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Merge pull request #12 from SamuMazzi/main
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Refactor and updates (Italian notation, support for flat chords, suppport for textScaleFactor, support for metadata)
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@paurakhsharma
paurakhsharma authored May 18, 2022
2 parents b2d2a40 + 6337f15 commit d6998b6
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Showing 7 changed files with 597 additions and 178 deletions.
316 changes: 191 additions & 125 deletions lib/src/chord_parser.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -3,131 +3,120 @@ import 'dart:math';
import 'package:flutter/material.dart';
import 'model/chord_lyrics_document.dart';
import 'model/chord_lyrics_line.dart';
import 'chord_transposer.dart';

class ChordProcessor {
final BuildContext context;
ChordProcessor(this.context);
final ChordNotation chordNotation;
final ChordTransposer chordTransposer;
final double media;
late double _textScaleFactor;

ChordProcessor(this.context, [this.chordNotation = ChordNotation.american])
: chordTransposer = ChordTransposer(chordNotation),
media = MediaQuery.of(context).size.width;

/// Process the text to get the parsed ChordLyricsDocument
ChordLyricsDocument processText({
required String text,
required TextStyle lyricsStyle,
required chordStyle,
widgetPadding = 0,
required TextStyle chordStyle,
double scaleFactor = 1.0,
int widgetPadding = 0,
int transposeIncrement = 0,
}) {
final lines = text.split('\n');

bool _chordHasStartedOuter = false;
String _currentCharacters = '';
int _lastSpace = 0;
String _currentLine = '';
String _character = '';
double _media = MediaQuery.of(context).size.width;
int _characterIndex = 0;

//list to store our updated lines without overflows
final _newLines = <String>[];

//loop through the lines
for (var i = 0; i < lines.length; i++) {
_characterIndex = 0;
_currentCharacters = '';
_currentLine = lines[i];
final List<String> lines = text.split('\n');
final MetadataHandler metadata = MetadataHandler();
_textScaleFactor = scaleFactor;
chordTransposer.transpose = transposeIncrement;

/// List to store our updated lines without overflows
final List<String> newLines = <String>[];
String currentLine = '';

///loop through the lines
for (int i = 0; i < lines.length; i++) {
currentLine = lines[i];

///If it finds some metadata skip to the next line
if (metadata.parseLine(currentLine)) {
continue;
}

//check if we have a long line
if (textWidth(_currentLine, lyricsStyle) >= _media) {
//work our way through the line and split when we need to
for (var j = 0; j < _currentLine.length; j++) {
_character = _currentLine[j];
if (_character == '[')
_chordHasStartedOuter = true;
else if (_character == ']')
_chordHasStartedOuter = false;
else if (!_chordHasStartedOuter) {
_currentCharacters += _character;
if (_character == ' ') {
//use this marker to only split where there are spaces. We can trim later.
_lastSpace = j;
}

//This is the point where we need to split
//widgetPadding has been added as a parameter to be passed from the build function
//It is intended to allow for padding in the widget when comparing it to screen width
//An additional buffer of around 10 might be needed to definitely stop overflow (ie. padding + 10).
if (textWidth(_currentCharacters, lyricsStyle) + widgetPadding >=
_media) {
_newLines.add(
_currentLine.substring(_characterIndex, _lastSpace).trim());
_currentCharacters = '';
_characterIndex = _lastSpace;
}
}
}
//add the rest of the long line
_newLines.add(_currentLine
.substring(_characterIndex, _currentLine.length)
.trim());
if (textWidth(currentLine, lyricsStyle) >= media) {
_handleLongLine(
currentLine: currentLine,
newLines: newLines,
lyricsStyle: lyricsStyle,
widgetPadding: widgetPadding);
} else {
//otherwise just add the regular line
_newLines.add(_currentLine.trim());
newLines.add(currentLine.trim());
}
}

List<ChordLyricsLine> _chordLyricsLines =
_newLines.map<ChordLyricsLine>((line) {
ChordLyricsLine _chordLyricsLine = ChordLyricsLine([], '');
String _lyricsSoFar = '';
String _chordsSoFar = '';
bool _chordHasStarted = false;
line.split('').forEach((character) {
if (character == ']') {
final sizeOfLeadingLyrics = textWidth(_lyricsSoFar, lyricsStyle);

final lastChordText = _chordLyricsLine.chords.isNotEmpty
? _chordLyricsLine.chords.last.chordText
: '';

final lastChordWidth = textWidth(lastChordText, chordStyle);
// final sizeOfThisChord = textWidth(_chordsSoFar, chordStyle);

double leadingSpace = 0;
leadingSpace = (sizeOfLeadingLyrics - lastChordWidth);

leadingSpace = max(0, leadingSpace);

final transposedChord = transposeChord(
_chordsSoFar,
transposeIncrement,
);

_chordLyricsLine.chords.add(Chord(leadingSpace, transposedChord));
_chordLyricsLine.lyrics += _lyricsSoFar;
_lyricsSoFar = '';
_chordsSoFar = '';
_chordHasStarted = false;
} else if (character == '[') {
_chordHasStarted = true;
} else {
if (_chordHasStarted) {
_chordsSoFar += character;
} else {
_lyricsSoFar += character;
}
}
});
List<ChordLyricsLine> _chordLyricsLines = newLines
.map<ChordLyricsLine>(
(line) => _processLine(line, lyricsStyle, chordStyle))
.toList();

_chordLyricsLine.lyrics += _lyricsSoFar;
return ChordLyricsDocument(_chordLyricsLines,
capo: metadata.capo,
artist: metadata.artist,
title: metadata.title,
key: metadata.key);
}

return _chordLyricsLine;
}).toList();
void _handleLongLine(
{required List<String> newLines,
required String currentLine,
required TextStyle lyricsStyle,
required int widgetPadding}) {
String _character = '';
int _characterIndex = 0;
String _currentCharacters = '';
bool _chordHasStartedOuter = false;
int _lastSpace = 0;

return ChordLyricsDocument(_chordLyricsLines);
//print('found a big line $currentLine');

