PDF Library for creating PDF with tables and text, in C#

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Introduction

This is my second article towards creating PDF files. The earlier one employed on simple text and this version in C# can add tables to the PDF files. This library can be used for simple HTML conversion, or conversion from other documents if you know that document format. At present, it can add only tables, and create PDF document with any number of pages.

Let us begin by using the library. Download the library and add a reference to the library in your .NET project.

Creating a PDF Document

Creating a PDF document can be divided into three steps.

1. Writing the header of the PDF file.
2. Creating pages of the document.
   1. Add text.
   2. Add table.
3. Finish the document.

In each step, you open a file specifying the output file name. In the first step, it's is opened as create, and in every other step it is open as append. In PDF format, every object we create and write are referenced by the byte offset of that object within the file.

Step One

I will go by explaining the code sample for using the PDF library.

//Create a Catalog Dictionary

CatalogDict catalogDict=new CatalogDict();

//Create a Page Tree Dictionary

PageTreeDict pageTreeDict=new PageTreeDict();

//Create a Font Dictionary

FontDict TimesRoman=new FontDict();
FontDict TimesItalic=new FontDict();

//Create the info Dictionary

InfoDict infoDict=new InfoDict();

//Create the font called Times Roman

TimesRoman.CreateFontDict("T1","Times-Roman");

//Create the font called Times Italic

TimesItalic.CreateFontDict("T2","Times-Italic");

//Set the info Dictionary. 

infoDict.SetInfo("title","author","company");

//Create a utility object

Utility pdfUtility=new Utility();

//Open a file specifying the file name as the output pdffile 

FileStream file=new FileStream(@"c:\text.pdf",FileMode.Create);
int size=0;
file.Write(pdfUtility.GetHeader("1.5",out size),0,size);
file.Close();
//Now we finished doing the first step

Create the pages in the document. Here we are creating only one page. This process can be repeated to include any number of pages. A page will have its contents. Contents are the text and table that we create. This content is an object of the type ContentDict. A page can have any number of ContentDicts, but two or more pages cannot have the same ContentDict.

Every page must be added to the PageTreeDict. This is the RootNode of the pages in the PDF Document structure. In a PDF document, there will be only one PageTree (created with this library). This is created by using PageTreeDict.AddPage(). The order of the page in the document will be in the order how there were added to the PageTree.

To every page, resources must be added. These resource include the font that must be used inside the page and the objects of the ContentDict. This is done by calling PageDict.AddResource. The font types that are to be used are specified in the library. In this library, only fonts of type Times New Roman will be correctly centered and right aligned. This is because, for aligning, we must have the width of all the character glimpses. I have stored only the width of Times New Roman.

In AddPage, we specify the objNum of the page to be added, and in AddResource, we add the objNum of the ContentDict.

For adding text and tables in the page, create an object of type TextAndTables. For adding text, call addText specifying the X and Y coordinates.

For adding table, first fill the parameters of the table using TableParams. In the constructor, specify the number of columns and their widths. If the widths are same then you can use the other constructor just specifying the number of columns and setting the numColumns parameter of the structure. In this version, only the three parameters of the table need to be set, they are:

1. row height
2. X coordinate
3. Y coordinate

Now, we can specify the alignment of each text within a cell. If we have two columns, create an array of two Align elements.

After this much initialization, call the TextAndTable.AddRow() member. This can be called as many times as to add new rows. When finished, call EndTable(). This will return a string. This string should be passed to content.SetStream().

Now add these things to the file. Then we have finished our second step.

//Create a Page Dictionary , this represents a visible page

PageDict page=new PageDict();
ContentDict content=new ContentDict();

//The page size object will hold all the page size information

PageSize pSize=new PageSize(612,792);
pSize.SetMargins(10,10,10,10);
page.CreatePage(pageTreeDict.objectNum,pSize);
pageTreeDict.AddPage(page.objectNum);
page.AddResource(TimesRoman,content.objectNum);

//Create a Text And Table Object that present the elements in the page

TextAndTables textAndtable=new TextAndTables(pSize);

//Add text to the page

textAndtable.AddText(20,10,"Testing",10,"T1",Align.CenterAlign);

//Create the array for alignment value.

//This is specified for text in each column 

//of the table, here we have two columns

Align[] align=new Align[2];
align[0]=Align.LeftAlign;
align[1]=Align.LeftAlign;

//Specify the color for the cell and the line

ColorSpec cellColor=new ColorSpec(100,100,100);
ColorSpec lineColor=new ColorSpec(98,200,200);

//Fill in the parameters for the table

TableParams table=new TableParams(2,200,200);
table.yPos=700;
table.xPos=100;
table.rowHeight=20;

//Set the parameters of this table

textAndtable.SetParams(table,cellColor,Align.CenterAlign,3);
textAndtable.AddRow(false,10,"T1",align,"First Column","Second Column");
textAndtable.AddRow(false,10,"T1",align,"Second Row","Second Row");

//Repeat till we require the number of rows.

//After drawing table and text add them to the page 

content.SetStream(textAndtable.EndTable(lineColor));
content.SetStream(textAndtable.EndText());
size=0;
file=new FileStream(@"c:\text.pdf",FileMode.Append); 
file.Write(page.GetPageDict(file.Length,out size),0,size);
file.Write(content.GetContentDict(file.Length,out size),0,size);
file.Close();

Step Three

Now that we have finished the creation of the page, we can end the creation of the PDF document. This is done by writing every piece of information to the file.

//Write everything file size=0;

file=new FileStream(@"c:\text.pdf",FileMode.Append);
file.Write(catalogDict.GetCatalogDict(pageTreeDict.objectNum, 
                                  file.Length,out size),0,size);
file.Write(pageTreeDict.GetPageTree(file.Length,out size),0,size);
file.Write(TimesRoman.GetFontDict(file.Length,out size),0,size);
file.Write(TimesItalic.GetFontDict(file.Length,out size),0,size);
file.Write(infoDict.GetInfoDict(file.Length,out size),0,size);
file.Write(pdfUtility.CreateXrefTable(file.Length,out size),0,size);
file.Write(pdfUtility.GetTrailer(catalogDict.objectNum,
                           infoDict.objectNum,out size),0,size);
file.Close();

Testing

All the code above is included inside a single function. Usually, for creating HTML files, the steps one and three will be done only once, but step two will be repeated many times. You can use this library and clarify any doubts as you go using this. Try experimenting with this.

Conclusion

This is a very basic library for creating PDF files. Once you know the PDF format, you can modify the library to include many more features like drawing lines and circles. Actually, the project I have been working only required simple tables to be added to the PDF files. That's is why I had to limit to only that feature.