Drop Site Example

The Drop Site example shows how to distinguish the various MIME formats available in a drag and drop operation.

It accepts drops from other applications and displays the MIME formats provided by the drag object.

Download this example

main.py

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations

import sys

from PySide6.QtWidgets import QApplication

from dropsitewindow import DropSiteWindow


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = DropSiteWindow()
    window.show()
    sys.exit(app.exec())

droparea.py

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations

from PySide6.QtCore import QMimeData, Qt, Slot, Signal
from PySide6.QtGui import QPalette, QPixmap
from PySide6.QtWidgets import QFrame, QLabel


class DropArea(QLabel):

    changed = Signal(QMimeData)

    def __init__(self, parent=None):
        super().__init__(parent)
        self.setMinimumSize(200, 200)
        self.setFrameStyle(QFrame.Sunken | QFrame.StyledPanel)
        self.setAlignment(Qt.AlignCenter)
        self.setAcceptDrops(True)
        self.setAutoFillBackground(True)
        self.clear()

    def dragEnterEvent(self, event):
        self.setText("<drop content>")
        self.setBackgroundRole(QPalette.Highlight)

        event.acceptProposedAction()
        self.changed.emit(event.mimeData())

    def dragMoveEvent(self, event):
        event.acceptProposedAction()

    def dropEvent(self, event):
        mime_data = event.mimeData()

        if mime_data.hasImage():
            self.setPixmap(QPixmap(mime_data.imageData()))
        elif mime_data.hasFormat("text/markdown"):
            self.setText(mime_data.data("text/markdown"))
            self.setTextFormat(Qt.MarkdownText)
        elif mime_data.hasHtml():
            self.setText(mime_data.html())
            self.setTextFormat(Qt.RichText)
        elif mime_data.hasText():
            self.setText(mime_data.text())
            self.setTextFormat(Qt.PlainText)
        elif mime_data.hasUrls():
            url_list = mime_data.urls()
            text = ""
            for i in range(0, min(len(url_list), 32)):
                text += url_list[i].path() + "\n"
            self.setText(text)
        else:
            self.setText("Cannot display data")

        self.setBackgroundRole(QPalette.Dark)
        event.acceptProposedAction()

    def dragLeaveEvent(self, event):
        self.clear()
        event.accept()

    @Slot()
    def clear(self):
        self.setText("<drop content>")
        self.setBackgroundRole(QPalette.Dark)

        self.changed.emit(None)

dropsitewindow.py

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations

import re
from PySide6.QtCore import QMimeData, Qt, Slot
from PySide6.QtGui import QGuiApplication
from PySide6.QtWidgets import (QAbstractItemView, QPushButton,
                               QDialogButtonBox, QLabel,
                               QTableWidget, QTableWidgetItem,
                               QVBoxLayout, QWidget)

from droparea import DropArea

DESCRIPTION = """This example accepts drags from other applications and
displays the MIME types provided by the drag object."""


_WHITESPACE_PATTERN = re.compile(r"\s+")


def simplify_whitespace(s):
    return _WHITESPACE_PATTERN.sub(" ", s).strip()


class DropSiteWindow(QWidget):

    def __init__(self):
        super().__init__()
        drop_area = DropArea()
        abstract_label = QLabel()
        self._formats_table = QTableWidget()

        button_box = QDialogButtonBox()
        abstract_label = QLabel(DESCRIPTION)
        abstract_label.setWordWrap(True)
        abstract_label.adjustSize()

        drop_area = DropArea()
        drop_area.changed.connect(self.update_formats_table)

        self._formats_table = QTableWidget()
        self._formats_table.setColumnCount(2)
        self._formats_table.setEditTriggers(QAbstractItemView.NoEditTriggers)
        self._formats_table.setHorizontalHeaderLabels(["Format", "Content"])
        self._formats_table.horizontalHeader().setStretchLastSection(True)

        clear_button = QPushButton("Clear")
        self._copy_button = QPushButton("Copy")
        quit_button = QPushButton("Quit")

        button_box = QDialogButtonBox()
        button_box.addButton(clear_button, QDialogButtonBox.ActionRole)
        button_box.addButton(self._copy_button, QDialogButtonBox.ActionRole)
        self._copy_button.setVisible(False)

        button_box.addButton(quit_button, QDialogButtonBox.RejectRole)

        quit_button.clicked.connect(self.close)
        clear_button.clicked.connect(drop_area.clear)
        self._copy_button.clicked.connect(self.copy)

        main_layout = QVBoxLayout(self)
        main_layout.addWidget(abstract_label)
        main_layout.addWidget(drop_area)
        main_layout.addWidget(self._formats_table)
        main_layout.addWidget(button_box)

        self.setWindowTitle("Drop Site")
        self.resize(700, 500)

    @Slot(QMimeData)
    def update_formats_table(self, mime_data):
        self._formats_table.setRowCount(0)
        self._copy_button.setEnabled(False)
        if not mime_data:
            return

        for format in mime_data.formats():
            format_item = QTableWidgetItem(format)
            format_item.setFlags(Qt.ItemIsEnabled)
            format_item.setTextAlignment(Qt.AlignTop | Qt.AlignLeft)

            if format == "text/plain":
                text = simplify_whitespace(mime_data.text())
            elif format == "text/markdown":
                text = mime_data.data("text/markdown").data().decode("utf8")
            elif format == "text/html":
                text = simplify_whitespace(mime_data.html())
            elif format == "text/uri-list":
                url_list = mime_data.urls()
                text = ""
                for i in range(0, min(len(url_list), 32)):
                    text += url_list[i].toString() + " "
            else:
                data = mime_data.data(format)
                if data.size() > 32:
                    data.truncate(32)
                text = data.toHex(" ").data().decode("utf8").upper()

            row = self._formats_table.rowCount()
            self._formats_table.insertRow(row)
            self._formats_table.setItem(row, 0, QTableWidgetItem(format))
            self._formats_table.setItem(row, 1, QTableWidgetItem(text))

        self._formats_table.resizeColumnToContents(0)
        self._copy_button.setEnabled(self._formats_table.rowCount() > 0)

    @Slot()
    def copy(self):
        text = ""
        for row in range(0, self._formats_table.rowCount()):
            c1 = self._formats_table.item(row, 0).text()
            c2 = self._formats_table.item(row, 1).text()
            text += f"{c1}: {c2}\n"
        QGuiApplication.clipboard().setText(text)