mirror of https://github.com/zulip/zulip.git
47 lines
1.2 KiB
JavaScript
47 lines
1.2 KiB
JavaScript
import * as ui from "./ui";
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export function scroll_delta(opts) {
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const elem_top = opts.elem_top;
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const container_height = opts.container_height;
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const elem_bottom = opts.elem_bottom;
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let delta = 0;
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if (elem_top < 0) {
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delta = Math.max(elem_top, elem_bottom - container_height);
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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(elem_top, elem_bottom - container_height);
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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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export function scroll_element_into_container($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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const elem_top = $elem.position().top;
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const elem_bottom = elem_top + $elem.innerHeight();
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const opts = {
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elem_top,
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elem_bottom,
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container_height: $container.height(),
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};
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const delta = scroll_delta(opts);
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if (delta === 0) {
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return;
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}
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$container.scrollTop($container.scrollTop() + delta);
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}
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