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Viewing changes to frescobaldi_app/widgets/imageviewer.py

  • Committer: Package Import Robot
  • Author(s): Ryan Kavanagh
  • Date: 2012-01-03 16:20:11 UTC
  • mfrom: (1.4.1)
  • Revision ID: package-import@ubuntu.com-20120103162011-tsjkwl4sntwmprea
Tags: 2.0.0-1
* New upstream release 
* Drop the following uneeded patches:
  + 01_checkmodules_no_python-kde4_build-dep.diff
  + 02_no_pyc.diff
  + 04_no_binary_lilypond_upgrades.diff
* Needs new dependency python-poppler-qt4
* Update debian/watch for new download path
* Update copyright file with new holders and years

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frescobaldi_app/widgets/imageviewer.py
 
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# This file is part of the Frescobaldi project, http://www.frescobaldi.org/
 
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#
 
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# Copyright (c) 2008 - 2011 by Wilbert Berendsen
 
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#
 
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# This program is free software; you can redistribute it and/or
 
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# modify it under the terms of the GNU General Public License
 
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# as published by the Free Software Foundation; either version 2
 
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# of the License, or (at your option) any later version.
 
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#
 
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# This program is distributed in the hope that it will be useful,
 
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
 
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
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# GNU General Public License for more details.
 
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#
 
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# You should have received a copy of the GNU General Public License
 
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# along with this program; if not, write to the Free Software
 
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# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
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# See http://www.gnu.org/licenses/ for more information.
 
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"""
 
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A simple scrollarea that can display an image.
 
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"""
 
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from __future__ import unicode_literals
 
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from PyQt4.QtCore import pyqtSignal, QMimeData, QSize, QRect, Qt
 
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from PyQt4.QtGui import (
 
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    QApplication, QDrag, QImage, QPainter, QPalette, QPixmap, QScrollArea,
 
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    QSizePolicy, QWidget)
 
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__all__ = ['ImageViewer']
 
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# internal constants
 
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MOVE = 1
 
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DRAG = 2
 
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class ImageViewer(QScrollArea):
 
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    actualSizeChanged = pyqtSignal(bool)
 
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    def __init__(self, parent=None):
 
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        super(ImageViewer, self).__init__(parent, alignment=Qt.AlignCenter)
 
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        self._actualsize = True
 
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        self._image = QImage()
 
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        self.setBackgroundRole(QPalette.Dark)
 
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        self.setWidget(ImageWidget(self))
 
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    def setActualSize(self, enabled=True):
 
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        if enabled == self._actualsize:
 
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            return
 
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        self.setWidgetResizable(not enabled)
 
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        if enabled and not self._image.isNull():
 
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            self.widget().resize(self._image.size())
 
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        self._actualsize = enabled
 
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        self.actualSizeChanged.emit(enabled)
 
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    def actualSize(self):
 
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        return self._actualsize
 
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    def setImage(self, image):
 
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        self._image = image
 
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        self._pixmap = None
 
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        self._pixmapsize = None
 
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        if self._actualsize:
 
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            self.widget().resize(image.size())
 
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        self.widget().update()
 
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    def image(self):
 
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        return self._image
 
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    def pixmap(self, size):
 
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        """Returns (and caches) a scaled pixmap for the image."""
 
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        if self._pixmapsize == size:
 
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            return self._pixmap
 
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        self._pixmap = QPixmap.fromImage(
 
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            self._image.scaled(size, Qt.KeepAspectRatio, Qt.SmoothTransformation))
 
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        self._pixmapsize = size
 
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        return self._pixmap
 
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    def startDrag(self):
 
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        image = self.image()
 
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        data = QMimeData()
 
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        data.setImageData(image)
 
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        drag = QDrag(self)
 
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        drag.setMimeData(data)
 
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        if max(image.width(), image.height()) > 256:
 
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            image = image.scaled(QSize(256, 256), Qt.KeepAspectRatio, Qt.SmoothTransformation)
 
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        pixmap = QPixmap.fromImage(image)
 
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        drag.setPixmap(pixmap)
 
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        drag.setHotSpot(pixmap.rect().center())
 
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        drag.exec_(Qt.CopyAction)
 
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class ImageWidget(QWidget):
 
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    def __init__(self, viewer):
 
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        super(ImageWidget, self).__init__()
 
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        self.viewer = viewer
 
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        self.setBackgroundRole(QPalette.Dark)
 
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        self.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Ignored)
 
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        self._mode = None
 
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        self._startpos = None
 
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    def paintEvent(self, ev):
 
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        image = self.viewer.image()
 
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        painter = QPainter(self)
 
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        if self.size() == image.size():
 
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            painter.drawImage(ev.rect(), image, ev.rect())
 
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        else:
 
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            s = image.size()
 
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            s.scale(self.size(), Qt.KeepAspectRatio)
 
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            r = QRect()
 
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            r.setSize(s)
 
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            r.moveCenter(self.rect().center())
 
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            painter.drawPixmap(r, self.viewer.pixmap(s))
 
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    def mousePressEvent(self, ev):
 
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        if ev.button() == Qt.LeftButton:
 
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            if ev.modifiers() & Qt.ControlModifier:
 
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                self._mode = MOVE
 
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            else:
 
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                self._mode = DRAG
 
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            self._startpos = ev.globalPos()
 
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    def mouseMoveEvent(self, ev):
 
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        diff = self._startpos - ev.globalPos()
 
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        if self._mode == MOVE:
 
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            self._startpos = ev.globalPos()
 
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            h = self.viewer.horizontalScrollBar()
 
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            v = self.viewer.verticalScrollBar()
 
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            h.setValue(h.value() + diff.x())
 
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            v.setValue(v.value() + diff.y())
 
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        elif self._mode == DRAG and diff.manhattanLength() >= QApplication.startDragDistance():
 
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            self.viewer.startDrag()
 
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    def mouseReleaseEvent(self, ev):
 
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        mode, self._mode = self._mode, None
 
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        if (ev.button() == Qt.LeftButton and
 
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                mode == DRAG and ev.globalPos() == self._startpos):
 
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            self.viewer.setActualSize(not self.viewer.actualSize())
 
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