qt::WA_ContentsPropagated);
spreadGroup->setTitle("Spread Method");
m_padSpreadButton = new QRadioButton("Pad Spread", spreadGroup);
m_reflectSpreadButton = new QRadioButton("Reflect Spread", spreadGroup);
m_repeatSpreadButton = new QRadioButton("Repeat Spread", spreadGroup);
QGroupBox *defaultsGroup = new QGroupBox(mainGroup);
defaultsGroup->setAttribute(Qt::WA_ContentsPropagated);
defaultsGroup->setTitle("Defaults");
QPushButton *default1Button = new QPushButton("1", defaultsGroup);
QPushButton *default2Button = new QPushButton("2", defaultsGroup);
QPushButton *default3Button = new QPushButton("3", defaultsGroup);
QPushButton *default4Button = new QPushButton("Reset", editorGroup);
QPushButton *showSourceButton = new QPushButton(mainGroup);
showSourceButton->setText("Show Source");
QPushButton *whatsThisButton = new QPushButton(mainGroup);
whatsThisButton->setText("What's This?");
whatsThisButton->setCheckable(true);
// Layouts
QHBoxLayout *mainLayout = new QHBoxLayout(this);
mainLayout->addWidget(m_renderer);
mainLayout->addWidget(mainGroup);
mainGroup->setFixedWidth(180);
QVBoxLayout *mainGroupLayout = new QVBoxLayout(mainGroup);
mainGroupLayout->addWidget(editorGroup);
mainGroupLayout->addWidget(typeGroup);
mainGroupLayout->addWidget(spreadGroup);
mainGroupLayout->addWidget(defaultsGroup);
mainGroupLayout->addStretch(1);
mainGroupLayout->addWidget(showSourceButton);
mainGroupLayout->addWidget(whatsThisButton);
QVBoxLayout *editorGroupLayout = new QVBoxLayout(editorGroup);
editorGroupLayout->addWidget(m_editor);
QVBoxLayout *typeGroupLayout = new QVBoxLayout(typeGroup);
typeGroupLayout->addWidget(m_linearButton);
typeGroupLayout->addWidget(m_radialButton);
typeGroupLayout->addWidget(m_conicalButton);
QVBoxLayout *spreadGroupLayout = new QVBoxLayout(spreadGroup);
spreadGroupLayout->addWidget(m_padSpreadButton);
spreadGroupLayout->addWidget(m_repeatSpreadButton);
spreadGroupLayout->addWidget(m_reflectSpreadButton);
QHBoxLayout *defaultsGroupLayout = new QHBoxLayout(defaultsGroup);
defaultsGroupLayout->addWidget(default1Button);
defaultsGroupLayout->addWidget(default2Button);
defaultsGroupLayout->addWidget(default3Button);
editorGroupLayout->addWidget(default4Button);
connect(m_editor, SIGNAL(gradientStopsChanged(const QGradientStops &)),
m_renderer, SLOT(setGradientStops(const QGradientStops &)));
connect(m_linearButton, SIGNAL(clicked()), m_renderer, SLOT(setLinearGradient()));
connect(m_radialButton, SIGNAL(clicked()), m_renderer, SLOT(setRadialGradient()));
connect(m_conicalButton, SIGNAL(clicked()), m_renderer, SLOT(setConicalGradient()));
connect(m_padSpreadButton, SIGNAL(clicked()), m_renderer, SLOT(setPadSpread()));
connect(m_reflectSpreadButton, SIGNAL(clicked()), m_renderer, SLOT(setReflectSpread()));
connect(m_repeatSpreadButton, SIGNAL(clicked()), m_renderer, SLOT(setRepeatSpread()));
connect(default1Button, SIGNAL(clicked()), this, SLOT(setDefault1()));
connect(default2Button, SIGNAL(clicked()), this, SLOT(setDefault2()));
connect(default3Button, SIGNAL(clicked()), this, SLOT(setDefault3()));
connect(default4Button, SIGNAL(clicked()), this, SLOT(setDefault4()));
connect(showSourceButton, SIGNAL(clicked()), m_renderer, SLOT(showSource()));
connect(whatsThisButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setDescriptionEnabled(bool)));
connect(whatsThisButton, SIGNAL(clicked(bool)),
m_renderer->hoverPoints(), SLOT(setDisabled(bool)));
connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
whatsThisButton, SLOT(setChecked(bool)));
connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
m_renderer->hoverPoints(), SLOT(setDisabled(bool)));
m_renderer->loadSourceFile(":res/gradients.cpp");
