Post Reply. Preview Exit Preview. You must be signed in to add attachments. About Adobe Acrobat. Adobe Inc. Whats new in Acrobat DC. Plan and Pricing. Edit PDFs. The stream dictionary specifies the exact number of bytes of the stream.
After the data there should be a newline and the endstream keyword. Common keywords used in all stream dictionaries are the following note that the Length entry is mandatory :. The stream data in the object stream will contain N pairs of integers, where the first integer represents the object number and the second integer represents the offset in the decoded stream of that object.
The First entry in the dictionary identifies the first object in the object stream. In PDF 1. Each cross-reference stream contains the information equivalent to the cross-reference table and trailer. First of all, we must know that any object in a PDF document can be labeled as an indirect object.
This gives the object a unique object identifier, which other objects can use to reference the indirect object. By declaring an object an indirect object, we are able to use it in the PDF document cross-reference table and reuse it by any page, dictionary and so on in the document. Since every indirect object has its own entry in the cross-reference table, the indirect objects may be accessed very quickly.
The object identifier of the indirect object consists of two parts; the first part is an object number of the current indirect object. The second part is the generation number, which is set to zero for all objects in a newly-created file. This number is later incremented when the objects are updated. We can refer to the indirect objects with indirect reference, which consists of the object number, the generation number and the keyword R.
To reference the above indirect object, we must write something like below:. Most of the objects in a PDF document are dictionaries. Page objects are connected together and form a page tree, which is declared with an indirect reference in the document catalog. The whole structure of the PDF document can be represented with the picture below [1]:. Figure 7: Structure of the PDF document source.
In the picture above, we can see that the document catalog contains references to the page tree, outline hierarchy, article threads, named destinations and interactive form.
From the picture above, we can see that the Document Catalog is the root of the objects in the PDF document. It also contains the information that declares how the document will be displayed on the screen.
The entries in the document catalog are as follows:. The reader can take a look at our sources for details. An example of the document catalog is presented below: 1 0 obj. The pages of the document are accessed through the page tree, which defines all the pages in the PDF document. The tree contains nodes that represent pages of the PDF document, which can be of two types: intermediate and leaf nodes.
Intermediate nodes are also called page tree nodes, while the leaf nodes are called page objects. The simplest page tree structure can consist of a single page tree node that references all of the page objects directly so all of the page objects are leafs.
Each node in a page tree has to have the following entries:. A basic example of a page tree can be seen below: 2 0 obj. We can also see that the leaves of the page tree are dictionaries specifying the attributes of a single page of the document.
There are multiple attributes that we can use when defining them for each document page. Figure 8: Simple document. We can see that the. We can compile the. The resulting PDF then looks like this shown in the picture below:. Figure 9: Result. Fullbanner This is pdfTeX, Version 3. We also need to remember that all the encoded data streams were removed and replaced with three dots for clarity and brevity.
The header can be seen in the picture below:. Figure PDF header. Figure PDF body. Figure PDF xref. And last, the Trailer section is represented below:. Figure PDF trailer. We presented all of the sections of the PDF document, but we still have to analyze them further. This is why we must first take a look at the xref section. We can see that the offset from the beginning of the file to the xref table is bytes, which in hexadecimal form is 0x4ef7.
Figure Hexadecimal representation of the file. Strings may contain newlines. Strings may contain balanced parentheses and. The following is an empty string. It has zero 0 length. The character immediately following the backslash determines its precise interpretation.
If the character following the backslash is not one of those shown in the following table, the backslash is ignored. The following table shows valid literal string escape sequences.
If a string is too long to be conveniently placed on a single line, it may be split across multiple lines by using the backslash character at the end of a line to indicate that the string continues on the following line. The backslash and the end-of-line marker following it are not considered part of the string. For example, the following strings examples are equivalent:. These two strings are the same.
Strings may also be written in hexadecimal form, which is useful for including arbitrary binary data in a PDF file. Consider the following example:. Each pair of hexadecimal digits defines one byte of the string. White-space characters such as space, tab, carriage return, line feed, and form feed are ignored.
If the final digit of a hexadecimal string is missing, that is, if there is an odd number of digits, the final digit is assumed to be 0. Arrays are one-dimensional collections of objects accessed by a numeric index.
Array indexes are zero-based and may be any combination of the Cos data types. Improve this question. Are you familiar with Dictionary..? Can you provide an Example, how you want to use the Dictionary specificly?
I used the technique of a quick and dirty way of counting occurrences in an array using it's index from another method — aremvee. Add a comment. Active Oldest Votes. Improve this answer. Scott Chamberlain Scott Chamberlain k 29 29 gold badges silver badges bronze badges. Yes, my domain models do implement those and they DO NOT get mutated while performing the operations.
My other concern is testing out the business logic. Using domain objects gives me freedom of writing simpler test cases. Sign up or log in Sign up using Google. Sign up using Facebook.
0コメント