zephyr/doc/_static/js/custom.js

123 lines
5.3 KiB
JavaScript

/**
* Copyright (c) 2020-2023, The Godot community
* Copyright (c) 2023, Benjamin Cabé <benjamin@zephyrproject.org>
* SPDX-License-Identifier: CC-BY-3.0
*/
// Handle page scroll and adjust sidebar accordingly.
// Each page has two scrolls: the main scroll, which is moving the content of the page;
// and the sidebar scroll, which is moving the navigation in the sidebar.
// We want the logo to gradually disappear as the main content is scrolled, giving
// more room to the navigation on the left. This means adjusting the height
// available to the navigation on the fly.
const registerOnScrollEvent = (function(){
// Configuration.
// The number of pixels the user must scroll by before the logo is completely hidden.
const scrollTopPixels = 156;
// The target margin to be applied to the navigation bar when the logo is hidden.
const menuTopMargin = 54;
// The max-height offset when the logo is completely visible.
const menuHeightOffset_default = 210;
// The max-height offset when the logo is completely hidden.
const menuHeightOffset_fixed = 63;
// The distance between the two max-height offset values above; used for intermediate values.
const menuHeightOffset_diff = (menuHeightOffset_default - menuHeightOffset_fixed);
// Media query handler.
return function(mediaQuery) {
// We only apply this logic to the "desktop" resolution (defined by a media query at the bottom).
// This handler is executed when the result of the query evaluation changes, which means that
// the page has moved between "desktop" and "mobile" states.
// When entering the "desktop" state, we register scroll events and adjust elements on the page.
// When entering the "mobile" state, we clean up any registered events and restore elements on the page
// to their initial state.
const $window = $(window);
const $sidebar = $('.wy-side-scroll');
const $search = $sidebar.children('.wy-side-nav-search');
const $menu = $sidebar.children('.wy-menu-vertical');
if (mediaQuery.matches) {
// Entering the "desktop" state.
// The main scroll event handler.
// Executed as the page is scrolled and once immediately as the page enters this state.
const handleMainScroll = (currentScroll) => {
if (currentScroll >= scrollTopPixels) {
// After the page is scrolled below the threshold, we fix everything in place.
$search.css('margin-top', `-${scrollTopPixels}px`);
$menu.css('margin-top', `${menuTopMargin}px`);
$menu.css('max-height', `calc(100% - ${menuHeightOffset_fixed}px)`);
}
else {
// Between the top of the page and the threshold we calculate intermediate values
// to guarantee a smooth transition.
$search.css('margin-top', `-${currentScroll}px`);
$menu.css('margin-top', `${menuTopMargin + (scrollTopPixels - currentScroll)}px`);
if (currentScroll > 0) {
const scrolledPercent = (scrollTopPixels - currentScroll) / scrollTopPixels;
const offsetValue = menuHeightOffset_fixed + menuHeightOffset_diff * scrolledPercent;
$menu.css('max-height', `calc(100% - ${offsetValue}px)`);
} else {
$menu.css('max-height', `calc(100% - ${menuHeightOffset_default}px)`);
}
}
};
// The sidebar scroll event handler.
// Executed as the sidebar is scrolled as well as after the main scroll. This is needed
// because the main scroll can affect the scrollable area of the sidebar.
const handleSidebarScroll = () => {
const menuElement = $menu.get(0);
const menuScrollTop = $menu.scrollTop();
const menuScrollBottom = menuElement.scrollHeight - (menuScrollTop + menuElement.offsetHeight);
// As the navigation is scrolled we add a shadow to the top bar hanging over it.
if (menuScrollTop > 0) {
$search.addClass('fixed-and-scrolled');
} else {
$search.removeClass('fixed-and-scrolled');
}
};
$search.addClass('fixed');
$window.scroll(function() {
handleMainScroll(window.scrollY);
handleSidebarScroll();
});
$menu.scroll(function() {
handleSidebarScroll();
});
handleMainScroll(window.scrollY);
handleSidebarScroll();
} else {
// Entering the "mobile" state.
$window.unbind('scroll');
$menu.unbind('scroll');
$search.removeClass('fixed');
$search.css('margin-top', `0px`);
$menu.css('margin-top', `0px`);
$menu.css('max-height', 'initial');
}
};
})();
$(document).ready(() => {
// Initialize handlers for page scrolling and our custom sidebar.
const mediaQuery = window.matchMedia('only screen and (min-width: 769px)');
registerOnScrollEvent(mediaQuery);
mediaQuery.addListener(registerOnScrollEvent);
});