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40ce4e0acc
When you make a call to set_message_position(), you already know that the pointer is gonna be onscreen, so set the flag to suppress scroll pointer updates. This should be faster and also avoid future confusing bugs where recenter_view() and keep_pointer_in_view() run for the same event. (Both callers to recenter_view pass in the selected message, and then the calls to set_message_position() set the scrollTop so that the selected message shows onscreen.) (imported from commit f1a6f189b7899b280a6316ea7eb03f015d3d4ae3)
115 lines
3.1 KiB
JavaScript
115 lines
3.1 KiB
JavaScript
var viewport = (function () {
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var exports = {};
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var jwindow;
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var height;
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var width;
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var in_stoppable_autoscroll = false;
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exports.at_top = function () {
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return (jwindow.scrollTop() <= 0);
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};
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exports.at_bottom = function () {
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// outerHeight(true): Include margin
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var bottom = jwindow.scrollTop() + jwindow.height();
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var window_size = $(document).height();
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// We only know within a pixel or two if we're
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// exactly at the bottom, due to browser quirkiness,
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// and we err on the side of saying that we are at
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// the bottom.
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return bottom + 2 >= window_size;
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};
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exports.set_message_position = function (message_top, viewport_info, ratio) {
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// message_top = offset of the top of a message that you are positioning
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// viewport_info = result of calling ui.message_viewport_info
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// ratio = fraction indicating how far down the screen the msg should be
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var hidden_top =
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viewport_info.visible_top
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- jwindow.scrollTop();
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var message_offset =
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viewport_info.visible_height * ratio
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+ hidden_top;
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var new_scroll_top =
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message_top
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- message_offset;
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suppress_scroll_pointer_update = true; // Gets set to false in the scroll handler.
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jwindow.scrollTop(new_scroll_top);
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};
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exports.scrollTop = function viewport_scrollTop () {
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return jwindow.scrollTop.apply(jwindow, arguments);
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};
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exports.height = function viewport_height() {
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if (arguments.length !== 0) {
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height = undefined;
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return jwindow.height.apply(jwindow, arguments);
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}
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if (height === undefined) {
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height = $(window).height();
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}
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return height;
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};
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exports.width = function viewport_width() {
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if (arguments.length !== 0) {
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width = undefined;
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return jwindow.width.apply(jwindow, arguments);
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}
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if (width === undefined) {
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width = jwindow.width();
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}
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return width;
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};
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exports.stop_auto_scrolling = function() {
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if (in_stoppable_autoscroll) {
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$("html, body").stop();
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}
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};
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exports.system_initiated_animate_scroll = function (scroll_amount) {
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suppress_scroll_pointer_update = true; // Gets set to false in the scroll handler.
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var viewport_offset = exports.scrollTop();
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in_stoppable_autoscroll = true;
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$("html, body").animate({
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scrollTop: viewport_offset + scroll_amount,
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always: function () {
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in_stoppable_autoscroll = false;
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}
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});
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};
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exports.user_initiated_animate_scroll = function (scroll_amount) {
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suppress_scroll_pointer_update = true; // Gets set to false in the scroll handler.
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in_stoppable_autoscroll = false; // defensive
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var viewport_offset = exports.scrollTop();
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// We use $('html, body') because you can't animate window.scrollTop
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// on Chrome (http://bugs.jquery.com/ticket/10419).
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$("html, body").animate({
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scrollTop: viewport_offset + scroll_amount
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});
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};
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$(function () {
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jwindow = $(window);
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// This handler must be placed before all resize handlers in our application
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jwindow.resize(function () {
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height = undefined;
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width = undefined;
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});
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});
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return exports;
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}());
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