PDF Viewer 's quality

hello

I'm using LeadTools 16.5 to show the pdf file in the viewer with RasterImageList controller.
like this:
///////////////////////////////////////////////////
Dim info As CodecsImageInfo = _codecs.GetInformation(fileName, True)

_codecs.Options.Load.Format =RasterImageFormat.RasPdfG4

_codecs.Options.Pdf.Load.XResolution = 400

_codecs.Options.Pdf.Load.YResolution = 400

_codecs.Options.Pdf.Save.UseImageResolution = True

rasterImage = _codecs.Load(fileName)

RasterImageViewer.Dock = DockStyle.Fill
RasterImageViewer.InteractiveMode = RasterViewerInteractiveMode.Pan
RasterImageViewer.HorizontalAlignMode = RasterPaintAlignMode.Center
RasterImageViewer.VerticalAlignMode = RasterPaintAlignMode.Center
RasterImageViewer.AutoResetScaleFactor = False
RasterImageViewer.UseDpi = True
Dim i As Integer
For i = 1 To info.TotalPages
Dim listItem As RasterImageListItem = New RasterImageListItem(rasterImage, i, String.Format("Page {0}", i))
Me.RasterImageList.Items.Add(listItem)
Next

///////////////////////////////////////////////////

By these codes,I can show the pdf in the viewer and the thumbnail. But the thumbnail's quality and viewer's quality is not good.Specifically when zoom out.Could you tell me how can I deal with it ?
By the way,the pdf file is from scanning by these codes:
_codecs.Save(e.Image,filename, RasterImageFormat.RasPdfG4, 1, 1, 1, 1, CodecsSavePageMode.Append)

And , I have already set the _codecs.Options.Pdf.Load.XResolution = 400
_codecs.Options.Pdf.Load.YResolution = 400

But,It's still poor when zoom out.

sorry,and it's multi-pdf file.

If you are trying to load 1-BPP black and white images, you can try using the RasterPaintDisplayModeFlags.ScaleToGray. You can use this by setting the PaintProperties property of the RasterImageList and RasterImageViewer controls. Please note that ScaleToGray requires Document support to be unlocked in order for it to affect the display.
For more information, please see this page:
http://www.leadtools.com/help/leadtools/v15/DH/WI/Leadtools.WinForms~Leadtools.WinForms.RasterImageViewer.html

Also, you can load the PDF file as 1-BPP by setting the codecs.Options.Pdf.Load.DisplayDepth property to 1.

Thanks,
Maen Badwan
LEADTOOLS Technical Support

I resolved it ! Thank you very much !!