mirror of
https://github.com/2234839/web-font.git
synced 2026-05-04 17:28:11 +08:00
391 lines
12 KiB
JavaScript
391 lines
12 KiB
JavaScript
/**
|
||
* WebFont SDK — 按需增量加载字体片段，无闪烁
|
||
*
|
||
* 架构：核心增量引擎 + 多种触发方式
|
||
* - 核心：FontLoader 按 fontKey 管理已加载字符集，只生成增量 CSS
|
||
* - 触发器：loadFont（轮询）、observeFont（DOM 事件）、loadText（手动传文本）
|
||
* - 同一 fontKey 下所有触发器共享字符集，绝不会重复请求
|
||
*
|
||
* 用法：
|
||
* // 轮询模式
|
||
* WebFont.loadFont({ fontName, selector, family, interval });
|
||
*
|
||
* // 事件驱动模式
|
||
* var obs = WebFont.observeFont({ fontName, selector, family });
|
||
* obs.dispose();
|
||
*
|
||
* // 直接传文本模式
|
||
* var loader = WebFont.loadText({ fontName, text: "你好世界", family });
|
||
* loader.update("追加文字");
|
||
* loader.dispose();
|
||
*
|
||
* // 清理全部
|
||
* WebFont.disposeAll();
|
||
*/
|
||
var WebFont = (function () {
|
||
/* ============================================================
|
||
* 核心增量引擎 — 按 fontKey 管理已加载字符集，生成增量 CSS
|
||
* ============================================================ */
|
||
|
||
/** @type {Object.<string, { loadedChars: Object.<string,boolean>, injectedStyles: Element[], applied: boolean, fontName: string, family: string, baseUrl: string }>} */
|
||
var loaders = {};
|
||
|
||
/**
|
||
* 生成 fontKey，同一字体+family 归入同一组
|
||
*/
|
||
function fontKey(fontName, family) {
|
||
return fontName + "|" + family;
|
||
}
|
||
|
||
/**
|
||
* 获取或创建对应 fontKey 的加载器
|
||
*/
|
||
function getLoader(fontName, baseUrl, family, outType) {
|
||
var key = fontKey(fontName, family);
|
||
if (!loaders[key]) {
|
||
loaders[key] = {
|
||
loadedChars: {},
|
||
injectedStyles: [],
|
||
applied: false,
|
||
fontName: fontName,
|
||
family: family,
|
||
baseUrl: baseUrl,
|
||
outType: outType || "woff2"
|
||
};
|
||
}
|
||
return loaders[key];
|
||
}
|
||
|
||
/**
|
||
* 差量加载新字符，生成 unicode-range CSS 并注入
|
||
* @param {Object} loader - getLoader 返回的加载器对象
|
||
* @param {string[]} newChars - 待加载的新字符数组
|
||
*/
|
||
function loadChars(loader, newChars) {
|
||
if (newChars.length === 0) return;
|
||
|
||
var fontName = loader.fontName;
|
||
var family = loader.family;
|
||
var baseUrl = loader.baseUrl;
|
||
var loadedChars = loader.loadedChars;
|
||
|
||
var text = newChars.join("");
|
||
var outType = loader.outType || "woff2";
|
||
var url = baseUrl + "/api?font=" + encodeURIComponent(fontName) + "&text=" + encodeURIComponent(text) + "&outType=" + outType;
|
||
var formatStr = outType === "woff2" ? "woff2" : "truetype";
|
||
var unicodeRanges = newChars
|
||
.map(function (c) { return "U+" + c.codePointAt(0).toString(16).padStart(4, "0"); })
|
||
.join(", ");
|
||
|
||
var style = document.createElement("style");
|
||
style.textContent =
|
||
'@font-face {\n' +
|
||
' font-family: "' + family + '";\n' +
|
||
' src: url("' + url + '") format("' + formatStr + '");\n' +
|
||
' unicode-range: ' + unicodeRanges + ';\n' +
|
||
'}\n';
|
||
document.head.appendChild(style);
|
||
loader.injectedStyles.push(style);
|
||
}
|
||
|
||
/**
|
||
* 从字符集中过滤出未加载的新字符，标记为已加载，并生成 CSS
|
||
* @param {Object} loader - getLoader 返回的加载器对象
|
||
* @param {Object.<string,boolean>} charSet - 待检查的字符集
|
||
* @returns {boolean} 是否有新字符被加载
|
||
*/
|
||
function processChars(loader, charSet) {
|
||
var loadedChars = loader.loadedChars;
|
||
var newChars = [];
|
||
for (var c in charSet) {
|
||
if (!loadedChars[c]) {
|
||
loadedChars[c] = true;
|
||
newChars.push(c);
|
||
}
|
||
}
|
||
loadChars(loader, newChars);
|
||
return newChars.length > 0;
|
||
}
|
||
|
||
/**
|
||
* 从字符串中过滤出未加载的新字符，标记为已加载，并生成 CSS
|
||
* @param {Object} loader - getLoader 返回的加载器对象
|
||
* @param {string} text - 待检查的文本
|
||
* @returns {boolean} 是否有新字符被加载
|
||
*/
|
||
function processText(loader, text) {
|
||
var loadedChars = loader.loadedChars;
|
||
var newChars = [];
|
||
for (var i = 0; i < text.length; i++) {
|
||
var c = text[i];
