Article Outline
Python pyqt (gui) example 'grabber'
Modules used in program:
import mathimport sys
grabber
Python pyqt example: grabber
#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2015 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.
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## $QT_BEGIN_LICENSE:BSD$
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## * 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
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## * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
## the names of its contributors may be used to endorse or promote
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## $QT_END_LICENSE$
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#############################################################################
import sys
import math
from PyQt5.QtCore import pyqtSignal, QSize, Qt, QTimer
from PyQt5.QtGui import QPixmap
from PyQt5.QtWidgets import (QAction, QApplication, QGridLayout, QLabel,
QLineEdit, QMainWindow, QMessageBox, QOpenGLWidget, QScrollArea,
QSizePolicy, QSlider, QWidget)
class GLWidget(QOpenGLWidget):
xRotationChanged = pyqtSignal(int)
yRotationChanged = pyqtSignal(int)
zRotationChanged = pyqtSignal(int)
def __init__(self, parent=None):
super(GLWidget, self).__init__(parent)
self.gear1 = 0
self.gear2 = 0
self.gear3 = 0
self.xRot = 0
self.yRot = 0
self.zRot = 0
self.gear1Rot = 0
timer = QTimer(self)
timer.timeout.connect(self.advanceGears)
timer.start(20)
def setXRotation(self, angle):
self.normalizeAngle(angle)
if angle != self.xRot:
self.xRot = angle
self.xRotationChanged.emit(angle)
self.update()
def setYRotation(self, angle):
self.normalizeAngle(angle)
if angle != self.yRot:
self.yRot = angle
self.yRotationChanged.emit(angle)
self.update()
def setZRotation(self, angle):
self.normalizeAngle(angle)
if angle != self.zRot:
self.zRot = angle
self.zRotationChanged.emit(angle)
self.update()
def initializeGL(self):
self.gl = self.context().versionFunctions()
self.gl.initializeOpenGLFunctions()
lightPos = (5.0, 5.0, 10.0, 1.0)
reflectance1 = (0.8, 0.1, 0.0, 1.0)
reflectance2 = (0.0, 0.8, 0.2, 1.0)
reflectance3 = (0.2, 0.2, 1.0, 1.0)
self.gl.glLightfv(self.gl.GL_LIGHT0, self.gl.GL_POSITION, lightPos)
self.gl.glEnable(self.gl.GL_LIGHTING)
self.gl.glEnable(self.gl.GL_LIGHT0)
self.gl.glEnable(self.gl.GL_DEPTH_TEST)
self.gear1 = self.makeGear(reflectance1, 1.0, 4.0, 1.0, 0.7, 20)
self.gear2 = self.makeGear(reflectance2, 0.5, 2.0, 2.0, 0.7, 10)
self.gear3 = self.makeGear(reflectance3, 1.3, 2.0, 0.5, 0.7, 10)
self.gl.glEnable(self.gl.GL_NORMALIZE)
self.gl.glClearColor(0.0, 0.0, 0.0, 1.0)
def paintGL(self):
self.gl.glClear(self.gl.GL_COLOR_BUFFER_BIT | self.gl.GL_DEPTH_BUFFER_BIT)
self.gl.glPushMatrix()
self.gl.glRotated(self.xRot / 16.0, 1.0, 0.0, 0.0)
self.gl.glRotated(self.yRot / 16.0, 0.0, 1.0, 0.0)
self.gl.glRotated(self.zRot / 16.0, 0.0, 0.0, 1.0)
self.drawGear(self.gear1, -3.0, -2.0, 0.0, self.gear1Rot / 16.0)
self.drawGear(self.gear2, +3.1, -2.0, 0.0,
-2.0 * (self.gear1Rot / 16.0) - 9.0)
self.gl.glRotated(+90.0, 1.0, 0.0, 0.0)
self.drawGear(self.gear3, -3.1, -1.8, -2.2,
+2.0 * (self.gear1Rot / 16.0) - 2.0)
self.gl.glPopMatrix()
def resizeGL(self, width, height):
side = min(width, height)
if side < 0:
return
self.gl.glViewport((width - side) // 2, (height - side) // 2, side, side)
self.gl.glMatrixMode(self.gl.GL_PROJECTION)
self.gl.glLoadIdentity()
self.gl.glFrustum(-1.0, +1.0, -1.0, 1.0, 5.0, 60.0)
self.gl.glMatrixMode(self.gl.GL_MODELVIEW)
