65 lines
3.3 KiB
Markdown
65 lines
3.3 KiB
Markdown
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# PDF Import
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Back to root overview: [README.md](../README.md#in-depth-documentation)
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`tc-lib-pdf` can import pages from existing PDFs as Form XObjects and place them on destination pages.
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## Source Registration and Page Count
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```php
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$sourceId = $pdf->setImportSourceFile('/path/to/source.pdf');
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// or: $sourceId = $pdf->setImportSourceData($rawPdfBytes);
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$count = $pdf->getSourcePageCount($sourceId);
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```
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The page count is derived from the page tree actually reachable through `/Kids`; the declared `/Count` entry of the `/Pages` dictionary is ignored, so a forged or wrong `/Count` cannot influence how many pages are counted or imported. Structurally broken page trees (missing `/Kids`, unexpected node types, duplicate or cyclic references) raise `ImportCorruptedSourceException`.
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The reachable-page walk runs once per registered source: it produces a flattened page index (one effective page dictionary per page, with inherited attributes already resolved) that is cached and reused by `getSourcePageCount()`, `importPage()`, and `importPages()`. Importing all pages of an n-page document therefore costs a single tree walk plus one index lookup per page, instead of one full walk per page.
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## Import One Page and Place It
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```php
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$tpl = $pdf->importPage($sourceId, 1, [
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'box' => 'CropBox', // MediaBox|CropBox|BleedBox|TrimBox|ArtBox
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'groupXObject' => true,
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'cache' => true,
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'respectRotation' => true,
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]);
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$pdf->addPage();
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$placed = $pdf->useImportedPage($tpl, 20, 20, 120, 80, [
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'keepAspectRatio' => true,
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'align' => 'CC', // TL|TC|TR|CL|CC|CR|BL|BC|BR
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'clip' => true,
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]);
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```
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## Append Pages from a Source Document
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```php
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// Append all pages.
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$templates = $pdf->appendDocument($sourceId);
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// Append only selected pages.
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$templates = $pdf->appendDocument($sourceId, [1, 3, 5]);
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// Add one imported page sized to the source page.
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$tpl = $pdf->addPageFromImport($sourceId, 2);
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```
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## Import Examples
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- Single page import: [examples/E065_import_single_page.php](../examples/E065_import_single_page.php)
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- Full document append: [examples/E066_import_document_append.php](../examples/E066_import_document_append.php)
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- Advanced N-up composition from imported pages: [examples/E067_import_page_region_nup.php](../examples/E067_import_page_region_nup.php)
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## Import Limitations and Fidelity Notes
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- Form and annotation semantics are not merged into editable destination structures; pages are imported as Form XObjects.
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- Digital signatures in source files are not preserved as valid signatures in the destination output.
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- Encrypted source PDFs are currently not importable with the bundled parser backend. Password-like options are accepted by the import API, but encrypted inputs fail with an explicit actionable exception.
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- For multi-stream page contents, import normalizes by decoding and concatenating stream bytes; this can change low-level byte representation while preserving rendered appearance in typical cases.
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- Transparency-group behavior is conformance-aware: when transparency is disallowed by the active PDF mode (for example PDF/X-1a or PDF/X-3), import suppresses transparency groups to remain compliant.
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- Setting `groupXObject` to `false` can reduce output size, but may change compositing on source pages that rely on transparency blending.
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