#!/usr/bin/env python
 
 
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited
## Copyright (C) 2010 Hans-Peter Jansen <hpj@urpla.net>.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
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## modification, are permitted provided that the following conditions are
## met:
##   * Redistributions of source code must retain the above copyright
##     notice, this list of conditions and the following disclaimer.
##   * Redistributions in binary form must reproduce the above copyright
##     notice, this list of conditions and the following disclaimer in
##     the documentation and/or other materials provided with the
##     distribution.
##   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
##     the names of its contributors may be used to endorse or promote
##     products derived from this software without specific prior written
##     permission.
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## $QT_END_LICENSE$
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#############################################################################
 
 
from PyQt5.QtCore import (pyqtSignal, QBuffer, QByteArray, QFile, QIODevice,
        QMimeData, Qt)
from PyQt5.QtGui import QDrag, QIcon, QImage, QPainter, QPixmap
from PyQt5.QtWidgets import (QApplication, QGridLayout, QLabel, QPushButton,
        QScrollArea, QWidget)
from PyQt5.QtSvg import QSvgWidget
 
import delayedencoding_rc
 
 
class MimeData(QMimeData):
 
    dataRequested = pyqtSignal(str)
 
    def formats(self):
        formats = QMimeData.formats(self)
        formats.append('image/png')
 
        return formats
 
    def retrieveData(self, mimeType, qvtype):
        self.dataRequested.emit(mimeType)
 
        return QMimeData.retrieveData(self, mimeType, qvtype)
 
 
class SourceWidget(QWidget):
    def __init__(self, parent=None):
        super(SourceWidget, self).__init__(parent)
 
        self.mimeData = None
 
        imageFile = QFile(':/images/example.svg')
        imageFile.open(QIODevice.ReadOnly)
        self.imageData = imageFile.readAll()
        imageFile.close()
 
        imageArea = QScrollArea()
        self.imageLabel = QSvgWidget()
        self.imageLabel.renderer().load(self.imageData)
        imageArea.setWidget(self.imageLabel)
 
        instructTopLabel = QLabel("This is an SVG drawing:")
        instructBottomLabel = QLabel("Drag the icon to copy the drawing as a PNG file:")
        dragIcon = QPushButton("Export")
        dragIcon.setIcon(QIcon(':/images/drag.png'))
        dragIcon.pressed.connect(self.startDrag)
 
        layout = QGridLayout()
        layout.addWidget(instructTopLabel, 0, 0, 1, 2)
        layout.addWidget(imageArea, 1, 0, 2, 2)
        layout.addWidget(instructBottomLabel, 3, 0)
        layout.addWidget(dragIcon, 3, 1)
        self.setLayout(layout)
        self.setWindowTitle("Delayed Encoding")
 
    def createData(self, mimeType):
        if mimeType != 'image/png':
            return
 
        image = QImage(self.imageLabel.size(), QImage.Format_RGB32)
        painter = QPainter()
        painter.begin(image)
        self.imageLabel.renderer().render(painter)
        painter.end()
 
        data = QByteArray()
        buffer = QBuffer(data)
        buffer.open(QIODevice.WriteOnly)
        image.save(buffer, 'PNG')
        buffer.close()
        self.mimeData.setData('image/png', data)
 
    def startDrag(self):
        self.mimeData = MimeData()
        self.mimeData.dataRequested.connect(self.createData, Qt.DirectConnection)
 
        drag = QDrag(self)
        drag.setMimeData(self.mimeData)
        drag.setPixmap(QPixmap(':/images/drag.png'))
        drag.exec_(Qt.CopyAction)
 
 
if __name__ == '__main__':
 
    import sys
 
    app = QApplication(sys.argv)
    window = SourceWidget()
    window.show()
    sys.exit(app.exec_())