THPDFPage.SetPageThumbnail Method

THPDFPage.SetPageThumbnail / ClearPageThumbnail

Pripne ali odstrani sličico strani (vnos PDF strani /Thumb, ISO 32000-1 §12.3.4). Pregledovalniki PDF (Adobe Acrobat, Foxit, pregledovalniki v brskalniku) prikazujejo navedeno sliko v navigacijski plošči, ne da bi sami rastrirali vsebino strani, kar opazno pospeši odpiranje arhivov z veliko slikami

Delphi syntax:

procedure SetPageThumbnail(ImageIndex: Integer);

procedure ClearPageThumbnail;

Parameters

ImageIndex je vrednost, ki jo vrne predhodni klic THotPDF.AddImage ali THotPDF.AddImageFromFile. Osnovni Image XObject je po specifikaciji naveden posredno, zato je isto sliko mogoče brez konflikta narisati tudi na navadni strani. Za odstranitev obstoječega vnosa /Thumb podajte negativen indeks

Description

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.

Primer

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.