generateSpansFromText method
Parses markup in text to fill spans with styled TextSpans.
Implementation
void generateSpansFromText(ChantContext ctxt, String text) {
text = text.replaceAll(RegExp(r'\s+'), ' ');
this.text = '';
spans = [];
if (text == '*' || text == '+' || text == '†') {
final List<Map<String, dynamic>> properties = switch (text) {
'*' => [ctxt.asteriskProperties],
'+' => [ctxt.plusProperties],
_ => [],
};
final mapped = ctxt.specialCharText(text);
spans.add(TextSpan(mapped, properties, []));
return;
}
final markupStack = <MarkupStackFrame>[];
var spanStartIndex = 0;
var newLineInNextSpan = 0;
bool filterFrames(MarkupStackFrame frame, String? symbol) =>
frame.symbol == symbol;
void closeSpan(
String spanText,
int index, [
Map<String, dynamic>? extraProperties,
]) {
if (spanText.isEmpty && dropCap == null) return;
this.text += spanText;
final properties = <Map<String, dynamic>>[];
for (final frame in markupStack) {
properties.addAll(frame.propertyArray);
}
if (extraProperties != null && extraProperties.isNotEmpty) {
properties.add(extraProperties);
}
final span = TextSpan(
spanText,
properties,
markupStack.map((frame) => frame.tagName).toList(),
index,
);
spans.add(span);
if (newLineInNextSpan > 0) {
span.newLine = newLineInNextSpan;
newLineInNextSpan = 0;
}
}
final markupRegex = RegExp(
r'(<br/?>)|<v>([\s\S]*?)(?:<\/v>|$)|(\*)(?=\s*\*|[^*]*(?:$|<v>))|(\+)|<sp>(?:(~)|('
"'"
r')?([ao]e|[æœaeiouy])|([arv])\/)<\/sp>|([arv])\/\.|([℣℟])\.?|(?:([*_^%])|<(\/)?([bceiuv]|ul|sc|font)(?:\s+(?:family="([^"]+)"|fill="([^"]+)"|class="([^"]+)"))*>)(?=(?:(.+?)(?:\11|<\/\13>))?)',
caseSensitive: false,
);
final vTagRegex = RegExp(
r"(\\grecross)|\{greextra\}\{([^}]*)\}|\{?(\\?')?(?:\\([ao]e|æœaeiouy))\}?",
caseSensitive: false,
);
var openedAsterisk = false;
void closeCurrentSpan(RegExpMatch match) {
closeSpan(text.substring(spanStartIndex, match.start), spanStartIndex);
}
for (final match in markupRegex.allMatches(text)) {
final newLine = match.group(1);
final vTag = match.group(2);
final asterisk = match.group(3);
final plus = match.group(4);
final tilde = match.group(5);
final accent = match.group(6);
final vowelLigature = match.group(7);
final specialCharSp = match.group(8);
final specialCharSlash = match.group(9);
final specialCharVbar = match.group(10);
final markupSymbol = match.group(11);
final closingTag = match.group(12);
var tagName = match.group(13);
final family = match.group(14);
final fill = match.group(15);
final cssClass = match.group(16);
final enclosedText = match.group(17);
final specialChar = specialCharSp ?? specialCharSlash ?? specialCharVbar;
if (newLine != null) {
if (match.start > spanStartIndex) {
closeCurrentSpan(match);
}
newLineInNextSpan++;
} else if (vTag != null) {
closeCurrentSpan(match);
var lastIndex = 0;
var iOffset = 0;
for (final vMatch in vTagRegex.allMatches(vTag)) {
if (lastIndex < vMatch.start) {
closeSpan(
vTag.substring(lastIndex, vMatch.start),
match.start + lastIndex + iOffset,
);
iOffset = 3; // length of '<v>'
}
final grecross = vMatch.group(1);
var greextra = vMatch.group(2);
final vAccent = vMatch.group(3);
final diphthong = vMatch.group(4);
var char = '';
if (diphthong != null) {
char = makeLigature(diphthong);
if (vAccent != null) char = addAccent(char);
closeSpan(char, match.start + vMatch.start + iOffset);
} else {
if (grecross != null) {
// grecross is just the command for the Cross:
// set up greextra so it will get handled with it below:
greextra = 'Cross';
}
char = glyphs.greextraGlyphs[greextra] ?? '';
if (char.isNotEmpty) {
closeSpan(char, match.start + vMatch.start + iOffset, {
'font-family': 'greextra',
});
}
}
lastIndex = vMatch.end;
iOffset = 3; // length of '<v>'
}
if (lastIndex < vTag.length) {
closeSpan(
vTag.substring(lastIndex),
match.start + lastIndex + iOffset,
);
}
} else if (asterisk != null) {
closeCurrentSpan(match);
// first check if it is just a symbol to close:
if (markupStack.isNotEmpty && markupStack.last.symbol == asterisk) {
markupStack.removeLast();
} else {
closeSpan(
ctxt.specialCharText(asterisk),
match.start,
ctxt.asteriskProperties,
