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/*
* This file is part of the MediaWiki extension MediaViewer.
*
* MediaViewer is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* MediaViewer is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with MediaViewer. If not, see <http://www.gnu.org/licenses/>.
*/
( function ( mw, $, oo ) {
var MPSP;
/**
* Handles scrolling behavior of the metadata panel.
*
* @class mw.mmv.ui.MetadataPanelScroller
* @extends mw.mmv.ui.Element
* @constructor
* @param {jQuery} $container The container for the panel (.mw-mmv-post-image).
* @param {jQuery} $aboveFold The control bar element (.mw-mmv-above-fold).
* @param {Object} localStorage the localStorage object, for dependency injection
*/
function MetadataPanelScroller( $container, $aboveFold, localStorage ) {
mw.mmv.ui.Element.call( this, $container );
this.$aboveFold = $aboveFold;
/** @property {Object} localStorage the window.localStorage object */
this.localStorage = localStorage;
/** @property {boolean} panelWasOpen state flag which will be used to detect open <-> closed transitions */
this.panelWasOpen = null;
/**
* Whether this user has ever opened the metadata panel.
* Based on a localstorage flag; will be set to true if the client does not support localstorage.
* @type {boolean}
*/
this.hasOpenedMetadata = undefined;
/**
* Whether we've already fired an animation for the metadata div in this lightbox session.
* @property {boolean}
* @private
*/
this.hasAnimatedMetadata = false;
this.initialize();
}
oo.inheritClass( MetadataPanelScroller, mw.mmv.ui.Element );
MPSP = MetadataPanelScroller.prototype;
MPSP.toggleScrollDuration = 400;
MPSP.attach = function () {
var panel = this;
this.handleEvent( 'keydown', function ( e ) {
panel.keydown( e );
} );
$.scrollTo().on( 'scroll.mmvp', $.throttle( 250, function () {
panel.scroll();
} ) );
this.$container.on( 'mmv-metadata-open', function () {
if ( !panel.hasOpenedMetadata && panel.localStorage ) {
panel.hasOpenedMetadata = true;
try {
panel.localStorage.setItem( 'mmv.hasOpenedMetadata', true );
} catch ( e ) {
// localStorage is full or disabled
}
}
} );
// reset animation flag when the viewer is reopened
this.hasAnimatedMetadata = false;
};
MPSP.unattach = function () {
this.clearEvents();
$.scrollTo().off( 'scroll.mmvp' );
this.$container.off( 'mmv-metadata-open' );
};
MPSP.empty = function () {
// need to remove this to avoid animating again when reopening lightbox on same page
this.$container.removeClass( 'invite' );
this.panelWasOpen = this.panelIsOpen();
};
/**
* Returns scroll top position when the panel is fully open.
* (In other words, the height of the area that is outside the screen, in pixels.)
*
* @return {number}
*/
MPSP.getScrollTopWhenOpen = function () {
return this.$container.outerHeight() - parseInt( this.$aboveFold.css( 'min-height' ), 10 ) -
parseInt( this.$aboveFold.css( 'padding-bottom' ), 10 );
};
/**
* Makes sure the panel does not contract when it is emptied and thus keeps its position as much as possible.
* This should be called when switching images, before the panel is emptied, and should be undone with
* unfreezeHeight after the panel has been populeted with the new metadata.
*/
MPSP.freezeHeight = function () {
var scrollTop, scrollTopWhenOpen;
if ( !this.$container.is( ':visible' ) ) {
return;
}
scrollTop = $.scrollTo().scrollTop();
scrollTopWhenOpen = this.getScrollTopWhenOpen();
this.panelWasFullyOpen = ( scrollTop === scrollTopWhenOpen );
this.$container.css( 'min-height', this.$container.height() );
};
MPSP.unfreezeHeight = function () {
if ( !this.$container.is( ':visible' ) ) {
return;
}
this.$container.css( 'min-height', '' );
if ( this.panelWasFullyOpen ) {
$.scrollTo( this.getScrollTopWhenOpen() );
}
};
MPSP.initialize = function () {
try {
this.hasOpenedMetadata = !this.localStorage || this.localStorage.getItem( 'mmv.hasOpenedMetadata' );
} catch ( e ) { // localStorage.getItem can throw exceptions
this.hasOpenedMetadata = true;
}
};
/**
* Animates the metadata area when the viewer is first opened.