|
||
if (!loadedChars[c]) {
|
||
loadedChars[c] = true;
|
||
newChars.push(c);
|
||
}
|
||
}
|
||
loadChars(loader, newChars);
|
||
return newChars.length > 0;
|
||
}
|
||
|
||
/**
|
||
* 销毁加载器及其所有注入的样式
|
||
*/
|
||
function destroyLoader(key) {
|
||
var loader = loaders[key];
|
||
if (!loader) return;
|
||
for (var i = 0; i < loader.injectedStyles.length; i++) {
|
||
loader.injectedStyles[i].remove();
|
||
}
|
||
delete loaders[key];
|
||
}
|
||
|
||
/* ============================================================
|
||
* 辅助函数
|
||
* ============================================================ */
|
||
|
||
/**
|
||
* 获取元素的文本内容
|
||
*/
|
||
function getText(el) {
|
||
var tag = el.tagName;
|
||
if (tag === "INPUT" || tag === "TEXTAREA" || tag === "SELECT") {
|
||
return el.value || "";
|
||
}
|
||
return el.textContent || "";
|
||
}
|
||
|
||
/**
|
||
* 收集选择器匹配元素中的所有字符
|
||
*/
|
||
function collectChars(selector) {
|
||
var charSet = {};
|
||
var elements = document.querySelectorAll(selector);
|
||
for (var i = 0; i < elements.length; i++) {
|
||
var text = getText(elements[i]);
|
||
for (var j = 0; j < text.length; j++) {
|
||
charSet[text[j]] = true;
|
||
}
|
||
}
|
||
return charSet;
|
||
}
|
||
|
||
/**
|
||
* 应用字体到元素
|
||
*/
|
||
function applyFamily(selector, family) {
|
||
var elements = document.querySelectorAll(selector);
|
||
for (var i = 0; i < elements.length; i++) {
|
||
elements[i].style.fontFamily = '"' + family + '", sans-serif';
|
||
}
|
||
}
|
||
|
||
/* ============================================================
|
||
* 任务管理 — 各触发器的清理
|
||
* ============================================================ */
|
||
|
||
/** 按 selector 索引的 loadFont 任务 */
|
||
var pollTasks = {};
|
||
|
||
/** 按选择器索引的 observeFont 任务 */
|
||
var observeTasks = {};
|
||
|
||
/* ============================================================
|
||
* 1. loadFont — 定时器轮询模式
|
||
* ============================================================ */
|
||
|
||
/**
|
||
* @param {Object} options
|
||
* @param {string} options.fontName
|
||
* @param {string} options.selector
|
||
* @param {string} [options.baseUrl]
|
||
* @param {string} [options.family]
|
||
* @param {number} [options.interval=1000] - 轮询间隔（ms）
|
||
*/
|
||
function loadFont(options) {
|
||
var selector = options.selector;
|
||
var fontName = options.fontName;
|
||
var baseUrl = options.baseUrl || location.origin;
|
||
var family = options.family || fontName.replace(/\.[^.]+$/, "");
|
||
var interval = options.interval || 1000;
|
||
|
||
/* 清理同一选择器的旧任务 */
|
||
if (pollTasks[selector]) {
|
||
clearInterval(pollTasks[selector].timer);
|
||
}
|
||
|
||
var outType = options.outType || "woff2";
|
||
var loader = getLoader(fontName, baseUrl, family, outType);
|
||
var applied = false;
|
||
|
||
function tick() {
|
||
var current = collectChars(selector);
|
||
if (processChars(loader, current) && !applied) {
|
||
applied = true;
|
||
applyFamily(selector, family);
|
||
}
|
||
}
|
||
|
||
tick();
|
||
var timer = setInterval(tick, interval);
|
||
pollTasks[selector] = { timer: timer };
|
||
}
|
||
|
||
/* ============================================================
|
||
* 2. observeFont — MutationObserver 事件驱动模式
|
||
* ============================================================ */
|
||
|
||
/**
|
||
* @param {Object} options
|
||
* @param {string} options.fontName
|
||
* @param {string} options.selector
|
||
* @param {string} [options.baseUrl]
|
||
* @param {string} [options.family]
|
||
* @param {number} [options.debounceMs=50] - 防抖间隔（ms）
|
||
* @returns {{ dispose: function }}
|
||
*/
|
||
function observeFont(options) {
|
||
var selector = options.selector;
|
||
var fontName = options.fontName;
|
||
var baseUrl = options.baseUrl || location.origin;
|
||
var family = options.family || fontName.replace(/\.[^.]+$/, "");
