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

Sample Obj-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.
//---------------------------------------------------------------------------------------

#import <OBJC/PDFNetOBJC.h>
#import <Foundation/Foundation.h>
#include <math.h>
#include <stdio.h>

//---------------------------------------------------------------------------------------
// 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[])
{
    @autoreleasepool {
        @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.
            [PTPDFNet Initialize: 0];

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

            // PDFNet::SetResourcesPath("../../../resources");
            // PDFNet::SetColorManagement();
            // 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");

            PTPDFDraw *draw = [[PTPDFDraw alloc] initWithDpi: 92];  // 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.
                PTPDFDoc *doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/tiger.pdf"];

                // 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: 1] Current] filename: @"../../TestFiles/Output/tiger_92dpi.png" format: @"PNG"];

                NSLog(@"Example 1: tiger_92dpi.png");

                // Export the same page as TIFF
                [draw Export:[[doc GetPageIterator: 1] Current] filename: @"../../TestFiles/Output/tiger_92dpi.tif" format: @"TIFF"];
            }
            @catch(NSException *e)	
            {
                NSLog(@"%@", e.reason);
            }

            //--------------------------------------------------------------------------------
            // Example 2) Convert the all pages in a given document to JPEG at 72 DPI.
            NSLog(@"Example 2:");
            PTObjSet *hint_set = [[PTObjSet alloc] init]; //  A collection of rendering 'hits'.
            @try 
            {
                PTPDFDoc *doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/newsletter.pdf"];
                // 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.
                PTObj *encoder_param=[hint_set CreateDict];
                [encoder_param PutNumber: @"Quality" value: 80];

                // Traverse all pages in the document.
                PTPageIterator *itr;
                for (itr=[doc GetPageIterator: 1]; [itr HasNext]; [itr Next]) {
                    NSString *filename = [NSString stringWithFormat: @"newsletter%d.jpg", [[itr Current] GetIndex]];
                    NSLog(@"%@", filename);
                    NSString *filenameWithPath = [@"../../TestFiles/Output/" stringByAppendingPathComponent: filename];

                    [draw ExportWithObj: [itr Current] filename: filenameWithPath format: @"JPEG" encoder_params: encoder_param];
                }

                NSLog(@"Done.");
            }
            @catch(NSException *e)	
            {
                NSLog(@"%@", e.reason);
            }
        
            // Examples 3-5
            @try  
            {				
                // Common code for remaining samples.
                PTPDFDoc *tiger_doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/tiger.pdf"];
                // Initialize the security handler, in case the PDF is encrypted.
                [tiger_doc InitSecurityHandler];  
                PTPage *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: e_pt90];  // Rotate all pages 90 degrees clockwise.

                PTBitmapInfo* buf = [draw GetBitmap: page pix_fmt: e_ptrgb demult: NO];

                // Save the raw RGB data to disk.
                [[buf GetBuffer] writeToFile: @"../../TestFiles/Output/tiger_100dpi_rot90.raw" atomically: NO];

                NSLog(@"Example 3: tiger_100dpi_rot90.raw");
                [draw SetRotate: e_pt0];  // 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.
                PTObj *mono_hint=[hint_set CreateDict];  
                [mono_hint PutNumber: @"BPC" value: 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 height: 1000 preserve_aspect_ratio: YES];		// Set the output image to be 1000 wide and 1000 pixels tall
                [draw ExportWithObj: page filename: @"../../TestFiles/Output/tiger_1000x1000.png" format: @"PNG" encoder_params: mono_hint];
                NSLog(@"Example 4: tiger_1000x1000.png");

                [draw SetImageSize: 200 height: 400 preserve_aspect_ratio: YES];	    // Set the output image to be 200 wide and 300 pixels tall
                [draw SetRotate: e_pt180];  // Rotate all pages 90 degrees clockwise.

                // 'gray_hint' tells the rasterizer to export the image as grayscale.
                PTObj *gray_hint=[hint_set CreateDict];  
                [gray_hint PutName: @"ColorSpace" name: @"Gray"];

                [draw ExportWithObj: page filename: @"../../TestFiles/Output/tiger_200x400_rot180.png" format: @"PNG" encoder_params: gray_hint];
                NSLog(@"Example 4: tiger_200x400_rot180.png");

                [draw SetImageSize: 400 height: 200 preserve_aspect_ratio: NO];  // The third parameter sets 'preserve-aspect-ratio' to false.
                [draw SetRotate: e_pt0];    // Disable image rotation.
				[draw  Export:page filename: @"../../TestFiles/Output/tiger_400x200_stretch.jpg" format: @"JPEG"];
                NSLog(@"Example 4: tiger_400x200_stretch.jpg");

                //--------------------------------------------------------------------------------
                // 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).
                PTPDFRect *zoom_rect = [[PTPDFRect alloc] initWithX1: 216 y1: 522 x2: 330 y2: 600];
                [page SetCropBox: zoom_rect];	// Set the page crop box.