);
}
} else if (plus != null) {
closeCurrentSpan(match);
closeSpan(ctxt.specialCharText(plus), match.start, ctxt.plusProperties);
} else if (tilde != null) {
closeCurrentSpan(match);
closeSpan('∼', match.start);
} else if (vowelLigature != null) {
var vowel = makeLigature(vowelLigature);
if (accent != null) vowel = addAccent(vowel);
closeCurrentSpan(match);
closeSpan(vowel, match.start);
} else if (specialChar != null) {
closeCurrentSpan(match);
closeSpan(
ctxt.textBeforeSpecialChar +
ctxt.specialCharText(specialChar) +
ctxt.textAfterSpecialChar,
match.start,
ctxt.specialCharProperties,
);
} else {
// otherwise we're dealing with matching markup delimeters
if (markupSymbol == '*') {
// we are only strict with the asterisk, because there are cases
// when it needs to be displayed rather than count as a markup
// symbol
if (enclosedText != null &&
RegExp(r'[^\s*]').hasMatch(enclosedText)) {
openedAsterisk = true;
} else if (openedAsterisk) {
openedAsterisk = false;
} else {
// actually use the asterisk, since it doesn't have a matching
// closing asterisk
continue;
}
}
if (markupSymbol != null) {
tagName = ctxt.markupSymbolDictionary[markupSymbol];
if (markupStack.isNotEmpty &&
markupStack.last.tagName == tagName &&
markupStack.last.symbol == markupSymbol) {
if (closingTag != null) {
closeCurrentSpan(match);
markupStack.removeLast();
}
// otherwise: matching symbol on top of stack but not a closing
// tag — fall through to group open below
else {
closeCurrentSpan(match);
final extraProperties = <String, dynamic>{};
if (family != null) extraProperties['font-family'] = family;
if (fill != null) extraProperties['fill'] = fill;
if (cssClass != null) extraProperties['class'] = cssClass;
markupStack.add(
MarkupStackFrame.createStackFrame(
ctxt,
tagName!,
match.start,
extraProperties,
markupSymbol,
),
);
}
} else if (markupStack.isNotEmpty &&
markupStack.last.tagName == tagName) {
if (closingTag != null) {
closeCurrentSpan(match);
markupStack.removeLast();
}
} else if (markupStack
.where((f) => filterFrames(f, markupSymbol))
.isNotEmpty) {
// trying to open a recursive group (or forgot to close a previous
// group). In either case, we just unwind to the previous stack
// frame
spanStartIndex = markupStack.last.startIndex;
markupStack.removeLast();
continue;
} else {
closeCurrentSpan(match);
if (closingTag != null) {
// out of order group close:
final index = markupStack.indexWhere(
(frame) => frame.tagName == tagName,
);
if (index >= 0) {
markupStack.removeRange(index, index + 1);
}
} else {
// group open
final extraProperties = <String, dynamic>{};
if (family != null) extraProperties['font-family'] = family;
if (fill != null) extraProperties['fill'] = fill;
if (cssClass != null) extraProperties['class'] = cssClass;
markupStack.add(
MarkupStackFrame.createStackFrame(
ctxt,
tagName!,
match.start,
extraProperties,
markupSymbol,
),
);
}
}
} else if (tagName != null) {
if (markupStack.isNotEmpty && markupStack.last.tagName == tagName) {
if (closingTag != null) {
closeCurrentSpan(match);
markupStack.removeLast();
}
} else if (markupStack
.where((f) => filterFrames(f, null))
.isNotEmpty) {
spanStartIndex = markupStack.last.startIndex;
markupStack.removeLast();
continue;
} else {
closeCurrentSpan(match);
if (closingTag != null) {
final index = markupStack.indexWhere(
(frame) => frame.tagName == tagName,
);
if (index >= 0) {
markupStack.removeRange(index, index + 1);
}
} else {
final extraProperties = <String, dynamic>{};
if (family != null) extraProperties['font-family'] = family;
if (fill != null) extraProperties['fill'] = fill;
if (cssClass != null) extraProperties['class'] = cssClass;
markupStack.add(
MarkupStackFrame.createStackFrame(
ctxt,
tagName,
match.start,
extraProperties,
'',
),
);
}
}
}
}
// advance the start index past the current markup
spanStartIndex = match.end;
}
// if we finished matches, and there is still some text left,
// or if we haven't generated any spans yet, create one final run
if (spanStartIndex < text.length || spans.isEmpty) {
closeSpan(text.substring(spanStartIndex), spanStartIndex);
}
}
