// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This code in inspired by the canvas arcs test on the animometer
// benchmark (https://pr.gg/animometer/developer.html).
// Javascript code: https://pr.gg/animometer/tests/master/resources/canvas-tests.js
function CanvasArc() {
var x;
var y;
var radius;
var width;
var start_angle;
var end_angle;
var arc_speed;
var counterclockwise;
var color;
var is_stroke;
this.init = function(arc_speed, max_width, max_height) {
// initialize parameters randomly
num_positions_x = 7;
position_incr_x = Math.floor(max_width / num_positions_x);
this.x = Math.floor(Math.random() * num_positions_x) * position_incr_x;
num_positions_y = 7;
position_incr_y = Math.floor(max_height / num_positions_y);
this.y = Math.floor(Math.random() * num_positions_y) * position_incr_y;
var max_radius = max_height / 10;
// radius is in [0.5*max_radius, max_radius)
this.radius = ((Math.random() + 1) / 2) * max_radius;
this.width = 1 + Math.pow(Math.random(), 4) * 30;
var colors = ["#101010", "#808080", "#c0c0c0",
"#e01040", "#10c030", "#e05010"];
this.color = colors[Math.floor(Math.random() * colors.length)];
this.is_stroke = (Math.floor(Math.random() * 3) == 0);
this.counterclockwise = (Math.floor(Math.random() * 2) == 0);
this.arc_speed = (Math.random() - 0.5) * Math.PI / 10;
this.start_angle = Math.random() * 2 * Math.PI;
this.end_angle = Math.random() * 2 * Math.PI;
}
this.draw = function(context) {
this.start_angle += this.arc_speed;
this.end_angle += this.arc_speed / 2;
// draw the canvas arc on the given context
if (this.is_stroke) {
context.strokeStyle = this.color;
context.lineWidth = this.width;
context.beginPath();
context.arc(this.x, this.y, this.radius,
this.start_angle, this.end_angle, this.counterclockwise);
context.stroke();
} else {
context.fillStyle = this.color;
context.beginPath();
context.lineTo(this.x, this,y);
context.arc(this.x, this.y, this.radius, this.start_angle,
this.end_angle, this.couterclockwise);
context.lineTo(this.x, this.y);
context.fill();
}
}
}
var arcs = (function() {
var initialized_arcs;
var width;
var height;
var arcs = {};
arcs.init = function(number_arcs, arc_speed, canvas_width, canvas_height) {
// initialize arcs and store variables
initialized_arcs = [];
for(var i = 0; i < number_arcs; i++) {
var new_arc = new CanvasArc();
new_arc.init(arc_speed, canvas_width, canvas_height);
initialized_arcs.push(new_arc)
}
};
arcs.draw = function(context) {
// draw all initialized_arcs on the context
for(var i = 0; i < initialized_arcs.length; i++) {
initialized_arcs[i].draw(context);
}
};
return arcs;
})();