mirror of https://github.com/zulip/zulip.git
53 lines
1.3 KiB
JavaScript
53 lines
1.3 KiB
JavaScript
exports.scroll_delta = function (opts) {
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var elem_top = opts.elem_top;
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var container_height = opts.container_height;
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var elem_bottom = opts.elem_bottom;
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var delta = 0;
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if (elem_top < 0) {
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delta = Math.max(
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elem_top,
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elem_bottom - container_height
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);
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delta = Math.min(0, delta);
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} else {
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if (elem_bottom > container_height) {
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delta = Math.min(
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elem_top,
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elem_bottom - container_height
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);
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delta = Math.max(0, delta);
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}
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}
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return delta;
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};
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exports.scroll_element_into_container = function (elem, container) {
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// This does the minimum amount of scrolling that is needed to make
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// the element visible. It doesn't try to center the element, so
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// this will be non-intrusive to users when they already have
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// the element visible.
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container = ui.get_scroll_element(container);
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var elem_top = elem.position().top;
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var elem_bottom = elem_top + elem.innerHeight();
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var opts = {
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elem_top: elem_top,
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elem_bottom: elem_bottom,
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container_height: container.height(),
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};
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var delta = exports.scroll_delta(opts);
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if (delta === 0) {
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return;
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}
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container.scrollTop(container.scrollTop() + delta);
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};
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window.scroll_util = exports;
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