gnome-shell/js/ui/pageIndicators.js

// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
/* exported PageIndicators, AnimatedPageIndicators */

const { Clutter, GObject, St } = imports.gi;

const Tweener = imports.ui.tweener;
const { ANIMATION_TIME_OUT, ANIMATION_MAX_DELAY_OUT_FOR_ITEM, AnimationDirection } = imports.ui.iconGrid;

var INDICATORS_BASE_TIME = 0.25;
var INDICATORS_BASE_TIME_OUT = 0.125;
var INDICATORS_ANIMATION_DELAY = 0.125;
var INDICATORS_ANIMATION_DELAY_OUT = 0.0625;
var INDICATORS_ANIMATION_MAX_TIME = 0.75;
var SWITCH_TIME = 0.4;
var INDICATORS_ANIMATION_MAX_TIME_OUT =
    Math.min (SWITCH_TIME,
              ANIMATION_TIME_OUT + ANIMATION_MAX_DELAY_OUT_FOR_ITEM);

var ANIMATION_DELAY = 0.1;

var PageIndicators = GObject.registerClass({
    Signals: { 'page-activated': { param_types: [GObject.TYPE_INT] } }
}, class PageIndicators extends St.BoxLayout {
    _init(vertical = true) {
        super._init({ style_class: 'page-indicators',
                      vertical,
                      x_expand: true, y_expand: true,
                      x_align: vertical ? Clutter.ActorAlign.END : Clutter.ActorAlign.CENTER,
                      y_align: vertical ? Clutter.ActorAlign.CENTER : Clutter.ActorAlign.END,
                      reactive: true,
                      clip_to_allocation: true });
        this._nPages = 0;
        this._currentPage = undefined;
        this._reactive = true;
        this._reactive = true;
    }

    vfunc_get_preferred_height(forWidth) {
        // We want to request the natural height of all our children as our
        // natural height, so we chain up to St.BoxLayout, but we only request 0
        // as minimum height, since it's not that important if some indicators
        // are not shown
        let [, natHeight] = super.vfunc_get_preferred_height(forWidth);
        return [0, natHeight];
    }

    setReactive(reactive) {
        let children = this.get_children();
        for (let i = 0; i < children.length; i++)
            children[i].reactive = reactive;

        this._reactive = reactive;
    }

    setNPages(nPages) {
        if (this._nPages == nPages)
            return;

        let diff = nPages - this._nPages;
        if (diff > 0) {
            for (let i = 0; i < diff; i++) {
                let pageIndex = this._nPages + i;
                let indicator = new St.Button({ style_class: 'page-indicator',
                                                button_mask: St.ButtonMask.ONE |
                                                             St.ButtonMask.TWO |
                                                             St.ButtonMask.THREE,
                                                toggle_mode: true,
                                                reactive: this._reactive,
                                                checked: pageIndex == this._currentPage });
                indicator.child = new St.Widget({ style_class: 'page-indicator-icon' });
                indicator.connect('clicked', () => {
                    this.emit('page-activated', pageIndex);
                });
                this.add_actor(indicator);
            }
        } else {
            let children = this.get_children().splice(diff);
            for (let i = 0; i < children.length; i++)
                children[i].destroy();
        }
        this._nPages = nPages;
        this.visible = (this._nPages > 1);
    }

    setCurrentPage(currentPage) {
        this._currentPage = currentPage;

        let children = this.get_children();
        for (let i = 0; i < children.length; i++)
            children[i].set_checked(i == this._currentPage);
    }
});

var AnimatedPageIndicators = GObject.registerClass(
class AnimatedPageIndicators extends PageIndicators {
    _init() {
        super._init(true);

        this.connect('notify::mapped', () => {
            this.animateIndicators(AnimationDirection.IN);
        });
    }

    animateIndicators(animationDirection) {
        if (!this.mapped)
            return;

        let children = this.get_children();
        if (children.length == 0)
            return;

        for (let i = 0; i < this._nPages; i++)
            Tweener.removeTweens(children[i]);

        let offset;
        if (this.get_text_direction() == Clutter.TextDirection.RTL)
            offset = -children[0].width;
        else
            offset = children[0].width;

        let isAnimationIn = animationDirection == AnimationDirection.IN;
        let delay = isAnimationIn ? INDICATORS_ANIMATION_DELAY :
                                    INDICATORS_ANIMATION_DELAY_OUT;
        let baseTime = isAnimationIn ? INDICATORS_BASE_TIME : INDICATORS_BASE_TIME_OUT;
        let totalAnimationTime = baseTime + delay * this._nPages;
        let maxTime = isAnimationIn ? INDICATORS_ANIMATION_MAX_TIME :
                                      INDICATORS_ANIMATION_MAX_TIME_OUT;
        if (totalAnimationTime > maxTime)
            delay -= (totalAnimationTime - maxTime) / this._nPages;

        for (let i = 0; i < this._nPages; i++) {
            children[i].translation_x = isAnimationIn ? offset : 0;
            Tweener.addTween(children[i], {
                translation_x: isAnimationIn ? 0 : offset,
                time: baseTime + delay * i,
                transition: 'easeInOutQuad',
                delay: isAnimationIn ? ANIMATION_DELAY : 0
            });
        }
    }
});