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Convert PDF to image (JPG, PNG, BMP, TIFF) in C++

Sample C++ code to use PDFTron SDK's built-in rasterizer to render PDF images on the fly and save the resulting images in various raster image formats (such as PNG, JPEG, BMP, TIFF). Learn more about our PDF Conversion Library.

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//---------------------------------------------------------------------------------------
// Copyright (c) 2001-2019 by PDFTron Systems Inc. All Rights Reserved.
// Consult legal.txt regarding legal and license information.
//---------------------------------------------------------------------------------------

#include <PDF/PDFNet.h>
#include <PDF/PDFDoc.h>
#include <PDF/PDFDraw.h>
#include <Filters/MappedFile.h>
#include <Filters/FilterWriter.h>
#include <cmath>
#include <string>
#include <iostream>
#include <fstream>
#include <sstream>
#include <SDF/ObjSet.h>

using namespace std;
using namespace pdftron;
using namespace PDF;
using namespace Filters;

//---------------------------------------------------------------------------------------
// The following sample illustrates how to convert PDF documents to various raster image 
// formats (such as PNG, JPEG, BMP, TIFF, etc), as well as how to convert a PDF page to 
// GDI+ Bitmap for further manipulation and/or display in WinForms applications.
//---------------------------------------------------------------------------------------
int main(int argc, char *argv[])
{
	try 
	{
		// The first step in every application using PDFNet is to initialize the 
		// library and set the path to common PDF resources. The library is usually 
		// initialized only once, but calling Initialize() multiple times is also fine.
		PDFNet::Initialize();

		// Optional: Set ICC color profiles to fine tune color conversion 
		// for PDF 'device' color spaces...

		// PDFNet::SetResourcesPath("../../../resources");
		// PDFNet::SetColorManagement(PDFNet::e_lcms);
		// PDFNet::SetDefaultDeviceCMYKProfile("D:/Misc/ICC/USWebCoatedSWOP.icc");
		// PDFNet::SetDefaultDeviceRGBProfile("AdobeRGB1998.icc"); // will search in PDFNet resource folder.

		// ----------------------------------------------------
		// Optional: Set predefined font mappings to override default font 
		// substitution for documents with missing fonts...

		// PDFNet::AddFontSubst("StoneSans-Semibold", "C:/WINDOWS/Fonts/comic.ttf");
		// PDFNet::AddFontSubst("StoneSans", "comic.ttf");  // search for 'comic.ttf' in PDFNet resource folder.
		// PDFNet::AddFontSubst(PDFNet::e_Identity, "C:/WINDOWS/Fonts/arialuni.ttf");
		// PDFNet::AddFontSubst(PDFNet::e_Japan1, "C:/Program Files/Adobe/Acrobat 7.0/Resource/CIDFont/KozMinProVI-Regular.otf");
		// PDFNet::AddFontSubst(PDFNet::e_Japan2, "c:/myfonts/KozMinProVI-Regular.otf");
		// PDFNet::AddFontSubst(PDFNet::e_Korea1, "AdobeMyungjoStd-Medium.otf");
		// PDFNet::AddFontSubst(PDFNet::e_CNS1, "AdobeSongStd-Light.otf");
		// PDFNet::AddFontSubst(PDFNet::e_GB1, "AdobeMingStd-Light.otf");

		// Relative path to the folder containing test files.
		string input_path =  "../../TestFiles/";
		string output_path = "../../TestFiles/Output/";

		PDFDraw draw;  // PDFDraw class is used to rasterize PDF pages.

