Article Outline
Python pyqt (gui) example 'svgviewer'
Modules used in program:
import svgviewer_rc
svgviewer
Python pyqt example: svgviewer
#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## 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:
##
## "Redistribution and use in source and binary forms, with or without
## 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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## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
## $QT_END_LICENSE$
##
#############################################################################
from PyQt5.QtCore import QFile, QSize, Qt
from PyQt5.QtGui import QBrush, QColor, QImage, QPainter, QPixmap, QPen
from PyQt5.QtWidgets import (QActionGroup, QApplication, QFileDialog,
QGraphicsItem, QGraphicsRectItem, QGraphicsScene, QGraphicsView,
QMainWindow, QMenu, QMessageBox, QWidget)
from PyQt5.QtOpenGL import QGL, QGLFormat, QGLWidget
from PyQt5.QtSvg import QGraphicsSvgItem
import svgviewer_rc
class MainWindow(QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.currentPath = ''
self.view = SvgView()
fileMenu = QMenu("&File", self)
openAction = fileMenu.addAction("&Open...")
openAction.setShortcut("Ctrl+O")
quitAction = fileMenu.addAction("E&xit")
quitAction.setShortcut("Ctrl+Q")
self.menuBar().addMenu(fileMenu)
viewMenu = QMenu("&View", self)
self.backgroundAction = viewMenu.addAction("&Background")
self.backgroundAction.setEnabled(False)
self.backgroundAction.setCheckable(True)
self.backgroundAction.setChecked(False)
self.backgroundAction.toggled.connect(self.view.setViewBackground)
self.outlineAction = viewMenu.addAction("&Outline")
self.outlineAction.setEnabled(False)
self.outlineAction.setCheckable(True)
self.outlineAction.setChecked(True)
self.outlineAction.toggled.connect(self.view.setViewOutline)
self.menuBar().addMenu(viewMenu)
rendererMenu = QMenu("&Renderer", self)
self.nativeAction = rendererMenu.addAction("&Native")
self.nativeAction.setCheckable(True)
self.nativeAction.setChecked(True)
if QGLFormat.hasOpenGL():
self.glAction = rendererMenu.addAction("&OpenGL")
self.glAction.setCheckable(True)
self.imageAction = rendererMenu.addAction("&Image")
self.imageAction.setCheckable(True)
if QGLFormat.hasOpenGL():
rendererMenu.addSeparator()
self.highQualityAntialiasingAction = rendererMenu.addAction("&High Quality Antialiasing")
self.highQualityAntialiasingAction.setEnabled(False)
self.highQualityAntialiasingAction.setCheckable(True)
self.highQualityAntialiasingAction.setChecked(False)
self.highQualityAntialiasingAction.toggled.connect(self.view.setHighQualityAntialiasing)
rendererGroup = QActionGroup(self)
rendererGroup.addAction(self.nativeAction)
if QGLFormat.hasOpenGL():
rendererGroup.addAction(self.glAction)
rendererGroup.addAction(self.imageAction)
self.menuBar().addMenu(rendererMenu)
openAction.triggered.connect(self.openFile)
quitAction.triggered.connect(QApplication.instance().quit)
rendererGroup.triggered.connect(self.setRenderer)
self.setCentralWidget(self.view)
self.setWindowTitle("SVG Viewer")
def openFile(self, path=None):
if not path:
path, _ = QFileDialog.getOpenFileName(self, "Open SVG File",
self.currentPath, "SVG files (*.svg *.svgz *.svg.gz)")
if path:
svg_file = QFile(path)
if not svg_file.exists():
QMessageBox.critical(self, "Open SVG File",
"Could not open file '%s'." % path)
self.outlineAction.setEnabled(False)
self.backgroundAction.setEnabled(False)
return
self.view.openFile(svg_file)
if not path.startswith(':/'):
self.currentPath = path
self.setWindowTitle("%s - SVGViewer" % self.currentPath)
self.outlineAction.setEnabled(True)
self.backgroundAction.setEnabled(True)
self.resize(self.view.sizeHint() + QSize(80, 80 + self.menuBar().height()))
def setRenderer(self, action):
if QGLFormat.hasOpenGL():
self.highQualityAntialiasingAction.setEnabled(False)
if action == self.nativeAction:
self.view.setRenderer(SvgView.Native)
elif action == self.glAction:
if QGLFormat.hasOpenGL():
self.highQualityAntialiasingAction.setEnabled(True)
self.view.setRenderer(SvgView.OpenGL)
elif action == self.imageAction:
self.view.setRenderer(SvgView.Image)
class SvgView(QGraphicsView):
Native, OpenGL, Image = range(3)
def __init__(self, parent=None):
super(SvgView, self).__init__(parent)
self.renderer = SvgView.Native
self.svgItem = None
self.backgroundItem = None
self.outlineItem = None
self.image = QImage()
self.setScene(QGraphicsScene(self))
self.setTransformationAnchor(QGraphicsView.AnchorUnderMouse)
self.setDragMode(QGraphicsView.ScrollHandDrag)
self.setViewportUpdateMode(QGraphicsView.FullViewportUpdate)
