pdf转换成jpg示例分享

using system; 
using system.collections.generic; 
using system.text; 
using system.runtime.interopservices; 
using system.collections; 
/**
convert pdf to image format(jpeg) using ghostscript api

convert a pdf to jpeg using ghostscript command line:
gswin32c -q -dquiet -dparanoidsafer  -dbatch -dnopause  -dnoprompt -dmaxbitmap=500000000 -dfirstpage=1 -daligntopixels=0 -dgridfittt=0 -sdevice=jpeg -dtextalphabits=4 -dgraphicsalphabits=4 -r100x100 -soutputfile=output.jpg test.pdf
see also:http://www.mattephraim.com/blog/2009/01/06/a-simple-c-wrapper-for-ghostscript/
and: http://www.codeproject.com/kb/cs/ghostscriptusewithcsharp.aspx
note:copy gsdll32.dll to system32 directory before using this ghostscript wrapper.
 * 
 */ 
namespace convertpdf 
{ 
    /// <summary> 
    ///  
    /// class to convert a pdf to an image using ghostscript dll 
    /// credit for this code go to:rangel avulso 
    /// i only fix a little bug and refactor a little 
    /// http://www.hrangel.com.br/index.php/2006/12/04/converter-pdf-para-imagem-jpeg-em-c/ 
    /// </summary> 
    /// <seealso cref="http://www.hrangel.com.br/index.php/2006/12/04/converter-pdf-para-imagem-jpeg-em-c/"/> 
    class pdfconvert 
    { 
        #region ghostscript import 
        /// <summary>create a new instance of ghostscript. this instance is passed to most other gsapi functions. the caller_handle will be provided to callback functions. 
        ///  at this stage, ghostscript supports only one instance. </summary> 
        /// <param name="pinstance"></param> 
        /// <param name="caller_handle"></param> 
        /// <returns></returns> 
        [dllimport("gsdll32.dll", entrypoint="gsapi_new_instance")] 
        private static extern int gsapi_new_instance (out intptr pinstance, intptr caller_handle); 
        /// <summary>this is the important function that will perform the conversion</summary> 
        /// <param name="instance"></param> 
        /// <param name="argc"></param> 
        /// <param name="argv"></param> 
        /// <returns></returns> 
        [dllimport("gsdll32.dll", entrypoint="gsapi_init_with_args")] 
        private static extern int gsapi_init_with_args (intptr instance, int argc, intptr argv); 
        /// <summary> 
        /// exit the interpreter. this must be called on shutdown if gsapi_init_with_args() has been called, and just before gsapi_delete_instance().  
        /// </summary> 
        /// <param name="instance"></param> 
        /// <returns></returns> 
        [dllimport("gsdll32.dll", entrypoint="gsapi_exit")] 
        private static extern int gsapi_exit (intptr instance); 
        /// <summary> 
        /// destroy an instance of ghostscript. before you call this, ghostscript must have finished. if ghostscript has been initialised, you must call gsapi_exit before gsapi_delete_instance.  
        /// </summary> 
        /// <param name="instance"></param> 
        [dllimport("gsdll32.dll", entrypoint="gsapi_delete_instance")] 
        private static extern void gsapi_delete_instance (intptr instance); 
        #endregion 
        #region variables 
        private string _sdeviceformat; 
        private int _iwidth; 
        private int _iheight; 
        private int _iresolutionx; 
        private int _iresolutiony; 
        private int _ijpegquality; 
        private boolean _bfitpage; 
        private intptr _objhandle; 
        #endregion 
        #region proprieties 
        public string outputformat 
        { 
            get { return _sdeviceformat; } 
            set { _sdeviceformat = value; } 
        } 
        public int width 
        { 
            get { return _iwidth; } 
            set { _iwidth = value; } 
        } 
        public int height 
        { 
            get { return _iheight; } 
            set { _iheight = value; } 
        } 
        public int resolutionx 
        { 
            get { return _iresolutionx; } 
            set { _iresolutionx = value; } 
        } 
        public int resolutiony 
        { 
            get { return _iresolutiony; } 
            set { _iresolutiony = value; } 
        } 
        public boolean fitpage 
        { 
            get { return _bfitpage; } 
            set { _bfitpage = value; } 
        } 
        /// <summary>quality of compression of jpg</summary> 
        public int jpegquality 
        { 
            get { return _ijpegquality; } 
            set { _ijpegquality = value; } 
        } 
        #endregion 
        #region init 
        public pdfconvert(intptr objhandle) 
        { 
            _objhandle = objhandle; 
        } 
        public pdfconvert() 
        { 
            _objhandle = intptr.zero; 
        } 
        #endregion 
        private byte[] stringtoansiz(string str) 
        { 
            //' convert a unicode string to a null terminated ansi string for ghostscript. 
            //' the result is stored in a byte array. later you will need to convert 
            //' this byte array to a pointer with gchandle.alloc(xxxx, gchandletype.pinned) 
            //' and gshandle.addrofpinnedobject() 
            int intelementcount; 
            int intcounter; 
            byte[] aansi; 
            byte bchar; 
            intelementcount = str.length; 
            aansi = new byte[intelementcount+1]; 
            for(intcounter = 0; intcounter < intelementcount;intcounter++) 
            { 
                bchar = (byte)str[intcounter]; 
                aansi[intcounter] = bchar; 
            } 
            aansi[intelementcount] = 0; 
            return aansi; 
        } 
        /// <summary>convert the file!</summary> 
        public void convert(string inputfile,string outputfile, 
            int firstpage, int lastpage, string deviceformat, int width, int height) 
        { 
            //avoid to work when the file doesn't exist 
            if (!system.io.file.exists(inputfile)) 
            { 
                system.windows.forms.messagebox.show(string.format("the file :'{0}' doesn't exist",inputfile)); 
                return; 
            } 
            int intreturn; 
            intptr intgsinstancehandle; 
            object[] aansiargs; 
            intptr[] aptrargs; 
            gchandle[] agchandle; 
            int intcounter; 
            int intelementcount; 
            intptr callerhandle; 
            gchandle gchandleargs; 
            intptr intptrargs; 
            string[] sargs = getgeneratedargs(inputfile,outputfile, 
                firstpage, lastpage, deviceformat, width, height); 
            // convert the unicode strings to null terminated ansi byte arrays 
            // then get pointers to the byte arrays. 
            intelementcount = sargs.length; 
            aansiargs = new object[intelementcount]; 
            aptrargs = new intptr[intelementcount]; 
            agchandle = new gchandle[intelementcount]; 
            // create a handle for each of the arguments after  
            // they've been converted to an ansi null terminated 
            // string. then store the pointers for each of the handles 
            for(intcounter = 0; intcounter< intelementcount; intcounter++) 
            { 
                aansiargs[intcounter] = stringtoansiz(sargs[intcounter]); 
                agchandle[intcounter] = gchandle.alloc(aansiargs[intcounter], gchandletype.pinned); 
                aptrargs[intcounter] = agchandle[intcounter].addrofpinnedobject(); 
            } 
            // get a new handle for the array of argument pointers 
            gchandleargs = gchandle.alloc(aptrargs, gchandletype.pinned); 
            intptrargs = gchandleargs.addrofpinnedobject(); 
            intreturn = gsapi_new_instance(out intgsinstancehandle, _objhandle); 
            callerhandle = intptr.zero; 
            try 
            { 
                intreturn = gsapi_init_with_args(intgsinstancehandle, intelementcount, intptrargs); 
            } 
            catch (exception ex) 
            { 
                //system.windows.forms.messagebox.show(ex.message); 