|
||
var debounceMs = options.debounceMs || 50;
|
||
|
||
/* 清理同一选择器的旧任务 */
|
||
if (observeTasks[selector]) {
|
||
observeTasks[selector].dispose();
|
||
}
|
||
|
||
var outType = options.outType || "woff2";
|
||
var loader = getLoader(fontName, baseUrl, family, outType);
|
||
var applied = false;
|
||
var debounceTimer = null;
|
||
|
||
function doLoad() {
|
||
var current = collectChars(selector);
|
||
if (processChars(loader, current) && !applied) {
|
||
applied = true;
|
||
applyFamily(selector, family);
|
||
}
|
||
}
|
||
|
||
function debouncedLoad() {
|
||
if (debounceTimer) clearTimeout(debounceTimer);
|
||
debounceTimer = setTimeout(doLoad, debounceMs);
|
||
}
|
||
|
||
var observer = new MutationObserver(function (mutations) {
|
||
for (var i = 0; i < mutations.length; i++) {
|
||
if (mutations[i].type === "childList" || mutations[i].type === "characterData") {
|
||
debouncedLoad();
|
||
return;
|
||
}
|
||
}
|
||
});
|
||
|
||
var inputHandler = function () { debouncedLoad(); };
|
||
|
||
var elements = document.querySelectorAll(selector);
|
||
observer.observe(document.body || document.documentElement, {
|
||
childList: true,
|
||
subtree: true,
|
||
characterData: true,
|
||
});
|
||
for (var i = 0; i < elements.length; i++) {
|
||
var el = elements[i];
|
||
if (el.tagName === "INPUT" || el.tagName === "TEXTAREA") {
|
||
el.addEventListener("input", inputHandler);
|
||
}
|
||
}
|
||
|
||
doLoad();
|
||
|
||
var disposed = false;
|
||
|
||
var task = {
|
||
dispose: function () {
|
||
if (disposed) return;
|
||
disposed = true;
|
||
observer.disconnect();
|
||
for (var j = 0; j < elements.length; j++) {
|
||
var el2 = elements[j];
|
||
if (el2.tagName === "INPUT" || el2.tagName === "TEXTAREA") {
|
||
el2.removeEventListener("input", inputHandler);
|
||
}
|
||
}
|
||
if (debounceTimer) clearTimeout(debounceTimer);
|
||
delete observeTasks[selector];
|
||
}
|
||
};
|
||
|
||
observeTasks[selector] = task;
|
||
return task;
|
||
}
|
||
|
||
/* ============================================================
|
||
* 3. loadText — 直接传文本模式
|
||
* ============================================================ */
|
||
|
||
/**
|
||
* @param {Object} options
|
||
* @param {string} options.fontName
|
||
* @param {string} options.text
|
||
* @param {string} [options.baseUrl]
|
||
* @param {string} [options.family]
|
||
* @returns {{ update: function(string): void, dispose: function(): void }}
|
||
*/
|
||
function loadText(options) {
|
||
var fontName = options.fontName;
|
||
var baseUrl = options.baseUrl || location.origin;
|
||
var family = options.family || fontName.replace(/\.[^.]+$/, "");
|
||
|
||
var outType = options.outType || "woff2";
|
||
var loader = getLoader(fontName, baseUrl, family, outType);
|
||
|
||
processText(loader, options.text);
|
||
|
||
var disposed = false;
|
||
|
||
return {
|
||
update: function (text) {
|
||
if (disposed) return;
|
||
processText(loader, text);
|
||
},
|
||
dispose: function () {
|
||
if (disposed) return;
|
||
disposed = true;
|
||
/** 移除该 loader 注入的所有 @font-face 样式，避免同名 family 的 CSS 优先级冲突 */
|
||
destroyLoader(fontKey(fontName, family));
|
||
}
|
||
};
|
||
}
|
||
|
||
/* ============================================================
|
||
* 公共 API
|
||
* ============================================================ */
|
||
|
||
/**
|
||
* 清理所有任务和加载器（页面卸载时调用）
|
||
*/
|
||
function disposeAll() {
|
||
for (var sel in pollTasks) {
|
||
clearInterval(pollTasks[sel].timer);
|
||
}
|
||
for (var oid in observeTasks) {
|
||
observeTasks[oid].dispose();
|
||
}
|
||
pollTasks = {};
|
||
observeTasks = {};
|
||
|
||
for (var key in loaders) {
|
||
destroyLoader(key);
|
||
}
|
||
}
|
||
|
||
return {
|
||
loadFont: loadFont,
|
||
observeFont: observeFont,
|
||
loadText: loadText,
|
||
disposeAll: disposeAll
|
||
};
|
||
})();
|