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50
51#include "coloritem.h"
52
53#include <QApplication>
54#include <QBitmap>
55#include <QCursor>
56#include <QDrag>
57#include <QGraphicsSceneMouseEvent>
58#include <QMimeData>
59#include <QPainter>
60#include <QRandomGenerator>
61#include <QWidget>
62
63//! [0]
64ColorItem::ColorItem()
65 : color(QRandomGenerator::global()->bounded(highest: 256), QRandomGenerator::global()->bounded(highest: 256), QRandomGenerator::global()->bounded(highest: 256))
66{
67 setToolTip(QString("QColor(%1, %2, %3)\n%4")
68 .arg(a: color.red()).arg(a: color.green()).arg(a: color.blue())
69 .arg(a: "Click and drag this color onto the robot!"));
70 setCursor(Qt::OpenHandCursor);
71 setAcceptedMouseButtons(Qt::LeftButton);
72}
73//! [0]
74
75//! [1]
76QRectF ColorItem::boundingRect() const
77{
78 return QRectF(-15.5, -15.5, 34, 34);
79}
80//! [1]
81
82//! [2]
83void ColorItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
84{
85 Q_UNUSED(option);
86 Q_UNUSED(widget);
87 painter->setPen(Qt::NoPen);
88 painter->setBrush(Qt::darkGray);
89 painter->drawEllipse(x: -12, y: -12, w: 30, h: 30);
90 painter->setPen(QPen(Qt::black, 1));
91 painter->setBrush(QBrush(color));
92 painter->drawEllipse(x: -15, y: -15, w: 30, h: 30);
93}
94//! [2]
95
96//! [3]
97void ColorItem::mousePressEvent(QGraphicsSceneMouseEvent *)
98{
99 setCursor(Qt::ClosedHandCursor);
100}
101//! [3]
102
103//! [5]
104void ColorItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
105{
106 if (QLineF(event->screenPos(), event->buttonDownScreenPos(button: Qt::LeftButton))
107 .length() < QApplication::startDragDistance()) {
108 return;
109 }
110
111 QDrag *drag = new QDrag(event->widget());
112 QMimeData *mime = new QMimeData;
113 drag->setMimeData(mime);
114//! [5]
115
116//! [6]
117 static int n = 0;
118 if (n++ > 2 && QRandomGenerator::global()->bounded(highest: 3) == 0) {
119 QImage image(":/images/head.png");
120 mime->setImageData(image);
121
122 drag->setPixmap(QPixmap::fromImage(image).scaled(w: 30, h: 40));
123 drag->setHotSpot(QPoint(15, 30));
124//! [6]
125//! [7]
126 } else {
127 mime->setColorData(color);
128 mime->setText(QString("#%1%2%3")
129 .arg(a: color.red(), fieldWidth: 2, base: 16, fillChar: QLatin1Char('0'))
130 .arg(a: color.green(), fieldWidth: 2, base: 16, fillChar: QLatin1Char('0'))
131 .arg(a: color.blue(), fieldWidth: 2, base: 16, fillChar: QLatin1Char('0')));
132
133 QPixmap pixmap(34, 34);
134 pixmap.fill(fillColor: Qt::white);
135
136 QPainter painter(&pixmap);
137 painter.translate(dx: 15, dy: 15);
138 painter.setRenderHint(hint: QPainter::Antialiasing);
139 paint(painter: &painter, option: nullptr, widget: nullptr);
140 painter.end();
141
142 pixmap.setMask(pixmap.createHeuristicMask());
143
144 drag->setPixmap(pixmap);
145 drag->setHotSpot(QPoint(15, 20));
146 }
147//! [7]
148
149//! [8]
150 drag->exec();
151 setCursor(Qt::OpenHandCursor);
152}
153//! [8]
154
155//! [4]
156void ColorItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *)
157{
158 setCursor(Qt::OpenHandCursor);
159}
160//! [4]
161

source code of qtbase/examples/widgets/graphicsview/dragdroprobot/coloritem.cpp