		//--------------------------------------------------------------------------------
		// Example 1) Convert the first page to PNG and TIFF at 92 DPI. 
		// A three step tutorial to convert PDF page to an image.
		try 
		{
			// A) Open the PDF document.
			PDFDoc doc((input_path + "tiger.pdf").c_str());

			// Initialize the security handler, in case the PDF is encrypted.
			doc.InitSecurityHandler();  

			// B) The output resolution is set to 92 DPI.
			draw.SetDPI(92);

			// C) Rasterize the first page in the document and save the result as PNG.
			draw.Export(doc.GetPageIterator().Current(), (output_path + "tiger_92dpi.png").c_str());

			cout << "Example 1: tiger_92dpi.png" << endl;

			// Export the same page as TIFF
			draw.Export(doc.GetPageIterator().Current(), (output_path + "tiger_92dpi.tif").c_str(), "TIFF");
		}
		catch(Common::Exception& e)	
		{
			cout << e << endl;
		}
		catch(...) 
		{
			cout << "Unknown Exception" << endl;
		}

		//--------------------------------------------------------------------------------
		// Example 2) Convert the all pages in a given document to JPEG at 72 DPI.
		cout << "Example 2:" << endl;
		SDF::ObjSet hint_set; //  A collection of rendering 'hits'.
		try 
		{
			PDFDoc doc((input_path + "newsletter.pdf").c_str());
			// Initialize the security handler, in case the PDF is encrypted.
			doc.InitSecurityHandler();  

			draw.SetDPI(72); // Set the output resolution is to 72 DPI.

			// Use optional encoder parameter to specify JPEG quality.
			SDF::Obj encoder_param=hint_set.CreateDict();
			encoder_param.PutNumber("Quality", 80);

			// Traverse all pages in the document.
			for (PageIterator itr=doc.GetPageIterator(); itr.HasNext(); itr.Next()) {
				ostringstream sstm;
				sstm << output_path << "newsletter" << itr.Current().GetIndex() << ".jpg";
				string path = sstm.str();
				cout << "newsletter" << itr.Current().GetIndex() << ".jpg" << endl;

				draw.Export(itr.Current(), path.c_str(), "JPEG", encoder_param);
			}

			cout << "Done." << endl;
		}
		catch(Common::Exception& e)	
		{
			cout << e << endl;
		}
		catch(...) 
		{
			cout << "Unknown Exception" << endl;
		}


		// Examples 3-6
		try  
		{				
			// Common code for remaining samples.
			PDFDoc tiger_doc((input_path + "tiger.pdf").c_str());
			// Initialize the security handler, in case the PDF is encrypted.
			tiger_doc.InitSecurityHandler();  
			Page page = tiger_doc.GetPage(1);

			//--------------------------------------------------------------------------------
			// Example 3) Convert the first page to raw bitmap. Also, rotate the 
			// page 90 degrees and save the result as RAW.
			draw.SetDPI(100); // Set the output resolution is to 100 DPI.
			draw.SetRotate(Page::e_90);  // Rotate all pages 90 degrees clockwise.

			int width = 0, height = 0, stride = 0;
			double dpi = 0.0;
			const UChar* buf = draw.GetBitmap(page, width, height, stride, dpi, PDFDraw::e_rgb);

			
			// Save the raw RGB data to disk.
			ofstream outfile((output_path + "tiger_100dpi_rot90.raw").c_str(), ofstream::binary);
			outfile.write((char*)buf, height * stride);
			outfile.close();
			

			cout << "Example 3: tiger_100dpi_rot90.raw" << endl;
			draw.SetRotate(Page::e_0);  // Disable image rotation for remaining samples.

			//--------------------------------------------------------------------------------
			// Example 4) Convert PDF page to a fixed image size. Also illustrates some 
			// other features in PDFDraw class such as rotation, image stretching, exporting 
			// to grayscale, or monochrome.

			// Initialize render 'gray_hint' parameter, that is used to control the 
			// rendering process. In this case we tell the rasterizer to export the image as 
			// 1 Bit Per Component (BPC) image.
			SDF::Obj mono_hint=hint_set.CreateDict();  
			mono_hint.PutNumber("BPC", 1);

			// SetImageSize can be used instead of SetDPI() to adjust page  scaling 
			// dynamically so that given image fits into a buffer of given dimensions.
			draw.SetImageSize(1000, 1000);		// Set the output image to be 1000 wide and 1000 pixels tall
			draw.Export(page, (output_path + "tiger_1000x1000.png").c_str(), "PNG", mono_hint);
			cout << "Example 4: tiger_1000x1000.png" << endl;

			draw.SetImageSize(200, 400);	    // Set the output image to be 200 wide and 300 pixels tall
			draw.SetRotate(Page::e_180);  // Rotate all pages 90 degrees clockwise.

