using System;

using ImageGear.Core;
using ImageGear.Formats;
using ImageGear.Formats.PDF;

private ImGearRasterPage CreateRasterPageFromPDFPage(ImGearPDFPage pdfPage)
       {
           // Bit depth for rasterization process. It may be changed.
           const int rasterizationBitDepth = 24;

           #region setResolution
           // Get device independent bitmap from input page.
           ImGearDIB dib = pdfPage.DIB;
           // Get resolution of source page.
           IImGearResolution resolution = dib.ImageResolution;
           // Convert source page resolution if the units are not inches.
           if (resolution.Units != ImGearResolutionUnits.INCHES)
           resolution.ConvertUnits(ImGearResolutionUnits.INCHES);
           // Get maximal size of source page for resolution calculation.
           int maximalPageSize = Math.Max(dib.Width, dib.Height);
           // Calculate X resolution for destination page so the X size of
           // destination page will be 250X250 pixels.
           int xResolution = 250 * resolution.XNumerator / resolution.XDenominator / maximalPageSize;
           // Adjust calculated resolution to 1 because there are conditions when
           // the resolution will be less or equal than 0.
           if (xResolution <= 0) xResolution = 1;
           // Calculate Y resolution for destination page so the X size of
           // destination page will be 250xX250 pixels.
           int yResolution = 250 * resolution.YNumerator / resolution.YDenominator / maximalPageSize;
           #endregion

           //Rasterize page.
           ImGearRasterPage rasterPage = pdfPage.Rasterize(rasterizationBitDepth, xResolution, yResolution);
           return rasterPage;
}

Imports ImageGear.Core
Imports ImageGear.Formats
Imports ImageGear.Formats.PDF

Private Function CreateRasterPageFromPDFPage(pdfPage As ImGearPDFPage) As ImGearRasterPage
            ' Bit depth for rasterization process. It may be changed.
            Const  rasterizationBitDepth As Integer = 24

            '#Region "setResolution"
            ' Get device independent bitmap from input page.
            Dim dib As ImGearDIB = pdfPage.DIB
            ' Get resolution of source page.
            Dim resolution As IImGearResolution = dib.ImageResolution
            ' Convert source page resolution if the units are not inches.
            If resolution.Units <> ImGearResolutionUnits.INCHES Then
                        resolution.ConvertUnits(ImGearResolutionUnits.INCHES)
            End If
            ' Get maximal size of source page for resolution calculation.
            Dim maximalPageSize As Integer = Math.Max(dib.Width, dib.Height)
            ' Calculate X resolution for destination page so the X size of
            ' destination page will be 250X250 pixels.
            Dim xResolution As Integer = 250 * resolution.XNumerator / resolution.XDenominator / maximalPageSize
            ' Adjust calculated resolution to 1 because there are conditions when
            ' the resolution will be less or equal than 0.
            If xResolution <= 0 Then
                        xResolution = 1
            End If
            ' Calculate Y resolution for destination page so the X size of
            ' destination page will be 250xX250 pixels.
            Dim yResolution As Integer = 250 * resolution.YNumerator / resolution.YDenominator / maximalPageSize
            '#End Region

            'Rasterize page.
            Dim rasterPage As ImGearRasterPage = pdfPage.Rasterize(rasterizationBitDepth, xResolution, yResolution)
            Return rasterPage
End Function

xResolution = 300;
yResolution = 300;