self.gl.glLoadIdentity()
self.gl.glTranslated(0.0, 0.0, -40.0)
def mousePressEvent(self, event):
self.lastPos = event.pos()
def mouseMoveEvent(self, event):
dx = event.x() - self.lastPos.x()
dy = event.y() - self.lastPos.y()
if event.buttons() & Qt.LeftButton:
self.setXRotation(self.xRot + 8 * dy)
self.setYRotation(self.yRot + 8 * dx)
elif event.buttons() & Qt.RightButton:
self.setXRotation(self.xRot + 8 * dy)
self.setZRotation(self.zRot + 8 * dx)
self.lastPos = event.pos()
def advanceGears(self):
self.gear1Rot += 2 * 16
self.update()
def xRotation(self):
return self.xRot
def yRotation(self):
return self.yRot
def zRotation(self):
return self.zRot
def makeGear(self, reflectance, innerRadius, outerRadius, thickness, toothSize, toothCount):
list = self.gl.glGenLists(1)
self.gl.glNewList(list, self.gl.GL_COMPILE)
self.gl.glMaterialfv(self.gl.GL_FRONT, self.gl.GL_AMBIENT_AND_DIFFUSE,
reflectance)
r0 = innerRadius
r1 = outerRadius - toothSize / 2.0
r2 = outerRadius + toothSize / 2.0
delta = (2.0 * math.pi / toothCount) / 4.0
z = thickness / 2.0
self.gl.glShadeModel(self.gl.GL_FLAT)
for i in range(2):
if i == 0:
sign = +1.0
else:
sign = -1.0
self.gl.glNormal3d(0.0, 0.0, sign)
self.gl.glBegin(self.gl.GL_QUAD_STRIP)
for j in range(toothCount+1):
angle = 2.0 * math.pi * j / toothCount
self.gl.glVertex3d(r0 * math.cos(angle), r0 * math.sin(angle), sign * z)
self.gl.glVertex3d(r1 * math.cos(angle), r1 * math.sin(angle), sign * z)
self.gl.glVertex3d(r0 * math.cos(angle), r0 * math.sin(angle), sign * z)
self.gl.glVertex3d(r1 * math.cos(angle + 3 * delta), r1 * math.sin(angle + 3 * delta), sign * z)
self.gl.glEnd()
self.gl.glBegin(self.gl.GL_QUADS)
for j in range(toothCount):
angle = 2.0 * math.pi * j / toothCount
self.gl.glVertex3d(r1 * math.cos(angle), r1 * math.sin(angle), sign * z)
self.gl.glVertex3d(r2 * math.cos(angle + delta), r2 * math.sin(angle + delta), sign * z)
self.gl.glVertex3d(r2 * math.cos(angle + 2 * delta), r2 * math.sin(angle + 2 * delta), sign * z)
self.gl.glVertex3d(r1 * math.cos(angle + 3 * delta), r1 * math.sin(angle + 3 * delta), sign * z)
self.gl.glEnd()
self.gl.glBegin(self.gl.GL_QUAD_STRIP)
for i in range(toothCount):
for j in range(2):
angle = 2.0 * math.pi * (i + (j / 2.0)) / toothCount
s1 = r1
s2 = r2
if j == 1:
s1, s2 = s2, s1
self.gl.glNormal3d(math.cos(angle), math.sin(angle), 0.0)
self.gl.glVertex3d(s1 * math.cos(angle), s1 * math.sin(angle), +z)
self.gl.glVertex3d(s1 * math.cos(angle), s1 * math.sin(angle), -z)
self.gl.glNormal3d(s2 * math.sin(angle + delta) - s1 * math.sin(angle), s1 * math.cos(angle) - s2 * math.cos(angle + delta), 0.0)
self.gl.glVertex3d(s2 * math.cos(angle + delta), s2 * math.sin(angle + delta), +z)
self.gl.glVertex3d(s2 * math.cos(angle + delta), s2 * math.sin(angle + delta), -z)
self.gl.glVertex3d(r1, 0.0, +z)
self.gl.glVertex3d(r1, 0.0, -z)
self.gl.glEnd()
self.gl.glShadeModel(self.gl.GL_SMOOTH)
self.gl.glBegin(self.gl.GL_QUAD_STRIP)
for i in range(toothCount+1):
angle = i * 2.0 * math.pi / toothCount
self.gl.glNormal3d(-math.cos(angle), -math.sin(angle), 0.0)
self.gl.glVertex3d(r0 * math.cos(angle), r0 * math.sin(angle), +z)
self.gl.glVertex3d(r0 * math.cos(angle), r0 * math.sin(angle), -z)
self.gl.glEnd()
self.gl.glEndList()
return list
def drawGear(self, gear, dx, dy, dz, angle):
self.gl.glPushMatrix()
self.gl.glTranslated(dx, dy, dz)
self.gl.glRotated(angle, 0.0, 0.0, 1.0)
self.gl.glCallList(gear)
self.gl.glPopMatrix()
def normalizeAngle(self, angle):
while (angle < 0):
