gnome-shell/js/ui/ripples.js

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// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
const { Clutter, St } = imports.gi;
const Tweener = imports.ui.tweener;
// Shamelessly copied from the layout "hotcorner" ripples implementation
var Ripples = class Ripples {
constructor(px, py, styleClass) {
this._x = 0;
this._y = 0;
this._px = px;
this._py = py;
this._ripple1 = new St.BoxLayout({ style_class: styleClass,
opacity: 0,
can_focus: false,
reactive: false,
visible: false });
this._ripple1.set_pivot_point(px, py);
this._ripple2 = new St.BoxLayout({ style_class: styleClass,
opacity: 0,
can_focus: false,
reactive: false,
visible: false });
this._ripple2.set_pivot_point(px, py);
this._ripple3 = new St.BoxLayout({ style_class: styleClass,
opacity: 0,
can_focus: false,
reactive: false,
visible: false });
this._ripple3.set_pivot_point(px, py);
}
_animRipple(ripple, delay, time, startScale, startOpacity, finalScale) {
// We draw a ripple by using a source image and animating it scaling
// outwards and fading away. We want the ripples to move linearly
// or it looks unrealistic, but if the opacity of the ripple goes
// linearly to zero it fades away too quickly, so we use Tweener's
// 'onUpdate' to give a non-linear curve to the fade-away and make
// it more visible in the middle section.
ripple.x = this._x;
ripple.y = this._y;
ripple._opacity = startOpacity;
ripple.visible = true;
ripple.opacity = 255 * Math.sqrt(startOpacity);
ripple.scale_x = ripple.scale_y = startScale;
ripple.set_translation( - this._px * ripple.width, - this._py * ripple.height, 0.0);
Tweener.addTween(ripple, { _opacity: 0,
scale_x: finalScale,
scale_y: finalScale,
delay: delay,
time: time,
transition: 'linear',
onUpdate() { ripple.opacity = 255 * Math.sqrt(ripple._opacity); },
onComplete() { ripple.visible = false; } });
}
addTo(stage) {
if (this._stage !== undefined)
throw new Error('Ripples already added');
this._stage = stage;
this._stage.add_actor(this._ripple1);
this._stage.add_actor(this._ripple2);
this._stage.add_actor(this._ripple3);
}
playAnimation(x, y) {
if (this._stage === undefined)
throw new Error('Ripples not added');
this._x = x;
this._y = y;
this._stage.set_child_above_sibling(this._ripple1, null);
this._stage.set_child_above_sibling(this._ripple2, this._ripple1);
this._stage.set_child_above_sibling(this._ripple3, this._ripple2);
// Show three concentric ripples expanding outwards; the exact
// parameters were found by trial and error, so don't look
// for them to make perfect sense mathematically
// delay time scale opacity => scale
this._animRipple(this._ripple1, 0.0, 0.83, 0.25, 1.0, 1.5);
this._animRipple(this._ripple2, 0.05, 1.0, 0.0, 0.7, 1.25);
this._animRipple(this._ripple3, 0.35, 1.0, 0.0, 0.3, 1);
}
};