PDF to Image

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The following CreateRasterPageFromPDFPage sample illustrates how you can create a raster page from a PDF page:

PDF support needs to be initialized first for this snippet to work. To get familiar with initializing IGNET, initializing PDF support, loading a PDF, saving a PDF, and terminating PDF support, try any one of the tutorials.

CS
VBNET

C#	Copy Code
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; }

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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;
}

VB.NET	Copy Code
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

VB.NET

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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

Remarks

Implementation of this method uses only the ImGearPDFPage.Rasterize(int bitDepth, int xResolution, int yResolution) method of ImageGear. Argument bitDepth defines the resulting image bit depth. In the above sample, the value 24 is used, however other values can be used. Arguments xResolution and yResolution define the resolution of the output raster image. For example, in the sample above, the region #region setResolution can be replaced for fixed resolutions as follows:

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xResolution = 300; yResolution = 300;

These resolutions will be used for the new image, i.e., in resultImage.DIB.ImageResolution.

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