[SOLVED] Trouble with PyQt4 and image displaying

vysero · 06-29-2018, 11:17 AM

Hey guys, I am attempting to display an image with this setWindowIcon command. However, I am getting an error. Here is my attempt:

Code:

import sys
from PyQt4 import QtGui

class Window(QtGui.QMainWindow):
  def __init__(self):
    super(Window, self).__init__() #returns parent object (q main window object)
    self.setGeometry(50, 50, 500, 300)
    self.setWindowTitle("PyQt4 Window")

    with open('Logo.png') as f:
      pngdata = f.read()

    self.setWindowIcon(QtGui.QIcon(pngdata))
    self.show()

app = QtGui.QApplication(sys.argv)
GUI = Window()

sys.exit(app.exec_())

The error:

/usr/bin/python3 /home/rob/PycharmProjects/untitled/xcfgh.py
Traceback (most recent call last):
File "/home/rob/PycharmProjects/untitled/xcfgh.py", line 17, in <module>
GUI = Window()
File "/home/rob/PycharmProjects/untitled/xcfgh.py", line 11, in __init__
pngdata = f.read()
File "/usr/lib/python3.5/codecs.py", line 321, in decode
(result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x89 in position 0: invalid start byte

I am a bit confused. Why would I be getting a utf-8 error this is an image not a string. Should I not be using f.read()?

vysero · 06-29-2018, 12:04 PM

Well this is not the right method. I did manage to open the file. The problem is I can't use a string. I need the pngdata to actually be a jpg or png file because that is the type that QIcon is expecting. Anyone know how to open a jpg or png so that it stays as a jpg or png and does not get converted into a string?

dugan · 06-29-2018, 12:05 PM

Code:

f.read()

This is where it's failing, right?

It's reading the file in text mode, not binary mode.

You want to precede that with:

Code:

with open('Logo.png', 'rb') as f:

To open the file for reading in binary mode.

See:

https://docs.python.org/3.3/tutorial...-writing-files

vysero · 06-29-2018, 12:29 PM

Quote:

Originally Posted by dugan

Code:

f.read()

This is where it's failing, right?

It's reading the file in text mode, not binary mode.

You want to precede that with:

Code:

with open('Logo.png', 'rb') as f:

To open the file for reading in binary mode.

See:

https://docs.python.org/3.3/tutorial...-writing-files

Right, yes I figured this out eventually. Unfortunately, I ran into another problem which I attempted to convey with my last post. Here is my altered version of the script:

Code:

import sys
from PyQt4 import QtGui

class Window(QtGui.QMainWindow):
  def __init__(self):
    super(Window, self).__init__() #returns parent object (q main window object)
    self.setGeometry(50, 50, 500, 300)
    self.setWindowTitle("PyQt4 Window")

    self.setWindowIcon(QtGui.QIcon('TeeJetLogo.jpg'))
    self.show()

app = QtGui.QApplication(sys.argv)
GUI = Window()

sys.exit(app.exec_())

The program runs just fine now but the image is not being displayed. I can not seem to figure out why it wont be displayed. This seems fairly straightforward but apparently that is not the case.

norobro · 06-29-2018, 07:31 PM

Your code displays an icon in the upper left corner of the title bar on my box. With a different jpeg obviously.

Is the image file in the same directory as your code?

If you want to display the image in the window, you'll have to do something like this:

Code:

...
    self.setWindowTitle("PyQt4 Window")
    self.label = QtGui.QLabel(self)
    self.label.setPixmap(QtGui.QPixmap('TeeJetLogo.jpg'))
    self.setCentralWidget(self.label)
    self.show()
...