Files
edx-platform/common/static/js/capa/drag_and_drop/scroller.js

206 lines
8.0 KiB
JavaScript

(function (requirejs, require, define) {
define(['js/capa/drag_and_drop/logme'], function (logme) {
return Scroller;
function Scroller(state) {
var parentEl, moveLeftEl, showEl, moveRightEl, showElLeftMargin;
parentEl = $(
'<div ' +
'style=" ' +
'width: 665px; ' +
'height: 102px; ' +
'margin-left: auto; ' +
'margin-right: auto; ' +
'" ' +
'></div>'
);
moveLeftEl = $(
'<div ' +
'style=" ' +
'width: 40px; ' +
'height: 102px; ' +
'display: inline; ' +
'float: left; ' +
'" ' +
'>' +
'<div ' +
'style=" ' +
'width: 38px; ' +
'height: 100px; '+
'border: 1px solid #CCC; ' +
'background-color: #EEE; ' +
'background-image: -webkit-linear-gradient(top, #EEE, #DDD); ' +
'background-image: -moz-linear-gradient(top, #EEE, #DDD); ' +
'background-image: -ms-linear-gradient(top, #EEE, #DDD); ' +
'background-image: -o-linear-gradient(top, #EEE, #DDD); ' +
'background-image: linear-gradient(top, #EEE, #DDD); ' +
'-webkit-box-shadow: 0 1px 0 rgba(255, 255, 255, 0.7) inset; ' +
'box-shadow: 0 1px 0 rgba(255, 255, 255, 0.7) inset; ' +
"background-image: url('"+baseUrl+"images/arrow-left.png'); " +
'background-position: center center; ' +
'background-repeat: no-repeat; ' +
'" ' +
'></div>' +
'</div>'
);
moveLeftEl.appendTo(parentEl);
// The below is necessary to prevent the browser thinking that we want
// to perform a drag operation, or a highlight operation. If we don't
// do this, the browser will then highlight with a gray shade the
// element.
moveLeftEl.mousemove(function (event) { event.preventDefault(); });
moveLeftEl.mousedown(function (event) { event.preventDefault(); });
// This event will be responsible for moving the scroller left.
// Hidden draggables will be shown.
moveLeftEl.mouseup(function (event) {
event.preventDefault();
// When there are no more hidden draggables, prevent from
// scrolling infinitely.
if (showElLeftMargin > -102) {
return;
}
showElLeftMargin += 102;
// We scroll by changing the 'margin-left' CSS property smoothly.
state.sliderEl.animate({
'margin-left': showElLeftMargin + 'px'
}, 100, function () {
updateArrowOpacity();
});
});
showEl = $(
'<div ' +
'style=" ' +
'width: 585px; ' +
'height: 102px; ' +
'overflow: hidden; ' +
'display: inline; ' +
'float: left; ' +
'" ' +
'></div>'
);
showEl.appendTo(parentEl);
showElLeftMargin = 0;
// Element where the draggables will be contained. It is very long
// so that any SANE number of draggables will fit in a single row. It
// will be contained in a parent element whose 'overflow' CSS value
// will be hidden, preventing the long row from fully being visible.
state.sliderEl = $(
'<div ' +
'style=" ' +
'width: 20000px; ' +
'height: 100px; ' +
'border-top: 1px solid #CCC; ' +
'border-bottom: 1px solid #CCC; ' +
'" ' +
'></div>'
);
state.sliderEl.appendTo(showEl);
state.sliderEl.mousedown(function (event) {
event.preventDefault();
});
moveRightEl = $(
'<div ' +
'style=" ' +
'width: 40px; ' +
'height: 102px; ' +
'display: inline; ' +
'float: left; ' +
'" ' +
'>' +
'<div ' +
'style=" ' +
'width: 38px; ' +
'height: 100px; '+
'border: 1px solid #CCC; ' +
'background-color: #EEE; ' +
'background-image: -webkit-linear-gradient(top, #EEE, #DDD); ' +
'background-image: -moz-linear-gradient(top, #EEE, #DDD); ' +
'background-image: -ms-linear-gradient(top, #EEE, #DDD); ' +
'background-image: -o-linear-gradient(top, #EEE, #DDD); ' +
'background-image: linear-gradient(top, #EEE, #DDD); ' +
'-webkit-box-shadow: 0 1px 0 rgba(255, 255, 255, 0.7) inset; ' +
'box-shadow: 0 1px 0 rgba(255, 255, 255, 0.7) inset; ' +
"background-image: url('"+baseUrl+"images/arrow-right.png'); " +
'background-position: center center; ' +
'background-repeat: no-repeat; ' +
'" ' +
'></div>' +
'</div>'
);
moveRightEl.appendTo(parentEl);
// The below is necessary to prevent the browser thinking that we want
// to perform a drag operation, or a highlight operation. If we don't
// do this, the browser will then highlight with a gray shade the
// element.
moveRightEl.mousemove(function (event) { event.preventDefault(); });
moveRightEl.mousedown(function (event) { event.preventDefault(); });
// This event will be responsible for moving the scroller right.
// Hidden draggables will be shown.
moveRightEl.mouseup(function (event) {
event.preventDefault();
// When there are no more hidden draggables, prevent from
// scrolling infinitely.
if (showElLeftMargin < -102 * (state.numDraggablesInSlider - 6)) {
return;
}
showElLeftMargin -= 102;
// We scroll by changing the 'margin-left' CSS property smoothly.
state.sliderEl.animate({
'margin-left': showElLeftMargin + 'px'
}, 100, function () {
updateArrowOpacity();
});
});
parentEl.appendTo(state.containerEl);
// Make the function available throughout the application. We need to
// call it in several places:
//
// 1.) When initially reading answer from server, if draggables will be
// positioned on the base image, the scroller's right and left arrows
// opacity must be updated.
//
// 2.) When creating draggable elements, the scroller's right and left
// arrows opacity must be updated according to the number of
// draggables.
state.updateArrowOpacity = updateArrowOpacity;
return;
function updateArrowOpacity() {
moveLeftEl.children('div').css('opacity', '1');
moveRightEl.children('div').css('opacity', '1');
if (showElLeftMargin < -102 * (state.numDraggablesInSlider - 6)) {
moveRightEl.children('div').css('opacity', '.4');
}
if (showElLeftMargin > -102) {
moveLeftEl.children('div').css('opacity', '.4');
}
}
} // End-of: function Scroller(state)
}); // End-of: define(['logme'], function (logme) {
}(RequireJS.requirejs, RequireJS.require, RequireJS.define)); // End-of: (function (requirejs, require, define) {