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feat(bookmark-pdf): improve bookmark extraction with reference resolution

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add helper functions to resolve PDF object references and handle named destinations
implement more robust page index finding and destination resolution
refactor traversal logic to use resolved references consistently
This commit is contained in:
abdullahalam123
2025-10-28 01:24:34 +05:30
parent 090146c600
commit ad49adb744
1 changed files with 111 additions and 36 deletions
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147
src/js/logic/bookmark-pdf.ts
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@@ -1547,15 +1547,103 @@ async function extractExistingBookmarks(doc) {
const pages = doc.getPages();
// Helper to resolve references
function resolveRef(obj) {
if (!obj) return null;
if (obj.lookup) return obj;
if (obj.objectNumber !== undefined && doc.context) {
return doc.context.lookup(obj);
}
return obj;
}
// Build named destinations map
const namedDests = new Map();
try {
const names = doc.catalog.lookup(PDFName.of('Names'));
if (names) {
const dests = names.lookup(PDFName.of('Dests'));
if (dests) {
const namesArray = dests.lookup(PDFName.of('Names'));
if (namesArray && namesArray.array) {
for (let i = 0; i < namesArray.array.length; i += 2) {
const name = namesArray.array[i];
const dest = namesArray.array[i + 1];
namedDests.set(name.decodeText(), resolveRef(dest));
}
}
}
}
} catch (e) {
console.error('Error building named destinations:', e);
}
function findPageIndex(pageRef) {
if (!pageRef) return 0;
try {
const resolved = resolveRef(pageRef);
// Try to match by object number
if (pageRef.objectNumber !== undefined) {
const idx = pages.findIndex(p => p.ref.objectNumber === pageRef.objectNumber);
if (idx !== -1) return idx;
}
// Try to match by reference string
if (pageRef.toString) {
const idx = pages.findIndex(p => p.ref.toString() === pageRef.toString());
if (idx !== -1) return idx;
}
// Try to match by page dictionary
if (resolved && resolved.get) {
const idx = pages.findIndex(p => {
const pageDict = doc.context.lookup(p.ref);
return pageDict === resolved;
});
if (idx !== -1) return idx;
}
} catch (e) {
console.error('Error finding page:', e);
}
return 0;
}
function getDestination(item) {
if (!item) return null;
// Try Dest entry first
let dest = item.lookup(PDFName.of('Dest'));
// If no Dest, try Action/D
if (!dest) {
const action = resolveRef(item.lookup(PDFName.of('A')));
if (action) {
dest = action.lookup(PDFName.of('D'));
}
}
// Handle named destinations
if (dest && !dest.array) {
const name = dest.decodeText ? dest.decodeText() : dest.toString();
dest = namedDests.get(name);
}
return resolveRef(dest);
}
function traverse(item) {
if (!item) return null;
item = resolveRef(item);
if (!item) return null;
const title = item.lookup(PDFName.of('Title'));
const dest = item.lookup(PDFName.of('Dest'));
const dest = getDestination(item);
const colorObj = item.lookup(PDFName.of('C'));
const flagsObj = item.lookup(PDFName.of('F'));
// let page = 0;
let pageIndex = 0;
let destX = null;
let destY = null;
@@ -1563,35 +1651,25 @@ async function extractExistingBookmarks(doc) {
if (dest && dest.array) {
const pageRef = dest.array[0];
pageIndex = pages.findIndex(
(p) => p.ref.toString() === pageRef.toString()
); // This is 0-indexed
if (pageIndex === -1) pageIndex = 0;
pageIndex = findPageIndex(pageRef);
// Extract destination coordinates
if (dest.array.length > 2) {
const xObj = dest.array[2];
const yObj = dest.array[3];
const zoomObj = dest.array[4];
const xObj = resolveRef(dest.array[2]);
const yObj = resolveRef(dest.array[3]);
const zoomObj = resolveRef(dest.array[4]);
if (xObj && xObj.numberValue !== undefined) {
destX = xObj.numberValue;
}
if (yObj && yObj.numberValue !== undefined) {
destY = yObj.numberValue;
}
if (xObj && xObj.numberValue !== undefined) destX = xObj.numberValue;
if (yObj && yObj.numberValue !== undefined) destY = yObj.numberValue;
if (zoomObj && zoomObj.numberValue !== undefined) {
zoom = String(Math.round(zoomObj.numberValue * 100));
}
}
}
// Rest of the color and style processing remains the same
let color = null;
if (colorObj && colorObj.array) {
const r = colorObj.array[0];
const g = colorObj.array[1];
const b = colorObj.array[2];
const [r, g, b] = colorObj.array;
if (r > 0.8 && g < 0.3 && b < 0.3) color = 'red';
else if (r < 0.3 && g < 0.3 && b > 0.8) color = 'blue';
else if (r < 0.3 && g > 0.8 && b < 0.3) color = 'green';
@@ -1604,7 +1682,6 @@ async function extractExistingBookmarks(doc) {
const flags = flagsObj.numberValue || 0;
const isBold = (flags & 2) !== 0;
const isItalic = (flags & 1) !== 0;
if (isBold && isItalic) style = 'bold-italic';
else if (isBold) style = 'bold';
else if (isItalic) style = 'italic';
@@ -1615,32 +1692,30 @@ async function extractExistingBookmarks(doc) {
title: title ? title.decodeText() : 'Untitled',
page: pageIndex + 1,
children: [],
color: color,
style: style,
destX: destX,
destY: destY,
zoom: zoom,
color,
style,
destX,
destY,
zoom
};
const first = item.lookup(PDFName.of('First'));
if (first) {
let child = first;
while (child) {
const childBookmark = traverse(child);
if (childBookmark) bookmark.children.push(childBookmark);
child = child.lookup(PDFName.of('Next'));
}
// Process children (make sure to resolve refs)
let child = resolveRef(item.lookup(PDFName.of('First')));
while (child) {
const childBookmark = traverse(child);
if (childBookmark) bookmark.children.push(childBookmark);
child = resolveRef(child.lookup(PDFName.of('Next')));
}
return bookmark;
}
const result = [];
let first = outlines.lookup(PDFName.of('First'));
let first = resolveRef(outlines.lookup(PDFName.of('First')));
while (first) {
const bookmark = traverse(first);
if (bookmark) result.push(bookmark);
first = first.lookup(PDFName.of('Next'));
first = resolveRef(first.lookup(PDFName.of('Next')));
}
return result;