55 lines
1.4 KiB
TypeScript
55 lines
1.4 KiB
TypeScript
export const PREVIEW_ZOOM_STORAGE_KEY = "md-to-pdf.preview-zoom.v1";
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export const DEFAULT_PREVIEW_ZOOM = 100;
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export const MINIMUM_PREVIEW_ZOOM = 50;
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export const MAXIMUM_PREVIEW_ZOOM = 400;
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export const PREVIEW_ZOOM_SLIDER_STEP = 5;
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type PreviewZoomStorage = Pick<Storage, "getItem" | "setItem">;
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export function normalizePreviewZoom(value: number) {
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if (!Number.isFinite(value)) {
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return DEFAULT_PREVIEW_ZOOM;
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}
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return Math.min(
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MAXIMUM_PREVIEW_ZOOM,
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Math.max(MINIMUM_PREVIEW_ZOOM, Math.round(value))
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);
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}
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export function parsePreviewZoom(
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value: string | null,
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fallback = DEFAULT_PREVIEW_ZOOM
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) {
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if (!value?.trim()) {
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return normalizePreviewZoom(fallback);
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}
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const parsed = Number(value);
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return Number.isFinite(parsed)
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? normalizePreviewZoom(parsed)
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: normalizePreviewZoom(fallback);
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}
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export function loadPreviewZoom(
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storage: PreviewZoomStorage = window.localStorage
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) {
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try {
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return parsePreviewZoom(storage.getItem(PREVIEW_ZOOM_STORAGE_KEY));
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} catch {
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return DEFAULT_PREVIEW_ZOOM;
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}
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}
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export function savePreviewZoom(
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value: number,
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storage: PreviewZoomStorage = window.localStorage
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) {
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try {
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storage.setItem(
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PREVIEW_ZOOM_STORAGE_KEY,
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String(normalizePreviewZoom(value))
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);
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} catch {
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// 预览缩放是非关键偏好，浏览器禁用缓存时保持当前会话值即可。
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}
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}
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