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Code Issues Actions 3 Packages Projects Releases 1 Wiki Activity

Chore/v2/fix auto zoom (#4903)

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This commit is contained in:
Reece Browne
2025-11-18 13:43:52 +00:00
committed by GitHub
parent 15b8447626
commit a8ea0b60cf
3 changed files with 20 additions and 66 deletions
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frontend/src/core/utils/viewerZoom.ts
+16 -30
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@@ -1,6 +1,6 @@
import { useEffect, useRef } from 'react';
export const DEFAULT_VISIBILITY_THRESHOLD = 80; // Require at least 80% of the page height to be visible
export const DEFAULT_VISIBILITY_THRESHOLD = 70; // Require at least 70% of the page height to be visible
export const DEFAULT_FALLBACK_ZOOM = 1.44; // 144% fallback when no reliable metadata is present
export interface ZoomViewport {
@@ -36,47 +36,33 @@ export function determineAutoZoom({
visibilityThreshold = DEFAULT_VISIBILITY_THRESHOLD,
fallbackZoom = DEFAULT_FALLBACK_ZOOM,
}: AutoZoomParams): AutoZoomDecision {
// Get aspect ratio from pageRect or metadata
const rectWidth = pageRect?.width ?? 0;
const rectHeight = pageRect?.height ?? 0;
const aspectRatio: number | null =
rectWidth > 0 ? rectHeight / rectWidth : metadataAspectRatio ?? null;
let renderedHeight: number | null = rectHeight > 0 ? rectHeight : null;
if (!renderedHeight || renderedHeight <= 0) {
if (aspectRatio == null || aspectRatio <= 0) {
return { type: 'fallback', zoom: Math.min(fitWidthZoom, fallbackZoom) };
}
const pageWidth = viewportWidth / (fitWidthZoom * pagesPerSpread);
const pageHeight = pageWidth * aspectRatio;
renderedHeight = pageHeight * fitWidthZoom;
// Need aspect ratio to proceed
if (!aspectRatio || aspectRatio <= 0) {
return { type: 'fallback', zoom: Math.min(fitWidthZoom, fallbackZoom) };
}
if (!renderedHeight || renderedHeight <= 0) {
return { type: 'fitWidth' };
}
const isLandscape = aspectRatio !== null && aspectRatio < 1;
// Landscape pages need 100% visibility, portrait need the specified threshold
const isLandscape = aspectRatio < 1;
const targetVisibility = isLandscape ? 100 : visibilityThreshold;
const visiblePercent = (viewportHeight / renderedHeight) * 100;
// Calculate zoom level that shows targetVisibility% of page height
const pageHeightAtFitWidth = (viewportWidth / pagesPerSpread) * aspectRatio;
const heightBasedZoom = fitWidthZoom * (viewportHeight / pageHeightAtFitWidth) / (targetVisibility / 100);
if (visiblePercent >= targetVisibility) {
// Use whichever zoom is smaller (more zoomed out) to satisfy both width and height constraints
if (heightBasedZoom < fitWidthZoom) {
// Need to zoom out from fitWidth to show enough height
return { type: 'adjust', zoom: heightBasedZoom };
} else {
// fitWidth already shows enough
return { type: 'fitWidth' };
}
const allowableHeightRatio = targetVisibility / 100;
const zoomScale =
viewportHeight / (allowableHeightRatio * renderedHeight);
const targetZoom = Math.min(fitWidthZoom, fitWidthZoom * zoomScale);
if (Math.abs(targetZoom - fitWidthZoom) < 0.001) {
return { type: 'fitWidth' };
}
return { type: 'adjust', zoom: targetZoom };
}
export interface MeasurePageRectOptions {