			// 'gray_hint' tells the rasterizer to export the image as grayscale.
			SDF::Obj gray_hint=hint_set.CreateDict();  
			gray_hint.PutName("ColorSpace", "Gray");

			draw.Export(page, (output_path + "tiger_200x400_rot180.png").c_str(), "PNG", gray_hint);
			cout << "Example 4: tiger_200x400_rot180.png" << endl;

			draw.SetImageSize(400, 200, false);  // The third parameter sets 'preserve-aspect-ratio' to false.
			draw.SetRotate(Page::e_0);    // Disable image rotation.
			draw.Export(page, (output_path + "tiger_400x200_stretch.jpg").c_str(), "JPEG");
			cout << "Example 4: tiger_400x200_stretch.jpg" << endl;

			//--------------------------------------------------------------------------------
			// Example 5) Zoom into a specific region of the page and rasterize the 
			// area at 200 DPI and as a thumbnail (i.e. a 50x50 pixel image).
			Rect zoom_rect(216, 522, 330, 600);
			page.SetCropBox(zoom_rect);	// Set the page crop box.

			// Select the crop region to be used for drawing.
			draw.SetPageBox(Page::e_crop); 
			draw.SetDPI(900);  // Set the output image resolution to 900 DPI.
			draw.Export(page, (output_path + "tiger_zoom_900dpi.png").c_str(), "PNG");
			cout << "Example 5: tiger_zoom_900dpi.png" << endl;

			// -------------------------------------------------------------------------------
			// Example 6)
			draw.SetImageSize(50, 50);	   // Set the thumbnail to be 50x50 pixel image.
			draw.Export(page, (output_path + "tiger_zoom_50x50.png").c_str(), "PNG");
			cout << "Example 6: tiger_zoom_50x50.png" << endl;
		}
		catch(Common::Exception& e)	
		{
			cout << e << endl;
		}
		catch(...) 
		{
			cout << "Unknown Exception" << endl;
		}

		

		//--------------------------------------------------------------------------------
		// Example 7) Convert the first PDF page to CMYK TIFF at 92 DPI.
		// A three step tutorial to convert PDF page to an image
		try 
		{
			pdftron::SDF::Obj cmyk_hint = hint_set.CreateDict();
			cmyk_hint.PutName("ColorSpace", "CMYK");
			// A) Open the PDF document.
			PDFDoc doc((input_path + "tiger.pdf").c_str());
			// Initialize the security handler, in case the PDF is encrypted.
			doc.InitSecurityHandler();  

			// B) The output resolution is set to 92 DPI.
			draw.SetDPI(92);

			// C) Rasterize the first page in the document and save the result as TIFF.
			Page pg = doc.GetPage(1);
			draw.Export(pg, output_path + "out1.tif", "TIFF", cmyk_hint);
			cout << "Example 7: out1.tif" << endl;
		}
		catch(Common::Exception& e)	
		{
			cout << e << endl;
		}
		catch(...) 
		{
			cout << "Unknown Exception" << endl;
		}

		//--------------------------------------------------------------------------------
		// Example 8) PDFRasterizer can be used for more complex rendering tasks, such as 
		// strip by strip or tiled document rendering. In particular, it is useful for 
		// cases where you cannot simply modify the page crop box (interactive viewing,
		// parallel rendering).  This example shows how you can rasterize the south-west
		// quadrant of a page.
		try 
		{
			// A) Open the PDF document.
			PDFDoc doc((input_path + "tiger.pdf").c_str());
			// Initialize the security handler, in case the PDF is encrypted.
			doc.InitSecurityHandler();  

			// B) Get the page matrix 
			Page pg = doc.GetPage(1);
			Page::Box box = Page::e_crop;
			Common::Matrix2D mtx = pg.GetDefaultMatrix(true, box);
			// We want to render a quadrant, so use half of width and height
			const double pg_w = pg.GetPageWidth(box) / 2;
			const double pg_h = pg.GetPageHeight(box) / 2;