# Prepare background check-board pattern.
tilePixmap = QPixmap(64, 64)
tilePixmap.fill(Qt.white)
tilePainter = QPainter(tilePixmap)
color = QColor(220, 220, 220)
tilePainter.fillRect(0, 0, 32, 32, color)
tilePainter.fillRect(32, 32, 32, 32, color)
tilePainter.end()
self.setBackgroundBrush(QBrush(tilePixmap))
def drawBackground(self, p, rect):
p.save()
p.resetTransform()
p.drawTiledPixmap(self.viewport().rect(),
self.backgroundBrush().texture())
p.restore()
def openFile(self, svg_file):
if not svg_file.exists():
return
s = self.scene()
if self.backgroundItem:
drawBackground = self.backgroundItem.isVisible()
else:
drawBackground = False
if self.outlineItem:
drawOutline = self.outlineItem.isVisible()
else:
drawOutline = True
s.clear()
self.resetTransform()
self.svgItem = QGraphicsSvgItem(svg_file.fileName())
self.svgItem.setFlags(QGraphicsItem.ItemClipsToShape)
self.svgItem.setCacheMode(QGraphicsItem.NoCache)
self.svgItem.setZValue(0)
self.backgroundItem = QGraphicsRectItem(self.svgItem.boundingRect())
self.backgroundItem.setBrush(Qt.white)
self.backgroundItem.setPen(QPen(Qt.NoPen))
self.backgroundItem.setVisible(drawBackground)
self.backgroundItem.setZValue(-1)
self.outlineItem = QGraphicsRectItem(self.svgItem.boundingRect())
outline = QPen(Qt.black, 2, Qt.DashLine)
outline.setCosmetic(True)
self.outlineItem.setPen(outline)
self.outlineItem.setBrush(QBrush(Qt.NoBrush))
self.outlineItem.setVisible(drawOutline)
self.outlineItem.setZValue(1)
s.addItem(self.backgroundItem)
s.addItem(self.svgItem)
s.addItem(self.outlineItem)
s.setSceneRect(self.outlineItem.boundingRect().adjusted(-10, -10, 10, 10))
def setRenderer(self, renderer):
self.renderer = renderer
if self.renderer == SvgView.OpenGL:
if QGLFormat.hasOpenGL():
self.setViewport(QGLWidget(QGLFormat(QGL.SampleBuffers)))
else:
self.setViewport(QWidget())
def setHighQualityAntialiasing(self, highQualityAntialiasing):
if QGLFormat.hasOpenGL():
self.setRenderHint(QPainter.HighQualityAntialiasing,
highQualityAntialiasing)
def setViewBackground(self, enable):
if self.backgroundItem:
self.backgroundItem.setVisible(enable)
def setViewOutline(self, enable):
if self.outlineItem:
self.outlineItem.setVisible(enable)
def paintEvent(self, event):
if self.renderer == SvgView.Image:
if self.image.size() != self.viewport().size():
self.image = QImage(self.viewport().size(),
QImage.Format_ARGB32_Premultiplied)
imagePainter = QPainter(self.image)
QGraphicsView.render(self, imagePainter)
imagePainter.end()
p = QPainter(self.viewport())
p.drawImage(0, 0, self.image)
else:
super(SvgView, self).paintEvent(event)
def wheelEvent(self, event):
factor = pow(1.2, event.delta() / 240.0)
self.scale(factor, factor)
event.accept()
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
window = MainWindow()
if len(sys.argv) == 2:
window.openFile(sys.argv[1])
else:
window.openFile(':/files/bubbles.svg')
window.show()
sys.exit(app.exec_())
Useful links
- Learn PyQt: https://pythonbasics.org/pyqt-hello-world/
- Install PyQt: https://pythonbasics.org/install-pyqt/