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Tutorial
This tutorial shows the basics of abc4j.
Introduction
The purpose of abc4j is to ease the the manipulation and the extract of information from abc tunes in general and abc files in particular.
Getting information from an abc file
Let's consider the following abc file tutorial.abc:
X:10 T:Simple scale exercise M:4/4 C:noOne K:C || C,D,E,F, | G,A,B,C | DEFG | ABcd | efga | bc'd'e' | f'g'a'b' || X:11 T:A multiple parts tune M:4/4 C:anyone P:(AB)2CCC K:C P:A aaaa P:B bbbb P:C cccc
There are many ways to get information from an abc file with abc4j. The simpliest one is to create a TuneBook from this file. Then you get access to all the information contained in this abc file like if it was parsed. Parsing phasis are hidden inside the TuneBook object. Once you get the instance of TuneBook that represents the "tutorial.abc" file, it's easy to know the number of tunes inside the TuneBook, titles of tunes contained in it or who composed the tune :
import java.io.File;
import abc.notation.Tune;
import abc.parser.TuneBook;
public void main(String[] arg)
{
File abcFile = new File ("tutorial.abc");
TuneBook book = new TuneBook(abcfile);
int tunesNb = book.size();
System.out.println("Nb of tunes in tutorial.abc : " + tunesNb);
// now retrieve the tune with reference number "10"
Tune aTune = book.getTune(10);
// display its title
System.out.print("Title n°10 is " + aTune.getTitles[0]);
// and the name of its composer.
System.out.println(" and has been composed by " + aTune.getComposer());
.
.The execution of this main class gives :
Nb of tunes in tutorial.abc : 2 Title n°10 is Simple scale exercise and has been composed by noOne
Getting the score from a tune
The score (class Tune.Score) is the place where information like key, notes, barlines, single or multiparts definition is stored. A score contains two types of elements:
- ScoreElementInterface : Those elements contain only "pure" score information without
any information about how the score should be displayed (layout).
- ScorePresentationElementInterface : Those elements describe the way the score should
Once we have a reference to a Tune, it's easy to retrieve its corresponding score and navigate into it to retrieve its content (notes, barlines...). This code retrieves the score of tune n°10 and displays all elements composing its score:
. . Tune.Score score = aTune.getScore(); Iterator iter = score.iterator(); while (iter.hasNext()) System.out.println(iter.next()); . .
How to play a tune
Here's the code to play a tune contained in an abc file ceili.abc using midi:
import java.io.File;
import abc.notation.Tune;
import abc.parser.TuneParser;
import abc.parser.TuneBook;
import abc.midi.TunePlayer;
.
.
//creates a file from the path to the abc file containing the tune to be played
File abcFile = new File ("ceili.abc");
//creates a tunebook from the previous file
TuneBook book = new TuneBook(abcfile);
//retrieves the first tune notation of the ceili.abc file
Tune tune = book.getTune(0);
//creates a midi player to play tunes
TunePlayer player = new TunePlayer();
//starts the player and play the tune
player.start();
player.play(tune);
.
..How to convert a tune into a midi file
The conversion of a tune object into a midi file is achieved using the abc4j midiConverter concept and some features of javaSound :
//The midi file result
File file = new File("test.mid");
//Create a converter to convert a tune into midi sequence
MidiConverterAbstract conv = new BasicMidiConverter();
//convert it !
Sequence s = conv.toMidiSequence(t);
//All available midi file type for the tune's sequence
int[] types = MidiSystem.getMidiFileTypes(s);
//Write the sequence as a midi file.
MidiSystem.write(s,types[0],file);
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Very interesting and clear : thanks !