summaryrefslogtreecommitdiffstats
path: root/examples/widgets/draganddrop/draggabletext/dragwidget.cpp
blob: d56f91e9001c2a552d4e0f1b35d5cea59e576f77 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

#include <QtWidgets>

#include "dragwidget.h"

static QLabel *createDragLabel(const QString &text, QWidget *parent)
{
    QLabel *label = new QLabel(text, parent);
    label->setAutoFillBackground(true);
    label->setFrameShape(QFrame::Panel);
    label->setFrameShadow(QFrame::Raised);
    return label;
}

static QString hotSpotMimeDataKey() { return QStringLiteral("application/x-hotspot"); }

DragWidget::DragWidget(QWidget *parent)
    : QWidget(parent)
{
    QFile dictionaryFile(QStringLiteral(":/dictionary/words.txt"));
    dictionaryFile.open(QIODevice::ReadOnly);
    QTextStream inputStream(&dictionaryFile);

    int x = 5;
    int y = 5;

    while (!inputStream.atEnd()) {
        QString word;
        inputStream >> word;
        if (!word.isEmpty()) {
            QLabel *wordLabel = createDragLabel(word, this);
            wordLabel->move(x, y);
            wordLabel->show();
            wordLabel->setAttribute(Qt::WA_DeleteOnClose);
            x += wordLabel->width() + 2;
            if (x >= 245) {
                x = 5;
                y += wordLabel->height() + 2;
            }
        }
    }

    setAcceptDrops(true);
    setMinimumSize(400, qMax(200, y));
    setWindowTitle(tr("Draggable Text"));
}

void DragWidget::dragEnterEvent(QDragEnterEvent *event)
{
    if (event->mimeData()->hasText()) {
        if (event->source() == this) {
            event->setDropAction(Qt::MoveAction);
            event->accept();
        } else {
            event->acceptProposedAction();
        }
    } else {
        event->ignore();
    }
}

void DragWidget::dropEvent(QDropEvent *event)
{
    if (event->mimeData()->hasText()) {
        const QMimeData *mime = event->mimeData();
        QStringList pieces = mime->text().split(QRegularExpression(QStringLiteral("\\s+")),
                                                Qt::SkipEmptyParts);
        QPoint position = event->position().toPoint();
        QPoint hotSpot;

        QByteArrayList hotSpotPos = mime->data(hotSpotMimeDataKey()).split(' ');
        if (hotSpotPos.size() == 2) {
            hotSpot.setX(hotSpotPos.first().toInt());
            hotSpot.setY(hotSpotPos.last().toInt());
        }

        for (const QString &piece : pieces) {
            QLabel *newLabel = createDragLabel(piece, this);
            newLabel->move(position - hotSpot);
            newLabel->show();
            newLabel->setAttribute(Qt::WA_DeleteOnClose);

            position += QPoint(newLabel->width(), 0);
        }

        if (event->source() == this) {
            event->setDropAction(Qt::MoveAction);
            event->accept();
        } else {
            event->acceptProposedAction();
        }
    } else {
        event->ignore();
    }
    for (QWidget *widget : findChildren<QWidget *>()) {
        if (!widget->isVisible())
            widget->deleteLater();
    }
}

void DragWidget::mousePressEvent(QMouseEvent *event)
{
    QLabel *child = qobject_cast<QLabel*>(childAt(event->position().toPoint()));
    if (!child)
        return;

    QPoint hotSpot = event->position().toPoint() - child->pos();

    QMimeData *mimeData = new QMimeData;
    mimeData->setText(child->text());
    mimeData->setData(hotSpotMimeDataKey(),
                      QByteArray::number(hotSpot.x()) + ' ' + QByteArray::number(hotSpot.y()));

    qreal dpr = window()->windowHandle()->devicePixelRatio();
    QPixmap pixmap(child->size() * dpr);
    pixmap.setDevicePixelRatio(dpr);
    child->render(&pixmap);

    QDrag *drag = new QDrag(this);
    drag->setMimeData(mimeData);
    drag->setPixmap(pixmap);
    drag->setHotSpot(hotSpot);

    Qt::DropAction dropAction = drag->exec(Qt::CopyAction | Qt::MoveAction, Qt::CopyAction);

    if (dropAction == Qt::MoveAction)
        child->close();
}