            } 
            finally 
            { 
                for (intcounter = 0; intcounter < intreturn; intcounter++) 
                { 
                    agchandle[intcounter].free(); 
                } 
                gchandleargs.free(); 
                gsapi_exit(intgsinstancehandle); 
                gsapi_delete_instance(intgsinstancehandle); 
            } 
        } 
        private string[] getgeneratedargs(string inputfile, string outputfile, 
            int firstpage, int lastpage, string deviceformat, int width, int height) 
        { 
            this._sdeviceformat = deviceformat; 
            this._iresolutionx = width; 
            this._iresolutiony = height; 
            // count how many extra args are need - hrangel - 11/29/2006, 3:13:43 pm 
            arraylist lstextraargs = new arraylist(); 
            if ( _sdeviceformat=="jpg" && _ijpegquality > 0 && _ijpegquality < 101) 
                lstextraargs.add("-djpegq=" + _ijpegquality); 
            if (_iwidth > 0 && _iheight > 0) 
                lstextraargs.add("-g" + _iwidth + "x" + _iheight); 
            if (_bfitpage) 
                lstextraargs.add("-dpdffitpage"); 
            if (_iresolutionx > 0) 
            { 
                if (_iresolutiony > 0) 
                    lstextraargs.add("-r" + _iresolutionx + "x" + _iresolutiony); 
                else 
                    lstextraargs.add("-r" + _iresolutionx); 
            } 
            // load fixed args - hrangel - 11/29/2006, 3:34:02 pm 
            int ifixedcount = 17; 
            int iextraargscount = lstextraargs.count; 
            string[] args = new string[ifixedcount + lstextraargs.count]; 
            /*
            // keep gs from writing information to standard output
        "-q",                     
        "-dquiet",

