I'm new to GUIs, but thinking about writing a GUI that is a little bit
like a simple vector drawing program. So I've been looking at various
toolkit and language options.
So far, it looks like my first choice would be PyQt... but it seems
slow. I wrote the attached code. If you select more than a couple dozen
shapes and move them, there's substantial lag, and I see python pegging
the CPU. The question:
1) Is there something I'm doing that is seriously inefficient and could
be rewritten for speed?
2) What sort of speedup might I expect from this same program if it were
rewritten in C++ with qt?
Vadim
from PyQt4.Qt import *
import random
import sys
def addshape(scene,x,y):
shapefunc=random.choice((scene.addRect,scene.addEllipse))
c=shapefunc(QRectF(x,y,random.randint(10,20),random.randint(10,20)))
c.setFlag(c.ItemIsMovable)
c.setFlag(c.ItemIsSelectable)
class myGui(QWidget):
def __init__(self,parent=None):
QWidget.__init__(self,parent)
quitButton=QPushButton("&Quit")
QObject.connect(quitButton,SIGNAL("clicked()"),qApp,SLOT("quit()"))
self.pane=QGraphicsScene()
self.view=QGraphicsView(self.pane)
self.view.setDragMode(QGraphicsView.RubberBandDrag)
zoomInButton=QPushButton("ZoomIn")
QObject.connect(zoomInButton,SIGNAL("clicked()"),lambda : self.view.scale(1.2,1.2))
zoomOutButton=QPushButton("ZoomOut")
QObject.connect(zoomOutButton,SIGNAL("clicked()"),lambda : self.view.scale(.8,.8))
[addshape(self.pane,x,y) for x in range(0,1000,25) for y in range(0,1000,25)]
lButtons=QHBoxLayout()
lButtons.addWidget(quitButton)
lButtons.addWidget(zoomInButton)
lButtons.addWidget(zoomOutButton)
layout=QVBoxLayout()
layout.addLayout(lButtons)
layout.addWidget(self.view)
self.setLayout(layout)
app=QApplication(sys.argv)
firstP=myGui()
firstP.show()
app.exec_()
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