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Support for calculating element visibility in relation to parent container defined with bind-scroll-to #12

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Support for calculating element visibility in relation to parent container defined with bind-scroll-to #12

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25 changes: 14 additions & 11 deletions dist/angular-scroll-animate.js
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Original file line number Diff line number Diff line change
Expand Up @@ -44,26 +44,29 @@ angular.module('angular-scroll-animate', []).directive('whenVisible', ['$documen
function($document, $window) {

var determineWhereElementIsInViewport =
function($el, viewportHeight, whenVisibleFn, whenNotVisibleFn, delayPercent, scope) {
function($el, whenVisibleFn, whenNotVisibleFn, delayPercent, scope, $scrollBindTo) {
var document = $document[0].documentElement;

var elementBounds = $el[0].getBoundingClientRect();
var scrollContainerBounds = $scrollBindTo ? $scrollBindTo[0].getBoundingClientRect() : null;

var panelTop = elementBounds.top;
var panelBottom = elementBounds.bottom;
var scrollContainerHeight = $scrollBindTo ? scrollContainerBounds.height : document.clientHeight;
var panelTop = $scrollBindTo ? elementBounds.top - scrollContainerBounds.top : elementBounds.top;
var panelBottom = $scrollBindTo ? elementBounds.bottom - scrollContainerBounds.top : elementBounds.bottom;

// pixel buffer until deciding to show the element
var delayPx = delayPercent * elementBounds.height;

var bottomVisible = (panelBottom - delayPx > 0) && (panelBottom < viewportHeight);
var topVisible = (panelTop + delayPx <= viewportHeight) && (panelTop > 0);
var bottomVisible = (panelBottom - delayPx > 0) && (panelBottom < scrollContainerHeight);
var topVisible = (panelTop + delayPx <= scrollContainerHeight) && (panelTop > 0);

if ($el.data('hidden') && bottomVisible || topVisible) {
whenVisibleFn($el, scope);
$el.data('hidden', false);
}

// scrolled out from scrolling down or up
else if (!($el.data('hidden')) && (panelBottom < 0 || panelTop > viewportHeight)) {
else if (!($el.data('hidden')) && (panelBottom < 0 || panelTop > scrollContainerHeight)) {
whenNotVisibleFn($el, scope);
$el.data('hidden', true);
}
Expand Down Expand Up @@ -103,14 +106,13 @@ angular.module('angular-scroll-animate', []).directive('whenVisible', ['$documen
}],

link: function(scope, el, attributes) {

var $scrollBindTo;
var delayPercent = attributes.delayPercent || 0.25; // lower = more eager to hide / show, higher = less eager
var document = $document[0].documentElement;
var checkPending = false;

var updateVisibility = function() {
determineWhereElementIsInViewport(el, document.clientHeight /* viewportHeight */ ,
scope.whenVisible(), scope.whenNotVisible(), delayPercent, scope);
determineWhereElementIsInViewport(el, scope.whenVisible(),
scope.whenNotVisible(), delayPercent, scope, $scrollBindTo);

checkPending = false;
};
Expand All @@ -129,7 +131,8 @@ angular.module('angular-scroll-animate', []).directive('whenVisible', ['$documen

/* allows overflow:auto on container element to animate for Safari browsers */
if (attributes.bindScrollTo) {
angular.element($document[0].querySelector(attributes.bindScrollTo)).on(documentListenerEvents, onScroll);
$scrollBindTo = angular.element($document[0].querySelector(attributes.bindScrollTo));
$scrollBindTo.on(documentListenerEvents, onScroll);
}

/* always bind to document scroll as well - works for overflow: auto on Chrome, Firefox browsers */
Expand Down
25 changes: 14 additions & 11 deletions src/angular-scroll-animate.js
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -44,26 +44,29 @@ angular.module('angular-scroll-animate', []).directive('whenVisible', ['$documen
function($document, $window) {

var determineWhereElementIsInViewport =
function($el, viewportHeight, whenVisibleFn, whenNotVisibleFn, delayPercent, scope) {
function($el, whenVisibleFn, whenNotVisibleFn, delayPercent, scope, $scrollBindTo) {
var document = $document[0].documentElement;

var elementBounds = $el[0].getBoundingClientRect();
var scrollContainerBounds = $scrollBindTo ? $scrollBindTo[0].getBoundingClientRect() : null;

var panelTop = elementBounds.top;
var panelBottom = elementBounds.bottom;
var scrollContainerHeight = $scrollBindTo ? scrollContainerBounds.height : document.clientHeight;
var panelTop = $scrollBindTo ? elementBounds.top - scrollContainerBounds.top : elementBounds.top;
var panelBottom = $scrollBindTo ? elementBounds.bottom - scrollContainerBounds.top : elementBounds.bottom;

// pixel buffer until deciding to show the element
var delayPx = delayPercent * elementBounds.height;

var bottomVisible = (panelBottom - delayPx > 0) && (panelBottom < viewportHeight);
var topVisible = (panelTop + delayPx <= viewportHeight) && (panelTop > 0);
var bottomVisible = (panelBottom - delayPx > 0) && (panelBottom < scrollContainerHeight);
var topVisible = (panelTop + delayPx <= scrollContainerHeight) && (panelTop > 0);

if ($el.data('hidden') && bottomVisible || topVisible) {
whenVisibleFn($el, scope);
$el.data('hidden', false);
}

// scrolled out from scrolling down or up
else if (!($el.data('hidden')) && (panelBottom < 0 || panelTop > viewportHeight)) {
else if (!($el.data('hidden')) && (panelBottom < 0 || panelTop > scrollContainerHeight)) {
whenNotVisibleFn($el, scope);
$el.data('hidden', true);
}
Expand Down Expand Up @@ -103,14 +106,13 @@ angular.module('angular-scroll-animate', []).directive('whenVisible', ['$documen
}],

link: function(scope, el, attributes) {

var $scrollBindTo;
var delayPercent = attributes.delayPercent || 0.25; // lower = more eager to hide / show, higher = less eager
var document = $document[0].documentElement;
var checkPending = false;

var updateVisibility = function() {
determineWhereElementIsInViewport(el, document.clientHeight /* viewportHeight */ ,
scope.whenVisible(), scope.whenNotVisible(), delayPercent, scope);
determineWhereElementIsInViewport(el, scope.whenVisible(),
scope.whenNotVisible(), delayPercent, scope, $scrollBindTo);

checkPending = false;
};
Expand All @@ -129,7 +131,8 @@ angular.module('angular-scroll-animate', []).directive('whenVisible', ['$documen

/* allows overflow:auto on container element to animate for Safari browsers */
if (attributes.bindScrollTo) {
angular.element($document[0].querySelector(attributes.bindScrollTo)).on(documentListenerEvents, onScroll);
$scrollBindTo = angular.element($document[0].querySelector(attributes.bindScrollTo));
$scrollBindTo.on(documentListenerEvents, onScroll);
}

/* always bind to document scroll as well - works for overflow: auto on Chrome, Firefox browsers */
Expand Down