guitar/static/js/song-controls.js
2025-03-12 23:43:05 +01:00

105 lines
3.1 KiB
JavaScript

const controls = document.querySelector(".controls");
const song = document.querySelector("iframe.song").contentWindow;
// Autoscroll
let scroll;
let scrollTimeout = 60;
const minTimeout = 10;
const maxTimeout = 120;
const scrollIncrement = 20;
function pageScroll() {
song.scrollBy(0, 1);
scroll = setTimeout(pageScroll, scrollTimeout);
}
function updateScrollSpeed() {
if (controls.querySelector("#autoscroll").classList.contains("active")) {
clearTimeout(scroll);
scroll = setTimeout(pageScroll, scrollTimeout);
}
}
controls.querySelector("#autoscroll-increase").addEventListener("click", () => {
scrollTimeout = Math.max(minTimeout, scrollTimeout - scrollIncrement);
updateScrollSpeed();
});
controls.querySelector("#autoscroll-decrease").addEventListener("click", () => {
scrollTimeout = Math.min(maxTimeout, scrollTimeout + scrollIncrement);
updateScrollSpeed();
});
controls.querySelector("#autoscroll").addEventListener("click", function() {
this.classList.toggle("active");
if (this.classList.contains("active")) {
pageScroll();
} else {
clearTimeout(scroll);
}
});
// Scaling
function pageScale(value) {
if (value === 0) {
song.document.body.style.transform = "scale(1)";
return;
}
const currentScale =
parseFloat(song.document.body.style.transform.split("scale(")[1]) || 1;
song.document.body.style.transform = "scale(" + (currentScale + value) + ")";
}
controls
.querySelector("#font-size-increase")
.addEventListener("click", () => pageScale(0.1));
controls
.querySelector("#font-size-decrease")
.addEventListener("click", () => pageScale(-0.1));
controls
.querySelector("#font-size-reset")
.addEventListener("click", () => pageScale(0));
// Display the controls on JS-enabled browsers
window.addEventListener("load", () => (controls.classList.remove = "hidden"));
// Transpose
let transCounter = 0;
const chords = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B",];
const chordsFlat = ["C", "Db", "D", "Eb", "E", "F", "Gb", "G", "Ab", "A", "Bb", "B",];
function transposeChord(chord, steps) {
let useFlats = chord.includes("b");
let chordList = useFlats ? chordsFlat : chords;
let match = chord.match(/^([A-G][#b]?)/);
if (!match) return chord;
let root = match[1];
let index = chordList.indexOf(root);
if (index === -1) return chord;
let newIndex = (index + steps + 12) % 12;
let transposedRoot = chordList[newIndex];
return transposedRoot + chord.slice(root.length);
}
function transposeSong(steps) {
const iframe = document.querySelector("iframe.song");
const innerDoc = iframe.contentDocument || iframe.contentWindow.document;
innerDoc.querySelectorAll("tr.chords td").forEach((td) => {
let chord = td.textContent.trim();
if (chord) {
td.textContent = transposeChord(chord, steps);
}
});
}
document.querySelector("#transpose-decrease").addEventListener("click", () => { transposeSong(-1); transCounter -= 1 });
document.querySelector("#transpose-increase").addEventListener("click", () => { transposeSong(1); transCounter += 1 });
document.querySelector("#transpose-reset").addEventListener("click", () => { transposeSong(transCounter * -1); transCounter = 0; });