angle += 360 * 16
while (angle > 360 * 16):
angle -= 360 * 16
class MainWindow(QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
centralWidget = QWidget()
self.setCentralWidget(centralWidget)
self.glWidget = GLWidget()
self.pixmapLabel = QLabel()
self.glWidgetArea = QScrollArea()
self.glWidgetArea.setWidget(self.glWidget)
self.glWidgetArea.setWidgetResizable(True)
self.glWidgetArea.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.glWidgetArea.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.glWidgetArea.setSizePolicy(QSizePolicy.Ignored,
QSizePolicy.Ignored)
self.glWidgetArea.setMinimumSize(50, 50)
self.pixmapLabelArea = QScrollArea()
self.pixmapLabelArea.setWidget(self.pixmapLabel)
self.pixmapLabelArea.setSizePolicy(QSizePolicy.Ignored,
QSizePolicy.Ignored)
self.pixmapLabelArea.setMinimumSize(50, 50)
xSlider = self.createSlider(self.glWidget.xRotationChanged,
self.glWidget.setXRotation)
ySlider = self.createSlider(self.glWidget.yRotationChanged,
self.glWidget.setYRotation)
zSlider = self.createSlider(self.glWidget.zRotationChanged,
self.glWidget.setZRotation)
self.createActions()
self.createMenus()
centralLayout = QGridLayout()
centralLayout.addWidget(self.glWidgetArea, 0, 0)
centralLayout.addWidget(self.pixmapLabelArea, 0, 1)
centralLayout.addWidget(xSlider, 1, 0, 1, 2)
centralLayout.addWidget(ySlider, 2, 0, 1, 2)
centralLayout.addWidget(zSlider, 3, 0, 1, 2)
centralWidget.setLayout(centralLayout)
xSlider.setValue(15 * 16)
ySlider.setValue(345 * 16)
zSlider.setValue(0 * 16)
self.setWindowTitle("Grabber")
self.resize(400, 300)
def grabFrameBuffer(self):
image = self.glWidget.grabFramebuffer()
self.setPixmap(QPixmap.fromImage(image))
def clearPixmap(self):
self.setPixmap(QPixmap())
def about(self):
QMessageBox.about(self, "About Grabber",
"The <b>Grabber</b> example demonstrates two approaches for "
"rendering OpenGL into a Qt pixmap.")
def createActions(self):
self.grabFrameBufferAct = QAction("&Grab Frame Buffer", self,
shortcut="Ctrl+G", triggered=self.grabFrameBuffer)
self.clearPixmapAct = QAction("&Clear Pixmap", self,
shortcut="Ctrl+L", triggered=self.clearPixmap)
self.exitAct = QAction("E&xit", self, shortcut="Ctrl+Q",
triggered=self.close)
self.aboutAct = QAction("&About", self, triggered=self.about)
self.aboutQtAct = QAction("About &Qt", self,
triggered=QApplication.instance().aboutQt)
def createMenus(self):
self.fileMenu = self.menuBar().addMenu("&File")
self.fileMenu.addAction(self.grabFrameBufferAct)
self.fileMenu.addAction(self.clearPixmapAct)
self.fileMenu.addSeparator()
self.fileMenu.addAction(self.exitAct)
self.helpMenu = self.menuBar().addMenu("&Help")
self.helpMenu.addAction(self.aboutAct)
self.helpMenu.addAction(self.aboutQtAct)
def createSlider(self, changedSignal, setterSlot):
slider = QSlider(Qt.Horizontal)
slider.setRange(0, 360 * 16)
slider.setSingleStep(16)
slider.setPageStep(15 * 16)
slider.setTickInterval(15 * 16)
slider.setTickPosition(QSlider.TicksRight)
slider.valueChanged.connect(setterSlot)
changedSignal.connect(slider.setValue)
return slider
def setPixmap(self, pixmap):
self.pixmapLabel.setPixmap(pixmap)
size = pixmap.size()
if size - QSize(1, 0) == self.pixmapLabelArea.maximumViewportSize():
size -= QSize(1, 0)
self.pixmapLabel.resize(size)
if __name__ == '__main__':
app = QApplication(sys.argv)
mainWin = MainWindow()
mainWin.show()
sys.exit(app.exec_())
Useful links
- Learn PyQt: https://pythonbasics.org/pyqt-hello-world/
- Install PyQt: https://pythonbasics.org/install-pyqt/