Why doesn't my QsciLexerCustom subclass work in PyQt4 using QsciScintilla?
- by Jon Watte
My end goal is to get Erlang syntax highlighting in QsciScintilla using PyQt4 and Python 2.6. I'm running on Windows 7, but will also need Ubuntu support.
PyQt4 is missing the necessary wrapper code for the Erlang lexer/highlighter that "base" scintilla has, so I figured I'd write a lightweight one on top of QsciLexerCustom. It's a little bit problematic, because the Qsci wrapper seems to really want to talk about line+index rather than offset-from-start when getting/setting subranges of text. Meanwhile, the lexer gets arguments as offset-from-start. For now, I get a copy of the entire text, and split that up as appropriate.
I have the following lexer, and I apply it with setLexer(). It gets all the appropriate calls when I open a new file and sets this as the lexer, and prints a bunch of appropriate lines based on what it's doing... but there is no styling in the document. I tried making all the defined styles red, and the document is still stubbornly black-on-white, so apparently the styles don't really "take effect"
What am I doing wrong? If nobody here knows, what's the appropriate discussion forum where people might actually know these things? (It's an interesting intersection between Python, Qt and Scintilla, so I imagine the set of people who would know is small)
Let's assume prefs.declare() just sets up a dict that returns the value for the given key (I've verified this -- it's not the problem).
Let's assume scintilla is reasonably properly constructed into its host window QWidget. Specifically, if I apply a bundled lexer (such as QsciLexerPython), it takes effect and does show styled text.
prefs.declare('font.name.margin', "MS Dlg")
prefs.declare('font.size.margin', 8)
prefs.declare('font.name.code', "Courier New")
prefs.declare('font.size.code', 10)
prefs.declare('color.editline', "#d0e0ff")
class LexerErlang(Qsci.QsciLexerCustom):
def __init__(self, obj = None):
Qsci.QsciLexerCustom.__init__(self, obj)
self.sci = None
self.plainFont = QtGui.QFont()
self.plainFont.setPointSize(int(prefs.get('font.size.code')))
self.plainFont.setFamily(prefs.get('font.name.code'))
self.marginFont = QtGui.QFont()
self.marginFont.setPointSize(int(prefs.get('font.size.code')))
self.marginFont.setFamily(prefs.get('font.name.margin'))
self.boldFont = QtGui.QFont()
self.boldFont.setPointSize(int(prefs.get('font.size.code')))
self.boldFont.setFamily(prefs.get('font.name.code'))
self.boldFont.setBold(True)
self.styles = [
Qsci.QsciStyle(0, QtCore.QString("base"), QtGui.QColor("#000000"), QtGui.QColor("#ffffff"), self.plainFont, True),
Qsci.QsciStyle(1, QtCore.QString("comment"), QtGui.QColor("#008000"), QtGui.QColor("#eeffee"), self.marginFont, True),
Qsci.QsciStyle(2, QtCore.QString("keyword"), QtGui.QColor("#000080"), QtGui.QColor("#ffffff"), self.boldFont, True),
Qsci.QsciStyle(3, QtCore.QString("string"), QtGui.QColor("#800000"), QtGui.QColor("#ffffff"), self.marginFont, True),
Qsci.QsciStyle(4, QtCore.QString("atom"), QtGui.QColor("#008080"), QtGui.QColor("#ffffff"), self.plainFont, True),
