我有下面的程序,它使用sympy和svgmath来呈现用户的代数表达式。它几乎可以工作,但有几个问题:
致以衷心的感谢和良好的祝愿。在
from __future__ import division
import sys
import sympy
from PySide.QtGui import *
from PySide.QtCore import *
from PySide.QtXml import *
from PySide.QtSvg import *
from xml import sax
from xml.sax.saxutils import XMLGenerator
from svgmath.tools.saxtools import XMLGenerator, ContentFilter
from svgmath.mathhandler import MathHandler, MathNS
from sympy.printing.mathml import mathml
from sympy.abc import x
from sympy.utilities.mathml import c2p
import libxml2
import StringIO
class Form(QDialog):
def __init__(self, parent=None):
super(Form, self).__init__(parent)
self.browser = QTextBrowser()
self.browser.setCurrentFont(QFont("Courier New",10,QFont.Bold))
self.lineedit = QLineEdit("please type an expression")
self.lineedit.selectAll()
self.svgwidget = QSvgWidget()
layout = QVBoxLayout()
layout.addWidget(self.browser)
layout.addWidget(self.lineedit)
layout.addWidget(self.svgwidget)
self.setLayout(layout)
self.lineedit.setFocus()
self.connect(self.lineedit, SIGNAL("textChanged (const QString&)"),self.updateUi)
def updateUi(self):
text = unicode(self.lineedit.text())
for z in range(0,9):
text = text.replace('x'+str(z),'x^'+str(z))
text = text.replace(')'+str(z),')^'+str(z))
text = text.replace(str(z)+'x',str(z)+'*x')
text = text.replace(str(z)+'(',str(z)+'*(')
try:
prettytext = sympy.printing.pretty(sympy.sympify(text))
self.browser.clear()
self.browser.append(prettytext)
# Open all files
output = open("test.svg", "w")
config = open("svgmath.xml", "r")
# Create the converter as a content handler.
saxoutput = XMLGenerator(output, 'utf-8')
handler = MathHandler(saxoutput, config)
# Parse input file with a namespace-aware SAX parser
parser = sax.make_parser()
parser.setFeature(sax.handler.feature_namespaces, 1)
parser.setContentHandler(handler)
parser.parse(StringIO.StringIO(c2p(mathml(sympy.sympify(text)), simple=True)))
self.svgwidget.load("test.svg")
except Exception:
if text=='': self.browser.clear()
app = QApplication(sys.argv)
form = Form()
form.show()
app.exec_()
您应该关闭文件句柄,否则写入的数据可能尚未刷新到文件系统。在
或者,使用
^{pr2}$with
表达式。在我认为
QSvgWidget
提供了一个load
槽,它接受文件内容的字节字符串。在相关问题 更多 >
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