THPDFPage.SetPageThumbnail Method

THPDFPage.SetPageThumbnail / ClearPageThumbnail

Priključuje ili uklanja sličicu stranice (PDF unos /Thumb, ISO 32000-1 §12.3.4). PDF preglednici (Adobe Acrobat, Foxit, preglednici u browseru) prikazuju referenciranu sliku u navigacijskoj ploči bez vlastitog rasteriziranja sadržaja stranice, što otvaranje arhiva s mnogo slika čini osjetno bržim

Delphi syntax:

procedure SetPageThumbnail(ImageIndex: Integer);

procedure ClearPageThumbnail;

Parameters

ImageIndex je vrijednost vraćena prethodnim pozivom THotPDF.AddImage ili THotPDF.AddImageFromFile. Temeljni Image XObject referencira se neizravno prema specifikaciji, pa se ista slika može također crtati na uobičajenoj stranici bez konflikta. Proslijedite negativan indeks za uklanjanje postojećeg /Thumb unosa

Opis

Each PDF page can carry an indirect reference to an Image XObject in its /Thumb key. The image is normally a downsampled 8-bit DeviceGray, DeviceRGB, or Indexed bitmap (Acrobat uses roughly one thumbnail point per page point), but HotPDF does not validate the color space – the caller chooses what to attach. ClearPageThumbnail removes any previously attached thumbnail. SetPageThumbnail(-1) is equivalent to ClearPageThumbnail. Passing an ImageIndex that is not in range of the document’s image list raises a descriptive exception.

Example

PDF := THotPDF.Create(nil);
PDF.FileName := 'archive.pdf';
PDF.BeginDoc;
Idx := PDF.AddImageFromFile('preview.jpg', icJpeg);
PDF.CurrentPage.SetPageThumbnail(Idx);
PDF.EndDoc;

Availability

HotPDF v2.119.13. The PDF /Thumb entry is a PDF 1.0 feature and is not gated under PDF/A, PDF/X, or PDF/UA compliance modes. To make the viewer open with the thumbnail panel visible, also set THotPDF.PageMode := pmUseThumbs.