//work our way through the line and split when we need to
for (var j = 0; j < currentLine.length; j++) {
_character = currentLine[j];
if (_character == '[') {
_chordHasStartedOuter = true;
} else if (_character == ']') {
_chordHasStartedOuter = false;
} else if (!_chordHasStartedOuter) {
_currentCharacters += _character;
if (_character == ' ') {
//use this marker to only split where there are spaces. We can trim later.
_lastSpace = j;
}

//This is the point where we need to split
//widgetPadding has been added as a parameter to be passed from the build function
//It is intended to allow for padding in the widget when comparing it to screen width
//An additional buffer of around 10 might be needed to definitely stop overflow (ie. padding + 10).
if (textWidth(_currentCharacters, lyricsStyle) + widgetPadding >=
media) {
newLines
.add(currentLine.substring(_characterIndex, _lastSpace).trim());
_currentCharacters = '';
_characterIndex = _lastSpace;
}
}
}
//add the rest of the long line
newLines
.add(currentLine.substring(_characterIndex, currentLine.length).trim());
}

/// Return the textwidth of the text in the given style
double textWidth(String text, TextStyle textStyle) {
return (TextPainter(
textScaleFactor: _textScaleFactor,
text: TextSpan(text: text, style: textStyle),
maxLines: 1,
textDirection: TextDirection.ltr,
Expand All @@ -136,31 +125,108 @@ class ChordProcessor {
.width;
}

/// Transpose the chord text by the given increment
String transposeChord(String chord, int increment) {
final cycle = [
"C",
"C#",
"D",
"D#",
"E",
"F",
"F#",
"G",
"G#",
"A",
"A#",
"B"
];
String el = chord[0];
if (chord.length > 1 && chord[1] == '#') {
el += "#";
}
final ind = cycle.indexOf(el);
if (ind == -1) return chord;
ChordLyricsLine _processLine(
String line, TextStyle lyricsStyle, TextStyle chordStyle) {
ChordLyricsLine _chordLyricsLine = ChordLyricsLine();
String _lyricsSoFar = '';
String _chordsSoFar = '';
bool _chordHasStarted = false;
line.split('').forEach((character) {
if (character == ']') {
final sizeOfLeadingLyrics = textWidth(_lyricsSoFar, lyricsStyle);

final lastChordText = _chordLyricsLine.chords.isNotEmpty
? _chordLyricsLine.chords.last.chordText
: '';

final lastChordWidth = textWidth(lastChordText, chordStyle);
// final sizeOfThisChord = textWidth(_chordsSoFar, chordStyle);

double leadingSpace = max(0, sizeOfLeadingLyrics - lastChordWidth);

final transposedChord = chordTransposer.transposeChord(_chordsSoFar);

_chordLyricsLine.chords.add(Chord(leadingSpace, transposedChord));
_chordLyricsLine.lyrics += _lyricsSoFar;
_lyricsSoFar = '';
_chordsSoFar = '';
_chordHasStarted = false;
} else if (character == '[') {
_chordHasStarted = true;
} else {
if (_chordHasStarted) {
_chordsSoFar += character;
} else {
_lyricsSoFar += character;
}
}
});

_chordLyricsLine.lyrics += _lyricsSoFar;

return _chordLyricsLine;
}
}

class MetadataHandler {
/// As specifications says "meta data is specified using “tags” surrounded by { and } characters"
final RegExp regMetadata = RegExp(r'^ *\{.*}');
final RegExp regCapo = RegExp(r'^\{capo:.*[0-9]+\}');
final RegExp regArtist = RegExp(r'^\{artist:.*\}');
final RegExp regTitle = RegExp(r'^\{title:.*\}');
final RegExp regKey = RegExp(r'^\{key:.*\}');
int? capo;
String? artist;
String? title;
String? key;

/// Try to find and parse metadata in the string.
/// Return true if there was a match
bool parseLine(String line) {
return _setCapoIfMatch(line) ||
_setArtistIfMatch(line) ||
_setKeyIfMatch(line) ||
_setTitleIfMatch(line);
}

/// Get key in line if it's present
/// Return true if match was found
bool _setKeyIfMatch(String line) {
String? tmpKey =
regKey.hasMatch(line) ? _getMetadataFromLine(line, 'key:') : null;
key ??= tmpKey;
return tmpKey != null;
}

/// Get capo in line if it's present
/// Return true if match was found
bool _setCapoIfMatch(String line) {
int? tmpCapo = regCapo.hasMatch(line)
? int.parse(_getMetadataFromLine(line, 'capo:'))
: null;
capo ??= tmpCapo;
return tmpCapo != null;
}

/// Get artist in line if it's present
/// Return true if match was found
bool _setArtistIfMatch(String line) {
String? tmpArtist =
regArtist.hasMatch(line) ? _getMetadataFromLine(line, 'artist:') : null;
artist ??= tmpArtist;
return tmpArtist != null;
}

/// Get title in line if it's present
/// Return true if match was found
bool _setTitleIfMatch(String line) {
String? tmpTitle =
regTitle.hasMatch(line) ? _getMetadataFromLine(line, 'title:') : null;
title ??= tmpTitle;
return tmpTitle != null;
}

final newInd = (ind + increment + cycle.length) % cycle.length;
final newChord = cycle[newInd];
return newChord + chord.substring(el.length);
String _getMetadataFromLine(String line, String key) {
return line.split(key).last.split('}').first.trim();
}
}
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