THPDFViewer Region Snapshots

Renders only a selected PDF page rectangle so memory use depends on the region rather than the full page

Declarations

function CreatePageRegionSnapshot(PageIndex: Integer;
  const PageRect: THPDFRectangle; DPI: Integer= 150): TBitmap;
function CreateCurrentPageRegionSnapshot(const PageRect: THPDFRectangle;
  DPI: Integer= 150): TBitmap;

Region handling

• The input rectangle uses PDF points and a lower-left origin
• Reversed left/right or bottom/top values are ordered automatically
• The region is intersected with the visible page box, the CropBox clipped to the MediaBox, before rendering
• An empty intersection or invalid page returns nil
• DPI values are clamped from 12 through 2400
• The returned bitmap includes both the PDF page rotation and current ViewRotation

Example

Region.Left := 72;
Region.Bottom := 72;
Region.Right := 288;
Region.Top := 216;
Bitmap := Model.CreateCurrentPageRegionSnapshot(Region, 300);