			// C) Scale matrix from PDF space to buffer space
			const double dpi = 96.0;
			const double scale = dpi / 72.0; // PDF space is 72 dpi
			const int buf_w = static_cast<int>(floor(scale * pg_w));
			const int buf_h = static_cast<int>(floor(scale * pg_h));
			const int bytes_per_pixel = 4; // BGRA buffer
			const int buf_size = buf_w * buf_h * bytes_per_pixel;
			mtx.Translate(0, -pg_h); // translate by '-pg_h' since we want south-west quadrant
			mtx = Common::Matrix2D(scale, 0, 0, scale, 0, 0) * mtx;

			// D) Rasterize page into memory buffer, according to our parameters
			std::vector<unsigned char> buf;
			PDFRasterizer rast;
			buf = rast.Rasterize(pg, buf_w, buf_h, buf_w * bytes_per_pixel, bytes_per_pixel, true, mtx);

			// buf now contains raw BGRA bitmap.
			cout << "Example 8: Successfully rasterized into memory buffer." << endl;
		}
		catch(Common::Exception& e)	
		{
			cout << e << endl;
		}
		catch (...) {
			cout << "Unknown Exception" << endl;
		}
		//--------------------------------------------------------------------------------
		// Example 9) Export raster content to PNG using different image smoothing settings. 
		try 
		{
			PDFDoc text_doc((input_path + "lorem_ipsum.pdf").c_str());
			text_doc.InitSecurityHandler();

			draw.SetImageSmoothing(false, false);
			string filename = "raster_text_no_smoothing.png";
			draw.Export(text_doc.GetPageIterator().Current(), (output_path + filename).c_str());
			cout << "Example 9 a): " << filename << ". Done." << endl;

			filename = "raster_text_smoothed.png";
			draw.SetImageSmoothing(true, false /*default quality bilinear resampling*/);
			draw.Export(text_doc.GetPageIterator().Current(), (output_path + filename).c_str());
			cout << "Example 9 b): " << filename << ". Done." << endl;

			filename = "raster_text_high_quality.png";
			draw.SetImageSmoothing(true, true /*high quality area resampling*/);
			draw.Export(text_doc.GetPageIterator().Current(), (output_path + filename).c_str());
			cout << "Example 9 c): " << filename << ". Done." << endl;
		}
		catch(Common::Exception& e)	
		{
			cout << e << endl;
		}
		catch (...) {
			cout << "Unknown Exception" << endl;
		}
		//--------------------------------------------------------------------------------
		// Example 10) Export separations directly, without conversion to an output colorspace
		try
		{
			PDFDoc separation_doc((input_path + "op_blend_test.pdf").c_str());
			separation_doc.InitSecurityHandler();
			pdftron::SDF::Obj separation_hint = hint_set.CreateDict();
			separation_hint.PutName("ColorSpace", "Separation");
			draw.SetDPI(96);
			draw.SetImageSmoothing(true, true);
			draw.SetOverprint(PDFRasterizer::e_op_on);

			string filename = "merged_separations.png";
			draw.Export(separation_doc.GetPageIterator().Current(), (output_path + filename).c_str(), "PNG");
			cout << "Example 10 a): " << filename <<". Done." << endl;

			filename = "separation";
			draw.Export(separation_doc.GetPageIterator().Current(), (output_path + filename).c_str(), "PNG", separation_hint);
			cout << "Example 10 b): " << filename <<"_[ink].png. Done." << endl;

			filename = "separation_NChannel.tif";
			draw.Export(separation_doc.GetPageIterator().Current(), (output_path + filename).c_str(), "TIFF", separation_hint);
			cout << "Example 10 c): " << filename << ". Done." << endl;
		}
		catch(Common::Exception& e)	
		{
			cout << e << endl;
		}
		catch (...) {
			cout << "Unknown Exception" << endl;
		}
		PDFNet::Terminate();
	}
	catch(Common::Exception& e)	
	{
		cout << e << endl;
	}
	catch (...) {
		cout << "Unknown Exception" << endl;
	}

	return 0;	
}
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