VexFlow - Music Engraving for HTML5 Copyright Mohit Muthanna 2010
This class implements varies types of ties between contiguous notes. The ties include: regular ties, hammer ons, pull offs, and slides.
/**
* Create a new tie from the specified notes. The notes must
* be part of the same line, and have the same duration (in ticks).
*
* @constructor
* @param {!Object} context The canvas context.
* @param {!Object} notes The notes to tie up.
* @param {!Object} Options
*/
Vex.Flow.TabSlide = (function() {
function TabSlide(notes, direction) {
if (arguments.length > 0) this.init(notes, direction);
}
TabSlide.SLIDE_UP = 1;
TabSlide.SLIDE_DOWN = -1;
TabSlide.createSlideUp = function(notes) {
return new TabSlide(notes, TabSlide.SLIDE_UP);
};
TabSlide.createSlideDown = function(notes) {
return new TabSlide(notes, TabSlide.SLIDE_DOWN);
};
Vex.Inherit(TabSlide, Vex.Flow.TabTie, {
init: function(notes, direction) {
/**
* Notes is a struct that has:
*
* {
* first_note: Note,
* last_note: Note,
* first_indices: [n1, n2, n3],
* last_indices: [n1, n2, n3]
* }
*
**/
TabSlide.superclass.init.call(this, notes, "sl.");
if (!direction) {
var first_fret = notes.first_note.getPositions()[0].fret;
var last_fret = notes.last_note.getPositions()[0].fret;
direction = ((parseInt(first_fret, 10) > parseInt(last_fret, 10)) ?
TabSlide.SLIDE_DOWN : TabSlide.SLIDE_UP);
}
this.slide_direction = direction;
this.render_options.cp1 = 11;
this.render_options.cp2 = 14;
this.render_options.y_shift = 0.5;
this.setFont({font: "Times", size: 10, style: "bold italic"});
this.setNotes(notes);
},
renderTie: function(params) {
if (params.first_ys.length === 0 || params.last_ys.length === 0)
throw new Vex.RERR("BadArguments", "No Y-values to render");
var ctx = this.context;
var first_x_px = params.first_x_px;
var first_ys = params.first_ys;
var last_x_px = params.last_x_px;
var direction = this.slide_direction;
if (direction != TabSlide.SLIDE_UP &&
direction != TabSlide.SLIDE_DOWN) {
throw new Vex.RERR("BadSlide", "Invalid slide direction");
}
for (var i = 0; i < this.first_indices.length; ++i) {
var slide_y = first_ys[this.first_indices[i]] +
this.render_options.y_shift;
if (isNaN(slide_y))
throw new Vex.RERR("BadArguments", "Bad indices for slide rendering.");
ctx.beginPath();
ctx.moveTo(first_x_px, slide_y + (3 * direction));
ctx.lineTo(last_x_px, slide_y - (3 * direction));
ctx.closePath();
ctx.stroke();
}
}
});
return TabSlide;
}());