Qsci.QsciStyle(5, QtCore.QString("macro"), QtGui.QColor("#808000"), QtGui.QColor("#ffffff"), self.boldFont, True),
Qsci.QsciStyle(6, QtCore.QString("error"), QtGui.QColor("#000000"), QtGui.QColor("#ffd0d0"), self.plainFont, True),
]
print("LexerErlang created")
def description(self, ix):
for i in self.styles:
if i.style() == ix:
return QtCore.QString(i.description())
return QtCore.QString("")
def setEditor(self, sci):
self.sci = sci
Qsci.QsciLexerCustom.setEditor(self, sci)
print("LexerErlang.setEditor()")
def styleText(self, start, end):
print("LexerErlang.styleText(%d,%d)" % (start, end))
lines = self.getText(start, end)
offset = start
self.startStyling(offset, 0)
print("startStyling()")
for i in lines:
if i == "":
self.setStyling(1, self.styles[0])
print("setStyling(1)")
offset += 1
continue
if i[0] == '%':
self.setStyling(len(i)+1, self.styles[1])
print("setStyling(%)")
offset += len(i)+1
continue
self.setStyling(len(i)+1, self.styles[0])
print("setStyling(n)")
offset += len(i)+1
def getText(self, start, end):
data = self.sci.text()
print("LexerErlang.getText(): " + str(len(data)) + " chars")
return data[start:end].split('\n')
Applied to the QsciScintilla widget as follows:
_lexers = {
'erl': (Q.SCLEX_ERLANG, LexerErlang),
'hrl': (Q.SCLEX_ERLANG, LexerErlang),
'html': (Q.SCLEX_HTML, Qsci.QsciLexerHTML),
'css': (Q.SCLEX_CSS, Qsci.QsciLexerCSS),
'py': (Q.SCLEX_PYTHON, Qsci.QsciLexerPython),
'php': (Q.SCLEX_PHP, Qsci.QsciLexerHTML),
'inc': (Q.SCLEX_PHP, Qsci.QsciLexerHTML),
'js': (Q.SCLEX_CPP, Qsci.QsciLexerJavaScript),
'cpp': (Q.SCLEX_CPP, Qsci.QsciLexerCPP),
'h': (Q.SCLEX_CPP, Qsci.QsciLexerCPP),
'cxx': (Q.SCLEX_CPP, Qsci.QsciLexerCPP),
'hpp': (Q.SCLEX_CPP, Qsci.QsciLexerCPP),
'c': (Q.SCLEX_CPP, Qsci.QsciLexerCPP),
'hxx': (Q.SCLEX_CPP, Qsci.QsciLexerCPP),
'tpl': (Q.SCLEX_CPP, Qsci.QsciLexerCPP),
'xml': (Q.SCLEX_XML, Qsci.QsciLexerXML),
}
... inside my document window class ...
def addContentsDocument(self, contents, title):
handler = self.makeScintilla()
handler.title = title
sci = handler.sci
sci.append(contents)
self.tabWidget.addTab(sci, title)
self.tabWidget.setCurrentWidget(sci)
self.applyLexer(sci, title)
EventBus.bus.broadcast('command.done', {'text': 'Opened ' + title})
return handler
def applyLexer(self, sci, title):
(language, lexer) = language_and_lexer_from_title(title)
if lexer:
l = lexer()
print("making lexer: " + str(l))
sci.setLexer(l)
else:
print("setting lexer by id: " + str(language))
sci.SendScintilla(Qsci.QsciScintillaBase.SCI_SETLEXER, language)
linst = sci.lexer()
print("lexer: " + str(linst))
def makeScintilla(self):
sci = Qsci.QsciScintilla()
sci.setUtf8(True)
sci.setTabIndents(True)
sci.setIndentationsUseTabs(False)
sci.setIndentationWidth(4)
sci.setMarginsFont(self.smallFont)
sci.setMarginWidth(0, self.smallFontMetrics.width('00000'))
sci.setFont(self.monoFont)
sci.setAutoIndent(True)
sci.setBraceMatching(Qsci.QsciScintilla.StrictBraceMatch)
handler = SciHandler(sci)
self.handlers[sci] = handler
sci.setMarginLineNumbers(0, True)
sci.setCaretLineVisible(True)
sci.setCaretLineBackgroundColor(QtGui.QColor(prefs.get('color.editline')))
return handler
Let's assume the rest of the application works, too (because it does :-)