        "-dparanoidsafer", // run this command in safe mode
        "-dbatch", // keep gs from going into interactive mode
        "-dnopause", // do not prompt and pause for each page
        "-dnoprompt", // disable prompts for user interaction           
        "-dmaxbitmap=500000000", // set high for better performance

        // set the starting and ending pages
        string.format("-dfirstpage={0}", firstpage),
        string.format("-dlastpage={0}", lastpage),   

        // configure the output anti-aliasing, resolution, etc
        "-daligntopixels=0",
        "-dgridfittt=0",
        "-sdevice=jpeg",
        "-dtextalphabits=4",
        "-dgraphicsalphabits=4",
            */ 
            args[0]="pdf2img";//this parameter have little real use 
            args[1]="-dnopause";//i don't want interruptions 
            args[2]="-dbatch";//stop after 
            //args[3]="-dsafer"; 
            args[3] = "-dparanoidsafer"; 
            args[4]="-sdevice="+_sdeviceformat;//what kind of export format i should provide 
            args[5] = "-q"; 
            args[6] = "-dquiet"; 
            args[7] = "-dnoprompt"; 
            args[8] = "-dmaxbitmap=500000000"; 
            args[9] = string.format("-dfirstpage={0}", firstpage); 
            args[10] = string.format("-dlastpage={0}", lastpage); 
            args[11] = "-daligntopixels=0"; 
            args[12] = "-dgridfittt=0"; 
            args[13] = "-dtextalphabits=4"; 
            args[14] = "-dgraphicsalphabits=4"; 
            //for a complete list watch here: 
            //http://pages.cs.wisc.edu/~ghost/doc/cvs/devices.htm 
            //fill the remaining parameters 
            for (int i=0; i < iextraargscount; i++) 
            { 
                args[15+i] = (string) lstextraargs[i]; 
            } 
            //fill outputfile and inputfile 
            args[15 + iextraargscount] = string.format("-soutputfile={0}",outputfile); 
            args[16 + iextraargscount] = string.format("{0}",inputfile); 
            return args; 
        } 
        public void pdf2jpgtest() 
        {             
            this.convert(@"c://tmp//pdfimg//test1.pdf",@"c://tmp//pdfimg//out.jpg",1,1,"jpeg",100,100); 
            //this.convert(@"c://tmp//pdfimg//test.pdf", @"c://tmp//pdfimg//out2.jpg", 291, 291, "jpeg", 800, 800); 
        } 
    } 
} 

测试winform：

可以采用下面的方式测试调用上面的功能，如：

 pdfconvert convertor = new pdfconvert();
 convertor.pdf2jpgtest();
 

using system; 
using system.collections.generic; 
using system.componentmodel; 
using system.data; 
using system.drawing; 
using system.linq; 
using system.text; 
using system.windows.forms; 
using convertpdf; 
namespace pdf2img 
{ 
    public partial class form1 : form 
    { 
        public form1() 
        { 
            initializecomponent(); 

        } 
        private void button1_click(object sender, eventargs e) 
        { 
            pdfconvert convertor = new pdfconvert(); 
            convertor.pdf2jpgtest(); 
            image img = image.fromfile(@"c://tmp//pdfimg//out.jpg"); 
            mybitmap = new bitmap(img); 

            graphics g = this.creategraphics(); 
            graphicsunit gu = g.pageunit; 
            bmpcontainer = mybitmap.getbounds(ref gu); //x,y = 0 

           // graphics g = this.creategraphics(); 
            //g.drawimage(mybitmap, 1, 1); 
            this.invalidate(); 
        } 
        private bitmap mybitmap; 
        private rectanglef bmpcontainer; 
        protected override void onpaint(painteventargs e) 
        { 
            graphics g = e.graphics; 
            if (mybitmap != null) 
            {            
                g.drawimage(mybitmap, bmpcontainer); 
            } 
            base.onpaint(e); 
        } 
    } 
}