                // Select the crop region to be used for drawing.
                [draw SetPageBox: e_ptcrop];
                [draw SetDPI: 900];  // Set the output image resolution to 900 DPI.
                [draw Export:page filename: @"../../TestFiles/Output/tiger_zoom_900dpi.png" format: @"PNG"];
                NSLog(@"Example 5: tiger_zoom_900dpi.png");

                // -------------------------------------------------------------------------------
                // Example 6)
                [draw SetImageSize: 50 height: 50 preserve_aspect_ratio: YES];	   // Set the thumbnail to be 50x50 pixel image.
                [draw Export:page filename: @"../../TestFiles/Output/tiger_zoom_50x50.png" format: @"PNG"];
                NSLog(@"Example 6: tiger_zoom_50x50.png");
            }
            @catch(NSException *e)	
            {
                NSLog(@"%@", e.reason);
            }
        
            PTObj *cmyk_hint = [hint_set CreateDict];
            [cmyk_hint PutName: @"ColorSpace" name: @"CMYK"];

            //--------------------------------------------------------------------------------
            // 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 
            {
                // A) Open the PDF document.
                PTPDFDoc *doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/tiger.pdf"];
                // 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.
                PTPage *pg = [doc GetPage: 1];
                [draw ExportWithObj: pg filename: @"../../TestFiles/Output/out1.tif" format: @"TIFF" encoder_params: cmyk_hint];
                NSLog(@"Example 7: out1.tif");
            }
            @catch(NSException *e)	
            {
                NSLog(@"%@", e.reason);
            }
        
            //--------------------------------------------------------------------------------
            // 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.
                PTPDFDoc* doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/tiger.pdf"];
                // Initialize the security handler, in case the PDF is encrypted.
                [doc InitSecurityHandler];

                    // B) Get the page matrix 
                PTPage* pg = [doc GetPage: 1];
                PTBox box = e_ptcrop;
                PTMatrix2D* mtx = [pg GetDefaultMatrix: YES box_type: box angle: e_pt0];
                    // 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 = 96.0f;
                const double scale = dpi / 72.0f; // PDF space is 72 dpi
                const size_t buf_w = floor(scale * pg_w);
                const size_t buf_h = floor(scale * pg_h);
                const int bytes_per_pixel = 4; // RGBA buffer
                const size_t buf_size = buf_w * buf_h * bytes_per_pixel;
                [mtx Translate: 0 v: -pg_h]; // translate by '-pg_h' since we want south-west quadrant
                    //mtx = Common::Matrix2D(scale, 0, 0, scale, 0, 0) * mtx;
                PTMatrix2D* scale_mtx = [[PTMatrix2D alloc] initWithA: scale b: 0 c: 0 d: scale h: 0 v:0];
                mtx = [scale_mtx Multiply: mtx];

                    // D) Rasterize page into memory buffer, according to our parameters
                PTPDFRasterizer* rast = [[PTPDFRasterizer alloc] initWithType: e_ptBuiltIn];
                NSData* buf = [rast Rasterize: pg width:(int)buf_w height:(int)buf_h stride: (int)buf_w * bytes_per_pixel num_comps: bytes_per_pixel demult: YES device_mtx: mtx clip: Nil scrl_clip_regions: Nil];

                // buf now contains raw BGRA bitmap.
                NSLog(@"Example 8: Successfully rasterized into memory buffer.");
            }
            @catch (NSException* e)
            {
                NSLog(@"%@", e.reason);
            }



            //--------------------------------------------------------------------------------
            // Example 9) Export raster content to PNG using different image smoothing settings. 
            @try 
            {
                PTPDFDoc* text_doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/lorem_ipsum.pdf"];
                [text_doc InitSecurityHandler];

                [draw SetImageSmoothing:false hq_image_resampling:false];
                [draw Export:[[text_doc GetPageIterator:1] Current] filename: @"../../TestFiles/Output/raster_text_no_smoothing.png" format:@"PNG"];
                NSLog(@"Example 9 a): raster_text_no_smoothing.png. Done.");

                [draw SetImageSmoothing:true hq_image_resampling:false];
                [draw Export:[[text_doc GetPageIterator:1] Current] filename: @"../../TestFiles/Output/raster_text_smoothed.png" format:@"PNG"];
                NSLog(@"Example 9 b): raster_text_smoothed.png. Done.");

                [draw SetImageSmoothing:true hq_image_resampling:true];
                [draw Export:[[text_doc GetPageIterator:1] Current] filename: @"../../TestFiles/Output/raster_text_high_quality.png" format:@"PNG"];
                NSLog(@"Example 9 c): raster_text_high_quality.png. Done.");
            }
            @catch (NSException *e)
            {
                NSLog(@"%@", e.reason);
            }


            //--------------------------------------------------------------------------------
            // Example 10) Export separations directly, without conversion to an output colorspace
            @try
            {
                PTPDFDoc* separation_doc = [[PTPDFDoc alloc] initWithFilepath: @"../../TestFiles/op_blend_test.pdf"];
                [separation_doc InitSecurityHandler];

                PTObj* separation_hint = [hint_set CreateDict];
                [separation_hint PutName:@"ColorSpace" name:@"Separation"];
                [draw SetDPI:96];
                [draw SetImageSmoothing:true hq_image_resampling:true];
                [draw SetOverprint: e_ptop_on];

                [draw Export:[[separation_doc GetPageIterator:1] Current] filename: @"../../TestFiles/Output/merged_separations.png" format: @"PNG"];
                NSLog(@"Example 10 a): merged_separations.png. Done.");

                [draw ExportWithObj:[[separation_doc GetPageIterator:1] Current] filename: @"../../TestFiles/Output/separation" format: @"PNG" encoder_params: separation_hint];
                NSLog(@"Example 10 b): separation_[ink].png. Done.");

                [draw ExportWithObj:[[separation_doc GetPageIterator:1] Current] filename: @"../../TestFiles/Output/separation_NChannel.tif" format: @"TIFF" encoder_params: separation_hint];
                NSLog(@"Example 10 c): separation_NChannel.tif. Done.");
            }
            @catch (NSException *e)
            {
                NSLog(@"%@", e.reason);
            }



        }
        @catch(NSException *e)	
        {
            NSLog(@"%@", e.reason);
        }




        return 0;
    }
}
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