m_renderer->loadDescription(":res/gradients.html");
QTimer::singleShot(50, this, SLOT(setDefault1()));
}
void GradientWidget::setDefault(int config)
{
QGradientStops stops;
QPolygonF points;
switch (config) {
case 1:
stops << QGradientStop(0.00, QColor::fromRgba(0));
stops << QGradientStop(0.04, QColor::fromRgba(0xff131360));
stops << QGradientStop(0.08, QColor::fromRgba(0xff202ccc));
stops << QGradientStop(0.42, QColor::fromRgba(0xff93d3f9));
stops << QGradientStop(0.51, QColor::fromRgba(0xffb3e6ff));
stops << QGradientStop(0.73, QColor::fromRgba(0xffffffec));
stops << QGradientStop(0.92, QColor::fromRgba(0xff5353d9));
stops << QGradientStop(0.96, QColor::fromRgba(0xff262666));
stops << QGradientStop(1.00, QColor::fromRgba(0));
m_linearButton->animateClick();
m_repeatSpreadButton->animateClick();
break;
case 2:
stops << QGradientStop(0.00, QColor::fromRgba(0xffffffff));
stops << QGradientStop(0.11, QColor::fromRgba(0xfff9ffa0));
stops << QGradientStop(0.13, QColor::fromRgba(0xfff9ff99));
stops << QGradientStop(0.14, QColor::fromRgba(0xfff3ff86));
stops << QGradientStop(0.49, QColor::fromRgba(0xff93b353));
stops << QGradientStop(0.87, QColor::fromRgba(0xff264619));
stops << QGradientStop(0.96, QColor::fromRgba(0xff0c1306));
stops << QGradientStop(1.00, QColor::fromRgba(0));
m_radialButton->animateClick();
m_padSpreadButton->animateClick();
break;
case 3:
stops << QGradientStop(0.00, QColor::fromRgba(0));
stops << QGradientStop(0.10, QColor::fromRgba(0xffe0cc73));
stops << QGradientStop(0.17, QColor::fromRgba(0xffc6a006));
stops << QGradientStop(0.46, QColor::fromRgba(0xff600659));
stops << QGradientStop(0.72, QColor::fromRgba(0xff0680ac));
stops << QGradientStop(0.92, QColor::fromRgba(0xffb9d9e6));
stops << QGradientStop(1.00, QColor::fromRgba(0));
m_conicalButton->animateClick();
m_padSpreadButton->animateClick();
break;
case 4:
stops << QGradientStop(0.00, QColor::fromRgba(0xff000000));
stops << QGradientStop(1.00, QColor::fromRgba(0xffffffff));
break;
default:
qWarning("bad default: %d\n", config);
break;
}
QPolygonF pts;
int h_off = m_renderer->width() / 10;
int v_off = m_renderer->height() / 8;
pts << QPointF(m_renderer->width() / 2, m_renderer->height() / 2)
<< QPointF(m_renderer->width() / 2 - h_off, m_renderer->height() / 2 - v_off);
m_editor->setGradientStops(stops);
m_renderer->hoverPoints()->setPoints(pts);
m_renderer->setGradientStops(stops);
}
GradientRenderer::GradientRenderer(QWidget *parent)
: ArthurFrame(parent)
{
m_hoverPoints = new HoverPoints(this, HoverPoints::CircleShape);
m_hoverPoints->setPointSize(QSize(20, 20));
m_hoverPoints->setConnectionType(HoverPoints::NoConnection);
m_hoverPoints->setEditable(false);
QVector<QPointF> points;
points << QPointF(100, 100) << QPointF(200, 200);
m_hoverPoints->setPoints(points);
m_spread = QGradient::PadSpread;
m_gradientType = Qt::LinearGradientPattern;
}
void GradientRenderer::setGradientStops(const QGradientStops &stops)
{
m_stops = stops;
update();
}
void GradientRenderer::mousePressEvent(QMouseEvent *)
{
setDescriptionEnabled(false);
}
void GradientRenderer::paint(QPainter *p)
{
QPolygonF pts = m_hoverPoints->points();
QGradient g;
if (m_gradientType == Qt::LinearGradientPattern) {
g = QLinearGradient(pts.at(0), pts.at(1));
} else if (m_gradientType == Qt::RadialGradientPattern) {
g = QRadialGradient(pts.at(0), qMin(width(), height()) / 3.0, pts.at(1));
} else {
QLineF l(pts.at(0), pts.at(1));
double angle = l.angle(QLineF(0, 0, 1, 0));
if (l.dy() > 0)
angle = 360 - angle;
g = QConicalGradient(pts.at(0), angle);
}
for (int i=0; i<m_stops.size(); ++i)
g.setColorAt(m_stops.at(i).first, m_stops.at(i).second);
g.setSpread(m_spread);
p->setBrush(g);
p->setPen(Qt::NoPen);
p->drawRect(rect());
}