*/
MPSP.animateMetadataOnce = function () {
if ( !this.hasOpenedMetadata && !this.hasAnimatedMetadata ) {
this.hasAnimatedMetadata = true;
this.$container.addClass( 'invite' );
}
};
/**
* Toggles the metadata div being totally visible.
*
* @param {string} [forceDirection] 'up' or 'down' makes the panel move on that direction (and is a noop
* if the panel is already at the upmost/bottommost position); without the parameter, the panel position
* is toggled. (Partially open counts as open.)
* @return {jQuery.Deferred} a deferred which resolves after the animation has finished.
*/
MPSP.toggle = function ( forceDirection ) {
var deferred = $.Deferred(),
scrollTopWhenOpen = this.getScrollTopWhenOpen(),
scrollTopWhenClosed = 0,
scrollTop = $.scrollTo().scrollTop(),
panelIsOpen = scrollTop > scrollTopWhenClosed,
direction = forceDirection || ( panelIsOpen ? 'down' : 'up' ),
scrollTopTarget = ( direction === 'up' ) ? scrollTopWhenOpen : scrollTopWhenClosed;
// don't log / animate if the panel is already in the end position
if ( scrollTopTarget === scrollTop ) {
deferred.resolve();
} else {
mw.mmv.actionLogger.log( direction === 'up' ? 'metadata-open' : 'metadata-close' );
if ( direction === 'up' && !panelIsOpen ) {
// FIXME nasty. This is not really an event but a command sent to the metadata panel;
// child UI elements should not send commands to their parents. However, there is no way
// to calculate the target scrollTop accurately without revealing the text, and the event
// which does that (metadata-open) is only triggered later in the process, when the panel
// actually scrolled, so we cannot use it here without risking triggering it multiple times.
this.$container.trigger( 'mmv-metadata-reveal-truncated-text' );
scrollTopTarget = this.getScrollTopWhenOpen();
}
$.scrollTo( scrollTopTarget, this.toggleScrollDuration, {
onAfter: function () {
deferred.resolve();
}
} );
}
return deferred;
};
/**
* Handles keydown events for this element.
*/
MPSP.keydown = function ( e ) {
if ( e.altKey || e.shiftKey || e.ctrlKey || e.metaKey ) {
return;
}
switch ( e.which ) {
case 40: // Down arrow
// fall through
case 38: // Up arrow
this.toggle();
e.preventDefault();
break;
}
};
/**
* Returns whether the metadata panel is open. (Partially open is considered to be open.)
*
* @return {boolean}
*/
MPSP.panelIsOpen = function () {
return $.scrollTo().scrollTop() > 0;
};
/**
* Receives the window's scroll events and and turns them into business logic events
*
* @fires mmv-metadata-open
* @fires mmv-metadata-close
*/
MPSP.scroll = function () {
var panelIsOpen = this.panelIsOpen();
if ( panelIsOpen && !this.panelWasOpen ) { // just opened
this.$container.trigger( 'mmv-metadata-open' );
// This will include keyboard- and mouseclick-initiated open events as well,
// since the panel is anomated, which counts as scrolling.
// Filtering these seems too much trouble to be worth it.
mw.mmv.actionLogger.log( 'metadata-scroll-open' );
} else if ( !panelIsOpen && this.panelWasOpen ) { // just closed
this.$container.trigger( 'mmv-metadata-close' );
mw.mmv.actionLogger.log( 'metadata-scroll-close' );
}
this.panelWasOpen = panelIsOpen;
};
mw.mmv.ui.MetadataPanelScroller = MetadataPanelScroller;
}( mediaWiki, jQuery, OO ) );