// Simple in-memory screenshot context manager per tab
// Used to scale coordinates from screenshot space to viewport space
export interface ScreenshotContext {
// Final screenshot dimensions (in CSS pixels after any scaling)
screenshotWidth: number;
screenshotHeight: number;
// Viewport dimensions (CSS pixels)
viewportWidth: number;
viewportHeight: number;
// Device pixel ratio at capture time (optional, for reference)
devicePixelRatio?: number;
// Hostname of the page when the screenshot was taken (used for domain safety checks)
hostname?: string;
// Timestamp
timestamp: number;
}
const TTL_MS = 5 * 60 * 1000; // 5 minutes
const contexts = new Map<number, ScreenshotContext>();
export const screenshotContextManager = {
setContext(tabId: number, ctx: Omit<ScreenshotContext, 'timestamp'>) {
contexts.set(tabId, { ...ctx, timestamp: Date.now() });
},
getContext(tabId: number): ScreenshotContext | undefined {
const ctx = contexts.get(tabId);
if (!ctx) return undefined;
if (Date.now() - ctx.timestamp > TTL_MS) {
contexts.delete(tabId);
return undefined;
}
return ctx;
},
clear(tabId: number) {
contexts.delete(tabId);
},
};
// Scale screenshot-space coordinates (x,y) to viewport CSS pixels
export function scaleCoordinates(
x: number,
y: number,
ctx: ScreenshotContext,
): { x: number; y: number } {
if (!ctx.screenshotWidth || !ctx.screenshotHeight || !ctx.viewportWidth || !ctx.viewportHeight) {
return { x, y };
}
const sx = (x / ctx.screenshotWidth) * ctx.viewportWidth;
const sy = (y / ctx.screenshotHeight) * ctx.viewportHeight;
return { x: Math.round(sx), y: Math.round(sy) };
}
