Display Math symbols in a QLabel

gworouge

Hi,

I can't find some information about how to display math symbolic expression in a Qlabel.

for example, how to display the mathematical symbol "alpha" instead of the word "alpha" ?

the math symbol "square root" instead of "sqrt" and so on ? ...

many thanks for any help you could bring

Gwo

loladiro

QLabel supports Unicode:
"Math Operators":http://en.wikipedia.org/wiki/Mathematical_operators_and_symbols_in_Unicode
"Mathemathical Alphanumeric Symbols":http://en.wikipedia.org/wiki/Mathematical_alphanumeric_symbols_Unicode_block

Of course you won't be able to display complex Mathematical expressions. For that you could use something like "this":http://doc.qt.nokia.com/solutions/4/qtmmlwidget/qtmmlwidget.html

EDIT: fixed link

EDIT2: "Source Code":ftp://ftp.qt.nokia.com/qt/solutions/lgpl/

ZapB

I have used the qmmlwidget before and it worked well from what I can recall. Just a shame that mml is so verbose. I dream of a text layout system for Qt that could render LaTeX.

loladiro

That would be ideal

gworouge

Thank you for those information.

my Gui doesn't show what I would like to see; can you tell me where I make a mistake ?

I have two files : init.py which calls untitled.py :

init.py :
@# -- coding: utf-8 --

"""The user interface for our app"""

import os,sys

Import Qt modules

from math import *
from PyQt4 import QtCore, QtGui
from PyQt4.QtGui import *
from PyQt4.Qt import *

from untitled import *

Create a class for our main window

class Main(QtGui.QMainWindow):
def init(self):
QtGui.QMainWindow.init(self)

    # This is always the same
    self.ui=Ui_MainWindow()
    self.ui.setupUi(self)

def main():
# Again, this is boilerplate, it's going to be the same on
# almost every app you write
app = QtGui.QApplication(sys.argv)
window=Main()
window.show()
# It's exec_ because exec is a reserved word in Python

sys.exit(app.exec_())

if name == "main":
main()

@

and untitled.py :
@# -- coding: utf-8 --

Form implementation generated from reading ui file 'untitled.ui'

Created: Sun Jun 19 11:26:12 2011

by: PyQt4 UI code generator 4.8.4

WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
_fromUtf8 = lambda s: s

class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(721, 502)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.label = QtGui.QLabel(self.centralwidget)
self.label.setGeometry(QtCore.QRect(80, 110, 441, 31))
self.label.setObjectName(_fromUtf8("label"))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 721, 20))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)

    self.retranslateUi(MainWindow)
    QtCore.QMetaObject.connectSlotsByName(MainWindow)

def retranslateUi(self, MainWindow):
    str_swt = QtCore.QString(U'\221A')
    MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "MainWindow", None, QtGui.QApplication.UnicodeUTF8))
    self.label.setText(QtGui.QApplication.translate("MainWindow", str_swt, None, QtGui.QApplication.UnicodeUTF8))

class Main(QtGui.QMainWindow):
def init(self):
QtGui.QMainWindow.init(self)

    # This is always the same
    self.ui=Ui_MainWindow()
    self.ui.setupUi(self)

def main():
# Again, this is boilerplate, it's going to be the same on
# almost every app you write
app = QtGui.QApplication(sys.argv)
window=Main()
window.show()
# It's exec_ because exec is a reserved word in Python

sys.exit(app.exec_())

if name == "main":
main()
@

Thanks again

gworouge

Sorry, there has been some code copied at the end of untitled.py; here it is again :
@# -- coding: utf-8 --

Form implementation generated from reading ui file 'untitled.ui'

Created: Sun Jun 19 11:26:12 2011

by: PyQt4 UI code generator 4.8.4

WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
_fromUtf8 = lambda s: s

class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(721, 502)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.label = QtGui.QLabel(self.centralwidget)
self.label.setGeometry(QtCore.QRect(80, 110, 441, 31))
self.label.setObjectName(_fromUtf8("label"))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 721, 20))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)

    self.retranslateUi(MainWindow)
    QtCore.QMetaObject.connectSlotsByName(MainWindow)

def retranslateUi(self, MainWindow):
    str_swt = QtCore.QString(U'\221A')
    MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "MainWindow", None, QtGui.QApplication.UnicodeUTF8))
    self.label.setText(QtGui.QApplication.translate("MainWindow", str_swt, None, QtGui.QApplication.UnicodeUTF8))

@

loladiro

I have so far not seen a string literal that consited directly of unicode chars but rather something like this (c++, python should be similar):
@
str1 = QString(QChar(0x221A));
str2 = QString("This is my very second unicode string: %1").arg(QChar(0x221A));
@

gworouge

hello loladiro,

all I can see is a "?" but not any alpha symbol (unicode u221A...).

if you have a chance, please copy paste and run the two files init.py :
@# -- coding: utf-8 --

"""The user interface for our app"""

import os,sys

Import Qt modules

from math import *
from PyQt4 import QtCore, QtGui
from PyQt4.QtGui import *
from PyQt4.Qt import *

from untitled import *

Create a class for our main window

class Main(QtGui.QMainWindow):
def init(self):
QtGui.QMainWindow.init(self)

    # This is always the same
    self.ui=Ui_MainWindow()
    self.ui.setupUi(self)

def main():
# Again, this is boilerplate, it's going to be the same on
# almost every app you write
app = QtGui.QApplication(sys.argv)
window=Main()
window.show()
# It's exec_ because exec is a reserved word in Python

sys.exit(app.exec_())

if name == "main":
main()
@

and untitled.py :

@# -- coding: utf-8 --

Form implementation generated from reading ui file 'untitled.ui'

Created: Sun Jun 19 11:26:12 2011

by: PyQt4 UI code generator 4.8.4

WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
_fromUtf8 = lambda s: s

class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(721, 502)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.label = QtGui.QLabel(self.centralwidget)
self.label.setGeometry(QtCore.QRect(80, 110, 441, 31))
self.label.setObjectName(_fromUtf8("label"))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 721, 20))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)

    self.retranslateUi(MainWindow)
    QtCore.QMetaObject.connectSlotsByName(MainWindow)

def retranslateUi(self, MainWindow):
    strswt = QtCore.QString("This is my very second unicode string: %1").arg(QtCore.QChar(0x221A))
    MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "MainWindow", None, QtGui.QApplication.UnicodeUTF8))
    self.label.setText(QtGui.QApplication.translate("MainWindow", QtCore.QString(strswt), None, QtGui.QApplication.UnicodeUTF8))

@

thanks for your patience and help.

bruceoutdoors

[quote author="ZapB" date="1308484736"]I have used the qmmlwidget before and it worked well from what I can recall. Just a shame that mml is so verbose. I dream of a text layout system for Qt that could render LaTeX.[/quote]

There is the KLFBackend library that renders LaTeX code, if I think that's what you're dreaming of:
http://qt-project.org/wiki/Qt_and_LaTeX_via_KLFBackend