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Fix broken math for scrolling at the top or bottom of a stream. 

(imported from commit 2ba6ab58800b86cd5b31a1b6e235c0be51d985c1)
This commit is contained in:
Jessica McKellar 2012-10-05 13:28:10 -04:00
parent 3166921057
commit 7a88fd71e6
1 changed files with 31 additions and 9 deletions
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40
zephyr/static/js/zephyr.js
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@ -470,29 +470,51 @@ function get_updates() {
$(get_updates);
function at_top_of_viewport() {
return ($(window).scrollTop() === 0);
}
function at_bottom_of_viewport() {
var viewport = $(window);
return (viewport.scrollTop() + viewport.height() >= $("#main_div").outerHeight(true));
}
function keep_pointer_in_view() {
var candidate;
var viewport = $(window);
var next_zephyr = get_zephyr_row(selected_zephyr_id);
if (above_view_threshold(next_zephyr)) {
if (above_view_threshold(next_zephyr) && (!at_top_of_viewport())) {
while (above_view_threshold(next_zephyr)) {
next_zephyr = get_next_visible(next_zephyr);
candidate = get_next_visible(next_zephyr);
if (candidate.length === 0) {
break;
} else {
next_zephyr = candidate;
}
}
} else if (below_view_threshold(next_zephyr)) {
} else if (below_view_threshold(next_zephyr) && (!at_bottom_of_viewport())) {
while (below_view_threshold(next_zephyr)) {
next_zephyr = get_prev_visible(next_zephyr);
candidate = get_prev_visible(next_zephyr);
if (candidate.length === 0) {
break;
} else {
next_zephyr = candidate;
}
}
}
if ((viewport.scrollTop() === 0) && (next_zephyr.attr("zid") > get_first_visible().attr("zid"))) {
if (at_top_of_viewport() && (parseInt(get_id(next_zephyr), 10) >
parseInt(get_id(get_first_visible()), 10))) {
// If we've scrolled to the top, keep inching the selected
// zephyr up to the top instead of just the latest one that is
// still on the screen.
next_zephyr = get_prev_visible(next_zephyr);
} else if ((viewport.scrollTop() + viewport.height() >= $("#main_div").outerHeight(true)) &&
(next_zephyr.attr("zid") < get_last_visible().attr("zid"))) {
// If we've scrolled to the bottom already, keep advancing the pointer
// until we're at the last message (by analogue to the above)
} else if (at_bottom_of_viewport() && (parseInt(get_id(next_zephyr), 10) <
parseInt(get_id(get_last_visible()), 10))) {
// If we've scrolled to the bottom already, keep advancing the
// pointer until we're at the last message (by analogue to the
// above)
next_zephyr = get_next_visible(next_zephyr);
}
update_selected_zephyr(next_zephyr);