55 lines
2.0 KiB
TypeScript
55 lines
2.0 KiB
TypeScript
/** Immutable font descriptor shared by clinical and patient document renderers. */
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export interface DocumentFont {
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id: string;
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name: string;
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regularSha256: string;
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boldSha256: string | null;
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}
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const loaded = new Map<string, Promise<string>>();
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export function loadDocumentFont(
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font: DocumentFont | null,
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apiBase: string,
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): Promise<string> {
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if (!font) return Promise.resolve("");
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const key = `${apiBase}:${font.id}:${font.regularSha256}:${font.boldSha256 ?? ""}`;
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const existing = loaded.get(key);
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if (existing) return existing;
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const family = `Medisign-${font.regularSha256}-${font.boldSha256 ?? "regular"}`;
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const load = async () => {
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const descriptors = [
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{ sha: font.regularSha256, weight: "400" },
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{ sha: font.boldSha256 ?? font.regularSha256, weight: "700" },
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];
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const faces = await Promise.all(
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descriptors.map(async ({ sha, weight }) => {
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const url = `${apiBase.replace(/\/$/, "")}/v1/document-fonts/${encodeURIComponent(font.id)}/${sha}.ttf`;
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const response = await fetch(url, {
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signal: AbortSignal.timeout(30000),
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});
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if (!response.ok)
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throw new Error("文书字体加载失败，请重试或联系管理员。");
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const bytes = await response.arrayBuffer();
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// The URL names an immutable digest; verify before registering the face.
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if (globalThis.crypto?.subtle) {
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const digest = await crypto.subtle.digest("SHA-256", bytes);
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const actual = Array.from(new Uint8Array(digest), (byte) =>
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byte.toString(16).padStart(2, "0"),
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).join("");
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if (actual !== sha) throw new Error("文书字体校验失败。");
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}
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return new FontFace(family, bytes, { weight }).load();
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}),
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);
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for (const face of faces) document.fonts.add(face);
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return `"${family}"`;
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};
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const promise = load().catch((error: unknown) => {
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loaded.delete(key);
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throw error;
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});
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loaded.set(key, promise);
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return promise;
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}
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