mORMot Open Source

Well, probably I need to provide mode information.
Here is the example, I want to make a hyperlink around "Prep" text.
Content is made by drawing on VCLCanvas. The origin of coordinates is moved to the point marked with a green circle (using SetWindowOrgEx).

In the code below, I draw a red rectangle around the link area, and create the link.
Input:
  R - link rectangle, in pixels, relative to the origin.
  DocRect - rectangle of document inside the margin

      
     // drawing a red rectangle
      FPdfDoc.VCLCanvas.Brush.Style := bsClear;
      FPdfDoc.VCLCanvas.Pen.Width := 1;
      FPdfDoc.VCLCanvas.Pen.Style := psSolid;
      FPdfDoc.VCLCanvas.Pen.Color := clRed;
      FPdfDoc.VCLCanvas.Rectangle(R.Left, R.Top, R.Right, R.Bottom);
      // adding a link
      OffsetRect(R, DocRect.Left, DocRect.Top);
      dpi := Screen.PixelsPerInch;
      PdfRect.Left := R.Left * 72 / dpi;
      PdfRect.Top := R.Top * 72 / dpi;
      PdfRect.Right := R.Right * 72 / dpi;
      PdfRect.Bottom := R.Bottom * 72 / dpi;
      FPdfDoc.CreateLink(PdfRect, StringToUTF8(Copy(Target, 2, MaxInt)));

The result is below:

Everything is correct except for Y coordinates. You can see that the link is shifted down a lot.

I assign FPdfDoc.DefaultPaperSize (FPdfDoc is TPdfDocumentGDI)
Additionally, I assign FPdfDoc.ScreenLogPixels (currently to Screen.PixelsPerInch, but in future it may be another value).
Then call FPdfDoc.AddPage.
Then I draw onto FPdfDoc.VCLCanvas using pixel coordinates.

I have pixels positions of bookmarks and links (relative to the top of the page), how to convert them to coordinates for CreateLink and CreateBookmark?
I tried Value * 75 / 96, the results are close, but not exactly correct: